997 GT3 track day silencers

[braddo]

Especially given that Brands Hatch is yet another track bringing in stricter noise limits, are there any GT3 owners here using bolt-on silencers to widen their choice of track days?

Searching through threads a while ago, someone linked to this:

http://www.actproducts.co.uk/product/si06-porsche-...

Does anyone here have one? What's it like and how effective is it?


My standard car was tested at a bit over 103db at Brands (aircon off, clutch in). I haven't tried the vacuum cap trick yet to get a lower static noise test reading. Anyone know how much difference it makes?

I really want to be able to do Brands Hatch GP!

[S1MMA]

Hi, I've done the vacuum pipe trick (Laguna seca mod as they call it in the states). Gets it down to about 101ish. I was also 103.6 static at Snetterton recently without Laguna seca mod.

From what I've been reading, the best and most cost effective thing we can do is fit downturned tips, this makes a good difference. Think some of the 911 racing cars have downturned tips.

There are a few products around, or a local place can weld these up for you I'm sure. Search for them.

[wtdoom]

I run turn downs on the RSR when I'm testing . Bad news is all non permanent exhaust noise solutionS(like down pipes )are illegal from next year apparently .

[S1MMA]

illegal for racing or track days?

If you get a GT3 end plate with turn downs welded on, and just bolt that up to the rear silencer, removing the standard black tips, won't that be a perm exhaust?

[v8ksn]

wtdoom said:

I bloody love that RSR of yours

Closest I have is a poster on my garage wall

[ttdan]

S1MMA said:

illegal for racing or track days?

If you get a GT3 end plate with turn downs welded on, and just bolt that up to the rear silencer, removing the standard black tips, won't that be a perm exhaust?

of course it would. Nonesense idea for trackdays, even racing why on earth not?

[braddo]

S1MMA said:

Hi, I've done the vacuum pipe trick (Laguna seca mod as they call it in the states). Gets it down to about 101ish. I was also 103.6 static at Snetterton recently without Laguna seca mod.

From what I've been reading, the best and most cost effective thing we can do is fit downturned tips, this makes a good difference. Think some of the 911 racing cars have downturned tips.

There are a few products around, or a local place can weld these up for you I'm sure. Search for them.

Thanks, that's useful stuff. I'd like to think if a 911 gets close to the 101 static limit at Brands that they'd show a little flexibility. At least that would get you on track...

I know a small fabricator not far from Brands so I might see what they quote for a pair of slip-on downturned tips.

[Cheburator mk2]

braddo said:

Thanks, that's useful stuff. I'd like to think if a 911 gets close to the 101 static limit at Brands that they'd show a little flexibility. At least that would get you on track...

I know a small fabricator not far from Brands so I might see what they quote for a pair of slip-on downturned tips.

Brands are evil when it comes to noise... They show zero leniency - I am about to modify some inserts from a Viper, so that my K400 can do Brands again....

[wtdoom]

v8ksn said:

I bloody love that RSR of yours

Closest I have is a poster on my garage wall

Thank you matey . I love her so much too , a dream really . The team looks at it as we are temporary custodians of her until we pass her on to the next custodian . It's a piece of history to me and I pinch myself every time I get in it . I promise you she will never be wrapped in cotton and imprisoned in a bubble . She will be raced and swap paint with gt40's etc regularly . If we are ever testing in the uk etc would be team RSD's pleasure to host you .

Here's a Twitter account for her if you are interested: https://mobile.twitter.com/brumos_rsr95 , Neil and rob will update it as he prepares her for her next race at Paul ricard in early October . Dino vids , testing vids etc . They will do the works , will be proper nerdy beardy st .

Edited by wtdoom on Thursday 26th May 20:25

[wtdoom]

S1MMA said:

illegal for racing or track days?

If you get a GT3 end plate with turn downs welded on, and just bolt that up to the rear silencer, removing the standard black tips, won't that be a perm exhaust?

Racing , track and test days . I was told / warned of this officially last time out at silver stone

I have no idea how your solution will be perceived sorry .

[hunter 66]

We ran a few 24 hrs at Silverstone in the RSR with just a small addition to the end of the exhaust with fins which you can alter to vary the DB s worked very well as never got black flagged in the night once unlike many others ...... cannot remember the name but we we got down to 98 Db static from 108 ............and maxed at 96 db drive by all night

[braddo]

wtdoom said:

Thank you matey . I love her so much too , a dream really . The team looks at it as we are temporary custodians of her until we pass her on to the next custodian . It's a piece of history to me and I pinch myself every time I get in it . I promise you she will never be wrapped in cotton and imprisoned in a bubble . She will be raced and swap paint with gt40's etc regularly . If we are ever testing in the uk etc would be team RSD's pleasure to host you .

Here's a Twitter account for her if you are interested: https://mobile.twitter.com/brumos_rsr95 , Neil and rob will update it as he prepares her for her next race at Paul ricard in early October . Dino vids , testing vids etc . They will do the works , will be proper nerdy beardy st .

Dammit, I really didn't think there was ever going to be a reason good enough for me to get onto Twitter, but...

Amazing how small the 'prototypes' are - imagine a 991 RS in the photo near your car.

[Steve Rance]

wtdoom said:

Thank you matey . I love her so much too , a dream really . The team looks at it as we are temporary custodians of her until we pass her on to the next custodian . It's a piece of history to me and I pinch myself every time I get in it . I promise you she will never be wrapped in cotton and imprisoned in a bubble . She will be raced and swap paint with gt40's etc regularly . If we are ever testing in the uk etc would be team RSD's pleasure to host you .

