Ok I have a slight problem with my Turbo II I am boosting to 1.38bar... sucks I am tryign to work it down to .5-.6bar. Now I hear everyone going on about porting a wastegate for a free mod. I am not interested in free. I want something that will work permantly and is adjustable (springs). Is the only reason for porting the $$$. Is there another option?

-josh

 

no, just cause its a free mod doesnt mean that its not worth anything. by porting the wastegate you allow more exhaust gas to bypass the turbine-side of your turbocharger more quickly when the wastegate is actuated, keeping boost from being produced. Now, the wastegate should begin to open at around 6 or 7 psi (slightly under .5 bar), and continues to open further as boost rises. As it opens further, it allows more and more exhaust to bypass the turbine. The problem with the wastegate on our cars is that the hole for the exhaust to escape thru is too small, so even if the wastegate is fully open, exhaust is still pushed thru the turbine, creating more boost and thus boost creep. This is probably what is getting you to 1.4 bar, especially if you still have the stock wastegate (integral to the turbine housing). So by porting the wastegate, you'll keep boost down, and increase the effectiveness of the wastegate. Its free, but that doesnt mean its not a good mod.

 

You need to port the wastegate. If you do it yourself, the only investment is time...

http://www.aaroncake.net/rx-7/s4wastegate.htm

 

Ok time to port...

I guess I just havent ever heard of porting it to lower boost. I am also coming from evos but I guess this is different.

Thanks

-josh

 

Porting the wastegate will always lower boost, no matter the application.

 

Its only because the stock wastegate is the size of a marble! I ported mine, and it still creeps so i have to go back in and port it way bigger and use a bigger flapper.

 

so why not just replace it? then never have a problem again? Sorry for being anti porting sounding.

 

and would you like to tell me were your going to put this new wastegate?
i'll let you in on a little hint theirs no place to bolt up an external wastegate on the stock manifold.

since you want to spend money, your going to need a new manifold, external wategate and a new turbo (since the stock one wont bolt up to an aftermarket manifold.)
or you could have a custom manifold made with a external wastegate port for the stock turbo.

 

to add to snowball's post, you'd then need to perminantly close the internal wastegate on the stock turbo. porting isnt hard, just time-consuming

 

that makes perfect sense now. Like I said I have been dealing with evos which you just throw new parts at. Not modify existing parts. So unless I want to do some major work your better off porting. ok got it thank you for explaining vs just saying port.

 

The time it takes to do the actual wastegate porting is minimal. The biggest PITA is pulling the turbo off the engine, particularly if you have never done it before or if your fastners have been on the car for 20 years.