exhaust leak or wastegate stuck open?

[Hiitman]

theres an extremely loud exhaust leak type sound coming from the manifold/turbo area. I dont know if its an exhaust leak because i have no boost at all. did a boost leak test and found no leaks. could the wastegate possibly be getting stuck open? or could a leak somewhere in the exhaust manifold cause a lack of boost? also should i put the 10 psi spring in the wastegate to handle the 50 trim?

 

[GVR4592]

Does the wastegate look like it's stuck open? It doesn't sound like you've spent a lot of time trying to locate the leak. I don't think we can tell you where it is without actually seeing the car.

What type of wastegate do you have and what spring do you have in it now?

 

[Hiitman]

ive got the turbosmart street gate with the 7psi spring in right now. i properly lifted and supported the car, turned it on and had the wife open it up to about 3k rpms. didnt look like the gate was open.

 

[Hiitman]

well its not an exhaust leak because i can hear, feel and see the wastegate opening up right off the start. its also making a backfiring sound and popping out a bue flame when i rev it...running to rich? time to switch to the 10psi spring?

 

[Hiitman]

wastegate still stays open off the start and still no boost. do i need to adjust my a/f ratios or anything? i did all the mods and still havnt tuned the car....trying to fix the no boost problem first.

 

[GVR4592]

The wastegate stays open all the time when the engine is running? Does it close when the engine is not running? How do you have the vacuum lines routed?

 

[Hiitman]

like this http://www.dsmtalk.com/gallery/data/500/wastegate.JPG

 

[GVR4592]

Is the wastegate open all of the time or only when the car is running?

 

[Hiitman]

only when the car is running. i can hear it because it sounds like an exhaust leak.

 

[Hiitman]

i plugged both ports on the wastegate and its still staying open

 

[Hiitman]

wastegaste is no longer stuck open and now i have an exhaust leak between the manifold and turbo. could a leak between the turbo/o2 housing/downpipe cause no boost?

 

[GVR4592]

If the leak is big enough between the manifold and turbo it can cause very slow spool. but you should still see some boost. Is the wastegate flapper welded shut on your turbo? Do you have a catalytic converter? Have you tried eliminating the mbc temporarily?

 

[Hiitman]

yes its welded shut but theres a couple small cracks in the welding. yes ive got a cat and yes ive tried eliminating the mbc (plug wastegate holes)

 

[GVR4592]

A clogged catalytic converter can cause the problems your experiencing. I would fix the exhaust leaks and inspect the catalytic converter.

 

[GVR4592]

Plugging the ports on the wastegate isn't the way to eliminate the mbc. You should run the boost source directly to the bottom port on the wastegate and leave the top port open to atmosphere.

Have you tried running the mbc off of the bottom port only?