greggmorton

ajw45

Assuming stock PSE depending on weather I get about 91-93db, 103db should be a non issue.

greggmorton

johnsopa

Hmmm... At Laguna Seca in December, my paddock neighbor was running a bone-stock GT4. He failed the sound check twice that day and the posted limit was 90dBA but the sound tech gives you 1dbA extra. He had to feather the throttle going by the sound booth. So, that meant a stock GT4 was reading 91dBA, at least at Laguna on that particular day.

I have Cargraphics race headers and also Gert Carnewal's PSE remote control (I can choose always open and always closed) and I can tell you that it is beautifully loud from the outside. I guess I should meter it someday.

AJW45 -- are you saying your car meters at 91-93dBA with race headers and stock exhaust?

TM5

switchface

I was thinking of a similar setup as I wouldn't mind some Dundon headers, but was concerned as to how loud it would be on my daily commute. I wanted a way to control the stock PSE so that, if needed, I could keep the valves closed. Jamie said that we shouldn't keep the valves closed, especially at t WOT, as it will hurt the engine due to the gasses needing to flow. Granted, I wasn't planning on tooling around town at WOT with the valves closed all the time, just that if I give it some throttle on a section to accelerate away, I wanted to prevent the valves from auto-opening and unleashing that sound.

Is this essentially what you are doing with your Carnewal remote or are you simply using it to remain open all the time?

Jamie@dundonmotorsports

AJW45 also picked up a Quiet Muffler for his GT3 muffler conversion, not something to run all the time mind you as it does it's job pretty well and kills some of the fun, but a great solution for those that are trying to run tracks that are "unrealistic" for dB output on modern high horsepower cars...

ajw45

YMMV and every track is different but Tremblant has a DB limit of 92db and on the right day I can pass or fail, so I'm right on the limit with DMS race headers and PSE off. Peak I've hit there is 93.5db. I switched to a DMS quiet GT3 exhaust and it shaved like 1db off the stock PSE so I can still exceed the limit but it's close enough I don't have to lift or short shift before the sound meter. By comparison with DMS race headers, stock GT3rs exhaust and PSE on I hit 100db+ at AMP

ajw45

Hah, right, it's too good! I figure with the quiet muffler and turn aways I can beat the Limerock limit (89db?)....

Charliekay

Is this with DMS over axle pipes? Do you have any sound clips of the DMS quiet muffler? Do you run them all the time?

ajw45

I'm running the TPC kit but I imagine it's similar from sound perspective. No sound clips unfortunately since I don't run it all the time. You totally could run the quiet muffler and headers full time, the combination still isn't really quiet, I just prefer the sound of the louder angrier RS exhaust.

I've actually been running the GT4 akra for a while now and even though it cost me a few hp up top I'm really liking the sound with the race headers. It's somewhere in between the stock RS exhaust and the Dundon quiet exhaust....

KOTYKB

I have Dundon headers on my GT4 and I'm bummed I won't be able to go to Laguna with my buddies this year with my setup. Are there any silencers that I can stick in my muffler tips?

Charliekay

Did you ever run the Dundon headers with PSE? If so how does the sound of the quiet dundon muffler compare to the standard PSE?

This is the concern I have. We have 96db limit on some tracks here and I know race headers will get flagged but my current catted headers had never been flagged. If the Dundon race headers with quiet muffler goes back to catted headers sound level or there abouts then I will be safe.

I wonder if anyone has done any testing of different sound levels of different setups.

ajw45

Yup, was 1-2db louder with the stock PSE (PSE off)! They sound totally different so hard to compare but the quiet muffler is a touch quieter. You could add turndowns and shave off a little more and probably get under 90db with race headers...

Charliekay

We have 96db limits here so if you can get it close to 90db with turn down then 96db should be fine for race headers and quiet muffler.

Race headers and quiet muffler might be around the same as catted headers and PSE.

I guess there is only one way to really find out. ��