4Rings::G2 boosted::

Here's the situation, my G1 supercharger is loosing boost at WOT. Let me clarify this, I get full boost at part/most throttle but as soon as I push the pedal all the way to the floor the boost drops down by around 2 psi. It's like an on/off switch. As soon as I let up on the throttle slightly the boost is back. I know what you're thinking, vacuum leak. However it's always been like this, since the day I installed it. I've changed all the lines, added the intercooler, increased boost, disabled the variable manifold. It doesn't matter what I do, there is always the same drop. Also, it's not just my system, I know of another G1 with the same issue. Here's another kicker, as I get closer to redline the boost comes back. At 6k RPM I get full boost again, even at full throttle. So what's going on? I have two theories.

Could it be a programming difference? Could the G1 chip be programmed to open the additional intake valves at WOT at lower RPMs, causing a drop of pressure? Since boost is really a measure of restriction of the airflow I could see this happening.

Second theory has to do with the vacuum lines hooked up to the throttle body. In the G1 the whole intake is pressurized, so any systems connected to the tb will also get boost. If any of these systems have a vent valve that opens at WOT that would explain the pressure drop. Then as the RPMs increase the pressure lost due to a small leak like this would be less of an issue, so at WOT the boost would be mostly restored.

I've been racking my brain about this for a long time now, but my understanding of some of these systems is lacking. Any insight would be appreciated.

Tomasz

RKA

If the AF's are funky, and your intake system and fuel system is in order, it's probably the programming. Have you contacted PES about this?

4Rings::G2 boosted::

so my values are good all the way across. 14.7 at idle and around 12.5 at WOT all the way to redline.
This was happening when I was running just the G1 chip and is happening now that I'm running S3 MAF, 5 bar FPR, S4 injectors, intercooler, a higher boost s/c pulley and the piggy back to bring it all in line. None of these changes had any effect on this pressure drop.

fussball.biturbo

I really haven't studied the 30v engine enough to understand what might be going on yet, though. If there is WOT, boost is lower, but anything below WOT and it is higher, instantly

4Rings::G2 boosted::

Must be something in the way G1 works. I'm considering plugging up vacuum ports one at a time (those not vital to operation) and seeing if one of them is causing this.

fussball.biturbo

you mean ones not necessarily connected to the boost pipe? I guess you could alter the operation of the BOV, perhaps...

Yippers®

My WAG is teh same as yours .. there is something opening at WOT that closes at anything less than WOT. Otherwise I'd be at a loss to explain why a slight lift would restore boost.
I've not paid much attention to the 30V layout so I have no ideas where to look ... so I'd suggest you shoot Rob an email and ask him what he thinks ...

4Rings::G2 boosted::

Well, the emissions stuff for one. Everything except BPV and FPR really.