New Exhaust System.

[SILVER BULLET]

Im seriously considering fitting a more tuneful exhaust to my 2002 car, I know some of you have already been through the comparison process and fitted new systems to your cars .What I would like to achieve is a slightly more sporty sound whilst keeping it road legal and passing scrutineering at the occasional track day .

I have looked at SoS and Dali and don't know whether the sytems shown are complete or do they still require other parts separately purchased.

Any help/,advice would be welcomed,

Thank's

Ian

[markc]

I have the Dali RR (Rice Rocket) fitted to my '97 (3.2Ltr 6spd). It's one of the cheaper options and I like the sound, much deeper than standard so that the car doesn't sound like it's revving quite as high. There is some boominess at lower revs and wide throttle openings but it's not bad. Subjectively the car felt stronger in the mid-range post fitting it but I need to get to a dyno to see if the numbers bear that out.
You do need adapter pipes for the later cars tho' as nearly all (all?) the aftermarket exhausts are designed to fit the early cars exhaust layout and require adapter pipes to make them fit a later car.
There are several adapter pipe options as well! Dali sent me all (4) of them and I returned the ones I didn't need.
In terms of trackday suitability they're JUST about OK. At a recent Bedford Autodrome 101dB trackday, I scraped in on the static test at 100.8dB and got black flagged for tripping one of the trackside monitors. Trip 3 of them (or the same one 3 times) and you get sent home.

I've yet to hear a GT-ROM in the flesh but there's a lot of nice things said about the noise they make. Anyone got any independant (track tested) noise readings for one of these systems?

Mark

[Rob_Fenn]

There was a video posted from a big BMI exhaust comparison video and just about all of them would fail noise tests on UK circuits unfortunately.

Sadly i can't see UK tracks getting any less stringent. I know with the Taitec exhausts you can get bungs for them.

If i had a road NSX i would defo go for the GT Rom 5.1, it sounds amazing.

[Kevin]

I have a Taitec JGTC centre exit system. According to the SoS website it's one of the louder ones.

With cats in and 'headers', it measures 96dB. No problem for any of the track noise limits.

I have some inserts which I made, which take some of the edge off the sound and bring it down to 92dB.

If you go cats out, then it's stupid loud, and you won't be getting anywhere near a track.

[markc]

Hi Kevin, are those the measurements from your own noise meter?

Do you know what level you were recorded at by the Bedford noise police? I mention it because with 3dB being twice as loud in the noise scale, that makes my car 1.5 times louder than yours :o

Subjectively it doesn't sound that much louder than yours does it... Paul, Mo, Rich did you earball me at Bedford?

Do we have any any other readings from members cars "officially" recorded at UK circuits?

I know these readings aren't always taken particularly accurately or in the most repeatable conditions but it might help us understand which systems we can use and still do the occassional track day.

Mark

[Kevin]

That was by the Bedford noise nazis.

At the car wash day, we measured from 1m away, that was 94dB, Bedford measure at .5m, 96dB.

If a table were to be constructed, we would have to measure at various angles and distances.

Also, Bedford said that the weather has an effect. If it's a cold heavy day, rather than hot.

Exhausts also get louder with age, if they use wadding for sound deadening.

I think yours is noticeably noisier than mine.

[AR]

GT_Rom estimates mine at 103db, but I wonder if that is with headers and catless!

[markc]

Hi Ary, hope to hear your GT-Rom in the flesh (recordings never do them justice) sometime soon :)

W.R.T their own estimate of 103dB, it's not really of any use without an explaination of how it was measured or estimated.

As Kevin says, if we start to collect readings when we attend meetings trackdays etc we can build up a table of differant systems and combinations.

Mark

[AR]

Hi Ary, hope to hear your GT-Rom in the flesh (recordings never do them justice) sometime soon :)

W.R.T their own estimate of 103dB, it's not really of any use without an explaination of how it was measured or estimated.

As Kevin says, if we start to collect readings when we attend meetings trackdays etc we can build up a table of differant systems and combinations.

Mark

Hi Mark,

Here is a good video of several exhausts being tested.

Cheers,

Ary

http://www.youtube.com/watch?v=w9C1iti8Ye0

[Senninha]

Mark,

A reference table as you suggest would be helpful for those looking for a new system. Various measurements will give one view as to the impact of a particular system. There is one on the home page attached to the wash day article.

