Sports Exhaust (PSE) - Looking for some help...

[badbiddy]

Hi guys,

My new car has a PSE fitted and I don't know if this behaviour is normal (987.2)

1/ When exhaust is OFF (light is off, valves meant to be closed) they seem to open automatically at around 5k RPM (not exactly, more like 4750ish).
2/ When exhaust is ON (light is on, valves meant to be open) they seem to close around 20mph in any gear

Is there any way to defeat these two scenarios (assuming they're not faults?). When I want the car quiet, I want it to be quiet - even if straying into higher rpm - I find it hard to believe the 'long way round' in the Sports Exhaust is so restrictive it opens to prevent backpressure. And likewise, when exhaust is open (ie, on a sporty drive when you want it to be noisy) it is a bit annoying for it to go quiet briefly and then back to loud...

I'm sure it's solvable, I assume you can just disconnect power to whatever drives the vacuum for the valves for it to stay on all the time, but what if you want it to stay off all the time? Some sort of custom wiring to always deliver power to the valves? (assuming it can't be fixed with programming/something else)

Any help would be appreciated, even a clarification on whether the scenarios I've posted are expected?

Thanks,

Jeff

 

[malarcy]

Is it a factory PSE ( i.e. not an aftermarket valved system)?

My car has factory PSE (987.2) - mine behaves like this

Exhaust is vacuum driven, and the vacuum keeps the valves closed, so when you start the car - the vales are open for a few seconds.

In my case, if they are closed, they stay closed - but - the rev range you are talking about is when the flat 6 starts to "pick up" - I think thats where one of the stages of the variocam changes the valve timing - so, are you sure that the valves are opening rather than, the car is just making more noise and the intake noise and regular engine note is picking up? What happens if you turn the exhaust on at say 6000rpm, does the note change?

I have read that factory PSE on the 9x7 cars has a "feature" that closes the valves at "neighbourhood" speeds - I think somewhere around the 20 mph mark, up to just over 30 - and whilst I cant be sure I have ever noticed it on mine - there's a burble at lower speed and it's certainly makes itself obvious at motorway speeds ( if you toggle the switch when pressing on you can hear the difference), so that may be normal ( the light stays on). I have never actually confirmed this but have read it's coded into the DME - so other than a remap I don't know of a way to stop that behaviour.

 

[Twinfan]

I'm afraid I don't know specifics about the 987.2, but for 718s (and very likely 981s) the exhaust valves are opened at higher revs regardless of exhaust button status for air flow reasons. This is factory programmed. Similarly with low speed or low revs and the valves closing, I expect for noise testing purposes.

So I would think both those behaviours are correct and normal operation.

 

[badbiddy]

So turns out:

1/ behaviour is normal

2/ there are solutions that will fix it by deleting the Porsche button and replacing it with a fob (aka. http://www.carnewal.com/products/997;987;997GT3/p97084/PSE-Controller )

 

[MrDemon]

on a 987.2 just unplug it, it's ok valves open 100% of the time imo. The dfi lump was never loud any way. Or buy the controler, but the valves will still open on WOT other wise you would damage the engine,

 

[badbiddy]

on a 987.2 just unplug it, it's ok valves open 100% of the time imo. The dfi lump was never loud any way. Or buy the controler, but the valves will still open on WOT other wise you would damage the engine,

It would be much simpler if I agreed with you!

But I want to retain the ability to open close, and I'm a little concerned it might be too loud for quiet trackdays as it currently sits (race manifolds) so being able to close valves and be quiet is better than not being able to participate.

Edit: if you have any more info on your last point I'm all ears, I've never heard of people having engine damage running an exhaust with valves shut since that is exactly the point (especially on stuff like GT3RS that breaks sound limits on a lot of UK track days). You're routing the gas through a much more silenced section of exhaust, it's not like sticking a banana in the tailpipe while the car is running.

 

[Briggy]

Mine doesn't behave like that. When I switch it on, it stays on until I switch it off. When I switch it off, it stays off until I switch it on. RPM makes no difference.

The only thing I can think is that mine was OPC dealership fit, rather than factory fit, so they may have coded it differently.

Just to confirm, it's a genuine PSE.

 

[badbiddy]

Mine doesn't behave like that. When I switch it on, it stays on until I switch it off. When I switch it off, it stays off until I switch it on. RPM makes no difference.

The only thing I can think is that mine was OPC dealership fit, rather than factory fit, so they may have coded it differently.

Just to confirm, it's a genuine PSE.

Sigh.

So retrofit PSE is better than factory PSE

Thanks for the info mate, super helpful!

 

[MrDemon]

All porkers open the vales esp on track, you cannot close the valves and go fast ! that's not the point, the point is to pass EU noise regs regs at low revs and though town.

it's not about agreeing with me lol it's how the system works !

 

[badbiddy]

All porkers open the vales esp on track, you cannot close the valves and go fast ! that's not the point, the point is to pass EU noise regs regs at low revs and though town.

it's not about agreeing with me lol it's how the system works !

Sorry David my agreeing with you comment was to do with “valves open 100% of the time is fine” comment.

And unless Briggy is mistaken in his comment above it seems that you can have a “quiet” Porsche at high rpm.. I’ve emailed my local dealer to enquire- I would much prefer to keep the button working instead of falling back to using a Chinese garage door opener

 

[Briggy]

All porkers open the vales esp on track, you cannot close the valves and go fast ! that's not the point, the point is to pass EU noise regs regs at low revs and though town.

it's not about agreeing with me lol it's how the system works !

Sorry David my agreeing with you comment was to do with “valves open 100% of the time is fine” comment.

And unless Briggy is mistaken in his comment above it seems that you can have a “quiet” Porsche at high rpm.. I’ve emailed my local dealer to enquire- I would much prefer to keep the button working instead of falling back to using a Chinese garage door opener

I'm certain that I can have it on or off at low revs, via the switch. I'm not quite so certain about off at high revs, because I always switch it on as soon as I leave my street and turn onto the main road, then just leave it that way. I'll check.

 

[badbiddy]

All porkers open the vales esp on track, you cannot close the valves and go fast ! that's not the point, the point is to pass EU noise regs regs at low revs and though town.

it's not about agreeing with me lol it's how the system works !

Sorry David my agreeing with you comment was to do with “valves open 100% of the time is fine” comment.

And unless Briggy is mistaken in his comment above it seems that you can have a “quiet” Porsche at high rpm.. I’ve emailed my local dealer to enquire- I would much prefer to keep the button working instead of falling back to using a Chinese garage door opener

I'm certain that I can have it on or off at low revs, via the switch. I'm not quite so certain about off at high revs, because I always switch it on as soon as I leave my street and turn onto the main road, then just leave it that way. I'll check.

Oh Bryan I hope you haven't fallen foul of posting misinformation online

You can see how a Porsche noob like me might be a bit confused at this point!! But I've ordered a Carnewal exhaust controller - half tempted to just find a system that's quieter than the PSE to solve it that way.