ttypecamaro

iTrader: (2)

I'm trying to put external wastegates on my twin turbo headers. The ideal collector location is totally out of the question so I was wondering how bad it would be to mount a wastegate on the #7 runner and the other on the #8.

I realize the reasons why NOT to do that but is it really all that bad? I know a bunch of DSM guys will run a wastegate on only one runner with no noticable issues.

I'm talking about 10psi on a 350 with two 38mm wastegates. (the runner I.D. is 36.6mm)

daves12secV6

iTrader: (3)

do u have room on the header flanges to make an adapter that bolts inbetween the header and turbo that would allow u to hookup the wastegate there ?

ttypecamaro

iTrader: (2)

nah, its barely a half inch of hood clearance with the stock hood on it. the weird angles the turbos sit at make it impossible. I made my headers so they bolt in with NO modifications other than bending the brake lines back for additional clearance, so its TIGHT in there.

First I'm going to buy a big drill bit and make the internal wastegates larger to see if that will help with the boost creep (from 19mm to 25mm).

ttypecamaro

iTrader: (2)

I drilled out the internal wastegate ports to 28mm, which more than doubled the area (217% increase) and cleaned it up with the die grinder. Now the max boost pressure is about 5 psi, where before there was no real limit to the boost (maybe 15 psi).

The spool time is still quick, but I'm going to move the reference lines from in front of the throttle body to a vacuum source, maybe add springs to the wastegates.... better yet maybe an electronic boost controller ($$$).

I also checked for boost leaks yesterday, but I feel like I might need to check again.

askulte

Is there room to run a squished tube, and then place the wastegate somewhere more convenient?

ttypecamaro

iTrader: (2)

There might be room to do that on the driver's side collector because the oil drains to the valve cover for now, but when I eventually make the oil return to the pan there won't be room.

What if I put a wastegate on the two middle pipes (3&5 and 4&6)? the problems I can think of would be that the runner length would be effectively 1 inch or so when the wastegate is open, and that the hole might interupt flow significantly being that close to the head.

The easiest thing to do would still be to put them on a single runner though (7 and 8).