Ok guys, I cleaned up a better video from my cell phone so you can hear the issue I am having (or maybe non issue). It happens when the turbo's are spooling up. Everything sounds fine when at full boost, it's just going from low boost to high boost. Sounds like a metallic ratcheting noise to me. Obviously something get's lost w/ a cellphone recording, but it's the best I could do given the circumstances. The engine on the car was out recently to fix a coolant leak (so pretty much everything was touched) at the same time I had exhaust put on (please note, I do not suspect that there is anything wrong w/ the exhaust at all). Do you guys here anything abnormal about 5 seconds in? Maybe some guys who already have exhaust can chime in if this noise is perfectly normal?

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The rattle at 5 seconds is not normal, you should hear a sweet turbo whistling sound instead.
Do you have 18 psi boost at full throttle with the sport chrono button activated?

 

Thanks for the reply Stef. Right now the car is at the dealership, who claims they dont hear anything abnormal. so i might eventually just have to take of work to help them hear it. I didnt check how well it held boost. I took the car straight back to the dealership and took the vid on the way. There is no funny noise if i rev in idle either. It seems very turbo related in regards to when i hear the noise, so my initial thought was boost leak, but it sounds pretty abrasive to me. Only other thing I can think of is maybe one of the new spark plugs is bad and its knocking under heavy boost at low rpms (not really sure what that would sound like though). I do not have any tune on the car. BTW I know I at least saw 17 boost with sc activated briefly. I am hoping someone on the forums might recognize the noise.

 

Ok thanks, keep us updated.

 

got the car back from the dealership and it is no longer making the noise. everything sounds great. i am calling this one an installation issue.

 

Did they tell you what they did to make the noise go away?

 

they did not. i think they just re tightened all of the connections. everything. Issue is gone so i am happy

 

All's well that ends well. Good luck as you spool that beast up.

 

I'm no Porsche expert...but that sound was most definitely cylinder pre-ignition/detonation.

I would try and find out why the engine was detonating and what the dealership did to fix it.

 

Agree - that's why I asked the question earlier. What was written on the repair order?

 

It sounds too low frequency to be the turbo in my opinion. I am guessing that at certain vibrations the exhaust is hitting something or there is a loose baffle somewhere. Hope it's nothing serious.

 

But it was fixed - see posts #5 & 7...just don't know what they fixed.

 

So far the issue doesn't seem to be recurring. I think (but I am not even 100% sure) I may have heard it a little bit during the first drive after I installed my tune as well (the car had never been tuned in the clip I uploaded, and I am not 100% sure I heard it either this second time). Assuming it is "pre-detonation", would the engine pull timing to correct the issue? Maybe I should do some durametric logging on it? Not sure what I could look for though. As of right now I don't hear anything out of the ordinary at all and it seems to be running great as far as I can tell.

 

Pre-ignition/detonation/knocking occurs when the air/gas mixture in your cylinger ignites before the spark plug actually fires. It could be caused by a combination of factors- high IAT's, too little fuel, too advanced timing etc. It sounds like a bunch of pebbles being rattled around in a metal coffee container.

Yes- your car will mitigate detonation by retarding the timing which results in a noticeable loss of power.

If your car was tuned, you've probably fixed the issue, but it never hurts to maybe log some hard runs and have your tuner assess them.

 

victory07. do you know if pre-ignition registers as a cylinder misfire using durametric? I did some runs and occasionally (not every time) I see a single misfire on a single cylinder, (seems to always be the same cylinder) last night the air temps dropped to about 67, so i would think it is running pretty cool actually. I am not sure if the misfire counter includes pre ignition, failed ignition, or both.

The plugs and coils were replaced about 800 miles ago, (the audio clip was with the new coils and plugs). One thing i cannot verify was the fuel at the time of the audio clip, since i had just gotten the car back from the dealer i dont know if they filled it up and with what or if the gas had been sitting for a while in the car.