I assume you need an A/W IC because it's downstream of the throttle body? What were your intake temps? How much boost?

 

No, you don't 'need' an A/W, it's just better due to the shorter piping/etc, since the roots blower compresses the air in the piping/IC, shorter is better.

 

Of course. I say "need" because if you're going to have all that volume after the TB you're going to have enormous throttle lag, at which point you may as well have gone with a turbo...

 

I was thinking about going supercharged, because I can get ahold of a M90 supercharger for cheap.. I was only only looking to boost to around 6 (maybe 8?) PSI, EvilAviator says that they work well for a low boost application. Would this be considered low boost? I've never really got to play with a boosted vehicle, so I figured that a "less than $350" supercharger setup would work out well for my introduction to boost..

Any thoughts on that?

 

Even with a massive frontmount and long piping you hardly notice.

 

That's what I did... Read averything I found + that I bougth a great book called, SUPERCHARGED written by Corky Bell. That's where I found all the numbers, facts and figures.

I do learn a lot here on the forum, I would not be here if I didn't...
I do thank you all for that!
And I will keep up with the building of my project, the first supercharged rotary in Sweden:

rx7 FB -83
13B streetported 6-port
Eaton M90
FMIC
Microtech LT10 with X4
Ford Racing 70mm Throttle body
Bigger secondary injectors
12Psi boost
calculate with 320hp

Thank's all of you out there!

 

And for sure, I need all help I can find...

 

I'd recommend looking for a Gen 5 M90 (2004 Grand Prix's have them) and adding an A/W intercooler on it. These have pushed 3200 lbs FWD cars into the 10s, with 3.8L engines, so it is possible to put out some power. These are HEAVILY modified blowers with very built engines and high efficiency intercoolers though, so YMMV.

Thanks for posting those graphs aviator, I couldn't find mine for the life of me.

The other thing to keep in mind here, is that it isn't the amount of "boost" that controls the heat of the air, it's how much air is being moved, which is not necessarily the same thing. The more efficient your engine is (i.e. street port, bridge port, etc) the more air will move through it, and the less boost you will make per given amount of supercharger RPM (speaking in roots). To make the maximum power from a roots charger, you'd want a high compression, high efficiency engine spinning it less then ~13K RPM. The thing is, you'll still have to be VERY careful on the tune, as it will NOT forgive mistakes, or cheap gas. I've got 3 blown 3800 Series II engines sitting in a garage (I didn't blow them) to attest to that, and those are MUCH more resilient then ANY rotary dreams of being.

An MP112 with an "S" port would be an even better option, as it takes less RPM per given volume of air output, with only slightly more parasitic drag (heavier rotors).