SiNi

Recently had a problem with actuation of sport exhaust on 991 C2S.

It seems to be stuck "mid-way" neither fully open or fully closed. With the engine off and ignition on, and switching either the exhaust button or Sport button on and off, I can hear mechanical actuation beneath the car so it's not an electrical problem. However, the exhaust note does not change with either switch and it sounds not quite fully closed or fully open.

Any ideas, thoughts, comments?

Viper3838

Pretty sure one of the vacuum hoses on your exhaust system came off. Soon your screen will show "cooling system error". For some reason Porsche really dropped the ball in this design. Hoses made just the right length, but actually too short because they tend to shrink with heat along with mickey mouse weak rubber hose connections causing the vacuum hoses to easily come off. Mine has come off in different spots so many times that I know how to reconnect them all myself. But I have to go back to dealer each time to reset the error code. In fact have to do again either today or tomorrow because the one at left the exhaust valve under the car came off last night and the error came on my screen. 4th time in 2 months. Thumbs down for porsche on this poor engineering!!!! Blah!!!

Viper3838

Btw, with a vacuum leak, the valves on the centre muffler stays naturally open (at least on my non pse anyways) and the exhaust gases always bypass the sides mufflers making the car louder.

terbiumactivated

+1 on a great point that is not limited to these hoses, some of Porsche's wiring seems awfully tight as well, I mean which bean counter determined that an extra eighth of an inch would break the bank?

SiNi

Makes sense - thanks.

Would explain why exhaust sounds loud even though switched off. Obviously will get dealer to check.

I would like to get a better understanding of how exactly PSE works. Probably already been posted somewhere here.

fbroen

"At least on my non pse anyway".

I'm confused, a non PSE has bypass valves?

Viper3838

Yes non pse also has bypass valves. But just a quieter set up overall and no pse button in cabin.

MerlinsGarage

Does "SPORT" mode enable the bypass valve on non-PSE?

kitwetzler

The base car does not have valves. The S has valves in the base exhaust.

Viper3838

Yes correct. 3.4 base cars do not have valves. 3.8 have valves.

E36325is

So if I were to order an aftermarket exhaust for the S, should I order the system with or without valve control?

Viper3838

Both will be fine. Depends on what you want and what is your budget. If you replace the center aftermarket muffler without valves, you will just simply plug the vacuum lines.

I have a slightly used fabspeed center muffler bypass xpipe available in Toronto. Pls pm me for details/price.

Dalema

Let's say you had a base 3.4L engine and installed a 3.8L S muffler. Does the 3.4L engine have a place for the vacuum lines to attached to? Ie could you get the valves to work in that config.

Viper3838

My guess is that it would probably take a lot effort and for a dealer to do....

rnl

No more than installing a pse on a base. If you are changing exhausts, just go with the pse. I did and I have enjoyed destabilizing tunnels, parking facilities and overpasses with the roar.

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