Anyone considered a...

[Schtoo]

...supercharger for a rotary engine?

Yes I know everyone uses a turbo, and yes I know they work well and all that. But why would a supercharger not be a viable option?

I don\'t mean and old roots thingy, something like the newer centrifigal jobbies.

Would it be a reasonable thing to try or not?

[grinder]

wasnt they looking to supercharge the 8 - or am i way off ??

[Schtoo]

As in Mazda, maybe they were. They have used blowers before.

Aftermarket, Knightsports uses a blower. Greddy, Amemiya and others use a turbo. One of the shops in the mag I have here uses a Nitrous (WHY???) system.

Just had a thought while I was doing some serious thinking in the smallest room. I wondered why no one uses a blower. There has to be a reason doesn\'t there?

[20B_boy]

Arent Knightpsorts having a lot of problems with their \'8 SC kit?

[nikp]

Aren\'t there rumours that there is going to be a Gen 4 RX7 with a 1.6 rotary and supercharger!?

[bill shurvinton]

The basic reason is that turbos work so well with the characterists of the rotary (hot exhaust, lots of energy there to make boost with). Superchargers at the end of the day are far less of a free lunch than a turbo, as you have to drive the thing off the crank.

There are 3 sorts of Superchargers:

Blowers: Rootes and eaton. Nasty inefficient things. Eaton best of bunch and available on Ebay. Used on mercs and the like
Screw compressor: Lysholm. Pretty good. batsrad expensive. Same boost at all RPM with operating range of unit (so big low down kick).
Centrifugal. Basically a  turbo compressor on a gearbox. Most efficient, can plumb and intercool like a turbo. Boost curve is exponential, so no boost at low RPM, max boost near red line.

All have been run on rotaries at  some point AFAIK.

[g11ary]

excellent.
Thanks

[GaryS]

Originally posted by bill shurvinton
Centrifugal. Basically a  turbo compressor on a gearbox. Most efficient, can plumb and intercool like a turbo. Boost curve is exponential, so no boost at low RPM, max boost near red line.

All have been run on rotaries at  some point AFAIK.

You can plumb and intercool an eaton with no problems as well.

SCs fall down at higher temperatures, plus have an efficiency range for rotar/screw spin speed.  Also you lose power to make power and if the belt starts to slacken you really notice it.

[antnicuk]

i have a Vortec SQ2 ready to go on my 20B,  its the centrifugal type. It makes any turbo compressor housing i have seen look tiny. The inlet is 5" and comp wheel is 4". It is rated to 650bhp.  The 20b has plenty of torque so it can spare a bit to spin the S/C.  Should be running in the summer. Its in FD so should be fun!

[Schtoo]

Just wondering.

I still might try it one day, but I\'ll use a design you can\'t buy. Which means I gotta make the thing.

But that\'s a way off I guess.

I guess a rotary is like a diesel in this regard. Yes you can stick a blower on, but they really like turbos better.

Thanks, more questions later.