TDi Dyno Day Results thread :)

[simonprelude]

Marker to collate all results :)

All discussion in here please :D

For anyone that didn't attend, all figures are at the wheel and no attempt has been made to 'guess' flywheel figures.

[simonprelude]

I'll start it off..........

simonprelude 1997 3.2
bhp related mods - standard
max power 259.3 bhp @ 7220 rpm
max torque 201.8 lb-ft @ 6450 rpm

[markc]

Markc 1997 3.2 (Type S)
bhp related mods - Exhaust (Dali RR)
max power 273.6 bhp @ 7250 rpm
max torque 207.9 lb-ft @ 6560 rpm

Lets get all the results in first but it would seem we've confirmed that the exhaust makes a big differance.

[NoelWatson]

NoelWatson 2004 3.2
bhp related mods - standard
max power 256.8 bhp @ 7250 rpm
max torque 197.9 lb-ft @ 6550 rpm

[Lankstarr]

Markc 1997 3.2 (Type S)
bhp related mods - Exhaust (Dali RR)
max power 273.6 bhp @ 7250 rpm
max torque 207.9 lb-ft @ 6560 rpm

Lets get all the results in first but it would seem we've confirmed that the exhaust makes a big differance.

Looks like it, maybe due to special type S extra powers!

Gives you 304bhp as well Mark! Acomparison of all the fly figures along with any other dyno results would be good to try and see what consistency there is and if there's a more accurate multiplier than (1.111111) that we can apply to the figures.

[kowalski]

Leigh - Kowalski 1991 3.0
bhp related mods - taitec exhaust, headers. procar intake
max power 267.7 @ 7750 rpm
max torque 188.9 @ 6860

[BlueNSX]

FMD :eek:

Mark

1995 3.0T Stock apart from 5Zigen Exhaust, very disapointing results

Max Power 238.6 @ 7160 (238.6@7160),
Max Torque 187.6 @ 5400 (187.6@5400)

Installation next week of Headers (Exhaust Manifold), Test Pipes & Apexi Intake.

[markc]

Hi Luke, the Type S myth is busted, Paul's car (Senninha) pipped mine and the other Paul (NSX200) was real close. Both, as well as me, have non factory exhausts. Look at Leigh's (Kowalski) numbers for what a 3.0Ltr car is capable of with exhaust mods, just make sure you have your fingers in your ears :)

A top event and some properly useful data and comparisons have been recorded.

The guys at TDI really know their stuff! Project "airbox" starts now... ;)

[Senninha]

....... he says with a big wide smile :D

Senninha 1998 3.2 Targa ... been telling you all Targa's are the best model ;)
bhp related mods - H&S exhaust + Procar airbox
max power 274.1 bhp @ 7290 rpm
max torque 209.5 lb-ft @ 6450 rpm

Very interesting chat with Sam of TDI as to how to overcome the air/fuel mix issues to release those extra ponnies. I'll email SOS and ask the question re throttle bodies and update if I get any answers

Great to meet up and sorry I couldn't get there earlier for all the runs.

regards, Paul

[Lankstarr]

VEry impressive results ... especially from Leigh :O)

IT seems that some 3.0s keep their power well and others are a bit lacking - there were a couple that were a bit down on power last time.

Really gutted I couldn;t make it; with the procar box on S5, the larini exhaust and decat pipes I'm sure I would have given Paul a really good run for his money! (Obviously I would say that wouldn't I!!)

Paul let me know how you get on with the throttle bodies Sounds liek a good plan to get her over 300!

Well done.

Luke

[kowalski]

Yep mine even surprised me!

Looks like I will have to go the same route as Paul with the throttle body as well, and also mine had problems running way to lean.

Interesting thing was that both the 91, 3.0 revved to 8200 whilst the other 94/95 3.0, limited at 7800.

Was nice to hear mine from outside as well, didnt realise it was that loud lol

leigh

[forumadmin]

What's this talk of throttle bodies all about?

No photos? Sounds like a good day, by people that know what they are talking about.

[BabyG]

Rich/ Baby G
1991 manual, standard spec

Max Power 241.2 @ 7390rpm
Max Torque 184.0 @ 6460rpm

Happy with that - I don't think the old girl's lost a single pony in 17 years!


Echoing earlier comments, big respect to what the guys at TDI know about this stuff - they know their engines! And, as it turns out, their brakes - watch this space ahead of the 'Ring in August...

[Senninha]

What's this talk of throttle bodies all about?

No photos? Sounds like a good day, by people that know what they are talking about.

I'm sure someone with greater technical knowledge will chip in here, but in basic terms, the guys at TDI were suggesting that whilst the larger airbox some of had fitted seems to be working ok, there is a restriction somewhere in the system that is causing a drop in pressure. This resulting drop in pressure is causing us to drop torque and therefore bhp. One theory is that it may be at the throttle bodies where this occurs.

If you look at the SOS larger bore TB, it has a larger and smoother intake area that in theory would reduce this restriction. The question I have put to SOS is simple. Have they developed this because of a genuine need, ie they have the same restriction problems we identified yesterday, or have the made them just because people asked them too.

The only other potential area for a small gain might be the cats. Interestingly Leigh runs without cats and showed great results. Honda cats are not usually over restrictive, but TDI suggested that if like me, you dont want to progress onto changing cams or other engine components, then to complete the 'external' upgrades this could be a consideration.

Hope this is clear

regards, Paul

PS - no photos because it was pi****g down ... and today it is snowing!

[britlude]

a pic of the setup.....

http://nsxcb.co.uk.sites.imotionhosting.com/testvb/attachment.php?attachmentid=3506&d=1207468745

i have a couple of pulls on vid is someone has somewhere to host them! must sort that out at some point!

[forumadmin]

I'm sure someone with greater technical knowledge will chip in here, but in basic terms, the guys at TDI were suggesting that whilst the larger airbox some of had fitted seems to be working ok, there is a restriction somewhere in the system that is causing a drop in pressure. This resulting drop in pressure is causing us to drop torque and therefore bhp. One theory is that it may be at the throttle bodies where this occurs.

If you look at the SOS larger bore TB, it has a larger and smoother intake area that in theory would reduce this restriction. The question I have put to SOS is simple. Have they developed this because of a genuine need, ie they have the same restriction problems we identified yesterday, or have the made them just because people asked them too.

The only other potential area for a small gain might be the cats. Interestingly Leigh runs without cats and showed great results. Honda cats are not usually over restrictive, but TDI suggested that if like me, you dont want to progress onto changing cams or other engine components, then to complete the 'external' upgrades this could be a consideration.

Hope this is clear

regards, Paul

PS - no photos because it was pi****g down ... and today it is snowing!

Did they take some kind of measurement for this, or was it down to experience? The thing is, where does it stop? If you do something to the throttle there will be a bottleneck somewhere else. There always will be.

It's snowing here too, but at least I can make use of it!

[markc]

Here's mysunderstanding of the science Kevin...

The TDI/Rototest setup monitored inlet pressure at 2 points. They tee'd into the inlet manifold side using one of the grey pipe/tubes top of the engine and also stick a sensor up into the passenger side inlet grill. They therefore measure airpressure at either side of the throttle body. The reasoning for sighting inlet restriction being a problem is that during the "pull" air pressure between these 2 points drops.

The chap described it as an air density problem. Being essentially an air pump, the engine will pump 3.2 litres of air (in my case) with each revolution regardless of air being available with restricted flow or not. However, with a perfect air mass and no resitriction the density (charge) of that 3.2 litres of air will be higher. Increased air "charge" directly increases torque produced, and because torque and power have a fixed relationship (bhp=(torque x revs) /5252), are directly related to power.

Look at my parameter plots attached...

The blue line (the one starting 2nd from top on the left side) is InletPressure, it's axis is Y4 and the scale 0.95 to 1.050 bar. On the left side of the graph it starts at base atmospheric pressure, 1.011 bar in my case. As the rev rise though the "pull" pressure steadily drops. In a perfect system it would be a flat line.

