GT3 997 Gen 2 Akrapovic system causing back pressure issues - Page 1 - 911/Carrera GT - PistonHeads UK

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. firstworldproblems http://m.youtube.com/watch?v=IyA1yM9GzT0

http://m.youtube.com/watch?v=HmgklHvqhi4

http://m.youtube.com/watch?v=aRdAF2kuxTo

Mother of God that sounds good, the exhaust that is, can't help on the misfire issue though I'm afraid.

I'd suggest talking to Akrapovic to see if it's a known issue.

I have a 997.2 RS and we had to have a remap to sort issues with the full Akrapovic, PARR sorted it, ecu sent to Germany, chap who writes the maps for Manthey.

Thanks lads. Good to know. Going to take it to Franz Simon here in Dubai. They said they they could remap it.

Tried Akrapovic, never replied, neither in the UAE or the Head Office. Lovely. Bearing in mind this unit was over 8,000 GBP, i find that very poor customer service.

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.

So they might have removed the lambda sensor? Some cars still run ok open loop. I guess the GT3 is not one of them.

I had a new exhaust fitted on my car recently from Kline Innovation. As part of the package i was sent, were Kat Decat pipes, these came with O2 Sensor bungs so the wires from the removed Kats would be connected there. I can't imagine Akrapovic would have neglected to do the same?

Thanks for all the feedback lads. Am going to Franz Simon in the morning. Will post pics and the resolution for other with with same issue. Cheers.

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

Cool. In fairness, if you replace a full system on ANY car, you'll need it mapped.

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.

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!

Callughan said: Would be nice if Akrapovic warned clients before, assuming they know. +1. Surely exhaust makers know this when developing the system and should clearly state he situation to buyers

hondansx said: Cool. In fairness, if you replace a full system on ANY car, you'll need it mapped. I think on Europipe you dont need to?