Hey people, i've got an overboosting problem.

When I stick in a 10psi spring, the car will overboost to 18psi at 8000rpm's.
When using a 7psi spring, it will overboost to 11 psi's.

Ofcourse we set up a fuel cut at 18 psi.

My setup:

InlinePro kit with turbosmart 38 wastegate, GT3076R 0.82 AR turbo.

This is what my tuner thinks, he maybe right but there are alot of these same setups around:

"In the turbo configuration installed in your car it seems the wastegate is not properly sized to the turbo. With a 10 PSI spring the boost creeps @ 8000 RPM to 1.2 bars (18 PSI). This is called boost creep and is caused by a too small wastegate or an too optimal (ball bearing with small A/R on the hot side) turbo compared to the wastegate.

An other option can be the hole that feeds the wastegate with exhaust gasses (the hole in the manifold), this might be too small.

The solution can be porting the manifold or install a bigger turbo with a bigger A/R in the back. The manifold dictates the use of the 38mm wastegate so replacing the wastegate is not an option."

Any ideas?

Whole project including lots of pics

 

I'd suggest a larger wastegate I'm running a Tial 44mm and I've had no problems with it whatsoever.

Good luck

 

Try a smaller spring and then using a MBC / EBC to up the pressure to 10.

There are a few people with the same setup without boost creep so I would be inclinded to say, there is something wrong with your system that you have to find/fix.

 

Are these people using the same dumptube InlinePro includes in the kit?

We enlarged the length of the tube so the gasses hit the ground and not the block.
You can see a pic of that in the other thread I mentioned.

Boost control is an option yes. But I want 1.5 bar on race gas as well.
So a 1 bar spring would be perfect if it works.

 

Are you using the same components?

 

I don't believe the dumptube is the problem. I would port the wastegate hole on the manifold and use one of these conversion flanges to step up to a TiAL 44mm.
http://www.atpturbo.com/Merchant2/merchant...y_Code=ATP-FLS2

 

I have an Inline Kit which is nearly identical to yours. I am running the smaller wastegate spring with a manual boost controller. I have no boost creep at all.

 

Do you have boost creep when you don't use boost control?
That is my case. I know I can use boost control but i'm setting up low boost and high boost. Low boost on spring pressure and High boost on boost control.

Porting the manifold and getting a Tial44 would be an option. But that means ripping everything out again, which i'm not keen on doing. It's a PITA.

 

I have only run it with the MBC in there. It could solve your problem for $60

 

That flange would defeat the purpose of the larger wastegate however. You would need to port the manifold hole to ~44mm to match the 44mm wastegate. Also, the placement of the wastegate makes it hard to fit anything taller into the location as the 38mm wastegate is only an inch below the AC line.




Makre sure you have no vacuum leaks anywhere.