Optimax or not?

[Senninha]

According to the owners manual, 95 RON fuel is all that's needed for the 3.2 NSX so this is what I'm currently using.

In previous cars I've run with Optimax (or similar) believing this would help both the performance and the cleanliness inside the combustion chamber.

My question to those far more technical than I is will a change to Optimax deliver any benefits? If it will, I'm assuming that it will take 2 or 3 tankfuls for the engine management to adjust to the higher 97 octance fuel. Additionally, is it likely to have an impact on fuel economy, not that this would be a restriction if the combined engine performance benefits are delivered.

I'd also be interested to hear if anyone else has made the switch from 95 to 97 and what changes (if any) were noticeble?

Your views appreciated.

regards

[AR]

On the way home from buying the NSX-R I had enough fuel to get me home. Once I was home I went to a Tesco's petrol station by my house on a Sunday morning ( they get the 99 RON on Saturday night ) and filled up the tank. I can feel the difference.

With my old 3.2 I could feel the difference between Optimax and Tesco's 97.

Cheers

AR

[ctrlaltdelboy]

higher octane fuel can make a difference provided the ECU makes the adjustments to the map to benefit from it.

in any car you can make more power from igniting the fuel slightly earlier (this is called timing advance) but at the risk of detonation (knock) which can destroy the engine.

the lower the octane rating, the higher the risk of detonation.

when you use a lower octane fuel and get a little bit of det, modern ECUs detect this and retard the timing a little for safety thereby making less power.

the best way to benefit from the higher octane fuel should you choose to use it is to reset the ECU forcing it back to factory timing.

once reset the ECU will try to find it's ideal level of advanced/retarded timing by advancing until it senses det and then backing off a little from there, so if you have a high octane fuel in use at this time your ECU will set itself in a more advanced state of timing which produces more power.

with aftermarket ECU's you can set different maps for different fuels and switch between them as desired.

[Senninha]

the best way to benefit from the higher octane fuel should you choose to use it is to reset the ECU forcing it back to factory timing.


Hi Darren,

Welcome back from holiday and thanx for your response. You say above that the best way is to reset the ECU. How is this done please? Is it a dealer function or something I could do?

Would I then be right that if using 97 at the time of reset, the ECU then does its stuff and will settle at the optimum setting for the higher grade fuel?

regards

Paul

[AR]

Hi Darren,

Welcome back from holiday and thanx for your response. You say above that the best way is to reset the ECU. How is this done please? Is it a dealer function or something I could do?

Would I then be right that if using 97 at the time of reset, the ECU then does its stuff and will settle at the optimum setting for the higher grade fuel?

regards

Paul

Paul,

Pull the clock fuse out for a few minutes, that should reset it.

Cheers

AR

[Lankstarr]

For info I think that the new shell Vmax is 100 RON.

I always run mine on this or the 99 avail at Ttescos so will be trying this "fuse job"

I'm not sure that 95 to 97 would make much of a difference but maybe going up to nearer 100 will :D

[AR]

Paul, did you get my PM a few days back?

Cheers

AR

[Senninha]

Ary,

you have pm

[Senninha]

For info I think that the new shell Vmax is 100 RON.

I always run mine on this or the 99 avail at Ttescos so will be trying this "fuse job" :D

I've spoken to the foreman at Norton Way this morning and he suggests the following steps to reset the ECU to new fuel grade;

1. Run engine upto normal operating temperature
2. Switch off and remove clock back up fuse
3. Leave car for 10 minutes
4. Replace switch and start engine without using the throttle
5. Leave car to idle for further ten minutes

You need to have the new fuel grade in the tank before you do the above and it will take 2/3 tanks of fuel for the ECU to have learnt its new setting.

Regards

Paul

[AR]

I've spoken to the foreman at Norton Way this morning and he suggests the following steps to reset the ECU to new fuel grade;

1. Run engine upto normal operating temperature
2. Switch off and remove clock back up fuse
3. Leave car for 10 minutes
4. Replace switch and start engine without using the throttle
5. Leave car to idle for further ten minutes

You need to have the new fuel grade in the tank before you do the above and it will take 2/3 tanks of fuel for the ECU to have learnt its new setting.

Regards

Paul

Paul,

When replacing exhaust, cats and Air Filters I've always done this. My other car was in essence the same as yours a 3.2 6speed. I can tell you that the car ran funny for a few minutes, then aftyer a " good #2 v-tec session it was fine 750 rpm and smooth as silk.

