Can't make big boost, wiseman needed

[Ho0ked]

So my car runs great but,
I wanted to turn up my boost some more. running about 23-24 atm profile is current.

My turbo is a G50 (slowboy)

I can't seem to get anymore out of it.
I have tightened my waste gate arm considerably more then when I received it.
No creep issues just lack of boost over 23-24.

I don't think I have any leaks but, I can't seem to pressure test over 10lbs with my current air pump but I get no leaks at that level.

3rd gear boost falls to 13 by redline after hitting 23 and slowly falls to static gate pressure and same with 4th and 5th gears......


Is my stock downpipe causing this lack of boost and fall off due to restriction in the air flow escaping to my exhaust ?


Perhaps bogging my exhaust side wheel ?

I was hoping to hit 28ish psi

Any ideas please let me know, thanks

 

[vr6chris]

With that 50 trim, are you running an internal wastegate or external? You may need a new spring in your wastegate if it is an external gate. Try getting a stiffer spring.

 

[CanadianTSi]

If I were you my first step would be to get rid of the stock DP and see what happens.

 

[vr6chris]

Sorry, didn't catch that. Yeah, definately get rid of the stock downpipe, big restricter.

 

[94awdcoupe]

I would say try running open downpipe and see what happens.

 

[hellotbone]

Im not seeing an aftermarket clutch in your profile do you have one? I would have to only wager a guess that you could be slipping when the boost comes on and not having the load on the engine would cause a lack of boost as you are describing. Its only something to concider. With my diesel if you can't load the engine enough you can't build boost so we use a very aggressive TQ to load the motor hard and drive the boost up.

 

[enid84]

I'm no wiseman here but get rid of your stock dp and that will probablly get rid of your problem also you might have issues with your boost controller.

 

[Ho0ked]

Thanks for the ideas and support gang

Stock clutch, no noticable slipping even under load she spins tires in 1st, 2nd, and chirps 3rd.

5th gear test stalls the car so it ain't fried yet.

My main question was, is the downpipe causing my turbo to bog because the exhaust is backing up on the exhaust wheel?, also the other mourning it was cold here and she hit 25-26 Psi

Other question was if that same exhaust backing up , is causing my boost to fall off , from bogging the exhaust wheel in unspent gas's that can't get down my tiny downpipe fast enough?

Thanks again

 

[urcnjoe]

Don't give up on the boost leak test. 10psi isn't cutting it considering you are trying to run 25+ psi. Pressurize the system to at least the psi you plan on running and make sure it holds without any signs of leaks.

 

[hellotbone]

I ran my 50 trim on the stock downpipe with no problems like you describe. I would lean towards boost leaks at higher PSI or leaking BOV.

 

[ddavisaf]

BOV would be my first guess.
Also, at high boost the normal 20psi test doesn't accurately display boost leaks. Crank it up to about 30 psi and don't forget about your soapy water!
If you have an adjustable BOV you might have to set it to "harder". At higher boost levels the soft setting can leak.

 

[enid84]

Not to jack your thread but also my "properlly" crushed 1g bov leaks after 12psi. Like right at 12 psi its not that bad but once it starts to get to like 18...i mean it leaks pretty good. Its not alot to make my boost drop off but it will probablly cause the turbo to work its ass off to make the desired boost.

 

[oldman]

I was hoping to hit 28ish psi

Is your profile updated? Are you still on stock head gasket and bolt?

 

[Ho0ked]

Profile is up to date wiseman

Yes my stock headgasket and bolts are holding atm (crosses fingers)

Yea I'm gonna try and get a good 30 psi leak test this week sometime

Also once I get my maf-t I can install my GM 3" maf and get an hks ssq bov and hopefully elimenate any bov leaks



Thanks again for the ideas guys.

 

[oldman]

Yes my stock headgasket and bolts are holding atm (crosses fingers)

You're a very brave man.