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Discussion Starter #1
for some reason or another my boost isn't working very well.. I have the sbc id boost controller. I have it set at 14.5 .. when i take off the boost will spike up to about 14 then right back down to about 7psi and stays. If i shift and floor it then it will spike back up to about 14psi and go back down to 7. Whats going on here? Help please.

Thanks
 

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curt93T/T
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sounds like maybe a vacuum leak.
 

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Discussion Starter #3
thats what I was thinking. but I cant find it anywhere it could be leaking. hmmm
 

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The stock turbos can't hold that much PSI to redline.... that does sound a little low, but the boost will trail off even under the best circumstances.
 

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Got Boost?
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Ebaines said:
The stock turbos can't hold that much PSI to redline.... that does sound a little low, but the boost will trail off even under the best circumstances.
I hold almost 11psi to redline with my stock turbos. 7psi sounds about where his wastegates are openning. Something isn't right.
 

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Discussion Starter #6
if it does trail off it should at least stick with the 9.5 to red line like it did with out the boost controller??
 

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As I said, it does sound a little low :)
 

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Jays93VR4 said:
if it does trail off it should at least stick with the 9.5 to red line like it did with out the boost controller??
I would check your boost controller setup. There might be a problem, somewhere. Make sure you have the correct hoses tapped and that you blocked off your other hoses on the stock solenoid. Etc etc etc etc. Sounds like a setup problem.
 

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Discussion Starter #9
ok... i have looked over everything. back and forth but everything still seam to be right. I did retighten all the clamps again. I'm going to go out and test it and see what happens.
 

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2 of my GTOs have done the same thing with standard setup...
Cant remember exactly where it holds, but on my 93' GTO it would boost up to about 12PSI, then just keep dropping until redline....this is on a stock setup, just the mods in my sig

Now I just bought a 91' GTO and it boosts up to about 11-12PSI on standard setup and just keeps dropping .... holds about 7PSI as well.... only extra thing I have is a HKS SSBOV on this car...

I thought it was normal after having it happen on 2 cars....
how can you get the car to hold boost ???
 

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Wrenchmonkey #839
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Same thing is happening to me

I have the same problem I use a MBC and I used to be able to boost to 14PSI then dfrop down to 10psi to redline.

Went to dragstrip anf JeremyG with similar setup he turned 13.0 qtr mile times and I turn 14.5 times:(

I notice on my next run that my boost is maxing out at 10-12 psi then dropping down to 7psi to redline:(

My thought of possible causes.

1. BOV is leaking off boost, I borrowed JermyG's RFL blowoff valve and situation di not get better.

2. MBC has problem, not setup right or ball valve is seating properly. Plumbing is good becasue I used to work correcty
3. I have a leak in intake system, I plan on making a intake pressure testor soon to check.
4. My turbos are dying.
5. Wastgates are shot and opening too easily. never heard of this happenignt o anyone else
6. Something stupid I forgot, any ideas?
 

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Jay, you realy have 17G's on your car! COOL! Now are they in a T05 or T04 housing ? On the losing boost Question try thaking off your by-pass valve and blowing through. If it is like my stocker you can hear it leak both ways, also I wouldn't replace it with a stock one like i did it leked worse than my old one.
 

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You have 17g's and cant hold boost to redline?????

You obviously have a BIG problem.
Im guessing that you forgot to disconnect and cap off the lines from the stock solenoid.

Just pull both lines off the stock solenoid, and use a pencil or other round small rod and join those two together. I also put a small clamp on that joint as well.

Either that, or you have the IN/OUT on the double valve backwards.

My SBC-iD works awesome!

Just my .02

Bob.
 

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I HAVE THE SAME GODDAMN PROBLEM

I got my sbc id a few months ago and boosted to 11-12 and drop strait down to around 7, and its pissin me off. I made a leak tester, and found a few leaks, which i repaired, there is still one, but it is extremely small and cannot lose that much pressure that fast. Im waitin on my egr block off plates to come and maybe clear up a few small leaks, but i still dont think that is the main problem. Sadly, i cant check my car right now, its currently being painted and havin my new pitroad bumper and bomex spoiler installed :D :) :D , but, after i get my baby back, im gonna check the engine out. Im gonna try to get this leak prob fixed, and im gonna do a comp check and leak down test to see where i stand.



anyone know where i can get a leak down tester thas long enough to work for our cars?
 

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Super Suck Machine
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Re: Same thing is happening to me

John Monnin said:
I have the same problem I use a MBC and I used to be able to boost to 14PSI then dfrop down to 10psi to redline.

Went to dragstrip anf JeremyG with similar setup he turned 13.0 qtr mile times and I turn 14.5 times:(

I notice on my next run that my boost is maxing out at 10-12 psi then dropping down to 7psi to redline:(

My thought of possible causes.

1. BOV is leaking off boost, I borrowed JermyG's RFL blowoff valve and situation di not get better.

2. MBC has problem, not setup right or ball valve is seating properly. Plumbing is good becasue I used to work correcty
3. I have a leak in intake system, I plan on making a intake pressure testor soon to check.
4. My turbos are dying.
5. Wastgates are shot and opening too easily. never heard of this happenignt o anyone else
6. Something stupid I forgot, any ideas?
John, I had the same problem. When I first installed the MBC, I could peak at 15 then fall to 10-11psi. About 4 weeks later, I start peaking at 11 and falling to 8.

There are only so many places it could be leaking. Check all the hoses and intercooler pipes first. If those are ok, you may want to take off the Y-Pipe, for me the rubber gasket inside was mangled and had rolled back into the pipe causing a leak. Straightened everything out and I was back to 15psi peak and holding 11!!
 
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