To take full advantage of the divided housing, do I need to have two wastegates (1 for the 1 and 4 side, one for the 2 and 3 side)? Also what material do you guys use to mock up your mani's?

Originally posted by dsmracr420a
To take full advantage of the divided housing, do I need to have two wastegates (1 for the 1 and 4 side, one for the 2 and 3 side)? Also what material do you guys use to mock up your mani's?

To take full advantage, yes, run two wastegates. Some guys join the two secondaries and run a single wastegate, but that really defeats the purpose of having a twin-scroll setup by potentially introducing back pressure to the other cylinders.

Possibly, but if that were the case one would assume you'd need a divided collector/independent runners ( read: No Logs Allowed :nono ) Personally, if I weren't building my own manifold and the one I bought didn't come setup for that, I wouldn't put too much thought to it, just bolt that badboy on and scotch guard the seat. If, on the other hand you were making your own manifold, there has been some evidence shown that keeping exhaust pulse's seperate for x amount of runner prior to entering the turbine housing will both reduce spool time and increase power, though I can't tell you where I saw that, nor am I going to take the time to chase resources cause I'm a fat prick. Good luck!

Yes, I am building my own manifold. I thought that I would need two wg's ,but just wanted to double check. Thanks!

As far as the fabrication, anything you can do to minimalize distortion the better it will come out, especially if youre using stainless steels. I recommend building a beefy jig out of 1/2" plate, bolting the head flange to that... shaping the first 2...3...4" primaries, then standing it up and working into it. Locate where you want the turbine flange with angle iron or some scrap and build into it. If you have a rotary table, the welds at the flange come out insane.




There is nothing wrong with checking out a manifold on like an F1 turbo car, and using some of the design principles to make your setup work better for you. Full race makes some nice ones for example.

check this out for a cool split in a tight space:





edit: oh and just a welding tip, if youre tig welding it...I recommend tacking everything twice as much as you would with mild steel. this helps a lot to keep it where you want it as it cools.

Thanks man, great info as always! That evo manifold is just sick, if mine comes out half that good I'll be ecstatic.

Check out Harper here, he's the lead guy for Skunk 2. His setup here is definately not enough for me to minimalize distortion, but maybe he's only tacking it I don't know. A peice of channel and ONE clamp....yea he better be just tacking it.

Originally posted by turbo8u
Check out Harper here, he's the lead guy for Skunk 2. His setup here is definately not enough for me to minimalize distortion, but maybe he's only tacking it I don't know. A peice of channel and ONE clamp....yea he better be just tacking it.

You Tell those pros how to do it Turby!

But seriously, I agree. That's why I use at least 1 1/2 in. stock and clamp/bolt to it when welding something delicate, and I'm just a nEwB.