The early runs, Noel's and Mark's for sure, used a differant scale so their plots won't be of any use but did anyone who attended get a flatter InletPressure plot??

I have a standard airbox and filter and the guys with Procar airboxes fared no better. We therefore suspect the probelm is elsewhere. The Procar airbox may be better than the stock one but if it is it's being strangled by something else. The most obvious thing is the throttle body hence Paul's question to SOS.

This could of course be a misleading result and taking us down a blind alley BUT there could be some more relatively low cost power to be had here :)

Cheers

Mark

[simonprelude]

The main issue that has been found with a lot of Honda systems firstly points to the TB, however when that has been opened up, either fully or venturi you then come across the restrictions in the intake manifold. Then dig deep :)

[NSX 2000]

2005 3.2 Manual Coupe
bhp related mods - Titec exhaust + Procar airbox
max power 267 bhp @ 7300 rpm
max torque 205 lb-ft @ 6440 rpm

Is it also worth our while to send the same email to detlef and ask what his dyno results had shown with regards to his airbox?

The only thing with a dyno test is the car is static; would you get a different result if moving? When I've spoken to engineers who prepare race cars they will spend weeks at the factory playing with the engine, then when they get to the track they start getting completely different results, iirc this is most evident in WRC cars.

I wonder if we move away from dyno and see what happens in a straight line at something like V max. Would the people with more HP be able to beat Noel's top speed?

Just to pee on Paul's parade I think he only got best HP due to the fact that the air was at its lowest temperature when he had his test :laugh:

Paul.

[NoelWatson]

I have a theory that the 2000 exhaust changes were detrimental to the 3.2's power output.

[NoelWatson]

. Would the people with more HP be able to beat Noel's top speed?


Bring it on!!! 162 to beat - I will be back if I can get another 12bhp

[markc]

Possibly so Simon but this issue is between the inlet manifold and the outside external air intake point. This shouldn't be impacted by the intake manifold itself but I suppose anything's possible.

The answer from SOS will be interesting. Just need to make sure we go back to TDI when we test the results should anyone take the plunge on a modified throttle body.

Mark

[Senninha]

I have a theory that the 2000 exhaust changes were detrimental to the 3.2's power output.

I would be very surprised if Honda were found to have engineered the exhaust for the later cars to be less efficient and therefore restrictive to the performance of the car. By way of example, even though the cats are large and heavy, they are very hard to beat in terms of efficiency.


I wonder if we move away from dyno and see what happens in a straight line at something like V max. Would the people with more HP be able to beat Noel's top speed?

I'm confident enough to say that I will beat the current NSX record which IIRC stands at 162mph. Had planned on having beaten it earlier in the year but diary clash stopped me attending. Hopefully be available for the next one.

Might as well add the Vmax trophy to S2's unbeaten record ;) and prove that the combined mods on this NSX really are working together as a package :cool:

Paul, I spoke with Sam after my runs and asked about the static vs moving results you're referring too. The set up they operate provides equivalent air speed from the fans at 130mph in the middle and 100mph for each side fan.

I have sent a thread link to Detlef (ProCar) to ask for his input/experiences as his airbox was present on 3 of the cars tested.

regards, Paul

[markc]

I supect a new exhaust will get you 10+ of those bhp's Noel. That and the superior aero of the 02+ car might well keep you ahead of Paul (Senninha).

It'll be interesting to see how your NSX-R bonnet effects things Paul? It looks like it should be less aerodynamic, in terms of slipperyness, than a stock flat bonnet but only 2miles of open runway will tell :)

Unless the other Paul (NSX 2000) show's up with his black beauty and shows both of you the way home ;)

Mark

[AR]

Gutted I could not make it as I was working that day at Brands Hatch. I did spot Paul's black 2005 on thbe A20 as I was leaving on Saturday.

[NoelWatson]

Unless the other Paul (NSX 2000) show's up with his black beauty and shows both of you the way home ;)

Mark

This could get expensive!

[Senninha]

This could get expensive!

It already has ;) .... thank goodness SWMBO doesn't actually log on to know about all the mods!!! Think I got away with just wheels and engine cover :shh: ... another advantage of going the OEM upgrade route, nothing is too obvious.

YOU ARE ALL SWORN TO SECRECY FROM THIS POINT FORWARD :laugh:

regards, Paul

[britlude]

YOU ARE ALL SWORN TO SECRECY FROM THIS POINT FORWARD :laugh:




and you thought it was expensive so far.....:)

[markc]

HaHa, Paul I think you could get away with the underfloor aero but she's going to notice the interior retrim for sure :)

Detlef, when you read this if you can guarantee your airbox will make 0.5hp and 1.6ft/lbs on my car you've got another sale ;)

Mark

[dan the man]

Nice Thread guys, really enjoyed reading it.

As for top speed runs, the AUTOBAHn can be zipped down in germany if u require :)

Is 162mph GPS or speedo?

I still think they should be faster, DC5s do 163 GPS with proof!

Ive had 160 + Speedo in my DC5 on an AUTOBAHn, all i could think of was 'i hope my tires are alright ' :D

[Senninha]

Dan,

I dont think the top speed is in doubt but this is over a measured distance at Bruntingthorpe rather than miles of Autobahn and simply keeping your foot in. If this were the case then the crown goes to Leigh with 183 :eek: on more than one occasion!

regards, Paul

[TheSebringOne]

Great read guys & congrats to those who attended! :thumbsup:

As Simon says these are figs at wheels rather than fly, but being less engine minded & noting Luke's comments that Mark's figs should equate to 304bhp, where does this generise 1.1111 multiple come from? Congrats to Paul S again! since on a previous RR you also came top at was it 297.7 ish bhp, was this at the fly? :dunno:

Whats more important? Ponies at the fly or wheels, I think wheels since that was moves the car via the tyres? :)

[NoelWatson]

Great read guys & congrats to those who attended! :thumbsup:

As Simon says these are figs at wheels rather than fly, but being less engine minded & noting Luke's comments that Mark's figs should equate to 304bhp, where does this generise 1.1111 multiple come from? Congrats to Paul S again! since on a previous RR you also came top at was it 297.7 ish bhp, was this at the fly? :dunno:

Whats more important? Ponies at the fly or wheels, I think wheels since that was moves the car via the tyres? :)

These numbers were at the hub, not wheels. The 1.111 number came from the rototest website and was the rough difference between other brand's hub numbers and claimed flywheel numbers. It should be taken with a pinch of salt as it is only a guess

[NoelWatson]

Nice Thread guys, really enjoyed reading it.

As for top speed runs, the AUTOBAHn can be zipped down in germany if u require :)

Is 162mph GPS or speedo?

I still think they should be faster, DC5s do 163 GPS with proof!

Ive had 160 + Speedo in my DC5 on an AUTOBAHn, all i could think of was 'i hope my tires are alright ' :D


162 when going through the timing beams was about 170 on my speedo

Best picture I could get

http://www.noelwatson.com/blog/content/binary/limiter.JPG

[NoelWatson]

Detlef, when you read this if you can guarantee your airbox will make 0.5hp and 1.6ft/lbs on my car you've got another sale ;)

Mark

Mark,

Shall we start a separate thread discussing our planned mods for the rest of the year? I think there will be a fair few others that are planning mods after Saturday's numbers so we may be able to do a few group buys (I for none will be going for an airbox and exhaust)

[NoelWatson]

The chap described it as an air density problem. Being essentially an air pump, the engine will pump 3.2 litres of air (in my case) with each revolution regardless of air being available with restricted flow or not.
Mark

Shouldn't this be ~1.6 each stroke on a 4 stroke machine?

[dan the man]

162 when going through the timing beams was about 170 on my speedo

Best picture I could get

http://www.noelwatson.com/blog/content/binary/limiter.JPG

Nice picture :)

And you think it woulkd squeeze xsome more but hey whats top speed anyway !