Cheers

AR

[Nick Graves]

Someone in the oil industry who posts on S2Ki (sorry, I'm a bugger for names!) mentioned that Optimax tends to go 'off' (to about 96 Ron) if it's standing in the tank for a few days. Since NSXs tend not to be everyday cars...you get my drift.

I tend to use Tesco's 99 in the S & the 'Lude. The S hates 95 and absolutely loved the 100ron Optimax they sell in Germany!

In the case of the 'Lude, it tends to 'pink' slightly if accelerating on cruise in 5th (the main gear one is in on cruise).

Again, the car generally has sharper throttle response, smoother 'feel'

When I get an NSX, I'll probably stick to the 99. With a flake.

[Lankstarr]

I dont want to start a b1tch fight here as I have no where near the technical knowledge:confused: to back myself up but after telling a friend about resetting the ECU he pointed me to the following artical about knocking:

Correct ignition timing is essential for optimum engine performance and fuel efficiency. Modern automotive and small-boat engines have sensors that can detect knock and retard (delay) the ignition (spark plug firing) to prevent it, allowing engines to safely use petrol of below-design octane rating, with the consequence of reduced power and efficiency.

A knock sensor consists of a small piezoelectric microphone, on the engine block, connected to the engine's ECU. Spectral analysis is used to detect the trademark frequency produced by detonation at various RPM. When detonation is detected the ignition timing is retarded, reducing the knocking and protecting the engine. See also Automatic Performance Control (APC).

full details can be found here:

http://en.wikipedia.org/wiki/Engine_knocking

He thinks taht a car as advanced as the X should automatically adjust to the fuel type that it is running on after a few miles and that resetting the ECU may make it lose any stored info about how your particular engine likes to run and any traits that it has.

Your thoughts gents please :D

thanks

Luke

[modarr]

Damn right bitch fighter general.

Re-setting the ECU should set the timing to maximum advance and the allow the ECU to back off to suit your octane rating.
Doing it your way would achieve the same end result but would ? take longer and require you to drive like I do.

Seems easier pulling a fuse than attempting to keep up with me.

Ding ding. Round 2

[Lankstarr]

require you to drive like I do.


If I wanted to drive like a girl then I'd need to find some 86RON... even ASDA don't sell that.

TKO

[modarr]

Ouch!

You finished bitch slappin ma ass?

I'se gonna scratch yo eyes out when you down the hair dressers next!

[Lankstarr]

OK so I reset my ECU a few days ago after filling with 99 (and a flake) but needed more juice last night ... to my horror Tescos' fuel bit was shut... bothe times I tried.

Got desperate this morning and had to put an Ayrton's of 95 in whilst I searched for VMax turns out I had plenty left but now I have a mixed tank of (x+y)/zRON... hopefully the one tank will have been enough to set the ECU to 99 or I am going to have to go to all the hassle of lifting the bonnet and defusing her again;)

[Senninha]

Luke,

I dont have a definitave (or tech answer) only what I was advised by Norton Way, which is the ECU will reset and will 'learn' its new settings over a couple of tanks of fuel.

My logic would say that if you now top up over the Senna's worth with the 99+ all should be well. I guess you need to decide if you're going to pull the fuse and start again.

Had you started to notice any difference at all??

Regards

Paul

[Lankstarr]

Paul,

I had a couple fo blasts with Paul on the way to and from getting our HiDs fitted last night (they look great btw!) and thinking about it she did feel fast but I'm not sure whether I could say I noticed the difference... at the time anyway!

Difficult as the difference will be quite small and partly psycological.. .. if I had to say Y/N I would go for N but I was always running it on 99(no flake) before so maybe I'd be looking for an even smaller power difference.

What a load of waffly rubbish... hope it makes some sort of sense!!!

L*

[TheQuietOne]

Had to do my clock fuse to sort out my changer again at the weekend, which coincided with a tank of V-Max...honestly I can't tell the difference. Interestingly my car's induction growl is loudest on Sainsbury's fuel...

[Senninha]

99 with a flake and now a waffle, thats bound to slow it down! :lol:

I guess we'll find out if any of its worthwhile on Saturday. Should have cafe details later today.

