I want ot run a straight exhaust and would like to port my wastegate. I was wondering how large i need to port it. Or should i just get an aftermarket external one?

 

Move the flapper around in all directions that it can move to found out the enter limits of it's movement. Then enlarge the opening so that the flapper just barely covers that area. I think it is about 1.1" to 1.2" but it has been over 4 years since I have done one.

 

i suggest a high flow cat with your exhaust. you were looking at the apexi n1 or GT spec. more than like like you will not like the sound of a wide open exhaust or the smell. with the highflow, you'll still get some restriction, but it will not be ungodly loud and smell horrible all the time.

i didn't even like driving my FD with strait exhaust because of the smell and noise. of course an external wastegate venting out did help either.

 

i used spray paint on mine and ported it till i almost hit the edge witch came out to the specs mentioned above.

 

Even with the high-flow cat ive heard ide need to port the waste gate, because boost creep is still a danger.

 

i get a little boost creep with just the gt spec on my car. i'm gonna port my waste gate as well but i'm going to run a high flow cat for the purpose of the noise and smell....

 

You will not get boost creep with a hi-flow cat.

 

I ported mine to ~1.35" but I also removed the stock flapper and welded on a larger diameter flapper. In addition, I beveled the edge of the hole and the flapper to match. The taper promoted a better seal and helps align the flapper when closing.

-chuck

 

I ported mine out to 1.380 ,on the BNR -3 supersized ,down pipe -Bola xr1 mid and Trust muffler .No creep ever . I can put in a bigger door than that if needed .I have also cut the doors and seat concave to seal better on the rich mans non seq set up .