stltim1979

Hello everyone,

I have a .1 GT3 with Shark bypass. I recently had the coolant failure, causing me to get the engine dropped and the lined pinned. A couple other items while the engine was out.

At the risk of sounding dumber than I already am, it seems as though the exhaust note isn't quite as loud/throaty than prior. Also, upon cold start, the exhaust would spit/gurgle at idle which isn't the case now.

The tech did note that one of the bypass valves was stuck open. So perhaps the car is still as loud, but is just louder than normal at lower revs <4k. So when it hits that threshold, the change in sound isn't as noticeable.

Could this be it? Am I just a moron?

Have a good one

jonwb

I would check that your side muffler bypass valves are operating correctly. I made this video a while back showing them in action. [Edit / add] You can reach under the car in the corners and feel the actuators, and (with the car off) manipulate them by hand. They should flip back and forth freely [edit (again): they should spring return to the open position]



[Edit] A couple threads for more info:
https://rennlist.com/forums/997-gt2-...cte-valve.html
https://rennlist.com/forums/997-gt2-...ts-arrive.html

andrewgt3

I had an exhaust actuator fail. This thread may help.

stltim1979

Thanks guys, I will try to move them by hand tomorrow. Ill also email the tech and ask if this was the part he referred to while the engine was out. He didn't have the part, I wanted my car back, told him not to worry. My fault on that one if its indeed the issue. Thanks again.