GT3 997 Gen 2 Akrapovic system causing back pressure issues
Discussion
I have a GT3 997 gen 2 with a Full Titanium Akrapovic system on it.
Sound like a cup car, probably a little too loud, however what's annoying is that around 1,500 rpm is jerks/misfires a little and then again at around 3,500rpm.
I don't believe it's a misfire, bit instead a problem with the exhaust pressure. In short, not enough. I have asked the dealer to adjust perhaps the air filter or remap but they say said doesn't need it.
Any suggestions? Just a bit annoying. And And here is a little video or 2.
Sound like a cup car, probably a little too loud, however what's annoying is that around 1,500 rpm is jerks/misfires a little and then again at around 3,500rpm.
I don't believe it's a misfire, bit instead a problem with the exhaust pressure. In short, not enough. I have asked the dealer to adjust perhaps the air filter or remap but they say said doesn't need it.
Any suggestions? Just a bit annoying. And And here is a little video or 2.
- firstworldproblems
So, spoken to Franz Simon in the UAE who specialist in performace pipes.
For everyones info, below:
Apparently, all porsche's have the "Emissions" sensor on them, on the cat Converter. So, when you change the pipe sometime they recomve the sensor. For some, like the GT3 and Turbos's, GT2 etc, this has a dramtic effect as the car cant work out what the emissions are and therefore, the car tries to adjext the mixture....often causing the car to run rich. Hence the increased smoke on start up and then the "Juddering" at low revs.
So in short, if the cat part of the pipe has been disconnected then the car needs to be retuned to make up for the different back pressure and mixture, so its runs right and not too rich. There ya go then.
For everyones info, below:
Apparently, all porsche's have the "Emissions" sensor on them, on the cat Converter. So, when you change the pipe sometime they recomve the sensor. For some, like the GT3 and Turbos's, GT2 etc, this has a dramtic effect as the car cant work out what the emissions are and therefore, the car tries to adjext the mixture....often causing the car to run rich. Hence the increased smoke on start up and then the "Juddering" at low revs.
So in short, if the cat part of the pipe has been disconnected then the car needs to be retuned to make up for the different back pressure and mixture, so its runs right and not too rich. There ya go then.
So, as a final update for others who may come across a similar issue.
I took the car to Simon Motorsport in Dubai and had it tuned to fit the back pressure of the Full Akrapovic system, and get rid of the rough running around 3,500rpm and 5,500rpm.
Turns out that it was running rich and the attached Dyno sheet shows clearly the difference of Power (Engine) compared to before the tune. So all in all, the flat spots have now gone and power is up quite considerably. The standard BHP without the Akrapovic is I believe 335 BHP, after the exhaust and the correct tune its gone to 380BHP....gain of 45 BHP overall. This is the one before last tune, but you get the idea.
Driving wise, shedloads more torque around 3,500 rpm and also another kick in the ass around 5,500rpm. Sorry, the attached sheet shows speed in kms instead of RPM, I am waiting on the updated one with RPM to post. All in all, sounds awesome, loads of power. Job done.
Video here also: http://www.youtube.com/watch?v=doEh0ZSyeoE
I took the car to Simon Motorsport in Dubai and had it tuned to fit the back pressure of the Full Akrapovic system, and get rid of the rough running around 3,500rpm and 5,500rpm.
Turns out that it was running rich and the attached Dyno sheet shows clearly the difference of Power (Engine) compared to before the tune. So all in all, the flat spots have now gone and power is up quite considerably. The standard BHP without the Akrapovic is I believe 335 BHP, after the exhaust and the correct tune its gone to 380BHP....gain of 45 BHP overall. This is the one before last tune, but you get the idea.
Driving wise, shedloads more torque around 3,500 rpm and also another kick in the ass around 5,500rpm. Sorry, the attached sheet shows speed in kms instead of RPM, I am waiting on the updated one with RPM to post. All in all, sounds awesome, loads of power. Job done.
Video here also: http://www.youtube.com/watch?v=doEh0ZSyeoE
Randompunter74 said:
So, spoken to Franz Simon in the UAE who specialist in performace pipes.
For everyones info, below:
Apparently, all porsche's have the "Emissions" sensor on them, on the cat Converter. So, when you change the pipe sometime they recomve the sensor. For some, like the GT3 and Turbos's, GT2 etc, this has a dramtic effect as the car cant work out what the emissions are and therefore, the car tries to adjext the mixture....often causing the car to run rich. Hence the increased smoke on start up and then the "Juddering" at low revs.
So in short, if the cat part of the pipe has been disconnected then the car needs to be retuned to make up for the different back pressure and mixture, so its runs right and not too rich. There ya go then.
Would be nice if Akrapovic warned clients before, assuming they know.For everyones info, below:
Apparently, all porsche's have the "Emissions" sensor on them, on the cat Converter. So, when you change the pipe sometime they recomve the sensor. For some, like the GT3 and Turbos's, GT2 etc, this has a dramtic effect as the car cant work out what the emissions are and therefore, the car tries to adjext the mixture....often causing the car to run rich. Hence the increased smoke on start up and then the "Juddering" at low revs.
So in short, if the cat part of the pipe has been disconnected then the car needs to be retuned to make up for the different back pressure and mixture, so its runs right and not too rich. There ya go then.
hondansx said:
Cool. In fairness, if you replace a full system on ANY car, you'll need it mapped.
I completely agree with you. I have always thought that ever since I had a full devil system on my old R5 GT Turbo! : ) However just that a few Porsche "Specialists" here said ..naahhhhh, its fine. I disagree. Evident that unlike a back box, a full system makes it run really rough and in fact worse than stock. Seeing as the chap before spanked like £8,000 on this system I thought it would be worth keeping on....and besides, it sounds evil. So anyways, like a new car, love it.
Akrapovic would not be my first choice of exhaust though, were I to purchase one myself. They never even got back to me. Unacceptable had I been the actual one which parted with such serious wedge for one of their systems!
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