well.. immarun a t2 engine with s5 na rotors with an s4 turbo. i know the waste gate is poopey doopey, and so i proceeded to port it. then it stuck me, how much is overkill? cus im at about 25mm right now. would yall suggest going more? or is that just fine?? plus i will be maxing out the turbo very badly cus i can do that. just kidding., more like 12 psi max.

 

i know that BNR ports their higher stage turbo upgrades to 35mm IIRC, so i dont think your going too far.

 

A waste gate port can't be too big, since the door only opens as much as needed to limit overboost.
Even if it's way big, the door will just open a little less.

 

Bigger is always better. I'd aim for at least 30 if you can.

 

cool. thanks guys.

 

just be careful about the material you choose if you weld a new door on, i am still experimenting with the materials used for my ported wastegates to see which hold up best as it is a harsh environment and i have had 2 doors go MIA, it is not due to poor welds but the doors themselves eroded into little nubs until boost started dropping off.

 

well... thats better than a boost spike aint it? lol. its gonna be a good piece of metal.

 

Piston engines have these things called "valves".

They survive inside the combustion chamber, so a cut off valve head makes a great waste gate door.

 

Yea, I heard people were using Honda Exhaust valves.

 

or any exhaust valves O_o. yeah im going to do this when i get my JDM motor, anyone used it? how has it held up?

 

Thanks, You guys just answered a question. I saw the thread on welding a washer on the wastegate door to make it bigger but I wasn't convinced that a washer would hold up to the heat. I also had the exhaust valve idea. Glad to hear that will work. That will be my plan.

 

How difficult would it be to just go with an aftermarket external wastegate instead of messing with the stock one? Could it be done with the stock turbo or only with like a BNR upgrade? Just seems to make more sence than porting the stock one.