997 GT3 Bedford noise level chat

[S1MMA]

There have been a few threads on GT3 noise levels on track, just wanted to share my experience at Bedford with and without the Laguna Seca mod. Car is a 2007 MY 997.1 GT3, track config was Bedford Sen.

Was a cold day, about 2 degrees at sign on. Static noise test was done without Laguna seca mod and registered 100.6db (limit was 101). I tested with clutch down and aircon off. I think this was low possibly due to low ambient temps.

On track I initially went out with sport off, no Laguna seca mod. I was up shifting slightly early on the main straight, had no problems initially. After a few sessions, I started to redline on the straights and then I got black flagged for noise, set off the drive by mic.

So I returned to pit and installed the vacuum bung, went back on track and had no problems for the rest of the day. Car did feel down on power though, it was noticeable. One of the guys in the States has dyno'd with and without Laguna Seca mod and the car does lose a hefty chunk of mid range torque (17.2 lb/ft), enough to notice.

So either change up early with sport off or use the vacuum bung and Bedford and hopefully you should be fine.

Details of the mod here for those that haven't heard of it (dyno at bottom of page): http://sharkwerks.com/porsche/technical-articles/1...

HTH

[Mario149]

My 997.1 GT3 with a standard exhaust won't pass a static noise test at Bedford. I tried with sport off, warm engine, weather a bit damp with outside temp of about 8 degs. Tried later in the day when it had warmed and dried, still no joy. It requires a sympathetic tester to get it on track. Once there it's fine and drive by limits are no problem.

[arcamalpha]

In my experience the drive-by is never a problem, just the static test. So no reason to disable sport mode once on the track.

Passing (or getting a waiver) for the static test is always a nuisance though.

[S1MMA]

anonymous said:

[redacted]

I was able to notice it, it's not massive but it is there, especially when passing other cars coming out of slower corners where the revs build from lower down the rev range, the GT3 definitely struggled more than I remember passing M3s and the like.

[S1MMA]

Mario149 said:

My 997.1 GT3 with a standard exhaust won't pass a static noise test at Bedford. I tried with sport off, warm engine, weather a bit damp with outside temp of about 8 degs. Tried later in the day when it had warmed and dried, still no joy. It requires a sympathetic tester to get it on track. Once there it's fine and drive by limits are no problem.

What did your car register on the static test?

[Mario149]

S1MMA said:

Mario149 said:

My 997.1 GT3 with a standard exhaust won't pass a static noise test at Bedford. I tried with sport off, warm engine, weather a bit damp with outside temp of about 8 degs. Tried later in the day when it had warmed and dried, still no joy. It requires a sympathetic tester to get it on track. Once there it's fine and drive by limits are no problem.

What did your car register on the static test?

About 1dB over, say 102 or so

[cook3471]

I would have no chance then with a nice shinney brand new full akropovic

[Tex]

I've been to Bedford with my 997.1 GT3 a few times, mostly its a battle to get through the static test. Having said that I was there on Saturday and passed with no issues. Prior to that they have helped out by testing slightly off centre. I do carry my Decibel Devils just in case but have never needed them.

On drive by I tend to get a warning every visit. My usual tactic when passing a meter is to upshift early and be on the opposite side of the track to the meter. However, I still get caught out if I am close to another car.

So basically a PITA...

Hopefully Oulton on Friday will be a bit easier.

[Cunno]

S1MMA said:

There have been a few threads on GT3 noise levels on track, just wanted to share my experience at Bedford with and without the Laguna Seca mod. Car is a 2007 MY 997.1 GT3, track config was Bedford Sen.

Was a cold day, about 2 degrees at sign on. Static noise test was done without Laguna seca mod and registered 100.6db (limit was 101). I tested with clutch down and aircon off. I think this was low possibly due to low ambient temps.

On track I initially went out with sport off, no Laguna seca mod. I was up shifting slightly early on the main straight, had no problems initially. After a few sessions, I started to redline on the straights and then I got black flagged for noise, set off the drive by mic.

So I returned to pit and installed the vacuum bung, went back on track and had no problems for the rest of the day. Car did feel down on power though, it was noticeable. One of the guys in the States has dyno'd with and without Laguna Seca mod and the car does lose a hefty chunk of mid range torque (17.2 lb/ft), enough to notice.

So either change up early with sport off or use the vacuum bung and Bedford and hopefully you should be fine.

Details of the mod here for those that haven't heard of it (dyno at bottom of page): http://sharkwerks.com/porsche/technical-articles/1...

HTH

Be careful with the vacum pipe trick. I used this to get passed noise issues at Donny once. By the end of the day the left bank header had split the weld behind the cat. Doing this retains a lot more heat in the system.