Hi,

Before modifying my car i was experiencing a 10-8-10 boost pattern in 3rd at wide open throttle. Now in 3rd WOT I am seeing 12-7-9 boost. Here are my modifications:

modified stock air box
mazda competition 2.5" downpipe
Greddy Power Extreme Catback
Pettit ECU
Holley carb jet #72 in wastegate line
Koyo Radiator

I have been reading other threads suggesting checking the vaccuum level in the vacuum tank and a check valve that is a possible culprit, could these be causing this pattern?, if so where do i find them in the shop manual?
Also, is this pattern a problem or is this typical following modifications, do i require something like the apexi AVCR to smooth out the boost curve? I would like to get rid of the dip at transition and run equal amounts on booth turbos, 11-11-11 if possible, please help!

Thanks,

Andrew Wojteczko
93 RX7 R1
87 944 Turbo
99 Civic DX H/B

 

I spoke with pettit in regards to this, they said to put a smaller waste gate pill in to increase boost on the secondary and to adjust out a rod to reduce boost on the primary.
Where is this rod, how do i adjust it, and will this fix my problem? please help.

Thanks again,

Andrew Wojteczko

 

Not sure on the pill numbers.... what about your Pre-control line? You might want to check for the pill in that. You could always go back to the stock pill. You sure you didn't touch any vacuum lines while doing those mods?

 

What in the world is a carb jet doing in the wastegate line?????

 

carb jets are commonly used in the wastegate line to replace the stock pill with a larger orifice once air flow mods have been performed to control boost levels. The stock pill equates to a 65 hole size i believe, by placing a 72 in it allows more boost to be dumped through the wastegate effectively reducing boost. With the stock pill I was seeing 14lbs of boost on the secondary which i feel is too much.

 

Sounds to me like a boost leak. You should do a real good search for leaks. I would bet $20 on a boost leak.

 

Maybe I have owned 3 messed up FDs, and maybe all the FDs I've worked on that weren't mine were problematic as well, but a 12-7-9 sounds to me close enough to a 12-8-10 that everything sounds perfectly fine with increased air flow from a "modified" intake, downpipe, and ecu. I would leave the car alone, it sounds like everything is fine, unless you are getting some bad surging. And NEVER adjust the actuator rod lengths to control boost, you're throwing another variable in a turbo system with plenty of variables already. I suggest if you plan on modding the car any more, ie intake, midpipe, IC, to get rid of that pettit ecu and pick up a power fc on the way... All of this is from personal experience, so take it for what it's worth. Good luck.

Richard

 

Interesting point. I'm not sure how many people will want to buy into it, but interesting nevertheless.

In regards to pills in the lines. I have the Team HD boost control valves, and even the slightest change (16th turn) on either valve causes a notable change. Popping in pills back and forth would be the last thing I would want to do to try an equal out my boost.

 

Did the home Depot boost controller as per Rob Robinette's sight. Went out and adjusted it up and am now getting 10-9-11 in 3rd gear, pretty happy with that, just figured i'd let everyone know that this worked for me.

Andrew Wojteczko