I've looked around doing a LITTLE bit of research on my work break.

I suggest anyone interested in compound DUAL turbo step who is serious spend days, if not weeks if not months researching how to lay out the system. Several different ways to plumb and size the setup, not to mention manifold setup.

The twins setup would be a hell of alot simpler to fab and lay out.

 

Here's a simple setup. I've seen some fancy wastegating control (all can be set up manual/non-controlled by stand alone if need be) going on but this seems straight forwards.

You could use ONE of your t25's to spool up a large holset. Say hx40/hc1 with an 18cm or 20cm housing and still come out with a decent budget than doing parallel twins. You can't technically benefit at all from using twin t25's in this setup since you're merging both rotor exhaust pulses into ONE hot side. Bottleneck of heat/pressure=bad. Very bad.

Whatever you choose will be virtually lagless in terms off boost response but compound will give you the best of both worlds. All the perks of a small turbo combined with the top end flow of a big turbo without any trade offs. Well, maybe more weight or something like that.

The thing that amazes me is how the large turbo feeds the small turbo yet the small turbo spools the larger one. That's pretty cool and can still be totally ghetto fabbed. You just have to find a large diesel turbo at a junkyard. A semi-truck/tractor yard would be a sure thing but there are a bunch of chevy vans that came factory with rather large garrets strapped to them. There was one at the yard here but it suffered an engine fire and completely melted the compressor housing. I came up on the rear/passenger side, seen what i thought was a turbo, came around to the front and wanted to cry. What a cocktease.....

 

One more setup.



And ****



If that doesn't get you hot, i dunno what will.

 

Holy ****!


...

What engine is that?

 

probably a nissan v8 used in a boat.

 

Hmm...so low and wide... Almost makes me want to say porsche.

This is EXACTLY the type of post I was hoping to elicit!