I was wondering if there was a way to set a Garrett wastegate (the one that comes with the Cartech Racing kit for the carbed 13B setup) to obtain higher boost levels. Right now I'm running around 12-15psi with the Garrett Rotomaster. Is there a way to set the dumpoff or something? I was told something about springs but that was a while ago and I don't remember wtf the guy was talking about. Any help or ideas are appreciated.

 

is there a vacuem fitting on the wastegate... 1 or 2 ?

 

not sure, i'll look tomorrow if the weather clears up.

 

You really should post this in the single Turbo section...

But, since you asked - The Wastegate opens at a preset boost level. this is determined by the spring loaded diaphram inside the wastegate.

To get more boost, the spring needs to be stiffer, so more boost can build up, rather than wasted out the wastegate.

I really don't recommend that you do that though. Just get a Boost Controller, that way you can adjust boost settings at will, without taking your wastegate apart for the springs.

A Boost controller will interfere with the boost reference signal the wastegate recieves, and tell the wastegate that you are producing less boost than you actually are. By doing this, the wastegate will remain closed longer, and you will make more boost.

As an example, I have a 7lb spring in my wastegate. With my Profec Boost Controller I have three settings for boost.

Boost Controller set on:
OFF: - Working off the wastegate spring only - 7lbs.
ON-LOW - Tricking Wastegate into giving me 11 lbs of boost.
ON-HIGH - Tricking wastegate into giving me 16lbs of boost.

There are many cheap boost controllers available, including "Home Depot" style ones that you can make for less than 10 bucks too.

On a side note, - If you are going to run more boost, you need more fuel, and more ignition retard for safety. In a carbed Turbo such as yours - this might include carb re-jetting. Make sure the rest of your components are in line for the higher boost levels. I wouldn't want you to pop your engine by turning up the wick.

 

I thought that my wastegate doesn't receive a reference signal because it's not hooked into a computer or anything, therefore how would I use a computer controlled boost controller? If it's carbed then the wastegate functions when the air is overpressurized in the chamber, correct?

 

The way a wastegate works is... boost pressure is fed into a diaphragm inside the wastegate which pushes against the spring tension. Once the pressure is high enough the spring is overcome and the wastegate opens up. Boost controllers work by bleeding off part of the boost signal fooling the wastegate into staying closed. You can get ones that are electronically controlled via the use of solenoids or fully manual.

 

The reference signal isn't a electrical one, it's that vac line thats hooked to your wastegate. What directfreak is talking about is a electronic boost controller that operates a air solenoid valve that alters the signal the wastegate sees. You put the solenoid valve in line in between the manifold and the wasteagate.

 

I see. What's a good boost controller for my setup?

 

For a answer to that question I'd go browse the single turbo section. I don't have a boost controller yet but I'm sure 95% of the people that have single turbos have one.