B5 s4 boost flutter under load.

[ChrisB5S4]

I received a cylinder 3 misfire, changed out that coil pack and its gotten somewhat better since the video.
Still breaking up at high rpm.

Im running a stage 3 kit with franken turbos on E85.

Could it be the spark plug gapping? What should the gap be?

Thanks for your help

[Corradovolksb]

It sounds like your DVs are opening and closing. What is your boost level before this started. Did it all of a sudden start? Plug gap with stock coils should be under .026 to avoid blowing out spark.

[Trb1]

Don't you love this? I've ran f21s for 35-40k miles since new and they've fluttered like this since the very first drive.

2 things:

1, wastegates Kinda suck. If you back them down to lower cracking pressure it can help. I'd suggest just throwing BW wastegates on your turbos.

2. It can be coding in the tune for requested pressure (your actual is greater than requested) at your throttle load. If your tune isn't finalized it might need to be tweaked. Look here: http://www.audizine.com/forum/showth...g-boost-issues

I have also seen suggestions of putting in stiffer DV springs if you run diverters with swappable srings.

[ChrisB5S4]

I just bought the car. Of course in the test rides it never did this.... The car runs great until its completely warmed up

[evilgti84]

I'm having the same problem when i installed my F21 turbo's as well. I haven't been able to fix mine yet either. is there a tuner out there that can fix this problem?

[Mille Bornes]

Mine got a lot better once I fixed my torn wg hose. sb_gli also revised my tune a bit and between those two things it barely ever does it now and even when it does it's hardly noticeable

[avant1987]

I have never really had that issue with my f21s. I experienced something close to that but it was a torn vacuum line. I also changed spark plugs from NGK plugs to Bosch side fires, and cleaned my forge diverter valves running the yellow springs which are the medium stiffness I believe. Since then I am running 20psi on 93 and the car pulls strong and smooth on a eurodyne base file. At 15psi you may want to lower your waste gate pressure or up your boost. Your max boost currently at 15psi is very close to what the FT wastegates are set to crack at out of the box which is 14psi.


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[RocksForsSale]

Weird that it's temperature related, I would look at that first.


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