And senninha- yeah i get ya now :)

[Senninha]

Gents,

Recieved this from SOS this morning. I have replied using Marks more scientific desription of events.
I have provided thread details and asked if SOS can respond into the thread. If they cannot due to registration then I will continue to update.

regards, Paul



hi Paul --
The throttle boring is not made to "fix" anything other than improve breathing. The only possible "fix" is the cleaning of the vacuum orifice bores when the throttles are stripped. What is your problem?
thanks,
-- Chris

[mutley]

Hi All,

Fantastic thread, and I'm gutted I couldn't be there if only to spectate (just waiting on phone call to collect my car, details willl be on my handling thread).

Unfortunately, I have a list of mods I'd like to complete too, mainly to do with exhaust,headers etc but something always seems to crop up to steal my mod fund.

After you guys do the mods to your car, are we looking at a re-run of the dyno day to check out improvements?

Jim

[markc]

Noel, yes I think that a new thread under the "NSX Technical" forum is a good plan, something like "Investigation of possible Inlet restriction"?

Rototest's guestimate of 1.1111 to allow for transmission loss does seem very reasonable given the number of cars they've tested and is also consistent with the specific results they recorded on Hondas. Look here... http://www.rototest.com/performance-graphs/graphs.php?Visitor=4&DN=33

Paul, sounds like SOS have interpreted "fix" as an individual failure rather than a design shortcoming. Hopefully your clarification will elicit the response we're after.

Mutley, we don't have to re-run the whole dyno day BUT any other results are only valid for comparison if done on Rototest dyno.
It'd be good to do another group day when we've got to the bottom of the potential inlet restriction issue :)

Mark

[simonprelude]

Ho hum, time to go and spunk a lot of money on I/H/E me thinks :)

[mutley]

Ho hum, time to go and spunk a lot of money on I/H/E me thinks :)

Funnily enough I had the exact same thought!!


Jim

[markc]

Shame this chap didn't have the Inlet pressure measured during his dyno session...

http://www.nsxprime.com/forums/showthread.php?t=103576

Although he was testing "chips" he has the bigger throttle body we think might help with the apparent restriction as measured at TDI

Mark

[AR]

Mark could it be the ribbed rubber connector causing some turbulence?

[Senninha]

Shame this chap didn't have the Inlet pressure measured during his dyno session...

Mark

But I notice that our new member, JetPilot3 also has the larger TB. I've given him the link in his new member thread and asked if he can offer any feedback.

regards, Paul

[NoelWatson]

I supect a new exhaust will get you 10+ of those bhp's Noel. That and the superior aero of the 02+ car might well keep you ahead of Paul (Senninha).

It'll be interesting to see how your NSX-R bonnet effects things Paul? It looks like it should be less aerodynamic, in terms of slipperyness, than a stock flat bonnet but only 2miles of open runway will tell :)

Unless the other Paul (NSX 2000) show's up with his black beauty and shows both of you the way home ;)

Mark

My basic investigations reveal the following.

Assuming Cd of 0.32 vs. 0.3, the 02+ cars require 10 bhp less to maintain 160. (I have assumed 1991 NSX had Cd of 0.31)

It takes 10 bhp extra to maintain 163 rather than 160.

This is a bit of an oversimplification as it doesn't take into account acceleration. If I have some time over summer I will write a Bruntingthorpe predictor which will take numerous variables and attempt to estimate your speed at the timing beams

http://www.noelwatson.com/blog/content/binary/NSX.xls

[markc]

AR, the rubber connector could possibly be involved in my case but the guys with the Procar airbox all had the same Inlet Pressure issue. I think the Procar box uses a differant connector so it shouldn't be that.

Paul, yes I saw that you asked Jetpilot for his feedback. I think the car had the SOS stage 1 kit (includes throttle body) when he purchased it but he may well have some before and after data that could elp us understand if it definately helps.

Noel, it'll be interesting to see how your predictor works out. The 02+ NSX-R brochure states it's CD(A) is the same as the older cars at 0.32 Paul's NSX-R like bonnet and front aero will make S2 a little harder to factor in.

Did you get the raw data file from TDI on Saturday?

Mark

[simonprelude]

OK who's going to order the TB then ??

I don't mind being the guinea pig if that's the way we think it should go.

[mutley]

Simon,

I just had a look on the SoS website and it looks like the throttle body in on an exchange part thing and turn around is about 2 weeks ( I guess that's withing the US??)

On a plus side, still looks pretty cheap $249 -$279 average so that about £125 -£140.

I'd be up for that.


Jim

[mutley]

Simon,

I just had a look on the SoS website and it looks like the throttle body in on an exchange part thing and turn around is about 2 weeks ( I guess that's withing the US??)

On a plus side, still looks pretty cheap $249 -$279 average so that about £125 -£140.

I'd be up for that.


Jim

AND also just noticed, Dali do it for $185 (about £95?) I might drop an email to Mark and see what the turn around time would be.

http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1671

[simonprelude]

If it's just boring and a larger butterfly then can't we get this done in the UK ??

[mutley]

If it's just boring and a larger butterfly then can't we get this done in the UK ??

good point, any ideas where? There must be engineering places that can do it.

[AR]

AR, the rubber connector could possibly be involved in my case but the guys with the Procar airbox all had the same Inlet Pressure issue. I think the Procar box uses a differant connector so it shouldn't be that.

Paul, yes I saw that you asked Jetpilot for his feedback. I think the car had the SOS stage 1 kit (includes throttle body) when he purchased it but he may well have some before and after data that could elp us understand if it definately helps.

Noel, it'll be interesting to see how your predictor works out. The 02+ NSX-R brochure states it's CD(A) is the same as the older cars at 0.32 Paul's NSX-R like bonnet and front aero will make S2 a little harder to factor in.

Did you get the raw data file from TDI on Saturday?

Mark

Mark,

Paul's car does not have the CF connector. I think that is a big par. One must however get a catch tank or breather as for the install the EGR valve pipe has to come out as well as the vacuüm line.

I tought about this as in fitting a hardpipe, but I am worry about MOT issues and disconnecting the EGR.

Cheers,

Ary

[Senninha]

Recieved this info from Chris at SOS today

http://www.scienceofspeed.com/products/exhaust%5Fairflow%5Fproducts/NSX/ScienceofSpeed/big%5Fbore%5Fthrottle%5Fbody/


hi Paul --
I would agree, any throttle body will not have a zero pressure loss in restriction. The throttle body we offer is both larger and has a throttle blade and fasteners that are less restrictive (you can find photos on our website). We have tested the throttles and have found that the throttles add around 3-4 hp on NA cars and up to 9 hp on superchargered cars.
Hope that helps.

In addition, I spoke to PLans today to see if they had ever been involved in this type of activity with the NSX. The short answer is no. However, they have done this on a number of occasions for the Elise. 2 things they mentioned to be wary off.
1. Ensure that where applicable, the TB's are for the drive by wire system (later 3.2's)
2. That the ECU would be able to accomodate the change. On the Elise they go up by 4mm. Any more than this and the ECU gets confused, more so at low revs when opening the throttle. It is not uncommon for this action to then put the car into limp home mode.

Jim,

Let us know what Mark (Dali) has to say and if his is for outright purchase.


If it's just boring and a larger butterfly then can't we get this done in the UK ??

I'm also wondering if we could find a spare TB for the 3.0 and 3.2 , could there may be a deal to be done with TDI on a rolling exchange from one car to another??

regards, Paul

[TheSebringOne]

Doesn't the speedo read 164 or 164.5 and not 162 at 8000 rpm?

[NoelWatson]

Doesn't the speedo read 164 or 164.5 and not 162 at 8000 rpm?

I think mine indicates about 165-166 on the limiter

[NoelWatson]

Noel, yes I think that a new thread under the "NSX Technical" forum is a good plan, something like "Investigation of possible Inlet restriction"?



Mark

I have started a thread to discuss upcoming mods

http://nsxcb.co.uk/testvb/showthread.php?t=4646

[jaytip]

Guys, before everyone goes off and spends thousands of pounds on aftermarket parts,would it not be a good idea to see what (on the road) gains would be achieved with said mods.
I think some head to head runs between a few different NSX's at a V-max event would (could) provide some definative answers.
Unless it's the different exhaust note you are after it could be a very expensive outlay for very little return.
JMO

Ivor.

