AC

Hello everyone,

I currently have installed:
Manual Boost Controller
A/F Guage
APE Stage 2 chips without the jetted banjo bolt
Adjustable FPR set at stock level

At around 4-4.5K RPM range my boost drops off only to pick back up again above the 4.5 range. The boost hits hard when it comes back on.

This also occured before I changed my chipset out. It also occured when I had a LBE and a custom set of chips that came with my car.

Could it possibly be my wastegate failing. I thought the manual boost controller would keep correct that.

Anyhow, please give me some feedback if this sounds familiar to anyone. Thanks again for your help. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

adrial

4500rpm is the typical torque peak...

What is your a/f gauge showing before you lose boost, during and after you get it back?

If you try giving it less throttle, does it pull straight through?

AC

Thanks for the response.

Yes it will pull right through when I do not floor it. It is only when I push the accelerator to the floor that around 3500RPM, it acts as though it does not want the full boost to come on. When it is under heavy acceleration, the A/F Guage is floating in the mid-rich section. Under normal acceleration, the A/F light is just below the rich line. The other thing I have discovered, is the PO had Bosch Platnum +2's. They will be changed out to rule that possibility out. Do you have any suggestions for Spark Plugs other than the Bosch Super with the copper core? Also the MBC is set to stock to allow the APE 2 chips to run at 15psi of boost.

Thanks again for comments and suggestions.

adrial

Under part throttle, the a/f gauge should dither up and down...it should not hold steady.
At idle, it should dither way up and way down...
It should be grounded direct to the battery.

Also, the autothority chips themself do not raise boost...the jet in the banjo bolt which you do not have installed is what raises boost. So the MBC is whats giving you 15psi not the chips.

Luke has been having a similar problem, except he has a big turbo upgrade.

Definetely change out the platinum's...the best plug you can buy is a silver...they're pretty expensive though....around $10 a plug I think. I like coppers just fine.

Let us know how it is with the copper plugs...
15psi with autothority chips at stock fuel pressure shouldn't be a big deal at all...so I don't think there's a need to mess with the FPR...

Ski

...and check all your boots on your intercooler pipes. There have been a couple of post lately similar to same thing and it ended up being a boost leak - the culprit was the intercooler boot on the left side(mine and a couple of other people). I had the clamp tight but it got misaligned unerneath; the new silicone hose(s) on the intercooler clamps ended up being very close to the front header panel. Took all the new boots off cleaned them and reinstalled. No more cut out, hesitation, or miss. The left front was the only clamp that was misaligned so I'm pretty sure it was leaking.

AC

Thanks you guys. I tightened up all my vac lines. Checked and changed my spark plugs. They were dirty. Also turned down my fuel pressure a bit. A non-Porsche mech thought he knew what the hell he was doing. Had it running way to rich. I did one thing at a time to try and determine the root. First I tightened the hoses. Slight improvement. Second, cleaned spark plugs. Major improvement. No hesitation even at WOT. Then turned the fuel down to as a result of the what I found with the spark plugs. Now it pulls hard again just over 5K rpm. My goofy grin is back. Oh how I love these cars.

Now if I could only get some MORE power....

Thanks again for your help.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

AC

Well it started again. After almost giving up, I finally saw the problem. It was definitely, this time, a vacuum leak. There was a one inch slit in the reducer hose that leads from the intercooler to the throttle body. With the car running, I took the reducer hose and pressed to make the slit open and it made a hissing sound. Just to be sure before purchasing a new one, I took some super glue and ran it along the almost invisible slit. Then applied duct tape all the way around the reducer hose. Let marinate for 24 hours. Took it for a test drive the next day. Bam, no hesitation, no black smoke out the tail pipe. Just pure unadulterated punch. Thank you again for your suggestions they kept me looking in the right direction.

Armond <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />