cas951

Hello all, I recently blew my headgasket (We thought I did)during the No. Cal dyno day in Sept. I've replaced the headgasket and as it turns out there was no damage. It was the turbo that blew. I had the turbo rebuilt rebuilt and now I can't adjust my manual boost controller will not adjust the boost below 16 PSI. I have a Lindsey Racing Wastegate and a manual boost controller. Before the turbo rebuild, my boost was @ 13PSI. Any one ever encounter this before?

Thanks
Efren

KW951

Could be a couple of things.

The wastegate could be stuck, or just not opening all the way. Usually this is the result of rust etc. The diaphram in the wastegate could be torn etc so that it isn't holding a seal. You can open the lindsey racing wastegate pretty easily with an allen wrench and then check it out.

Are you still running the stock exhaust and cat? There is a small converter in the wastegate dump tube on there and if it were to plug up, you wastegate would essentially be closed all the time even if it opened up.

You might try disconnecting the hose from your boost controller as well (I'm assuming this is the dual port wastegate they make). With just the pressure signal the wastegate should only hold about 7-8psi of boost.

When your turbo was rebuilt, was it upgraded? If you had some really huge turbo on there the wastegate might just be too small to vent enough exhaust to stop it from boosting that much. If the turbo is stock or near stock, that shouldn't be an issue though.

cas951

I'm using 3" exhaust, test pipe. The turbo is rebuilt to stock.

Efren

Ski

Your manual controller could be the problem too. Basically they are just a regulator. I would take it out and get it tested with some low volume air. The diaphram in the controller may be bad.

Danno

There may be some vacuum leaks in the boost-control plumbing circuit that can cause this inability to manage boost. I assume you have the pressure-regulator ****-type of controller? We just had this exact problem on our test car last week. I would turn the **** all the way to one wide or the other and boost would remain the same regardless.

Also makes a difference whether you have your wastegate plumbed in single or dual-port configuration. This determines whether you turn the **** towards + or - to lower boost.