[NoelWatson]

Guys, before everyone goes off and spends thousands of pounds on aftermarket parts,would it not be a good idea to see what (on the road) gains would be achieved with said mods.
I think some head to head runs between a few different NSX's at a V-max event would (could) provide some definative answers.
Unless it's the different exhaust note you are after it could be a very expensive outlay for very little return.
JMO

Ivor.

Ivor,

Unfortunately there would be too many variables to make it accurate (different drag coefficients etc). I think an accurate dyno is the bext way forward

[jaytip]

Ivor,

Unfortunately there would be too many variables to make it accurate (different drag coefficients etc). I think an accurate dyno is the bext way forward
I think you are missing my point.For BHP figures,then yes,an RR is the best method,but i'm talking about real world performance,not paper performance.You mention drag,and thats a fair point,but would it not be fair then to say that a car with lower BHP but a better drag coefficient could be as fast as the higher BHP car.This is the sort of comparison i'm talking about.
Someone could spend several thousand pounds on modifications to be only a fraction of a second faster 0-60 and a few MPH faster at the top end-where it's largely irrelevent anyway,and for me personaly that would be a waste of money.

[NoelWatson]

I think you are missing my point.For BHP figures,then yes,an RR is the best method,but i'm talking about real world performance,not paper performance.You mention drag,and thats a fair point,but would it not be fair then to say that a car with lower BHP but a better drag coefficient could be as fast as the higher BHP car.This is the sort of comparison i'm talking about.
Someone could spend several thousand pounds on modifications to be only a fraction of a second faster 0-60 and a few MPH faster at the top end-where it's largely irrelevent anyway,and for me personaly that would be a waste of money.

"but would it not be fair then to say that a car with lower BHP but a better drag coefficient could be as fast as the higher BHP car"

It would be - see my spreadsheet for my attempts at cacculating the differences.

Without at least one of us doing pre and post tests on an accurate dyno, we have no way of knowing what the improvements are for a gien modification. There are too many variables on a V-Max day - for example Simonprelude went there with a high ambient temperature and mananged only 156. I went on a chilly day with a tail wind and achieved 162. You cannot compare these numbers. I think we are in agreement that TDI give accurate and repeatable numbers, so I think this is the best way forward, not just for the individual concerned, but for others considering the same modification for their car.
For me personally I need to find an extra 3 mph at Bruntongthopre to defeat the Cayman and Z4 M Coupe - I think an extra 12-15 bhp will help me achieve this.

[NoelWatson]

Did you get the raw data file from TDI on Saturday?

Mark

Mark,

Phoned them just now - they give it on a car by car basis (they need reg no so I couldn't ask for others). I will get mine, see how the data can be imported then suggest anyone that is interested contact TDI, send me the data and I will get a spreadsheet together.

[jaytip]

"but would it not be fair then to say that a car with lower BHP but a better drag coefficient could be as fast as the higher BHP car"

It would be - see my spreadsheet for my attempts at cacculating the differences.

Without at least one of us doing pre and post tests on an accurate dyno, we have no way of knowing what the improvements are for a gien modification. There are too many variables on a V-Max day - for example Simonprelude went there with a high ambient temperature and mananged only 156. I went on a chilly day with a tail wind and achieved 162. You cannot compare these numbers. I think we are in agreement that TDI give accurate and repeatable numbers, so I think this is the best way forward, not just for the individual concerned, but for others considering the same modification for their car.
For me personally I need to find an extra 3 mph at Bruntongthopre to defeat the Cayman and Z4 M Coupe - I think an extra 12-15 bhp will help me achieve this.
You are talking about different events on different days here,i'm talking about the cars at the same event,same day,running head to head.I think that is a far better comparison of actual V paper performance.

[NoelWatson]

You are talking about different events on different days here,i'm talking about the cars at the same event,same day,running head to head.I think that is a far better comparison of actual V paper performance.

Unfortunately it is never likely to happen, despite my previous coaxing!!

[NoelWatson]

AR, the rubber connector could possibly be involved in my case but the guys with the Procar airbox all had the same Inlet Pressure issue. I think the Procar box uses a differant connector so it shouldn't be that.

Paul, yes I saw that you asked Jetpilot for his feedback. I think the car had the SOS stage 1 kit (includes throttle body) when he purchased it but he may well have some before and after data that could elp us understand if it definately helps.

Noel, it'll be interesting to see how your predictor works out. The 02+ NSX-R brochure states it's CD(A) is the same as the older cars at 0.32 Paul's NSX-R like bonnet and front aero will make S2 a little harder to factor in.

Did you get the raw data file from TDI on Saturday?

Mark


Mark,

I have the raw data and am having a quick look through it. You will have to remind me what they needed the gear ratios for. The reason I ask is because my car was showing as only doing 254kmh/h at 8080 revs in 5th. I know my car will do 160 in 5th (257.6km/h), so the ratios inputted were slightly out.
Also,I'm not sure they were measuring the actual rpm as that column is blank - only the calculated rpm has values.

The data is simple to cut and paste into Excel - it would be good for someone who had the airbox fitted to get the raw data so we can compare pressure loss

[simonprelude]

RPM was calculated from the gearing figures :)

[NoelWatson]

RPM was calculated from the gearing figures :)

I realised that gear ratios don't come into it when calculating in gear sppeds - they are taking using rpm of hub and multiplying it by circumference. Mine was entered at 1980mm - does this sound right? I assume there is an element of tyre expansion at 160mph so maybe this explains the difference.

Back to the rpm - are we 100% confident that the gear ratios entered are correct? Otherwise Mark may still believe the 8300 limiter theory!!

[markc]

Engine revs were calculated from the measured hub revs. Assuming the gear ratios were entered correctly, and I think they were, this should be VERY accurate.

The speed "measurement" is a another calculation from the hub revs using the standard tyre size and therefore cirumference, 1980mm in your case. The system has to make some assumptions here, could be a brand new tyre with full tread depth ie approx 8mm (but not always) or a part worn tyre? Also there is some tyre growth/expansion at big speeds. I wouldn't worry too much about the calculated speed.

I'll request my raw file as well. Looking at my graph the revs peak at about 8200rpm.

I'm pretty sure all the guys with Procar airboxes had the same pressure drop during runs us those of us with stock airbox/filters.

Mark

[Senninha]

I'm pretty sure all the guys with Procar airboxes had the same pressure drop during runs us those of us with stock airbox/filters. Mark

Mark, if you recall, we put both our print outs side by side and there were almost identical. Even Sam commented that it was very rare to see such similar results from two engines.

regards, Paul

[markc]

I do indeed remember, I think we were looking at the laminated "Performance Snapshot" graph though?

The other all parameters graph, with the "InletPressure" plot at Y4, is the one that shows the air pressure drop we all need to fix to release a few more ponies.

Here's my graph again and where to check. Look at the blue line...

If EVERYONE's "InletPressure" plot shows the same result it could be either a genuine issue ie an inlet restriction, most likely the throttle body OR an anomoly thown up by way TDI measured it, most likely the point they tee'd into the inlet manifold.

Mark

[NoelWatson]

Engine revs were calculated from the measured hub revs. Assuming the gear ratios were entered correctly, and I think they were, this should be VERY accurate.

The speed "measurement" is a another calculation from the hub revs using the standard tyre size and therefore cirumference, 1980mm in your case. The system has to make some assumptions here, could be a brand new tyre with full tread depth ie approx 8mm (but not always) or a part worn tyre? Also there is some tyre growth/expansion at big speeds. I wouldn't worry too much about the calculated speed.

I'll request my raw file as well. Looking at my graph the revs peak at about 8200rpm.

I'm pretty sure all the guys with Procar airboxes had the same pressure drop during runs us those of us with stock airbox/filters.

