Woes with AA stage 2 turbo

[Dakine M3]

A little background; this kit was installed and tuned by Nick G over a year ago and has been virtually trouble and maintenance-free. It has 12k miles on a rebuilt 20g turbo. Never had a reason to post except for now.

I was on my way back to Miami from Toronto after driving 1300 miles stopping only to fuel and restroom duties. I started noticing what sounds like a louder than usual hissing when spooling up. I'm still able to attain 13 psi but noticeably less power according to butt dyno. Driveability is good with no signs of smoke, misfiring or hesitation upon WOT. I'm speculating that it's on the exhaust side of the turbo but it's not an exhaust leak.

I'm stumped at this point and was hoping for suggestions. Also is it possible to install a different turbo on the AA manifold without drastic pipe re-configuring? BTW this is longest non-stop drive I've done and it's soooo nice to be able to pass 99% of vehicles on the interstate with no worries. I'm sure you guys know what I mean.

Thanks in advance for your help.

[RRdawho?]

You sure your butt-dyno isn't just getting used to the power?

[slcook54]

Do you have a vacuum gauge?

[Dakine M3]

Seat of the pants dyno is calibrated and I'm certain it is ,ahem, slower.
Also, I do have a vacuum gauge which reads between -24 at idle and about -28 when in 5th gear off throttle at highway speeds.

I don't recall what the normal vacuum was prior to me noticing this problem. Could that be the problem?

[Shuasha]

Sounds to me like you could have a boost leak somewhere. The turbo is able to spool up more to compensate, but the air is hotter which is killing your power.

Do you still have a draw thru MAF? What were your LTFT's before and what are they now?

[DakarDave]

Sounds to me like you could have a boost leak somewhere. The turbo is able to spool up more to compensate, but the air is hotter which is killing your power.

Do you still have a draw thru MAF? What were your LTFT's before and what are they now?

When you check your LTFTs, check to see what your IATs are at speed and idle. They should be +20-30 degrees or so above ambient temps.

If you can do some data logging, you might want to log your timing... plot the timing over RPM, and see if you see the engine pull timing.

Good luck!

[paul e]

Seat of the pants dyno is calibrated and I'm certain it is ,ahem, slower.
Also, I do have a vacuum gauge which reads between -24 at idle and about -28 when in 5th gear off throttle at highway speeds.

I don't recall what the normal vacuum was prior to me noticing this problem. Could that be the problem?

That sounds like great vacuum... its about what I see on mine..

[Dakine M3]

I am going to Active tomorrow to see what the problem really is. Just wish I had more time and tools to deal with small sh*& like this. Thanks for the help fellas, much appreciated.

[ZimDoc]

Sounds to me like you could have a boost leak somewhere. The turbo is able to spool up more to compensate, but the air is hotter which is killing your power.

Do you still have a draw thru MAF? What were your LTFT's before and what are they now?

I think we have a WINNER!!!

That sounds like your problem 100%. Check all hose clamps, seeing that they do move, but slow. It will cause a hose to pop off under boost and boost only.