Hello all. Just picked up a 2007 GT3! Love the car and am thinking of using it as a semi-daily driver for a while.

The car came with a center muffler bypass and an EVOMS “Heel/Toe” tune. I loved the raw sound but wondered if it was a bit much for daily driving. So, this past weekend, I put the stock exhaust back on the car. The stock exhaust is much more civilized, but it has a drone at about 2500 rpm. The sport button also does not seem to affect the tone at all; I can’t tell if it is in sport or normal from driving or listening.

Do all stock exhausts drone around 2500, or are my exhaust valves perhaps nonfunctional? Maybe the EVOMS tune switched them to always open? Am I supposed to notice a difference between sport and normal?

To be honest, with the drone at low revs, I think I prefer the center muffler bypass.

 

Are you sure it's the exhaust droning? From my experience, these GT3 motors seem to run rough in the 3k RPM range, and you get noticeable vibration that you can see in the rearview mirror shaking and any interior rattles you have really can be heard in this range. Perhaps the stock exhaust quieted everything else down, so in relation, now you're just noticing that motor vibration more. This roughness is even mentioned in the owner's manual.

 

It's possible the valves on your stock exhaust are no longer functional. It's been my experience that there is some slight droning between 2,500-3000 RPM if you keep the valves opened, whether intentionally or due to bad valves.

 

The valves close and open at different RPM's. Yours are probably stuck open al the time. My car with stock exhaust never droned.

 

Thanks! Do you think the valves just need replacing, or is it an ecu thing? Can you normally hear an audible difference in the exhaust note when the sport button is engaged/disengaged?

 

they're probably unplugged (full time) intentionally - I think most of us roll that way

 

I thought that, but they are plugged in, actually.

 

3k is where everything vibrates in this car. Has helped me diagnose and fix a few rattles. I have a feeling this is normal. Simple way to see if the valves are working - rev the motor with sport button on and off. You'll def hear a difference if the valves are working.

 

Check both the vacuum lines on the valves and the electronic connector on the right side of the engine.

 

Crawl on the ground to where you can see your vacuum actuators and have someone inside the toggle the 'sport' button on and off. At idle the valves will open and close just w/ the press of that button, like this:



When I got my car several years ago, I came to realize that a previous owner had plugged the line at the solenoid and that both my vacuum actuators needed replacement. Not a hard job to correct, just putzy... Enjoy your GT3...

 

you bought the white one from Nico?
Nice car. I actually drove it around Sebring for a session

 

when driving on the street or freeway I like to keep at it 4K rpm or above, no reason to lug this motor around, gas mileage is ****, but who cares

 

4k is perfect for this car. 2k is lugging, although can be ok for cruising with light throttle. 3-4k is when the engine harmonics are vibrating everything.

 

Bought a white one from a guy named Dave, here in Miami. Different car I guess, but definitely looking forward to a nice drive around Sebring at the next 48 hours, pandemic permitting.

 

This was very helpful, thank you. I will try it this weekend.