what would you use to weld a larger flapper door in place of the stock wastegate? would you have to braze it or something? im a newb welder, so help me out here.

 

Wholy snit, brazing would melt off very quickly. Hmmmm...... The correct metal for the high heat would be #1, then the welding technique, tig or mig prolly..
If you have access to it, tig is nice, you have to know how to use it though. Mig is rather easy, PRACTICE MAKES PERFECT though..

 

Take it to a turbo shop. They'll replace the flap with a bigger one.

 

I used an exhasut valve from a piston motor with the stem cut off

 

Anyone know how much this may cost if the turbo was already out of the car? I ported mine as big as I could with the stock flapper but was considering maybe getting this done prior to installing it. I have a microtech and the proper fuel for it but how high do you think the boost would spike with a tid mod and 3 inch exhaust, wastegate ported as big as the stock flapper will allow and I drilled a hole through the middle runner wall so the wastegate will exhaust gasses from both runners.

 

you need to port way past the flapper door to achieve anythign good with the stock flapper door.. it is ok to port past the flapper door.. port till you can wiggle your thumb around in it.. then set your boost to what u wanna run and forget about it..

 

For porting and a larger flap expect to pay US$50-100 depending on the shop.

But that will slow boost response (i.e. increase turbo lag) because the wastegate is essentially leaking all the time. Exhaust gases are bypassing the turbine when they're not supposed to.

 

what exactly is the turbo made of? couldnt i just get a sheet of something, cut out a new door and weld it on?

 

NZ, do you know On a series 4 turbo if the wastegate was ported to the size of the stock flapper could boost be held at 12 psi? This is with 3 inch exhaust and free flowing intake.

thanks