Mark

Let me know when you get your data and we can do some comparisons

Here is my data

http://www.noelwatson.com/blog/PermaLink,guid,4db503bc-9ba3-4f8a-a3c9-620cf2efac53.aspx

[duncan]

All of this discussion on new air boxes is predicated on the basis of a pressure loss of Inlet Pressure. The cars all had air blown at their fronts and along each side, said to be 100 and something and 70mph [ish?] respectively. Reviewing your raw data between atmospheric and inlet pressures, rather than a graphical interpretation of the loss alone; your engine was actually supercharged until your revs went above about 4500 rpm.
Given the engine and packaging was engineering driven and the side strike/inlet was probably stylist driven, how about a scoop or splitter to get more of the air outside to the inside, failing that, change early - change often?

[markc]

Noel, my raw data file is attached... CAN'T DO THIS AS THE FILE IS TOO BIG

Duncan, I checked with TDI regarding the "supercharging" effect you observed. They advised that the 2 pressure probes are independant and independantly calibrated which exlains why they start at slightly differant figures. It doesn't explain the "supercharging" effect that Noel's car gets upto 4.5K rpm. We can only guess that this is a mild pulse induced resonance effect created by the inlet strokes?

My car also shows the same effect but to a smaller degree and only up 2.5K rpm

My car limits almost 90rpm higher than Noel's recording a peak revs of 8,172rpm on Run 2 compare to Noel's cars 8082rpm on Run 3.

As we also noted on the SRR dyno my car made a little more power on each subsequent run whereas Noel's made a little less.

Lies, damn lies and statistics ehh :)

Mark

[NoelWatson]

Noel, my raw data file is attached... CAN'T DO THIS AS THE FILE IS TOO BIG

Duncan, I checked with TDI regarding the "supercharging" effect you observed. They advised that the 2 pressure probes are independant and independantly calibrated which exlains why they start at slightly differant figures. It doesn't explain the "supercharging" effect that Noel's car gets upto 4.5K rpm. We can only guess that this is a mild pulse induced resonance effect created by the inlet strokes?

My car also shows the same effect but to a smaller degree and only up 2.5K rpm

My car limits almost 90rpm higher than Noel's recording a peak revs of 8,172rpm on Run 2 compare to Noel's cars 8082rpm on Run 3.

As we also noted on the SRR dyno my car made a little more power on each subsequent run whereas Noel's made a little less.

Lies, damn lies and statistics ehh :)

Mark

See private message..

[markc]

Hi Noel, I emailed the file to you... do your thing with it :)

Cheers

Mark

[NoelWatson]

Hi Noel, I emailed the file to you... do your thing with it :)

Cheers

Mark

Uploaded raw data file - and added gear changing optimiser!

http://www.noelwatson.com/blog/PermaLink,guid,4db503bc-9ba3-4f8a-a3c9-620cf2efac53.aspx

We need to think what other bits of data we want to look at - maybe Paul's 2005 inlet pressure drop?

[AR]

One for you guys:

http://www.dalmotorsports.com/cars.asp#Throttle%20Bodies

Cheers,

AR

[NSX 2000]

One for you guys:

http://www.dalmotorsports.com/cars.asp#Throttle%20Bodies

Cheers,

AR

This is taken from the above link.

18 Air filter- I have heard that tests have been performed with various air filter styles, and none of them drastically out perform the OE box. In the same breath they say “and the K&N can allow more dirt”. Hogwash! I have personally seen minimal improvements with the K&N and even more with no filter at all. If your too lazy to wash and lube a race filter, then you should probably use the OE filter… I however need every horsepower I can get. As for the filter housings- of course you’re not going to see an improvement on a stationary chassis dyno, ram air designs need movement. The design I’m fond of is the Cantrell ram air. I’m too poor to afford a pit bike cost worth of air filter components, but I think you will get the majority of the gains by utilizing the OE box with the Cantrell ram air nozzle. My thought is that the air still has to go through the same size filter regardless of the box it’s in… it does look nice though. (DALI gives you the choice and sells it this way for us non Ferrari owners).

[markc]

Good spot AR...

I do remember seeing this website before but hadn't read through it for a while... there's some really good information and top tips from Rob and DAL motorsport there :)

Regarding the possible inlet restriction issue... it confirms that someone else (other than TDI) has measured it. This is good and (probably) proves we're not chasing a non issue.

There are a number of other things that DAL have measured after changing/upgrading on the inlet side...

1) The article is more confirmation that changing the airbox on it's own doesn't help, from a performance standpoint anyway.

2) They like the Cantrell scoop a.k.a Fender scoop a.k.a Le Mans Supersucker but don't provide any definitive power improvements.

3) A bigger throttle body had a negligable effect.

4) The VVIS (Variable Volume Inlet System) doesn't work... shock horror!?!

5) A possible valve train restriction (but I have my doubts this causing the observed restriction)

Mark

[BlueNSX]

Good spot AR...

I do remember seeing this website before but hadn't read through it for a while... there's some really good information and top tips from Rob and DAL motorsport there :)

Regarding the possible inlet restriction issue... it confirms that someone else (other than TDI) has measured it. This is good and (probably) proves we're not chasing a non issue.

There are a number of other things that DAL have measured after changing/upgrading on the inlet side...

1) The article is more confirmation that changing the airbox on it's own doesn't help, from a performance standpoint anyway.

2) They like the Cantrell scoop a.k.a Fender scoop a.k.a Le Mans Supersucker but don't provide any definitive power improvements.

3) A bigger throttle body had a negligable effect.

4) The VVIS (Variable Volume Inlet System) doesn't work... shock horror!?!

5) A possible valve train restriction (but I have my doubts this causing the observed restriction)

Mark

There is a person known to us all ,a certain German CF expert who undoubtably will know all. Has direct contact with Honda R&D in Germany.

"Hondas new V10 engine is actually in germany for some special tests.
Its a well known company who also did the full engine development program for the Bugatti Veyron.
This company has dynamic test stands for oil flow measurement under extreme conditions (track cornering)

And yes, this engine has ITB'S http://www.nsxprime.com/forums/images/smilies/smile.gif
Tried to make some pictures, but all is still top secret.":eek:

I think theres a comment about it in here some where

http://www.nsxprime.com/forums/showthread.php?t=36427&page=4

[Senninha]

Hi all, please have a look at the new thread for CATS ....

http://nsxcb.co.uk/testvb/showthread.php?p=45233#post45233

regards, Paul

[NoelWatson]

Just flicking through Brian Long's book and it says that the 2000 model years got a revised ECU for "better response" - this also happened to be the year it qualified for LEV and exhaust changes were implemented. I still maintain that the pre 2000 cars are more powerful

[Senninha]

Just flicking through Brian Long's book and it says that the 2000 model years got a revised ECU for "better response" - this also happened to be the year it qualified for LEV and exhaust changes were implemented. I still maintain that the pre 2000 cars are more powerful

Sounds like an excuse to me ;):laugh:

When are gettin gall your pony release extras installed?

regards, Paul

[NoelWatson]

Sounds like an excuse to me ;):laugh:

When are gettin gall your pony release extras installed?

regards, Paul

Cat arrival + 0-7 days

[Lankstarr]

Just flicking through Brian Long's book and it says that the 2000 model years got a revised ECU for "better response" - this also happened to be the year it qualified for LEV and exhaust changes were implemented. I still maintain that the pre 2000 cars are more powerful

That would make the 98 - 2000 models the most desirable in terms of power... sounds good to me!

It will be interesting to see everybody's figures with the sports cats but TBH I think it will be a 2 pony race:laugh:;)

L*

[NoelWatson]

That would make the 98 - 2000 models the most desirable in terms of power... sounds good to me!

It will be interesting to see everybody's figures with the sports cats but TBH I think it will be a 2 pony race:laugh:;)

L*

In terms of power, maybe, but in terms of weight, drag and top speed, maybe not.

[Senninha]

In terms of power, maybe, but in terms of weight, drag and top speed, maybe not.

Mmmm,

Power, think I've got this one done :)
Weight, mine is down 136lb, so even as a Targa theres probably not much in it (actually, be good to have a weigh in at TDI)
Drag, full NSX-R aero package should have this sorted too

I guess the next step is to get to Vmax and go for the line!!

regards, Paul

[Lankstarr]

In terms of power, maybe, but in terms of weight, drag and top speed, maybe not.

