Compound system

PARTS FOR SALE: Limited availability on 1UZFE EGR Delete Kits, Torque Converters and Supercharger Fish Brackets. No turbo kits. Email for info: [email protected]


New Member
Hi guys, I want to run compound turbos on my 1uzfe non vvti. It is in a BMW e30.

I'm thinking of using a Holset super 40 with a 14cm exhaust housing for the smaller or first turbo to something like a Holset hx55 with a 18cm exhaust housing for the second, might even go bigger on the exhaust. Will fit one turbo on one side of the engine as I would like to run the connecting pipe from turbo one through a smaller intercooler before entering turbo two, back through another intercooler to the intake to keep charged air as cool as possible.

Space is a bit of a problem but since I am doing a custom suspension front to a 4link rear I was thinking I can just as well move the engine/firewall back maybe 15cm.

Any advice/comment would be appreciated. Build is more drag orientated than the street, motor fully build on th400 trans, Toyota d4d 3.66diff( for now) as 9inch diffs are very rare in South Africa.
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Staff member
Interesting build for sure! Do you have any pics or updates? Hopefully someone can jump in and provide some insight here.


Super Moderator
Staff member
Sydney, Australia
Moving firewalls creates lots of interesting problems with lots of interesting solutions.

If you want (or need) to keep things like heating and defrosting functional it is a real task.

Think about it very hard before you start cutting.

I've built two vehicles (well the same vehicle twice!) with an altered firewall and it's a total head f--k.

Compound isn't easy to do and doesn't give quite as much as you expect.


"Supra" Moderator
Staff member
Houston, TX
JustenGT8 did a compound setup with a supercharger & a turbo IIRC, or it might've been twin turbos (memory fails me). But it didn't work out for whatever reason. Maybe too much boost for his engine?