Sequential Turbo Build

[IceV_760]

Compound setup aint not bad at all. I have been planning it just to some car, and know kind a lot about it.
Firstly, pressure didnt multiply. It gives even more.
You calculate it this way:

20psi = (20psi+14.7psi)/(14.7psi) = 2.36 PR. So, that is pressure ratio on turbo, you calculate how much boost you want it gives, and add air pressure to it

2.36 PR x 2.36 PR = 5.57 PR. So, we have two turbos which will boost same amount, now just do the math

5.57-1 = Relative PR = 4.57. From that 5.57 PR you minus air pressure 1, and get the boost.

4.57 PR = 67psi. You see now, you dont multiply it, its over three times more by that "setup".

As a second turbo, which is on exh. mani, stock can be used. Bigger exhaust A/R recommended tho.

And then, how you calculate correct size where to look the big turbo?

Lets go for it.

D24TIC, 2.4 liters engine. OEM turbo is Garrett t03. And we want final boost to be, lets say 2.5bar, which is same as 3.5 Pressure Ratio, PR.
Engine revs will be 5´000.

So, displacement 2.4ltr x PR 3.5 x revs 5000= 42´000

Second part goes little to " i quess" side on some parts, but anyways, lets do it.
There you pic some bigger engine as compartment engine. "Just pulling some numbers from my hat."
What numbers we want then? Revs from big engine, and PR. So we downsize revs from d24tic some, and pic roughly normal PR from bigger engine.
Big engine will have PR of 2.2 ( 1.2bar boost) and will rev up to 4'500rpm.

So. 42´000 ( what we calculated correctly just minute ago) : big engines PR 2.2 : big engines revs 4500 = 4.2424.

So, engine where we start to look correct big turbo, has roughtly displacement of 4.2 litres. Search car with displacement of around 4.0-4.5 litres,
and search what turbo it uses.

I have far more longer done plans, but i dont want to
tell everything now. Just wanted to give some help to calculate what you may be planning to do. And at it is possible.
Here in finland we have few compound-charged diesels, atleast one toyota and few MB's as far as i know.

PS. Compound setup dont require any electricity to control it, you control it with wastegates. YOU will figure out how