Thanks man, I'm definitely open to try anything right now. Been dealing with it for so long it's disappointing. lol...What confuses me the most is what i see at the boost gauge connected to my actuator. 10 psi actuator and I never see close to 10 on it if I'm not using a boost controller. I even ran a different line, taking my boost controller completely out of the mix and it's the same.

 

Initial thoughts are the flow/boost/hp charts line up to what I would expect to see in that the relationship between them makes sense. The way the MAF jumps around at higher rpm could be a clue .........

Need to think about it some more .

How about that BOV test ?

 

I've pressure tested the piping and its not leaking at the bov. Would it be any different with the car running and the signal to the bov unplugged? I could test that tomorrow.

 

I can't remember - did Steve (or anyone for that matter) hook up a Mighty-Vac and test the cracking and full-open pressure of your actuator?

 

i tested the cracking pressure, which was about 7 psi. haven't tested the fully open yet, but i'll add that to the to-do list.

 

on second thoughts I do believe your charts are out of whack with eachother .

with over 300 g/s you should be making way more hp than 250
but 6psi and 250hp line up pretty well

So the inference is that there is more air going past the maf than is making it to the engine .
Seeing as you don't have any boost leaks I would definately look at the BOV .............


yes , the BOV could leak even if it pressure tests ok . Not sure if unplugging it will seal it up or not .............. Is there an easy way top block it off at the flange ?

 

Come to think of it, the ssqv works off pressure differential, so it won't be shut if unplugged...

I can try to fab up a plate to put in place of the bov when I get some time. I'll also retest for boost leaks.

 

All those numbers scream boost leak, especially if your AFR's look ok.

Assuming your tune is not so rich as to bog the motor down, or misfire then I'd really me looking for a boost leak or maybe even a WG diaphragm leak... though that usually causes over-boosting not the other way around for an IW.

 

when i pressure tested my car i cut a thin piece of aluminum to shape (used a soda can) of the flange and placed the bov on top, it sealed nicely for me. quick and easy way to seal that bov area

 

Ngo, looks like you're going to be busy testing out a bunch of things but THANKS to all who are helping to try and diagnose this issue.
SoCal needs more boosted 8's!

 

thanks for the info greg, i'll do that.

Also, Thanks to Brettus, Kane, and MM.

I will attempt to test the wastegate cracking and fully open pressure and test for boost leaks for clarification. Should I do a run with the bov blocked off or a pressure test?

 

Definately block it off completely - you need to eliminate it as a possible leak source .

The way the boost and maf are fluctuating wildly screams BOV to me . But i must admit I've never seen one leak so....

 

So I did a few 2nd gear runs. looks like I was wrong...

Going WOT at 4k rpm I would hit between 8-9 psi before it begins to drop

Going WOT at 6k rpm I would hit between 6-7 psi before dropping

This was with the boost controller on.
Looks to be similar in regards to my boost profile from the dyno.

Brettus, did you want me to do a WOT run at 7000 rpm with the wastegate disconnected to see if it goes over 6 psi?

 

ummmm - I don't think it is the wastgate now . But if it is an easy test to do for you - you may as well try it .

 

just did a couple 2nd gear WOT runs at 6-7k rpm with wastegate disconnected.

boost was still between 6-7 psi.

 

leaking.....me thinks.

Can you disconnect the BOV and try?

 

in the process of making a piece to block it off, it'll be the next test.

 

blocked off the ssqv bov with a piece of aluminum. drove it, and problem still exists. so looks like it's not leaking...

 

Bugger .

Next question . How do you have your air injection tube hooked up ?

 

damn it, I was really hoping it would be the BOV.

 

I deleted the air pump. My turbo is on the greddy manifold with downpipe.

 

The way both your boost and maf jump up and down still makes me think it is something opening and closing allowing a leak - that is why I kept going on about the BOV . But what else in the system can do that ................... ?

 

Sure you don't have a coupler leak..or split?

 

A spun turbo could.... or a small hose leak that is flapping open and closed.

 

I'm taking one last stab at it for today. pressure testing for leaks.

Thanks for the help guys.

Kane, what do you mean by spun turbo? any way to check it?