You should ask Paul (NSX2000) just how much straight line speed those lightened aerodynamic 02+ cars have over us poor pop up models... I think it amounts to about minus 1.5 car lengths!

I'll be happy to see how much more aerodynamic your car is at the next Basingstoke meet:cool:

Luke

[NoelWatson]

You should ask Paul (NSX2000) just how much straight line speed those lightened aerodynamic 02+ cars have over us poor pop up models... I think it amounts to about minus 1.5 car lengths!

I'll be happy to see how much more aerodynamic your car is at the next Basingstoke meet:cool:

Luke

I have the record for fastest measured speed in the UK by an NSX at 162mph until I hear otherwise....

Take that you ruffian!

http://www.noelwatson.com/blog/content/binary/limiter.JPG

Note that this was the best photo I had - 162 measured equates to 170 on speedo

[Senninha]

I have the record for fastest measured speed in the UK by an NSX at 162mph until I hear otherwise....

Take that you ruffian!



See you, via the rear view mirror, at Vmax then ....

Let the challenge begin

PS, can I use 6th gear? :laugh:

[TheSebringOne]

Noel, how does a measured 162 mph equates to 170 mph? Did you use GPS which is more accurate? The needle looks like it smidge over 164 mph on the dial? :dunno::)

[NoelWatson]

Noel, how does a measured 162 mph equates to 170 mph? Did you use GPS which is more accurate? The needle looks like it smidge over 164 mph on the dial? :dunno::)

I was measured by the timing beams at Bruntingthorpe at 162. The photo was in 5th gear during the previous visit when I only got 160 (measured). 6th gear acceleration is painfully slow above 160.

http://maps.google.co.uk/maps?hl=en&q=bruntingthorpe&ie=UTF8&ll=52.492554,-1.127901&spn=0.026861,0.054932&t=h&z=14&iwloc=addr

[TheQuietOne]

Does anyone else think Noel's picture shows a little 02+ desperation to convince us of vmax? :eek:

[NoelWatson]

Does anyone else think Noel's picture shows a little 02+ desperation to convince us of vmax? :eek:

I like it! To be honest I just want one of us NSX drivers to beat the Cayman and E46 M3/M4 Coupe

[AR]

Well some of us are working on it, no turbos, SC or ITBs.

[markc]

What's all this fighting torque (geddit) gentlemen ;)


Well some of us are working on it, no turbos, SC or ITBs.

Cool... Capacity increase or head work (port flowing) or both?? I think any non FI (Turbo or Supercharged) 3.0Ltr will struggle to beat a 3.2 with even mild i/h/e mods.

Remember, only Rototest dyno figures count for comparision purposes. Either that or 1.6 miles of deserted runway :)

When is the next VMAX day?

Mark

[AR]

I think any non FI (Turbo or Supercharged) 3.0Ltr will struggle to beat a 3.2 with even mild i/h/e mods.

Mark

http://www.w3bdevil.com/forums/Flame-Bring_it_on_(Darth_Vader).jpg

Once is finished.

[AR]

Capacity increase or head work (port flowing) or both??Mark

Neither of those :)

[reg]

I'll be happy to see how much more aerodynamic your car is at the next Basingstoke meet:cool:

Luke

Hey,

When is the next meet. Be cool to catch up.

BTW POB has had a diet of carbon, big valves, porting, throttle bodies and mapping. I can't say 'how much' it is going to make but I hope more than the 190 it made last time!

Last one to 100 gets the beers in:laugh:

Sorry for derailing. Carry on chaps.

[reg]

Well some of us are working on it, no turbos, SC or ITBs.

My guess would be a bottle for easy power.

[AR]

My guess would be a bottle for easy power.


Nope but you'll soon get to see the pictures, I just have to get a few things sorted.

Cheers,

Ary

[Senninha]

Well some of us are working on it, no turbos, SC or ITBs.

If you're not using NOS, or any of the above, then I'd stab a guess at the electronics. Maybe you've found a good tuning house to reprogramme the ECU?? I've read that by moving the vtec zone you can delvier more power for longer?

When do we get to see the photo's Ary?

regards, Paul

PS - what color did you go with for the new look?

[reg]

If you're not using NOS, or any of the above, then I'd stab a guess at the electronics. Maybe you've found a good tuning house to reprogramme the ECU?? I've read that by moving the vtec zone you can delvier more power for longer?


More fuel and tweaked ignition timing along with more revs, sounds like a recipe for detonation:D

[AR]

If you're not using NOS, or any of the above, then I'd stab a guess at the electronics. Maybe you've found a good tuning house to reprogramme the ECU?? I've read that by moving the vtec zone you can delvier more power for longer?

When do we get to see the photo's Ary?

regards, Paul

PS - what color did you go with for the new look?

Paul still nothing changed. No time to even scratch my back. I will post some photos of the parts in the next week or two when I get them on.

[NoelWatson]

NoelWatson 2004 3.2
bhp related mods - standard
max power 256.8 bhp @ 7250 rpm
max torque 197.9 lb-ft @ 6550 rpm


I popped over to TDI this afternoon to see how the air intake and exhaust affected performance. Firstly the numbers

max power 271.3 bhp @ 7410 rpm
max torque 204.8 lb-ft @ 6630 rpm

Things of note:

1. There was no difference in power below 5500rpm, after that the modified car keeps gaining until there is around 20bhp difference between the cars at 8000 rpm. When Mark and I were at SRR (and Rob), Mark's car was showing greater performance across the board. Originally we put this down to the exhaust, but I think that the Type S may have something after all. I guess we need to do some back to back testing on the exhausts.
2. The intake loss is a lot smaller - I will get the raw data at some point
3. TDI still do group days for free, but people are expected to donate to charity for their run. Proceeds go to Gt. Ormand St. Suggest we revisit after cats are fitted.
4. The black NSX with the scoop on the rear hatch was still there.
5. I said that >10bhp will make me go back to VMax for another attempt. Still waiting on Pistonheads for details.

[Lankstarr]

Hey,

When is the next meet. Be cool to catch up.

BTW POB has had a diet of carbon, big valves, porting, throttle bodies and mapping. I can't say 'how much' it is going to make but I hope more than the 190 it made last time!

Last one to 100 gets the beers in:laugh:

Sorry for derailing. Carry on chaps.

You were meant to be letting me know about the POB track day in Abingdon... you were going to scare the sh*t out of me or something ;o)

I'll let you know when the next one is set up and you can come down in your go kart!

Do you think it will make 200 then (I take it you;re still in km/h?)

Why does nobody stick a bottle on? sounds like the best way to maintain efficiency and set up whilst allowing a huge shot of power when that Porsche turbo steps up!?

Luke

[markc]

max power 271.3 bhp @ 7410 rpm
max torque 204.8 lb-ft @ 6630 rpm

Things of note:

1. There was no difference in power below 5500rpm, after that the modified car keeps gaining until there is around 20bhp difference between the cars at 8000 rpm. When Mark and I were at SRR (and Rob), Mark's car was showing greater performance across the board. Originally we put this down to the exhaust, but I think that the Type S may have something after all. I guess we need to do some back to back testing on the exhausts.
2. The intake loss is a lot smaller - I will get the raw data at some point


Hi Noel, almost exactly as predicted then ie +14hp and +5ft/lb :)

Did you get the raw data file from this latest run? I'd like to see your 2 runs overlaid on the same graph and also add my data to see visually where your mods kick in and how they differ to my curve/s.

If you do have the raw data file, please post it to your blogg and I'll attempt to do the excel jiggery-pokery.

Cheers

Mark

[Senninha]

I popped over to TDI this afternoon to see how the air intake and exhaust affected performance. Firstly the numbers

max power 271.3 bhp @ 7410 rpm
max torque 204.8 lb-ft @ 6630 rpm



Senninha 1998 3.2 Targa ... been telling you all Targa's are the best model ;)
bhp related mods - H&S exhaust + Procar airbox
max power 274.1 bhp @ 7290 rpm
max torque 209.5 lb-ft @ 6450 rpm

Still a bit of work to do then Noel ;) good effort though!

