In 1908 they were running 3:1 compression and 1000kg engines. Was that with pure alcohol?

I heard that an A-series engine can't take 60 psi, it is impossible. Let's see you prove them wrong!

it was on diesel tractors, im not using an a series its a ca18det

Got interested a while ago about 2005 on Compounded turbo setups cause of some Mitsu 4g63 mitsu beat pretty everything out there with over 60psi and his name was Brent Rau or other breaking 6 seconds, mad stuff.

What i have heard is back pressure is a problem with compound turbo charging the second turbo needs bigger rear housing to stop flow problems but i don't know for sure at the moment because i haven't tested mine out yet AND wheres your build thread :P

Great work! Can't wait to see the result!

60psi so a pressure ratio of about 5 or sqrt(5) per stage.

Engineering guestimate to get started would be first turbo as normal, second turbo to match the new flows, so if you're going for a PR of 2 on the first stage you size the second turbo for an engine of twice the size (roughly speaking).

Pressure sensors before each turbine and after the final turbine would help refine the housing sizes. When a stage starts to choke the pressure will rise rapidly with rpm before that turbine.

Mechanical strength and maximum heat loading will likely be the limiting factors. Water injection eases the heat loading issue. I've thought about this before and thought that Water injection post the first compressor for the first inter-cooling (essentially to prevent reaching the temperature limit of the second compressor and getting a creep failure) followed by a bar and plate intercooler. Some water will condense in the intercooler (depending on how much you spray in). You can either recollect and reinject it or let it bleed off through a pin hole or float valve. A simpler but more expensive option would be a titanium compressor for the second stage and one intercooler. You've already gone air-water so see if that works first. Test how robust it is by sealing it off and filling it with compressed air.

Love to see this thing working, it's been done successfully elsewhere.

looks like the big turbo is going to sit outside/above the bonnet :O
What size rear housing you running on the big turbo?

Sounds interesting!
At 60 Psi, It`ll probably go over 1000Hp. I`d love to know how to size the turbos for a compound setup. How does the math work?
Those hoses and clamps on the intake plumbing wont cope with those presures. If you run tie bars either side of each joint, it will help a little. Wiggens type clamps would be what i`d use.
Maybe use a bar and plate intercooler, i cant see a tube and fin type holding up.
What comp ratio and fuel are you going to run?


Keep us updated, Ive never played with compound stuff before.

I`ll be watching with interest.