I have this boost controller: http://www.summitracing.com/parts/TNT-10402-25
I'm running a 38mm wastegate with a 4 psi spring. The boost controller/wastegate are on their own separate vacuum source. Motor is stock F22B2 with 6300 rev limit.

I've installed it as per the instructions(see attached pic). The boost controller does work, and after some testing I've gotten my desired boost level out of it BUT it will not hold the boost at a steady level. Full spool, I'll get 10psi out of it initially(which is what I want) but the boost steadily falls off at higher RPMS(starting around 5k), all the way back down to about 6psi at redline. Prior to this(without MBC) it would hold boost fine on 2 different springs, no spiking.

I've checked for boost leaks, ensured that all fittings are tight, etc. Any ideas? I'm stumped.

 

What wastegate and manifold are you running?

 

eBay wastegate, log manifold. Other than the 4psi spring, I also ran a 12psi spring and it boosted just fine but I wasn't comfortable running that much boost on the stock MAP so I took it out.

 

EBay manifold to? I'd say that one of those 2 were your problems. Engine tuned?

 

Sure is.

 

if it wasnt doing it before with the same manifold and wg i doubt its the fact they are ebay. i hate ebay with a passion and would never buy from there, but thats besides the point.

how long are the vacuum lines and what size? if the vaucuum lines are really long and fairly large in diameter this could affect it.

you said you used two different springs before and didnt have the problem. im assuming one was 12psi but what size was the other?

 

Yeah I didn't want this to turn into another eBay bashing thread because it's beside the point, so I just disregarded it. It's kind of hard to screw up a cast manifold & the wastegate is actuating fine. The diaphragm has no tears/damage either. The car was tuned on 8psi on a different style of MBC, but I spiked 15psi on it and immediately junked it. The two springs were the ones mentioned 4psi and 12. I made the vacuum lines as short as possible(3 sections are about 10 inches, the other about 6), and they are the whatever size the boost controller came with, I couldn't give you specifics, but they're about the same diameter as a pencil.

 

you see ebay parts will make your car explode so.....

okay, maybe i won't bullshit you that much but you basically talked yourself right into the answer. you hooked it up right and are having problems...what could that possibly be? hmm

 

X2 what did you think would happen when you get a manifold and wastegate that costs less then the boost controller you bought

 

Hunted down a leak in one of the lines, problem solved. eBay haters - keep tryin hard to get accepted.

 

You said you checked for leaks in the first post so we figured that everything was right, that's why I said that

 

I checked all my couplings, etc. There was a small leak at the T where it goes to the boost controller.