A new thought for twins - Compound Turbos? Maybe?

[TitaniumTT]

Originally Posted by classicauto

Ive seen a number of trucks in here with compound setups, and always had wet dreams about one on a rotary.

I know there's a kit for supra's using a compound plumbing setup, and its laying down RIDICULOUS spool and insane top end on the 2JZ. Search around the net, can't recall the name of the kit ATM.

Thanks Joe, I'll check it out.

Originally Posted by classicauto

Personally, I think taking the general idea and adjusting it to suit the rotary's strengths is the best approach. I would personally like to see the small turbo fed first, but reversing the direction of the intake air. Have the large turbo suck through the smaller one. Thoughts behind that being: the smaller turbo would have -essentially- vaccum on the compressor which is going to help it gain shaft speed very early. These babies like the air volume as we all know And once that snowball effect starts to roll on as the exhaust pumps out more and more pressure and volume - well we're off the races

I'd also love to see this scaled for a rotary as well. The dyno charts that I've seen for the diesels look exactely like what I'm after. Instant and constant torque.

What I'm wondering is, could we have the smaller turbo feeding the the larger turbo, both intake and exhaust. What would the larger turbo do when it sees compressed air and spinning at low shaft speeds? Would it pose a restriction? Or just let it pass? If the smaller turbo is running a 2:1 and the larger is just starting to spin, would it allow the 2:1 to pass through, wold it start to spool up with a positive charge thus evacuating more exhaust? Or would it just act like a plug?

Originally Posted by classicauto

I do feel though that cooling will become a larger issue with this setup. We know its a problem that you have manage well on these things already, and 2X the exhaust plumbing, 2X the compressors etc is going to create a larger easy bake oven then a single turbo. It may be worth considering a small cooler between the first and second turbo (which ever you mount first) like one of those tubular style babies. Just something to add some extra density and take some load off the main intercooler.

Heat can be managed, I think size constraints in the engine bay are going to be the limitations

Originally Posted by classicauto

I love the idea, and think that with a well tohught out setup, we can see a true example of what Mazda may have designed if the intended the FD to be 550whp from the show room

How sick would that be?

Originally Posted by classicauto

If there was ever a man I would have hoped to tackle this task - its you Brian. If you head down this road, I know its going to be all it can be.

Thanks Joe! Something will be done, and it will be done in an unconventional way. I just don't know what it is yet.

I've done some research on VVT's as well. Garrett has a GT37 designed for diesels with this technology. I need to call them soon and get some information. There's also a company callled Aerocharger that's offering some promise as well. I was VERY skeptical about this until I saw all the military applications for it. Still seems "gimicky" to me though.