I have an ITR with fully built C1, tuned on S200, Greddy Profec B boost controller, wastegate with 7psi spring.

I just got it tuned, but it doesn't want to go to full boost (14 psi) most of the time, and when it does, it studders down then back to 14psi, never staying consistently at 14.
I'll hit full throttle, the turbo will spool up to 7psi and stay there until I get into high rpms, then it'll jump up to 14 and start studdering between 7 and 14.

I was adjusting my BOV the other day - I tightened it up, and the car would no longer go past 7psi. I loosened it and now it is back to the above state.

Any ideas?

 

did it not act this way during your tuning??

 

It acted that way during tuning as well. The tuner said maybe the vacuum lines on the boost controller were too small, or maybe the boost controller is busted. I'm not sure I believe that yet, especially since adjusting the BOV seemed to affect it.

 

Has anyone had a boost controller go bad (the solenoid)?

 

That should have nothing at all to do with your BOV. Try disconnecting your boost controller and see if it stays steady at 7psi. Also, check all your connections and hoses with your boost controller. Also, what boost controller are you using?

 

Yeah I know the BOV is totally independent of boost pressure build, but when I tightened it up, the pressure would not go above 7psi at all.
As stated above, I'm using an ancient Greddy Profec B controller.

I'm pretty sure the WG is acting properly, and if I disconnect the boost controller it'll stay at 7psi all day - I'll disconnect it though just to make sure.

 

Sorry, i must have missed the boost controller part. Anyways, you say when you take the boost controller out of the equation, it stays solid at 7psi which is what your spring is. But when the boost controller is hooked up it doesnt hold the proper pressure. Which would lead me to believe the boost controller is acting up or is bad. If youre sure you wanna run 14psi, just get a new spring for your wastegate and be done with it. That way you dont have to spend a ton of money on a new boost controller and its an easy, cheap way to fix and check it. New springs are like $30.

 

Yep it's tuned for 14psi.

I'm planning on getting some cam gears and doing a dyno tune in the spring, so it would be nice to have the flexibility of the boost controller. But whatever, if a $30 spring will fix it I'll just do that for now. Thanks for the suggestion. Where should I order a new spring from?

The boost controller would make a tick tick tick sound when I turn the key on first thing in the morning when my charge pipe was disconnected - I'm guessing that is the solenoid opening and closing really quickly, and leading me to believe that the pressure sensor in the controller isn't reading properly.

 

They sell a .9bar spring which is 13.05psi or a 1bar spring which is 14.7psi. But yeah, definately sounds like a problem with the boost controller.

http://www.full-race.com/catal...b7b5c

 

It ends up it was the BOV and not the boost controller after all.
I took apart the BOV and the rubber diaphragm inside wasn't seated properly between the top and bottom halves. I was hoping that it just wasn't put together right and I could seat it in properly.
I put it back together and the boost acted like it should - climbed right up to 14 psi no problem - for a while.

I took apart the BOV again and I'm assuming the diaphragm got unseated again because I put it back together and it seemed fixed for a while, then back to the old behavior.

So I'm looking for a cheap BOV or a way to fix that diaphragm from unseating. Any ideas?

 

Buy a good BOV so you never have to worry about this problem again. I reccomend getting a Tial. I guarentee you wont have any problems with that one.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">Buy a good BOV so you never have to worry about this problem again. I reccomend getting a Tial. I guarentee you wont have any problems with that one. </TD></TR></TABLE>

Sounds good to me. Can you provide some info so I know that the one I buy will fit the flange on my intake piping? My current BOV looks like the Greddy Type S.

 

I'm guessing I need to either get another Greddy BOV since Greddys seem to all use the same flange or get a different brand BOV and get the corresponding flange welded on. Is this correct?

 

Yes, if you got a Tial you would have to get a new flange welded on. I've had tial and greddy and I would definately never have any other bov after using the tial. Its a great piece of equipment for sure.

 

Well I ended up putting a new Greddy BOV on - I woulda got a Tial but the Greddy was available and simpler because of the flange...

Unfortunately it didn't fix my problem with not reaching full boost.

Another reason I got the new BOV is because I could hear my turbo fluttering when I took my foot off the gas. The new BOV didn't change a thing though. It seems like the BOV kicks in late - I'll close the throttle, I'll hear the turbo flutter a bit, then the bov will open up. Anyone know what would cause that?

 

I fixed the compressor surge - One of the Y fittings for the vacuum line from the intake manifold to the BOV had little brass 'reducers'(?) - plugs that have a tiny hole for the air to go through - that were limiting the air flow to the BOV - I'm assuming they were slowing the air from running through the hose... so I replaced the Y with a regular one.

Does anyone know what the Y fitting with the reduced holes is used for / why I'd need it?

 

Anyone?

I've replaced all my vacuum lines now. Ever since swapping the BOV and the Y fitting, I consistently only hit 7 psi even though I'm tuned for 14...

 

FIXED!!!!

Last night I pulled apart the boost controller solenoid box... inside it there was some carbon build up, so I pulled apart some of the rubber lines inside it, and low and behold, one of them was all clogged up with soot. I cleaned that out, put it back together, and bam! it's all good.