just as the title says i just need to know what kind of wastegate do i need for the GT42R

i think the one i have is too small!

 

If you're running 15psi~ish you'll probably want to run a 60mm; 25psi~ish and the 44mms work just fine..

 

thanks!

 

I was using 2 tial 35's and it would boost creep. I then switched to 2 tial 44's and it was perfect. If I would do it over again I would have just gotten 1 Tial 60mm. Less lines and less money.

 

why so big?

 

What's the minimum boost you plan to run?

 

/\ 20-27 max

 

It wouldn't anything less than 22psi with the 35's when it got below 60 degress outside. Plus it would spike even when it was warm outside until the gates could "catch up."

 

not to thread hijack, but if i have an s475, which is similar sized, am i gunna be able to get >15 psi off of twin 44mm gates? Its something that i am concerned about.

 

how comes you use a smaller wastgate when you runner higher boost i thought you would need a bigger one.

 

above says greater than, and the answer is yes. i think you want to ask if you can run less than 15 and that depends on how well your manifold is designed.

 

If you think about the purpose of the wastegate, you will understand. A wastegate is used to redirect exhaust flow away from the turbo to control boost. If your running higher boost, you want to use more of the exhaust gas to power the turbo, therefore you don't need to redirect as much flow through the wastegate, hence a smaller wastegate will due.

thewird

 

More boost means more pressure inside the exhaust manifold. The higher the pressure the greater the flow for a given gate size. I.E. a 44mm gate will flow much more at 30 PSI than it will at 15 PSI. This means that as the pressure goes up a smaller valve will flow as much as a bigger one would at a lower boost. Simple.



Not with a P-Port IMO.

 

so mabey twin 60mm gates?

 

One well placed 44 would work for that. A lot depends on how well everything flows. 44's work great on some cars and not so good on others.

 

You could possibly run into other problems with too much valve surface area (like Zero R stated). It is going to be very hard for you to control boost at the lower levels. Turbo p-ports are very curious animals. Most racers that go full p-port switch back to semi after only a few races The peak numbers are good but the power under the curve suffers. I will tell you this, turbine A/Rs are very critical.

 

****.. any ideas then? mabey just twin 44mm gates that are positioned at the exact angle for optimum performance?