[Lankstarr]

Should have cafe details later today.


mmmmm greasy spoons and waffles and flakes:p

[Paul]

Paul,

I had a couple fo blasts with Paul on the way to and from getting our HiDs fitted last night (they look great btw!) and thinking about it she did feel fast but I'm not sure whether I could say I noticed the difference... at the time anyway! And a good couple of blasts they were too :-D it will be interesting to see the diference on paper between a 3.2 and 3.0 ... there didn't seem to be much in it last night :-D

I've been putting nothing but Optimax and now V-Max in mine since I got it two years ago so I suppose I should pull my clock fuse and follow the steps outlined in this forum, just to be sure I'm geting the most out of the petrol.

Will be interesting to see what the photo's look like of HiD and non HiD in the dark side by side ... they certainly looked good all lined up with nice new HiDs in ... although I think Matt's weren't quite as bright as ours with the heatsinks ;-)

Certainly makes a difference to driving at night on dipped beam ... much more light.

[Senninha]

When I bought S2 it was already fitted with an HID upgrade so I've no reference to how they compare to std lights. However I did have an 04 S2k with factory HID and I would say they were far better. It may be an alignment issue although all was fine for the MOT. Maybe its just the power of this particular kit. I'll be interested to compare install and ratings at the weekend.

regards

[Lankstarr]

I'm not going to the RR for any "my bulb is brighter than yours" competitions!!

If you really must then we could test them by seeing how long we can stare straight at each head light before our vision starts to blurrrr;)

[Lankstarr]

I think Matt's weren't quite as bright as ours with the heatsinks ;-)


IMO no think about it... ours are definitely brighter!

[Martin]

Whats Vmax? Excuse my ignorance

Cheers
Martin

[Senninha]

Whats Vmax?

8,200rpm :p No, seriously, its the replacement from Shell for Optimax.

[AR]

8,200rpm :p No, seriously, its the replacement from Shell for Optimax.

Ahem...8400 rpm :D but I would not know that :rolleyes: ;) .

[darkblueturbo]

8,200rpm :p No, seriously, its the replacement from Shell for Optimax.

I thought it was called VPower?

It's a whole 99RON instead of the old Optimax 98.6 RON.

The main reason I've always used Optimax (or BP ultimate if I can't find it) is the cleaning properties of it over other 'normal' super's.
Evo Mag ran a test a couple of years back with a few cars - one was an old Volvo or something with sooted up injectors.
Three tanks of Optimax later and they were almost as good as new...

There was an article on pistonheads.com recently about the virtues of Optimax, Tesco 99 and Ulitimate - Tesco came out on top in terms of performance (each car was run for 3 tanks then dyno tested on each fuel) but I haven't made the change unless I see similar evidence that it keeps the engine as clean and healthy as Shell...

http://www.pistonheads.com/news/default.asp?storyId=14919

[Senninha]

I'm now converted to the V-Power and whilst I can't argue its performance benefits, the combined benefits of my other mods and the fuel defeinately work well as a package. Add to this the cleaning benefits claimed by Shell and I'm very pleased :D

[Nick Graves]

Whats Vmax? Excuse my ignorance

Cheers
Martin

Excused, because you bothered to find out!

Vmax is the engineering/mathematical symbol for maximum velocity.

It was also a 1200cc Yamaha V-4 - a bit of a puller!

[Paul]

Whats Vmax? Excuse my ignorance

Cheers
MartinNo ignorance required ... some pillock called Shell's Optimax successor V'Max instead of V-Power ... I don't know ... these pillocks using the wrong term and confusing people ... they should be banned from the forums ... ;-)

[madras]

Paul,

Pull the clock fuse out for a few minutes, that should reset it.

Cheers

AR

stupid question?? i think so, but anyway:
does the battery being flat equate to pulling the fuse out of the clock?

Thanks!

[TheSebringOne]

I was using Shell Optimax 98 RON & notice significant feel in the car over 95 RON,now replaced by V-power 99 RON, but since I drive less than 1k a yr I shamelessly admit 2, then suppose its worth the extra 6-7p a litre over 95 for drive treats. Last wk 4 the 1st time, put in BP ulimate 97 RON, which claims like Shell to have better cleaning properties & increase power!, but does 28 mpg more than BP'S 95 RON?. BP website did a test with two Toyota Advensis going round circuit at 70mph average until fuel ran out,with ultimate going 28 miles longer. Sadly I worked out since ultimate costs 4p more a litre than V-power,then the extra miles gained is cancelled out dearer fuel!! Not sure of the extra BHP gained over 95 RONS for either Shell or BP? My fave serious car mag EVO states overall that Shell is the best all rounder for naturally aspirated engines, so going back to Shell frm now on! :D

[simonprelude]

The only thing I would suggest if you don't drive your car very much, is to not keep much fuel in the tank.