I've been busy of late so not around much but will chase the CATS for progress report.

Happy to regroup once installed and help out GOSH!

regards, Paul

[NoelWatson]

Hi Noel, almost exactly as predicted then ie +14hp and +5ft/lb :)

Did you get the raw data file from this latest run? I'd like to see your 2 runs overlaid on the same graph and also add my data to see visually where your mods kick in and how they differ to my curve/s.

If you do have the raw data file, please post it to your blogg and I'll attempt to do the excel jiggery-pokery.

Cheers

Mark

I am on the case. Basically, the curves are the same below 5500rpm.

[NoelWatson]

I am on the case. Basically, the curves are the same below 5500rpm.


I got the data today. The numbers I originally posted were for the first run. The second run was

272.5 @7410
206.5 @6560

So a small improvement from the first run. Unfortunately I only did two runs - it is a shame as the modified car seems to get better on each run, unlike the unmodified car. This is similar behaviour to Mark's car when we were at SRR.

I have attached the spreadsheet with the data from all five runs (three unmodified, two modified)

The image below shows run 5 against (IIRC) run 2. One further thing to note was that my car had a flat battery so the ECU had been reset. The drive round the M25 to Essex should've sorted it but something to bear in mind


http://nsxcb.co.uk/testvb/attachment.php?attachmentid=4540&stc=1&d=1222372306

[markc]

Hi Noel,

Can take another look at your spreadsheet for Run 5. There's something wrong with the figures, compared to all the other runs, until the 6500rpm figures. Could you have read or copied these out of the raw file incorrectly?

If these were "corrected", a combo of Run 4's low output (<6000rpm)and Run 5's high output (>6000rpm) would give your overall best figures.

I'll add my numbers to the speadsheet/chart when you confirm your's are correct.

Cheers

Mark

[NoelWatson]

Mark,

Run5 starts at 2500rpm. I can remove that datapoint if necessary. Not sure why they included it for this run and not the others. I copied from laminated sheet as I don't believe the raw file is corrected.

[markc]

Ah ha, yes that explains it :-)

So, I've added my numbers to the attached file and changed the graph to plot your Run 5 and my numbers.

You're correct that my car makes better power low down but once VTEC kicks in at 5,800rpm they're VERY similar.

I wonder if you have a small problem with your VVIS system? It is supposed to change (inlet volume) at 4,800rpm. Closed for high torque at the low end and open for better top end power. Could yours be open all the time?

A vacuum pipe controls the switch. Page 295-298 of the downloadable Service Manual describes the operation. (http://www.nsxprime.com/FAQ/Reference/1991_svcman/1991servman.pdf) This for the earlier manual throttle cable cars rather than the DBW cars though.

Other questions...
How did you hook up the new airbox to the throttle body? Did you use the original flexi/concertina rubber pipe or a newly supplied smooth one?
Does the raw data file show the same inlet manifold pressure drop we saw last time?

Cheers

Mark

[NoelWatson]

Ah ha, yes that explains it :-)

So, I've added my numbers to the attached file and changed the graph to plot your Run 5 and my numbers.

You're correct that my car makes better power low down but once VTEC kicks in at 5,800rpm they're VERY similar.

I wonder if you have a small problem with your VVIS system? It is supposed to change (inlet volume) at 4,800rpm. Closed for high torque at the low end and open for better top end power. Could yours be open all the time?

A vacuum pipe controls the switch. Page 295-298 of the downloadable Service Manual describes the operation. (http://www.nsxprime.com/FAQ/Reference/1991_svcman/1991servman.pdf) This for the earlier manual throttle cable cars rather than the DBW cars though.

Other questions...
How did you hook up the new airbox to the throttle body? Did you use the original flexi/concertina rubber pipe or a newly supplied smooth one?
Does the raw data file show the same inlet manifold pressure drop we saw last time?

Cheers

Mark

"I wonder if you have a small problem with your VVIS system? It is supposed to change (inlet volume) at 4,800rpm. Closed for high torque at the low end and open for better top end power. Could yours be open all the time?"

We will probably need to get more of a sample size, but if you recall Rob's and my car were pretty similar at SRR (where yours was showing a big gain from low down). I think that you have a bleuprint engine. I recall reading that the VVIS was not much good anyway (think it was Rob Fenn).

"Did you use the original flexi/concertina rubber pipe or a newly supplied smooth one? "

I used the original one as I am led to believe that fitting the CF smooth one is a pain

"Does the raw data file show the same inlet manifold pressure drop we saw last time?"

Pressure drop was much lower - you have no excuse if you want to become #1!!

[TheQuietOne]

Not wanting to tread on anyone's toes so please take this in the right way but this is a proper geek thread, we don't have enough on the forum since Darren and Kevin stopped posting so much!

Imagine all those secret numbers out there waiting to challenge the big hp boys....AR, step up sir! :D We MUST do a really comprehensive day when a really good cross section are available, including at least one NSX-R!

Calling;

Chris?
Flemke?
David?

[markc]

Geek, moi? Guilty as charged :)

Remember, for comparative purposes only Rototest hub dyno's (ideally TDI's) count.

Mark

[NoelWatson]

Not wanting to tread on anyone's toes so please take this in the right way but this is a proper geek thread, we don't have enough on the forum since Darren and Kevin stopped posting so much!

Imagine all those secret numbers out there waiting to challenge the big hp boys....AR, step up sir! :D We MUST do a really comprehensive day when a really good cross section are available, including at least one NSX-R!

Calling;

Chris?
Flemke?
David?

I think we should also get the cars on the scales when next at TDI. Compare NA1/NA2/02+/TypeS/Coupe/Targa

[Senninha]

I think we should also get the cars on the scales when next at TDI. Compare NA1/NA2/02+/TypeS/Coupe/Targa

Good call and I was a bit slow off the mark last time otherwise I would have done this to see what mine is weighing in at.

I'm pretty sure we can cover all bases and a variety of mods, we just need a NSX-R to complete the stats and to prove of bust the mythe about bespoke engine builds and higher hp/torques #

regards, Paul

PS, keep up the geekiness!! :)

[NSX 2000]

I'm pretty sure we can cover all bases and a variety of mods, we just need a NSX-R to complete the stats and to prove of bust the mythe about bespoke engine builds and higher hp/torques #

OR somebody could buy the engine that Detlef has for sale and fit it to their car.

Just an idea.

[NoelWatson]

OR somebody could buy the engine that Detlef has for sale and fit it to their car.

Just an idea.

I guess this would make sense for owners with <270 bhp :)

[NoelWatson]

"I wonder if you have a small problem with your VVIS system? It is supposed to change (inlet volume) at 4,800rpm. Closed for high torque at the low end and open for better top end power. Could yours be open all the time?"

We will probably need to get more of a sample size, but if you recall Rob's and my car were pretty similar at SRR (where yours was showing a big gain from low down). I think that you have a bleuprint engine. I recall reading that the VVIS was not much good anyway (think it was Rob Fenn).

"Did you use the original flexi/concertina rubber pipe or a newly supplied smooth one? "

I used the original one as I am led to believe that fitting the CF smooth one is a pain

"Does the raw data file show the same inlet manifold pressure drop we saw last time?"

Pressure drop was much lower - you have no excuse if you want to become #1!!

"I wonder if you have a small problem with your VVIS system? It is supposed to change (inlet volume) at 4,800rpm. Closed for high torque at the low end and open for better top end power. Could yours be open all the time?"

Forgot to mention that if you compared my pre mod runs with yours, I think the gap would be pretty consistent across the rev range - it's just that the mods allow mine to catch up as the revs rise.

[NoelWatson]

Interesting thread

http://www.nsxprime.com/forums/showthread.php?t=112547

Will be good to see how 02+ and 97+ differ when the sports cats are fitted

[Lankstarr]

Great write up on the home page Mark - thanks.

L*

[simonprelude]

Interesting thread

http://www.nsxprime.com/forums/showthread.php?t=112547

Will be good to see how 02+ and 97+ differ when the sports cats are fitted

I'm game ;)

Standard car, sports cats, I expect 270 at the wheels................ (TDI)

[NSXGB]

Any dyno days planned this year?

