Roots Blown Rotary?
 

Hey all. Got to thinking. Over the years I have seen plenty of Turbo rotaries, but never a crank (eccentric)-driven supercharger on one.

Seems like it would be easy to fabricate the intake to do this as you'd just basically need 2 flanges, and could plumb the pipe between them whereever it needed to go, so long as the blower and eccentric shaft pulley lined up.

Or is there a reason I never see anyone do this?

http://www.camdensuperchargers.com/

A friend has one on his REPU, one on his FB, and soon one on his rotary 510. My cousin has one on his RX-4. There are a number of people on the forum that have them.

I've also seen centrifugal and twin-screw blowers on rotaries.

It seems that way, but it's actually a major pain to get everything lined up properly, find a correctly-sized blower, find space for the blower, and tune the darn thing.

1. Roots blowers are the least efficient (hottest) common form of forced induction, they are difficult to intercool, and rotary engines don't like detonation.
2. Roots blowers are low boost machines and all the kids nowadays want high boost.
3. The only Roots blower kit on the market is about the same price as a turbocharger kit capable of twice the boost.
4. Rotary engines make their power higher in the rpm band and have a very strong exhaust pulse, which is a good environment for the superior turbocharger.
5. There is a huge supply of factory turbocharged rotary engines, and you can buy an entire Turbo II RX-7 in good condition for the price of the Camden kit.

Depends on what you want out of it. For a supercharger you don't have to redo your exhaust, you start boosting basically right off idle, and there's no lag. If you're carbureted, it really doesn't cost that much more than a comparable turbo setup (including exhaust, boost controller, intake piping, carb hat, and the other things you need for a turbo that you don't need for a supercharger). No, you won't make tons of power, but the carbureted Camden kits are braindead easy to set up and are a very nice power increase over stock. That said, I'm still going with a blow-through turbo setup.

Now, if you're EFI, everything Evil Aviator said applies.

I was thinking a Predator carb and a 3-71 or 4-71 poking through the hood of something barbaric and pre-smog. A Model T Roadster if I wanted to be fancy...Or Possibly a certain '71 Postal Jeep. It currently had a VW/Audi 4 banger, and if I didn't like the GMC blower/Rotary combo I could always use the blower on a slant 6 in another car later, and go turbo with a rotary on it OR just stick a V8 in the Jeep...But that's almost too easy these days.:rlaugh:

This is not something I am considering in kit form, this would be hideously homebrew.

Most of my experience may be with V8's and Slant 6's but I can assure you I am into freakish renegade fabrication, not just sending someone a blank check for polished parts.:lol: