Thread: twin scroll on an undivided manifold with a valve....

good bad or indiferent then?

I like the idea. I think it's great. A good stop-gap between regular turbos and continuously variable A/R turbos.

^^ yep thats the one, cant be used with fully dived manifolds.

i think for it to work well you have to have the waste gate pressure for the flap set lower than the wastegate pressure for the boost control.

a negative of the set up however is that it has to run a undivided merge collector, and when the flap ovens you will get turbulence caused from the actual divided between the two scrolls and then again from the flap.

what would be really cool, is if you could have a flap in the ex housing that works like a door hinge, and when its open it makes the wall for the divided housing, then once its shut it flips over and makes a 45deg against the side of the housing shutting off one of the scrolls. this would be better as you will have a better entry into the single scroll, and when its open you can still run a fully divided manifold set up.

I think the evo's have 2 wastegate flappers inside the exhaust housing on their twin scrol turbos. You may want to look into how those work. I was thinking about using one of the evo 8-10 turbos as they are pretty cheap used and make very good power.

I see what you're saying. Something like this? =]





Or did you want it actually inside the turbo housing?

Maybe this is more what you were after?

Both of those diagrams look promising except you're in trouble if you can't keep the "door" shut in the middle position without fluttering or slamming "open" due to the pressures created from the passing exhaust gas.

yeah something like those would be nice.

either would be good, but i originally thought it would be easier to make work inside the actual turbine housing. However if a company made an actual machined collector with the first design in it that could as well i suppose, then you can just weld up the divided manifold to the collector.

you are right you would be in trouble if you couldn't keep it shut, but if the flap when in the middle position was slightly counter sunk the gasses would atcually help keep it in position

**so in your drawing have the flapper rest up against a piece of metal extending from the bottom a few mm the shelf, extend past where the flapper is, so not flush so the gasses will push the flapper against the metal lip**

now if you can understand that and draw it, my hat goes off to you, as i doubt i would if i was reading it lol