[NSX 2000]

Any dyno days planned this year?

I think we are waiting to get our quick flow cats and then once fitted do another dyno day.

[Lankstarr]

Any dyno days planned this year?

I'm ready for y'all:rolleyes:

[NSXGB]

I think we are waiting to get our quick flow cats and then once fitted do another dyno day.

Well, you'll be going next Christmas! :)

[NoelWatson]

Well, you'll be going next Christmas! :)

Are you Nostradamus!!

[NSXGB]

Are you Nostradamus!!


....I could tell you the results too but that would just spoil the fun. :)

[AR]

Around 5 bhp extra.

I still don't get why you guys did not go for test pipes.

[markc]

Around 5 bhp extra.

That would be nice :)


I still don't get why you guys did not go for test pipes.

I'm thinking they'd be A) too noisy and B) on our OBDII cars the "bodge" of locating the post cat sensor/s in extended fittings is hit and miss to say the least.

Cheers

Mark

[AR]

That would be nice :)



I'm thinking they'd be A) too noisy and B) on our OBDII cars the "bodge" of locating the post cat sensor/s in extended fittings is hit and miss to say the least.

Cheers

Mark

Mark I had them on a 3.2 before and no problem there, most exhaust shops can build you an extended bung. You can also have a pair of resonators built instead of the straight pipe design.

[markc]

Mark I had them on a 3.2 before and no problem there, most exhaust shops can build you an extended bung. You can also have a pair of resonators built instead of the straight pipe design.

Well they may "work", some or most of the time, but you have to admit it is a bodge. By work I mean prevent a CEL (Check Engine Light) being triggered.

The second sensor is there to both determine that the CAT is working AND work with the first one, via the ECU, to ensure that the fuel/air ratio is correct. I wouldn't want to risk running too long with potentially incorrect fueling.

Even if the the sensor relocation does work and you run de-cat (test) pipes you may well fail your MOT emissions test and therefore have the hassle of swapping back to standard cats every year. Too much hassle for me.

Cheers

Mark

[Senninha]

The second sensor is there to both determine that the CAT is working AND work with the first one, via the ECU, to ensure that the fuel/air ratio is correct. I wouldn't want to risk running too long with potentially incorrect fueling.

Even if the the sensor relocation does work and you run de-cat (test) pipes you may well fail your MOT emissions test and therefore have the hassle of swapping back to standard cats every year. Too much hassle for me.

Cheers

Mark

This is exactly why I have opted for high flo CAT's over test pipes, as well as not wanting to be too loud. I much prefer the ability to cruise into town un-announced and keep the loud bit for when I want to play :)

[NoelWatson]

Talking of cats, was looking at resetting ECU, and found this

http://itisfresh.com/how-to-reset-ecu-acura-nsx.html

"or you may decide to erase the catalytic converters (obviously for track use) and the car bogs down.. "

Mine felt like it was bogging down so have just done this

[drplc3]

Hi Luke, the Type S myth is busted, Paul's car (Senninha) pipped mine and the other Paul (NSX200) was real close. Both, as well as me, have non factory exhausts. Look at Leigh's (Kowalski) numbers for what a 3.0Ltr car is capable of with exhaust mods, just make sure you have your fingers in your ears :)

A top event and some properly useful data and comparisons have been recorded.

The guys at TDI really know their stuff! Project "airbox" starts now... ;)
Very interesting chat with Sam of TDI as to how to overcome the air/fuel mix issues to release those extra ponnies. I'll email SOS and ask the question re throttle bodies and update if I get any answers

[markc]

Very interesting chat with Sam of TDI as to how to overcome the air/fuel mix issues to release those extra ponnies. I'll email SOS and ask the question re throttle bodies and update if I get any answers

I've spoken with a couple of knowledgeable and well respected sources about this.

The consensus is that the 3.0Ltr cars will not benefit from a bigger throttle body even if the more usual I/H/E upgrades have been done. It won't hurt but it won't help.

It will however benefit 3.2Ltr cars as they have slightly better breathing (bigger valves) and the cross sectional area of the standard throttle body does "strangle" the motor a touch. There is science behind this which I don't have to hand but someone else might chip in with that ;)

Science of Speed will claim a few hp's for mechanical standard 3.0 and 3.2Ltr cars but in truth it really only comes into it's own for FI and their increased capacity (3.3/3.6/3.8Ltr) NA builds.

I plan to get me one at some point anyway :)

Cheers

Mark

[greenberet]

I'll email SOS and ask the question re throttle bodies and update if I get any answers

In theory, the intake tract of a naturally aspirated engine should be shaped kind of like a funnel, slowly getting wider the further you get away from the cylinder head.

If my measurements are correct, a stock NSX’s intake tract has the following cross sections:

Intake opening in cylinder head: 18.0 cm2. This is also the cross section of the exits of the individual runners in the intake manifold.
Intake manifold entrance: 34.2 cm2. In our six-cylinder four stroke engine, 1.5 cylinders will always be inhaling at once, so you’d want the intake manifold entrance to be somewhat more than 1.5 times as large as the intake openings in the cylinder head. Our manifold fits the bill nicely with an entrance 26.6% larger than 1.5 times the cross section of the openings in the cylinder heads.
Throttle body outlet: 32.2 cm2. A tad smaller than the entrance to the intake manifold, if my measurements are correct, so not quite ideal.
Throttle plate: 29.6 cm2 effective cross section. Narrower again and now only 9.7% larger than 1.5 times the intake openings in the cylinder heads. How much of a restriction this poses will depend on the flow rate through the throttle body. According to informed sources, it does not cause a noticeable restriction with stock or lightly modified NA1 engines. With heavily modified NA1 engines and stock NA2 engines, it does.
Airbox exit: 59.1 cm2. Much, much larger than the cross section of the things downstream of it so this shouldn’t pose any restriction.
Air filter: 496.9 cm2. Not even accounting for the pleats. How much or even whether an aftermarket filter is really less restrictive than the OEM filter is open for contention. I would love to see some dedicated pressure drop measurements carried out in an NSX. The measurements taken during the 2009 TDi dyno day indicated no difference in pressure drop between the cars with OEM vs. aftermarket airboxes/air filters.
Exit of OEM intake snorkel: 65.1 cm2. Larger than the exit of the airbox, so the funnel analogy holds and this shouldn’t be a restriction, either.
Main opening of intake snorkel: 50.6 cm2. In stock form, this is the only entrance used. It’s still 47.9% larger than the entrance of the intake manifold, so it may not pose much of a restriction. In this configuration however, the funnel analogy doesn’t hold.
Resonator opening in intake snorkel: 19.6 cm2. Getting rid of the resonator will increase intake noise and the two openings in the intake snorkel together have a larger cross section than the exit. In this configuration, the stock intake snorkel doesn’t look like it would be a bottleneck either.
How generous the radii in the intake system are impact its efficiency as do its resonant frequencies (which the VVIS helps out with). Just looking at the cross sections, though, the following two modifications seem logical in an otherwise stock intake system:
Get rid of the resonator in the OEM intake snorkel, replacing it with a bellmouth, if possible.
Get the stock throttle body bored out so that the effective cross section at the throttle plate is no longer smaller than the entrance to the intake manifold and have the exit of the throttle body port matched to the stock intake manifold. I spoke with Chris at Science of Speed and their big bore throttle body porting service does both of these things. Edit: SoS increase the size of the throttle plate from 65.5 mm to 70.5 mm. Subtracting the height of the spindle, this increases the effective cross section to 34.7 cm2. They bore the exit of the throttle body out to 66mm, port matching it to the intake manifold.
With those two modifications, an NSX’s intake looks like a well balanced system without obvious bottlenecks. Further changes will probably have a noticeable impact on horsepower only if you modify the intake system along its entire length, starting at the cylinder heads. New airboxes and intake snorkels can make the engine sound more powerful, though!

[markc]

That'll be the science bit I was referring to, thanks Andreas :)

Cheers

Mark