94tkt

well im gonna start off by listing my mods( intake, downpipe, cat back, smic, greddy pulleys, and midpipe)

i just installed my midpipe with a 2.25" restrictor plate to keep boost creep as a non issue. everything went fine, i didnt see any boost creep on the gauge just stayed at the same psi. now the primary turbo boosts really slowly till the seconday comes online then its like a bat out of hell. what would cause the primary to only boost up to 5-7 lbs when before it would be right at 12psi?

thank you

mike

DaveW

Sounds to me like the pre-control solenoid is stuck shut, or the precontrol actuator/gate is stuck open. That would give what you are describing.

Dave

94tkt

how would i find out if either of these are the issue? and what size pill sould be in the precontrol hose?

dgeesaman

iTrader: (7)

First, this is not boost creep. I also think a precontrol issue is less likely than a CRV, CCV, or TC issue.

In essence, these three valves keep the primary boost path sealed off up to 4500rpm. At 4500 they open completely to allow both secondary and primary to work together. Your case suggests that one of these is leaking during primary operation, which of course is a non-issue when the valves open up at 4500+.

I would start with looking for loose hoses, and failing that, the KOKO test, (http://www.fd3s.net/boost_test.html) and see 1) if you're getting good vacuum storage, 2) if your CCA and TCA cycle as they should.

Dave

94tkt

well i read the site and i am confused on how to do all these tests.. where are the hoses/valves that should be checked for leaks? i looked over my whole engine snd everything seems to be connected as it should

DaveW

Dave G, I agree that it's not creep.
And I would normally agree with you on the other points, except that 94tkt said that once the second turbo comes on, "it's like a bat out of hell" which indicated to me that the second turbo was excessively pre-spooled. Am I out to lunch?

Comments?

Dave W

dgeesaman

iTrader: (7)

Dunno. I figure if it's goes to a solid 12psi coming from 5-7psi, then it's going to feel like a bat out of hell regardless. I also figure the CRV, CCV, and TCA are much more problematic in general than the precontrol.

Dave (G)

dgeesaman

iTrader: (7)

Question 1: when you had your exhaust worked on, did you remove anything in the engine bay? (e.g. to pull the downpipe?)

Question 2: do you have a Mityvac? Have you compared what's under your hood with the standard vacuum hose diagram?

Dave

vtakk eg

what does boost creep have to do with this?
please dont put misinformed titles

94tkt

the only thing that was touched was the cat.. (nothing removed from engine bay or touched)

the air pump was eliminated but that was done by pettit ages ago and the tube coming from the oil filler neck to the turbo inlet was taken off and is now just atmospheric venting.

sorry for the mis representation of the thread.

94tkt

bump

dgeesaman

iTrader: (7)

Start by looking for leaking/cracked/loose vacuum hoses.

Then run the KOKO test in the link I specified.

Dave