Got my new turbo and manifold on, I had a turbo b18c1 in my 89 si, changed to a new manifold, new turbo, new charge pipe, new bov. That's it. Now, the car falls out of boost around 7k to 7400. I'm doing low boost tuning at 10psi, so the datalog shows 10psi and around 7k it falls back down to manifold vacuum. Any suggestions? Spool time is normal, it pulls hard, then just dumps out of boost. Could the bov be doing this? wastegate possibly? I'm gonna try to eliminate something tonight.


Modified by Jared at 11:28 PM 8/25/2003

 

The BOV happy and healthy? Sounds like it may be opening itself + sticking against your will.

Damn cars.

 

Hmm I didn't think about that, it's a brand new Turbonetics Godzilla. Never seen one go bad but I'll pull the vacuum line off and see what happens.

 

bump for the afternoon crew.

 

did the new vac hose do the trick.

 

Nope, reseated all the orings on the bov, changed the vacuum line, retapped all the holes for the bov flange and resealed it, no change. I think the bov is just letting the boost out at high rpms. driving me nuts. I'm gonna try to borrow one tomorrow that is known good.

 

Yeah, I had a similar problem with a sissy Bosch unit. 3.5 psi, and no more, until I stomped on the POS and got a new one.

 

I hope it's not the bov, this is a Turbonetics Godzilla, almost a $300 bov.

 

ive never heard of it before, but could the Deltagate be causing this???
usually they SPIKE, but ya never know really...

 

I hope the deltagate isn't causing it. It's from the old setup and It's worked fine for the last two years, I don't see how changing manifolds and turbos could change how the deltagate works.

 

I swapped the bov for a known good one last night and that still didn't fix the problem. I can hear the exhaust note change quite a bit when this happens, but I'm not sure if this is due to the wastegate opening or due to my losing boost. I'm gonna pull the wastegate tonight and check it out, see if I see anything. I had someone tell me that the valve in the wg could start sticking if it sat for too long without use, this car has been apart for a month, I don't consider that too long. I'll also check out the source for the wastegate boost. I tried with and without the boost controller, but didn't change the boost source to the side port of the wastegate. I'll keep you guys updated as I find more.

 

It could be the deltagate. but best of luck to you

 

im using a Turbonetics Godzilla @ 30psi and had no problems. im not saying thats not it .

 

Well, tried a known good godzilla and i still had the problem, so i'm about 95% sure its the wastegate. gonna pull it tonight.

 

I changed the boost source to the wastegate with no effects. I'm pulling the wastegate tonight.

 

Just pulled the wastegate, didn't see anything obvious. Gonna disasseble it and check it out. If still nothing, I'll try to find a known good gate.
thanks,
Jared

 

I just pulled the gate and I think I've found my problem. I used shop air regulated to 15psi to pressurize the wastegate and simulate operating conditions. The seal around the valve stem where it goes up into the aluminum housing is leaking off pressure as fast as I could supply it. Anyone ever seen this before?
thanks,
Jared

 

New update. I tried a brand new 38mm tial gate, didn't fix the problem. Pressure tested the entire system, and found only one very small leak, fixed it, problem is still there. I'm stumped. Gonna reexamine my intake pipe tonight.

 

That is some wierd ****.

BTW, met a couple of your friends last night.

 

Well, I guess I've fixed it. Either my cheap air filter wasn't flowing enough, or the coupler between the filter and charger was collapsing, I ran it just now with no filter at all and it pulls all the way to redline except for a couple misfires that I solved with new spark plugs.
thanks for all the help,
Jared