Engine/Transmission (1994 - 1998) home made twins!?

[HoleshotHolset]

IMHO - an HX-55 isn't a big enough bottom turbo when you're using an HX-35 up top.



I want to experiment with using an HX-35/12cm² (wastegated) AND a big external wastegate dumping into the inlet (hot pipe) of the bottom turbo. I hope to get really good spool and top end without insane drive pressures...



The non-wastegated housings are cheap compared to the wastegated housings... if you want to play - you gotta pay.



Matt

 

[Jim Fulmer]

I know while i have the cam out i am going to go ahead and put a piers regroung cam in there. this ought to help my twin set up out once i get them done.



Do you realize this is now above me in the cam stuff?



Jim

 

[BPonci]

Matt, The 12cm works great with an external w/g.

 

[1dslram]

TT:

If you don't wastegate your top turbo your backpressure will be so great you won't get any real help from the twins. You have to be able to get the exhaust out. With my H2E turbo with a wastegated 14cm housing I could get 45# of boost but that was with 70# of backpressure. With twins and a 12cm housing backpressure would be worse than that.

Bruce

 

[BPonci]

With twins and a 12cm housing backpressure would be worse than that.

(That all depends on how you set it up. )

 

[HoleshotHolset]

"Matt, The 12cm works great with an external w/g. "



That's one positive vote. Cool - there's hope for my plan afterall.



What size turbine housing are you running on the big turbo? My 36cm² is a bit on the large side. :-laf



Matt

 

[vssman]

Any suggestions on type/size of external wastegate?

 

[Forrest Nearing]

tial has a sweet little 42mm wastegate w/ v-band inlet/outlet setup... unfortunately, it's in the $375-425 range. (still a far cry cheaper than turbonetics v-band new gen gate that lists for almost $700!)



I'll probably just end up with a little 38mm gate as I'll still have the internal gate on the top turbo, and I'll port that orifice out and grind my flange to allow the flapper to open a little more as well.



Forrest

 

[BPonci]

What size turbine housing are you running on the big turbo? 26cm

 

[Forrest Nearing]

I've got a 22 undivided and a 26 undivided. The consensus is that I'll be happier w/ the 26, so that's what I plan to run.