With Japan in the state that it’s in, my wife traded her summer trip home for a family trip to Seattle. So I’ve been out of town for the last week and haven’t actually gotten anything done on the car. I did get in a few minutes before leaving however, to finish off the turbine outlet flange. As I said before, it was originally a Vibrant flange. Maybe there was some science behind it’s design that I don’t comprehend? Or maybe it was just a piece of shit? Since one of the bolt holes didn’t line up, I leaned towards the later and ported the hell out of it. The wastegate side, originally had about a 0.75″ radius. It’s now it’s closer to 1″ and matches the turbo itself.
I considered running a divorced pipe specifically for the wastegate, lots of people pay good money for downpipes that do so, but upon closer examination I realized that such setups might be mostly about impressing people at meets. I couldn’t figure out a way to design a divorced downpipe where the wastegate door would not seriously impede exhaust flow out of the wastegate, so I decided to make everything as open and smooth as possible instead. This also makes my downpipe a lot simpler to build, and in theory could help the turbo spool a bit faster by decreasing pressure on the outlet side. Not that I’m really going to notice faster spooling at a whopping 4psi.
….so it begins 🙂 I really need to do the same, my ihi has a puny port, I had it properly bored but it didn’t make much diff however I only added about two mm. this left about one mm for the flap to seal. I think I need to do some extensive housing porting and get a bigger flap, I really don’t want to do anymore serious fab work, so I’m not willing to go external, however my boost spike with the new 2.5″ exhaust is just too much, 15psi on a 6 psi gate, add to the mix a bad tank of gas this morning and I was just about ready to ditch the whole turbo thing.
Scarey. That much boost creep will surely be the end of my un-managed small port. Maybe I’ll port the wastegate now!
Oops, thought you had enlarged it all, if it’s close to 1″ already you will be fine, mine is probably 5/8 at most.