MBC how much PSI???

[Spudboy]

Originally Posted by mkiiisupra

I run into the fuel cut problem on stock boost with my current set up. TAking care of other problems before i address the FC one. Would suggest fixing the problem as in lexus AFM mod + 550cc injectors and a good tune rather than putting a FCD on it and turning up the boost

mkiiisupra...what is this 'divorced wastegate' you list in your mods?

I have the lexus AFM, took off my JC 550cc's because the performance shop who installed my AEM EMS and dyno tuned couldn't get them to work correct. He claims that the stock injectors are more than enough. My problem that he can't figure out for sure is my boost wont hold above 8 PSI. (modified turbo to 47 trim good to about 22 psi if I want to blow up my engine) He suggests a 3" downpipe may do the trick (I have stock still, but a big HKS drager cat-back over 3.5 inch diameter) but I'm not convinced. My feeling is the stock wastegate actuator I am running may be the culprit.
(I'm sure the downpipe and a good intercooler with hardpipes will be a great help but I'm not sure that's the root of this boost cut.)

Dyno'd at 252 hp and 318 lbs torgue at 4000 rpm when the turbo boost drops off, dropping HP and torgue a little before rising up again and leveling off at about 252 HP and 252 torgue around 5k through 6k rpm before slowly declining.

Any ideas?

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Current Engine Mods as of July 08

1) Metal HG with ARP studs
2) Turbo rebuild/upgrade by Majestic Turbo, TX to 48 trim.
3) K&N intake/filter
4) Flex-a-lite electric engine cooling fan
5) Lexus MAF (with stock Supra sensor)
6) HKS Super Drager Catback exhaust (95 mm or 3.75 inch piping)
7) Blitz SBC i-D (boost controller)
8) AEM EMS (Dyno tuned)