Here's a Twitter account for her if you are interested: https://mobile.twitter.com/brumos_rsr95 , Neil and rob will update it as he prepares her for her next race at Paul ricard in early October . Dino vids , testing vids etc . They will do the works , will be proper nerdy beardy st .

Edited by wtdoom on Thursday 26th May 20:25

I think that I've seen the leading black Chevron at Silverstone. Very quick indeed. Shockingly quick

Sorry for drifting off topic chaps..

Edited by Steve Rance on Friday 27th May 06:39

[Trev450]

hunter 66 said:

We ran a few 24 hrs at Silverstone in the RSR with just a small addition to the end of the exhaust with fins which you can alter to vary the DB s worked very well as never got black flagged in the night once unlike many others ...... cannot remember the name but we we got down to 98 Db static from 108 ............and maxed at 96 db drive by all night

I think what you are refering to are called Super Traps. Very efficient but quite costly from what I remember when I used them a few years back.

[ttdan]

These are worth a look. Knocked about 4 to 5 db off a GT3 with an x pipe fitted, so 110 ish to 105 ish. When used on a standard rear box with the vacuum mod it was ~100 at Goodwood static.

http://www.decibeldevil.co.uk/

[hunter 66]

No Trev they were just small fins that into the tail pipe and by flexing a vane you reduced the noise but I guess increased the back pressure and needed fine tuning ........
They came around to everyone who failed noise tests at the 24 Britcar events ....... was brilliant though

[braddo]

ttdan said:

These are worth a look. Knocked about 4 to 5 db off a GT3 with an x pipe fitted, so 110 ish to 105 ish. When used on a standard rear box with the vacuum mod it was ~100 at Goodwood static.

http://www.decibeldevil.co.uk/

Do they fit straight out of the box?

[ttdan]

braddo said:

ttdan said:

These are worth a look. Knocked about 4 to 5 db off a GT3 with an x pipe fitted, so 110 ish to 105 ish. When used on a standard rear box with the vacuum mod it was ~100 at Goodwood static.

http://www.decibeldevil.co.uk/

Do they fit straight out of the box?

Yes and no. Yes they will fit the tailpipes (you will need two dd's obviously) mine were modded slightly for the x pipe so that they fiited a bit further into the pipe.

[nxi20]

braddo said:

Especially given that Brands Hatch is yet another track bringing in stricter noise limits, are there any GT3 owners here using bolt-on silencers to widen their choice of track days?

Searching through threads a while ago, someone linked to this:

http://www.actproducts.co.uk/product/si06-porsche-...

Does anyone here have one? What's it like and how effective is it?

I've been using these on my 996 GT3 track car for a couple of years now. They work extremely well and are a quality product; I've not had any trouble getting on at Brands GP (101dB) or Castle Combe (100dB). I can do Donington 98dB days with no bother too. I was using Decibel Devils before but found they were restricting the upper rev range & didn't really cut the noise by all that much. My exhaust is an M+M Cup exhaust with side cans & a centre exit; "naked" it measures around 110dB at 6K rpm on the static test. Unfortunately(), my Syvecs ECU map doesn't allow the engine to rev over 4200rpm when the car is stationary (launch control, don't you know ) so the testers have to measure at that; it's generally 99dB with the cans on. They always say they'll monitor me on drive-by but I've never tripped the meter at any UK track or been told that I can't use the cans. I think circuits appreciate it when you are obviously making an effort to comply.

At Silverstone & Spa I don't need the cans with a 103dB driveby. I take the cans to Zandvoort as I have once tripped the driveby there but don't fit them unless required.

ETA: I believe that the 991 GT3 also limits the revs when stationary, no doubt to allow them to pass ever-restrictive static noise limits which seem to have little relevance to driveby noise.

Edited by nxi20 on Friday 27th May 19:01

[Fl0pp3r]

nxi20 said:

braddo said:

Especially given that Brands Hatch is yet another track bringing in stricter noise limits, are there any GT3 owners here using bolt-on silencers to widen their choice of track days?

Searching through threads a while ago, someone linked to this:

http://www.actproducts.co.uk/product/si06-porsche-...

Does anyone here have one? What's it like and how effective is it?

I've been using these on my 996 GT3 track car for a couple of years now. They work extremely well and are a quality product; I've not had any trouble getting on at Brands GP (101dB) or Castle Combe (100dB). I can do Donington 98dB days with no bother too. I was using Decibel Devils before but found they were restricting the upper rev range & didn't really cut the noise by all that much. My exhaust is an M+M Cup exhaust with side cans & a centre exit; "naked" it measures around 110dB at 6K rpm on the static test. Unfortunately(), my Syvecs ECU map doesn't allow the engine to rev over 4200rpm when the car is stationary (launch control, don't you know ) so the testers have to measure at that; it's generally 99dB with the cans on. They always say they'll monitor me on drive-by but I've never tripped the meter at any UK track or been told that I can't use the cans. I think circuits appreciate it when you are obviously making an effort to comply.

At Silverstone & Spa I don't need the cans with a 103dB driveby. I take the cans to Zandvoort as I have once tripped the driveby there but don't fit them unless required.

ETA: I believe that the 991 GT3 also limits the revs when stationary, no doubt to allow them to pass ever-restrictive static noise limits which seem to have little relevance to driveby noise

Cheers for sharing mate - am looking for a suitable solution for the 7.2 GT3 post Sharkworks bypass treatment! :-@