However, I think the more difficult information to record is the 'actual' sound the systems make. By example, when Kevin took the readings at the wash day, OEM, Tubi and my H&S all gave the same reading, however, I recall commenting that compared to the Tubi for example, mine sounded much quieter, with a deeper, softer tone. The Tubi IMO is a sharper more raspy sound. IIRC, Greybloke has the RR that you have. This sounds much louder and as his recent post suggests, attracted unwanted attention.

I dont know how we can define this element but its probably the data that most are interested and would be part of the answer that Ian (Silver Bullet) was looking for in the initial post.

Any ideas anyone?

regards, Paul

PS, there are more sound recordings taken by Kevin from the September 06 rolling road day.

[AR]

Mark,

A reference table as you suggest would be helpful for those looking for a new system. Various measurements will give one view as to the impact of a particular system. There is one on the home page attached to the wash day article.

However, I think the more difficult information to record is the 'actual' sound the systems make. By example, when Kevin took the readings at the wash day, OEM, Tubi and my H&S all gave the same reading, however, I recall commenting that compared to the Tubi for example, mine sounded much quieter, with a deeper, softer tone. The Tubi IMO is a sharper more raspy sound. IIRC, Greybloke has the RR that you have. This sounds much louder and as his recent post suggests, attracted unwanted attention.

I dont know how we can define this element but its probably the data that most are interested and would be part of the answer that Ian (Silver Bullet) was looking for in the initial post.

Any ideas anyone?

regards, Paul

PS, there are more sound recordings taken by Kevin from the September 06 rolling road day.

Paul,

You also heard mine at the services! :)

Quiet at iddle and high pitch at full chat!

After Barry got 293 BHP with my exhaust design ( not the one I have on ), I feel like making a few copies and market it at a reasonable price.

Cheers,

AR

[Senninha]

Paul,

You also heard mine at the services! :)

Quiet at iddle and high pitch at full chat!

Cheers,

AR

So I did ... my ears are still ringing :laugh:

So on the sound scale I would say as loud as the RR, but deeper in the mid range. Both a high pitch when used in anger :)

regards, Paul

[markc]

Hi Ary, I have seen that youtube video before and you're right it is a useful one for the noise measurements IF you can work out what the details of the measurement are. Anyone here read Japanese?? :)

Reading between the Japanese characters in the intro panel, it looks like the static tests were performed at 45(degrees) and 0.5 meters distance, at 5,100rpm for NA1 cars and 5475rpm for NA2. Why the differance? Also, 75% of something is mentioned but of what, those revs ranges aren't 75% of full revs???

I'm guessing the first of the 3 measurements is at idle, the second at 5,100/5,475rpm and the last at 8000+rpm?

The actual sounds recorded gives you a taste of the differant exhausts but as Paul says you need to hear them in the flesh get a proper feel for them.

Mark

[Senninha]

..... Anyone here read Japanese?? :)

Nope, but this helps http://www.google.com/language_tools ;)

[SILVER BULLET]

Thanks all for advice and help so far, this sound thing is very subjective !

I like the look of the Taitec GT Lightweight exhaust but don't know whether this fits straight onto the standard (manifold)header or whether it is best practice to fit new headers at the same time, also would i need to fit new cats as well ? I apologise for all these questions but i am a new boy to NSX ownership and do not want to do anything detrimental to this fantastic car,plus I dont want to be excluded from a track day because of excessive noise.

Maybe the Taitec quiet tip silencers would be a good idea for a track session.

Thanks,

Ian.

[lotusolly]

I have a noise meter that I can bring along to the next meet and take readings of the vehicles there to create a table if thats of help

Olly

[AR]

Maybe the Taitec quiet tip silencers would be a good idea for a track session.

Thanks,

Ian.

Yes they can brig down the noise. The only thing you need is a set of adaptors that are included when you buy an exhaust for a 3.2 NSX.

Hope that helps,

Ary

[Steveycaz]

I fitted the Taitec GT006 Lightweight pipes to my standard cats recently. Very very pleased with the noise! I should be in N. Devon (Tiverton) late Feb if you want a look-see (or look-hear?)?

Steve.

[SILVER BULLET]

Steve,it would be good to meet you at Tiverton at end of Feb and hear your exhaust,NXS owners are a bit thin on the ground down here so don't get much oppotunity to compare cars/exhausts etc.

Ary, thanks for your input,

Olly ,I think your noise meter will be very popular at the next meet,I will be at Castlecombe in May,are there any earlier meets ?

Thanks for all replies,

Ian,

[Steveycaz]

Cool! I will be in Tiverton on weekend of 21st Feb! Anyone else around for an Exmoor cruise?