I have been reading lately (uh oh) and read a bit about twin scroll turbo systems. It seems like a great system for a 2 rotor.



Thoughts?

 

hmmmm

 

How would you split it up? front and front siamese port on one runner, and rear siamese and rear port on the other?

I haven't ever really looked into Twin Scoll turbos, but the only car i can think of is older jdm STI's. (series 4 or 5 i think) even though I know there are more out there. Are there any with enough flow for what you'd want out of it?

edit: May have just found the answer. AP makes a GT35R twin scroll upgrade for the Evo X

I'd imagine that would answer the "what turbo" question

 

I know EVO's. Mini's, and BMW's run them. I'm not sure how the manifold would work but I'm sure some of the expert fabricators here could figure it out.

 

I think it's an interesting option for sure.

scribed for the edumacashun.

 

The center exhaust port would be the tricky part.

 

S5 TII's have a twin scroll turbo...are you thinking about running a twin scroll on your greddy kit???

 

Well I am just thinking it would be an efficient setup, but I am no expert so I am not sure what the disadvantages are.

 

I dont see how it could be a disadvantage...spool up would increase dramatically...i was doing some reading on this before i came back from iraq i know a lot of the dsm crowd run holset twin scroll set ups...its pretty much gona come down to manifold design so like you said that center exhaust port is the tricky part...

 

Can anyone find a good pic of the center exhaust port on a renny? My search skills must be lacking today.

 

I'm no expert but, the center exhaust port is shared which would make it very difficult/impossible to do properly.

If I am wrong someone please help me understand.

 

I dont think it would be possible to split the middle port? Idk? Even if it were split those would be some narrow runners.

 

That's why I am trying to find a pic to see how it is divided. Also, I'm not sure but I think the exhaust pulse would effect things as well.

 

Okay so bring the existing split in the center exhaust port out and work it into the exhaust manifold as well?

 

I was about to post that same pic.

I assume it could be done but to get it to be sealed would be the tricky part, also being FI will cause a lot more heat there so it would have to be made out of some very heat resistant materials to last for a good while.

 

Yeah it might be more trouble than it's worth. But I wonder if just the other two ports would be enough and then jut rout the third port post turbo?

 

Another route would be to split the middle runner itself into 2 after the flange.

 

True, it would force it into two separate pathways.

 

It would probably take some fine tuning to figure out how far away from the flange to put the split. too close might impede flow, and too far away might not divert it evenly.

 

You're not really writing about a twin scroll in the traditional sense but instead a divided turbine/manifold setup. Twin scroll are valve actuated designs that change the angle the exhaust gas flows into the turbine wheel.


Best option would be to do what Mazdatrix is up to as it should also benefit exhaust manifold pressure issues.

 

Where are the valves?

 

FD builds do it,

My crazy idea would be to plum the center port to the wastegate, then have the other t split, but that could cause some restricted flow and heat build up

 

1984-1985 exhaust p-port housings with the Renesis side ports plated off and you're golden, you will also need to modify the rotors for deeper 13B apex seals

friend recently built a divided turbine twin scroll 13B with custom two pipe header to each scroll, equivalent to a Garrett 28xx size, makes boost right off idle with 430 hp peak and extra fat tq curve

 

This is an interesting concept, subscribing for more info

 

I guess I'm just not seeing the advantage of running a twin scroll in the RX-8 since one of the intake ports would have to share pressure from both turbo chambers anyway. Maybe someone could enlighten me?

Edit: I have been enlightened