Cant run more than 15psi of boost.....WHY? (FIXED)

[Lee]

I'm wanting to run about 18-20 psi of boost on my car & cant seem to make any more than 15psi.
The boost builds up very fast, and holds a steady 15psi till red-line.
But I want to run more & I cant for some reason.

I have even taken off the wastegate line & STILL no more than 15 !!!
I have just had a full forged APC rebuild and I had this problem before the engine got done.
What could it be?

Might it be the fact that I'm still running the stock cast dump pipe, But then have a full 3" mandrel bent. (With 3.5" Magic CAT)
I have tested the wastegate & seems to work fine.
Just doesn't make sence to me, even with NO wastegate control I get 15psi and no more.

 

[yelevo]

no boost

I have the same problem but I get 0.8 bar max. Have checked everything now suspecting that the cast dump is cracked around the wastegate flapper wheel. Will get around to removing it soon.

 

[brisvr4]

Have you tried doing a boost leak test yet?
That would be my first port of call, cracks in the exhaust housing would have to be pretty bad before they cause too much bother.

Mine is cracked pretty bad and still gives me 23psi when I want it.

Tim

 

[Lee]

Humm, If the exhaust housing was cracked would it make a tractor noise? like a exhuast leak, and would it affect the boost responce?
I still have awesome boost spool-up.

 

[Benny]

Drop your exhaust from the dump back and try again with the wastegate disconnected... but be VERY careful...

I'm suspecting a blocked exhaust, most likely at the cat unless its a straight pipe?

 

[WyDa]

My old turbo had this problem, but it would be pushing it to make about 12psi and wouldnt come on boost til abou t 4000 rpm with a 14b. My wastegate flap and the exhaust housing were cracked...

first place i would be looking, short of intercooler piping.

 

[3zercrowd]

Hey Lee.

Have you checked all of the vac lines to and from the factory BCS (Boost Control Solenoid)??

What manual boost controller have you got fitted now, if any? Factory still? Turbosmart?

Have you chucked on that TURBOTECH yet?

Is the wastegate actuator rod bent?

Is the wastegate actuator diaphragm damaged/dented?

Are the exhaust manifold bolts tight? Especially the 2 end bolts!

Are the 4 exhaust bolts holding the turbo tight?

What about the 4 dump pipe bolts?

Lots of things to check! Not forgetting the intercooler piping as before mentioned :wink:

Again....Feel free to drop around to my place and pick Dave/Josh and Jason's brains and use my garage

Feel free to look at my engine bay to see how i hooked up my Turbotech boost controller too :wink:

Hope you got your window winder sorted or at least temporarely fixed

 

[Lee]

Hey Lee.

Have you checked all of the vac lines to and from the factory BCS (Boost Control Solenoid)??

What manual boost controller have you got fitted now, if any? Factory still? Turbosmart?

Have you chucked on that TURBOTECH yet?

Is the wastegate actuator rod bent?

Is the wastegate actuator diaphragm damaged/dented?

Are the exhaust manifold bolts tight? Especially the 2 end bolts!

Are the 4 exhaust bolts holding the turbo tight?

What about the 4 dump pipe bolts?

Lots of things to check! Not forgetting the intercooler piping as before mentioned :wink:

Again....Feel free to drop around to my place and pick Dave/Josh and Jason's brains and use my garage

Feel free to look at my engine bay to see how i hooked up my Turbotech boost controller too :wink:

Hope you got your window winder sorted or at least temporarely fixed

Yeah I have checked ALL of them, APC had just re-done all of them any way on the new engine.
I dont think it's the wastegate cause even when it's not connected it still runs 15 & spools up VERY fast all most instant!
I can also turn the boost back down to stock setting of 8-9 with the controler.
Getting a new window motor fixed tomorrow. :wink:

 

[youda]

is it possible there is a boost control solonoid somewhere in the enginebay running off the computer?

 

[3zercrowd]

is it possible there is a boost control solonoid somewhere in the enginebay running off the computer?

As above

Hey Lee.

Have you checked all of the vac lines to and from the factory BCS (Boost Control Solenoid)??

:wink:

 

[blackvr]

If you are running the stock BOV, it is quite common for them to push open, and therefor leak and bypass boost under hi boost conditions. Try removing the BOV and blanking the holes ( welch plugs), or it was common for the rally guys to reverse the BOV.

 

[Lee]

Yeah I am running the stock BOV, might give it a try.

 

[Lee]

If you are running the stock BOV, it is quite common for them to push open, and therefor leak and bypass boost under hi boost conditions. Try removing the BOV and blanking the holes ( welch plugs), or it was common for the rally guys to reverse the BOV.

Your a Champ!!!!! :smt023
I reversed the Factory BOV & the boost went up.
So I went & got a aftermarket BOV, Now running sweet!!
Thanks for the reply's.
Cant wait to hit the drag strip now.

 

[youda]

lol, good stuff let me know when you run i wanna see you tear up the strip

 

[blackvr]

AAAh... excellent news ! Hope you enjoy the extra grunt. I do this all day on the dyno ! Took me a while to work out years and years ago. Was a bit frustrating at the time.....

Cheers Mike

 

[Lee]

AAAh... excellent news ! Hope you enjoy the extra grunt. I do this all day on the dyno ! Took me a while to work out years and years ago. Was a bit frustrating at the time.....

Cheers Mike

Yeah your not wrong there mate.
It's just something that you over-look (Well I did anyway)
It's like a totaly differant car, hauls arse on 20psi.
Thanks again mate.

 

[Liberoz]

If you are running the stock BOV, it is quite common for them to push open, and therefor leak and bypass boost under hi boost conditions. Try removing the BOV and blanking the holes ( welch plugs), or it was common for the rally guys to reverse the BOV.

reversing the bov isnt a good idea as your acually blocking it off so doing this you can blow hoses off But the boost is Bloody insane its just uncontrolable power ...not really recommended tho :shock:

 

[Lee]

If you are running the stock BOV, it is quite common for them to push open, and therefor leak and bypass boost under hi boost conditions. Try removing the BOV and blanking the holes ( welch plugs), or it was common for the rally guys to reverse the BOV.

reversing the bov isnt a good idea as your acually blocking it off so doing this you can blow hoses off But the boost is Bloody insane its just uncontrolable power ...not really recommended tho :shock:

I'm not running with it reversed, I just did that to test it if it was leaking. (And it was)
I now have a aftermarket BOV, runs sweet now!

 

[3zercrowd]

Sorry to drag up older threads but.......

What is the stock boost for an Evo3 Turbo's actuator?[TDOH-16G(big)]
Havnt got the stock boost control solenoid hooked up either.
Can it please be confirmed?

Some say its 10psi and ive heard more.

I want the right answer because we are trying to tune from stock boost and THEN adding a boost controller to add more.

Thankyou.

 

[oscar]

I had the same problem,it was my boost controller.