Cant boost over 1.5 bar...

[tpunx99GSX]

Hey guys,
I have been having this problem with my current setup and have racked my brain trying to figure it out.
I cannot boost over 1.5 bar, my target boost is around 30 psi (~2.xx bar). The turbo is a SCM6152e, boost controller is a AVCR, No boost leaks that i could see.
It seems like the turbo is REALLY laggy. I made sure the exhaust manifold gasket was good tonight. And the one between the mani and head were fine, the one between the mani and the turbo had two cracks on opposite sides. I wouldnt think that this would affect it that much. Would it?
Im making a new gasket tomorrow, made of 4 layers of thin sheet metal with copper spray between each layer.
Theres no shaft play on the turbo. The timing is good. I was thinking about rebuilding the RRE head i had that has 4 bent valves and trying that one. I would say boost leak but i wouldnt think that would affect spoolup greatly. The car sounds like its struggleing in the upper RPMs but no knock whatsoever. Any ideas what else could be wrong?

[Super Bleeder!!]

Time for a leak down test.

[Matt D.]

Things that could cause your problem, assuming your turbo isn't bad:

• boost leak
• exhaust leak
• weak or leaking wastegate
• bad boost controller

How did you not see boost leaks? Did you actually do a boost leak test and listen for leaks and spray couplers and every other mating surface with soapy water?

Replace that cracked gasket with an OEM one. WTF is with making your own gasket? This isn't homemadeturbo.com.

[turbotalon1g]

My turbo was leaking at the comp. cover.

[scheides]

Do yourself a favor and disconnect the AVC-R, at least to troubleshoot this. My blue car did the SAME thing, it was laggy as hell with just a big16g. First I hooked the boost line straight to the WGA, and verified I got 12psi, nice and prompt. THen I got a nice cheap (but not ebay) MBC (it was a DB Performance one), and put it in. I have it dialed in for ~18psi now, and it is perfect; nice and smooth power to redline, boost kicks in right where it should. AVC-R is currently being ripped out of the car

[311evo]

Originally Posted by scheides

Then I got a nice cheap (but not ebay) MBC (it was a DB Performance one), and put it in.

Glad you could use it Scheides!

[BLaCk_1cE]

What Matt D said

[HiImBrian]

Could you go a little in detail about your wg setup? External/Internal and where/how it's mounted.

I had an external wg setup on my mani and had the top part of the exhaust housing welded shut. I blew that weld and my fiddy spooled slow as nuts. 20 psi by 7000 rpms lol

[EclipseGST]

I agree with Scheides...

If you are not 100% use to the settings on the AVC-R, unhook it and get a MBC.

The duty cycles on the AVC-R arent the easiest to get down and most likely are your problem. If you really want to use the EBC, set your duty to 100% and your boost to where you want it. Do a pull but be ready to let off because you will overshoot your "set boost". This would be only to test if the duty is too low.

What is the "duty" at right now?

You could also try raising the percentage 5-10%, doing a pull, raising, doing a pull... Until you get to the boost you want to be at. Continue raising it until you over shoot the set boost by 2-4psi and dial it back a few percent on the duty.

[tpunx99GSX]

Originally Posted by Matt D.

Things that could cause your problem, assuming your turbo isn't bad:

• boost leak
• exhaust leak
• weak or leaking wastegate
• bad boost controller

How did you not see boost leaks? Did you actually do a boost leak test and listen for leaks and spray couplers and every other mating surface with soapy water?

Replace that cracked gasket with an OEM one. WTF is with making your own gasket? This isn't homemadeturbo.com.

Yes i did do an actual boost leak test like i always do with soapy water at each mating joint. there was no large or small boost leaks.
Making my own gasket is cutting out one that is the same size as the one i have.
Do you or anyone have the part number for the gasket with the 7cm center hole? The oem one is too small and i would rather not have a restriction like that.

[tpunx99GSX]

Originally Posted by EclipseGST

I agree with Scheides...

If you are not 100% use to the settings on the AVC-R, unhook it and get a MBC.

The duty cycles on the AVC-R arent the easiest to get down and most likely are your problem. If you really want to use the EBC, set your duty to 100% and your boost to where you want it. Do a pull but be ready to let off because you will overshoot your "set boost". This would be only to test if the duty is too low.

What is the "duty" at right now?

You could also try raising the percentage 5-10%, doing a pull, raising, doing a pull... Until you get to the boost you want to be at. Continue raising it until you over shoot the set boost by 2-4psi and dial it back a few percent on the duty.

Currently the duty is at 40% and the boost is at 1.9 kg/cm (or whatever) I have turned it to 2.3 kg/cm and it still only boosts until 1.5
The wierd thing is i have not heard the wastegate open at all. Tonight im going to replace that gasket and make a pull to see if that corrects it. Other then that ill work on the other things.

[tpunx99GSX]

Originally Posted by Mr.98GSX

Could you go a little in detail about your wg setup? External/Internal and where/how it's mounted.

I had an external wg setup on my mani and had the top part of the exhaust housing welded shut. I blew that weld and my fiddy spooled slow as nuts. 20 psi by 7000 rpms lol

SCM6152E, External Tial 38mm wastegate mounted on the O2 housing. Mounted with gasket no visable/audible leaks, dumping to atmos.

[EclipseGST]

40% is your problem... Go turn it up to 70%. Seriously.

Do it slowly, just keep an eye on your boost gauge so you dont blow anything up. But you should be around 65-75%.

[EclipseGST]

Originally Posted by tpunx99GSX

SCM6152E, External Tial 38mm wastegate mounted on the O2 housing. Mounted with gasket no visable/audible leaks, dumping to atmos.

You are running both lines on the w/g right? 1 coming from the intake manifold going to the w/g and the boost solenoid, the other just coming from the boost solenoid.

[EclipseGST]

This is how you should have the solenoid hooked up with your w/g.

If its not like that, you could also be having issues.

[tpunx99GSX]

Yes i have it hooked up like the diagram. Ill try the higher settings.

[Project2G]

Originally Posted by tpunx99GSX

I cannot boost over 1.5 bar, my target boost is around 30 psi (~2.xx bar).

Stock head studs. Ouch