91 TII , steet ported intake/exhaust, Greddy FMIC, haltech, BNR Stage 3 turbo on a S4 hotside.

Anyways, was having some boost control issues. Today I pulled the turbo to add some springs to the WG rod thinking that would help the low boost off the line.

So, I pull the back plate off the turbo to check things out. And I find this....



The odd thing was...my boost control still sucks even with NO flapper door. It would do 14psi by redline.

Honestly, I am about sick of this stock/hybrid turbo BS. Boost control problems out the *** and it is always a PITA to work on.

Not sure what I am going to do. I assume the flapper is somewhere in the exhaust. I guess find the flapper and weld it on...maybe a little better this time.

James

 

crazy talk!

 

Here is the before picture...it looked like a good weld.

 

wow, impressive. And you were still making 14 psi, thats kinda impressive

 

Dude, that sucks - I guess they didn't get enough weld penetration or else they used something with a melting point less than the temps you were seeing on the exhaust side.

 

Yeah, that is what I was thinking...I never really thought much about that and welding...I wonder what type of welding was used to put those two pieces together. That area hits what...1800F?

James

 

d00d, i think you found your problem.

from the pic the weld looks alright, i mean its still there...its the flapper metal that melted off the weld. maybe you ran a little lean and heated up the exhaust past 1600F? Your EGT shouldn't go over 1600. looks like it did and you have a tuning issue

 

Wow - 14PSI with the WG wide open.

Time to go big time with an external WG.

 

So, I emailed Bryan over and BNR and he said just mail back the hotside and he will fix it up for me even though I have had it over two years. Super fast reply to my email/phone call. Thanks BNR!

James

 

+1 for bryan's service.

 

-1 for shipping cost and lack of welder

 

I asked him if he could just send me the flapper and have a local shop do it but he said it really had to be fitted at his place...I can see where he is coming from on that though.

But I would like to not have the down time.

I just doubt I could find a shop in Dallas that speaks the same language I am talking and do the work I am lookn' to get done.

James

 

Thats not the problem. The problem is too small of a turbine housing. Wastegates were never designed to compensate for too small of a turbine housing.

This is just one reason why hyrbid turbos are a complete waste of time.
We can build hyrbids here, but refuse to...

 

You know...that is the most logical thing I have heard about the turbine housing being way to small and the WG not really having that much to do with it.

Would it have been less of a problem if I had stock ports?

Honestly, I really want a full turbo with a hotside around .96 - 1.00 and a 60-1 . With a big ol wastegate so I don't have these problems again. That sound about right ?

James

 

Yes.

 

But for the wrong reasons!

 

all I can say is wow.....thats crazy.....blew that sucker right off huh??

 

You know I was always wondering this....

I have had the low boost off the line prob for a while. So, from 3000rpm - 6000 it would build boost linerally to a max of 12-14 at redline. I wonder how bad that hurts power. Not having good boost off the line. In terms of torque?

James