GT4 - does it pass the track noise test?

[Stephen Walker]

Hello.

On a recent trackday at Goodwood, with GRRC I was told that the GT4 typically struggles with noise levels.

My concern is I am booked into Snetterton on a PCGB trackday, in a couple of weeks, which is 105db and I plan to take my GT4 - which is factory standard.

Does anyone have any first hand experience on whether the GT4 will pass the 105dB noise test?

The other option I have is to take my 991.2 GTS - again, has anyone any experience on passing noise tests with this model (I am assuming it'll pass no problem).

Any first hand knowledge feedback on the above would be greatly appreciated.

SW

 

[Steve Brookes]

105 db is a static noise test. Oulton Park operate the same test and all GT4s passed the noise test that day. However, noise testing can be inconsistent as some tracks ask for more RPM than others. In theory it should 3/4 of max RPM and the meter held at 0.5 M from the exhaust.

To be sure...do not put the sport exhaust on and press the clutch down while revving to the required RPM.

 

[crafty72]

I saw a GT4 being driven at Snetterton about a year ago, as far as I understand it the 2 tricky places for noise these days are Goodwood and Brands, even though they are also 105db static I think the drive by is the issue at Brands, not sure about Goodwood.

 

[Stephen Walker]

Many thanks for the feedback and tips.

I too heard Brands was difficult with noise and it was at Goodwood that the guys testing mentioned previous issues with GT4's. At Goodwood I was in a 458 Italia and I got black flagged on a drive by, so I suspect the drive by metering there catches GT4's too.

Nice to know crafty72 has eyeballed a GT4 at Snetterton - GT4 it is on the 27th then[]

 

[ChrisW]

Yes, so far !!

I would suggest also having the engine nice and warm, as Steve suggests dipping the clutch, and build the revs up slowly ... cheating is allowed !

 

[gmcraib]

Just hold back a bit with the rev's. 3/4 of max is fairly subjective, make it as subjective as possible!

3/4 of say 6000rpm is 4500..... Just aim for 3-4 ish she'll be a'right!

I got black flagged at Donnington in my 987S (with a Carnewal exhaust) a few years ago, they allowed me to fit exhaust baffles and carry on. But I sussed where the microphone was and short shifted/relaxed throttle when passing.

 

[Chris_James]

I recently did Castle Coombe, quiet day, and passed test easily - 97db at 4500. Engine warm, clutch in and Sports Exhaust OFF. No problems on the day either with drive by and CC are very strict.

Chris

 

[ChrisW]

At Oulton 5500rpm engine cool, clutch dipped, read 103dB

Yesterday at Cadwell Park, engine at normal operating temperature (I had just arrived) ... clutch dipped at 5300 rpm, read 99dB.

I have only had noise issues at Zandvoort (evening trackday) and Zolder ... who try to be scientific and then take no account of the cumulative effect of multiple cars passing the noise meter, so they black flag the car nearest to the meter.

I haven't been to Bedford or Brands or Goodwood in the GT4 (they are mentioned as being potentially strict) ... but a Porsche Club 105dB day at Snetterton will I am sure be fine ....

 

[ChrisW]

P.S> The sports exhaust valve opens itself when the car thinks it should ... even if switched off. (I never turn mine on ...).

 

[Steve Brookes]

There was a GT4 at Spa this week that has been fitted with race cats. Is sounded lovely at full chat. Great for Spa but I think would get black flagged at any UK track!

 

[ChrisW]

I always thought that Spa was 107 dB ??

 

[Steve Brookes]

I always thought that Spa was 107 dB ??

Still is Chris. The GT4 with the modified cats had no problems with noise limits at Spa. I was just saying that it would fail at other tracks (like Oulton) as it sounded louder than a standard GT4.

 

[ChrisW]

Thanks Steve, If I start failing noise checks I will not be happy

But I believe Jens knows what he is talking about ... and I will have all the original bits ...

My old N-GT had cat bypass, primary exhaust bypass, secondary silencer and Wills Tip ... and came in just at 105dB.

We shall have to see ....

With the new particulate filters I'd guess that P are doing a lot of work on ways to maintain power whilst managing noise levels ... ??

 

[ralphmusic]

Moving to a 200 cell cat manifold will increase noise plus I believe the flaps open under load conditions whether Sports On/Off so overriding that or having no flap system will reduce noise.

 

[ChrisW]

Yes the flaps open at certain revs even with the exhaust in quiet mode.

The 62.5mm diameter exhaust without flaps should according to Jens be quieter than the standard exhaust ... with the stage 3 mods ...

 

[Luffy_GT]

There was a GT4 at Spa this week that has been fitted with race cats. Is sounded lovely at full chat. Great for Spa but I think would get black flagged at any UK track!

And what a day it was Steve. Great to meet you and all the Porsche's looked and sounded fantastic.

It's good to know my GT4 won't be too much of a nuisance with noise tests

Ben