Ok so i have been experiencing some MAJOR boost creep problems on my car. my setup, holset WH1E, 4 inch exhaust turbo back with a 18in burns "muffler", and a HKS standard wastegate. My manifold is a ebay OBX and the wastegate runners are not optimal, but anyways i got to thinking about something today. i have had an exhaust leak right at the v-band flange where the DP connects to the turbo. my question is simple, could this be contributing to my creep problems?

 

No

 

That is probably not you're problem. When you move to a very free flowing turbo back exhaust in conjunction with standard size turbine housings with bigger compressors you will get this problem. The correct solution is to move to a bigger waste-gate and design the turbo manifold around boost control if you are trying to run lower boost levels. If you're motor is also heavily ported its very hard to run low boost pressures.

 

Large streetport, but the turbine housing is very large, 26cm. im running or trying to run 15 psi. with the obx mani would a 60mm do the job, or would a redesigned mani with twin 44 tials be better?

 

How much are you currently over-boosting?

 

i scared to push it but i has been to 20 psi before. this is with a one bar spring btw.

 

Probably need a new exhaust manifold. Its hard to say though...

 

right i hear ya, thats what i was thinking also. twin 44 mm sound a little overkill?

 

you've got a 4 inch exhaust and only a 40mm wastegate?

 

It all depends on the combo. I've done full 3.5" exhaust on a 40mm before with ZERO boost control problems. I've done 4" on a 60mm Tial and seen boost creep...

Catch-22. I think you could do twin Tial 38's and just position them on the outside of each 1st bend on the turbo manifold. That two the atmosphere should do it...

Are you currently rerouted into your exhaust? Shouldn't be the problem with a 4" exhaust unless its 90 degree entrance...

 

Sweet thanks alot for the help revvin. i was searching around for a good manifold thread and found a few with really good info on them, but what i cant seem to find is where i can get the stainless els at. I dont want to go with burns because there a bit out of my budget. also what would be better schedule 10 or 40? what is schedule? lol. any direction in the right way would be appreciated.

 

nm found out where to get the pipe. next question how much do i need for a long runner manifold. about the length of the greddy manifolds.