The high octane fuels degrade much quicker than 95 RON.

Personally I only use 95 RON anyway in my car due to local availability so whilst this fuel problem is ongoing she is staying in the garage.

[TheSebringOne]

I agree that fuel does degrade, even with the same type of RON at the different Shell or BP stations. Best advice is 2 go2 a filling station thats busy as that means fresh supplies more often & less degraded fuel. My question is whether higher RONS than standard 95, is worth the extra for alledged power increases, better engine piston cleaning & MPG? Cheers Simon, but I only fill in small amounts anyway, think full tank is 60-65 squid? (never tried), I normally put in 15-20 squid! Lighter car means quicker off the line ! PWR ! Cheers:o

[Silver Surfer]

Do the NA2 have bigger tanks then the NA1?

My NA1 can only fit 50 litres in before it spits on my loafers. So thats around 50 squids max.

SS

[TheSebringOne]

NA2 holds 70 litres or 15.4 Gallons according the owners Manual, but holding more than NA1 & on full tank means extra 20 litres = worse PWR! Strange 20 more BHP & 20 more litres !?! Spooky co-incidence, But then again, never done full tank, only quarter tank a time as ashamingly only do 1k pa !! & fuel degrades too. oh Since I'm new why NA1 & NA2, I know they are the slight modifications or series changes, but why NA? :confused: :D

[Kevin]

The only thing I would suggest if you don't drive your car very much, is to not keep much fuel in the tank.



I thought if a car is being stored, then the tank should be filled up to the brim. I can only suppose that would prevent any chance of condensation forming on the tank sides or something.

I hardly use my car but I still did 2000 miles last year. Are you sure there's any point in owning the car for only 1000miles a year? A Ferrari 250GTO or Aston DB5 I can understand, but not an NSX.

We saw on the dyno day (look in past events) cars that get used produce more power! Also my car on that day was filled with 95 petrol, just like I always use.

[DamianW]

Thought if you were storing the car for a long time you needed to use a fuel stabliser - in fact I seem to recall an NSXCB member knew quite a bit about this stuff?

[madras]

Do the NA2 have bigger tanks then the NA1?

My NA1 can only fit 50 litres in before it spits on my loafers. So thats around 50 squids max.

SS

my 93 (built in 92 apparently) has about 70 litre tank.

think i'm going to use VPower from now on

[Silver Surfer]

Maybe I have chickened out from running to near 'truely' empty as I fill up when the needle just reach the first marker. Is there a 20 litre residual for emergenciy?!?

SS

[Steveycaz]

My '91 has a 50 litre tank.

[TheSebringOne]

Tried the chicken test,when the orange warning light glows fully,my NA2 has 2.4 gallons left,which means roughly 40m driving HARD based on (ave16mpg) OR driving AVERAGE 54m (ave 22.7) OR BEST 58m (ave 24.4) Based on info frm NSX portfolio book compilation.
May b theres a 20 litres diff bewteen the earlier cars when compare to later cars when full tank? Maybe check your driver's manuals?
Fuel Stabilizers? Does fuel becomes unstable after a fews months storage over winter? I only keep as little fuel as poss as fuel degrades & during rest of the yr,only put a quarter of a tank max as aid aceleration! :o

[TheSebringOne]

Hi Kevin, I know u might question y I shud keep the car since I drive little mileage, but I intend hopefully 2 keep the car for a very very long time, so want2 keep mileage reasonable each yr! As for the 250 GTO, average £ is 3-4 million, Did'nt 1 go 4 a reputed £10 million at the height of rare car speculation in late 90s. As for Bond's type car the DB5, mint 1's 250-300k?! I know these are very rare cars, but hey I enjoy my car more when I use it less, less is more & each drive is more special! I'm going 2 the Japfest in May, so maybe this yr I will do more than a 1000 miles ! :D

[madras]

my 93 (built in 92 apparently) has about 70 litre tank.

think i'm going to use VPower from now on

pretty sure my reserve is 15, took a while for me to run it low enough for the fuel light to even come on, I thought the fuel light was gone as it doesn't light on start up. most i've fitted in is 64litres, never ran it down with a can in boot.