Quote Originally Posted by Quik View Post
a wastegate should never be merged into the exhaust as a 90*. With any airflow merger its always best to stay with direction of flow as best as possible.

Since the two pressure are at different rates they can cause turbulance and also effect back pressure. it can also cause boost creep
That's what all the books say and in theory, it is best, and probably does work better in an ideal world, but in the actual world, I haven't seen it affect a turbo kit at all.
I built the first few kits with an angled downpipe for the wg, then decided on a 90deg entry, same results on both kits and same back pressure on both kits.
Check out the single log kits that are around, no way is that wg in the ideal spot lol, being so far down and on only one side of the engine, on the crossover tube, but it does work and controls boost rather well.

I'm sure at an extreme power level it does make a difference.