Turbo dyno dilemma

[St Louis SHO]

No way that could be the cause. I'm leaning more towards a vacuum leak at the couplers or one side of the butterflies are not opening or are not opening correctly. But then again, I am no Boost expert. Where's TT when you need him?

James

on second thought maybe a stuck exhaust valve?

 

[Geek SHO]

I'm no expert either, but isn't that curve somewhat reminiscent of a SHO running only on the long intake runners, as SHO Amo suggests? I've personally only seen the opposite; a SHO with secondaries always open, and it looked like a Honda dyno (no low end grunt).

 

[Lightning]

what's the verdict, did you find the problem?

 

[Power Surge]

what's the verdict, did you find the problem?

Not yet, I am questioning the wastegate, as removing the vacuum line off it makes no difference in boost. I have a new .8 bar spring coming for it which should get me about 10-11 psi, so I'll continue from that point.

 

[Lightning]

Ahhh, I see.

Keep us posted.

 

[Sho Amo]

did you ever check the butterflies??

 

[kzoosho]

Not yet, I am questioning the wastegate, as removing the vacuum line off it makes no difference in boost. I have a new .8 bar spring coming for it which should get me about 10-11 psi, so I'll continue from that point.

so your saying you pulled the line and the wastegate still opened?

 

[Power Surge]

so your saying you pulled the line and the wastegate still opened?

Yes, I pulled the line off the gate, and it made zero difference in boost.

 

[kzoosho]

That is funny. Your wastegate should immediately close. I would say that your wastgate isnt closeing at all. What kinda wastegate is it?

 

[Power Surge]

That is funny. Your wastegate should immediately close. I would say that your wastgate isnt closeing at all. What kinda wastegate is it?

I know, that's why I suspect it's a gate issue. It's a 38mm Tial, but I did buy it used. I am going to go through it once the new spring gets here.

 

[kzoosho]

I know, that's why I suspect it's a gate issue. It's a 38mm Tial, but I did buy it used. I am going to go through it once the new spring gets here.

Also there is a small little ring that ensures that the gate closes. If that isnt there it will never close. Check and make sure thats there. If you need a pic let me know man. I have plenty. Also these can be had direct from tial here in michigan.

 

[Sho Amo]

im agreeing with the wastegate. sounds pretty bulletproof to me.

 

[somedude_001]

Also there is a small little ring that ensures that the gate closes. If that isnt there it will never close. Check and make sure thats there. If you need a pic let me know man. I have plenty. Also these can be had direct from tial here in michigan.

that ring was a pain in my ass. I can't tell you how many times I lost that stupid thing moving parts around in my bedroom. Yes my bedroom is my safe heaven my new unused car parts.

 

[adidas_kn]

Get it fixed sal I want to see what a nicely tuned low boost Turbo SHO will run with a stock 3.0L.

 

[kzoosho]

Well hopefully in a couple more months i will have my newly accuired 91 boosted. Still debating if i should keep it a 3.0 or do a 3.2 since i have 2 sitting here.

 

[kzoosho]

http://cgi.ebay.com/ebaymotors/TIAL...003QQitemZ130185676829QQrdZ1QQsspagenameZWDVW

Thats probably what you need.

 

[Power Surge]

I have that. As I previously said, I even water tested the valve seal area to ensure no leakage.

 

[kzoosho]

I have that. As I previously said, I even water tested the valve seal area to ensure no leakage.

Well its leaking some how man. that would be were i would look.

 

[91southfloridaSHO]

i once had a piece of metal get stuck between the waste gate seat and the valve. we had to take the whole thing part and then it was fine from then on. the spring could be bad? i like the turbo smart stuff you should look in to it. that is what i install on all my turbo setups. good luck and happy new year.

 

[Power Surge]

I pulled the gate out the other day and completely dissasembled it. Replaced the housing oring, cleaned everything, and installed the new spring. Checked the opening pressure with regulated shop air and a boost gauge. Opens precisely at 13 psi. A little higher than the spring rating, but I'm not complaining . Gate seals perfect to the ring.

Driving the car, it's hard to tell what it's doing. Maybe I'll throw it back on the dyno today.