how can you estimate the speed ratio (crank:SC pulley) for a wanted boost value, created with a supercharger?

say you have a 13B, with a positive disp 1200cc/rev supercharger.

 

I had looked into doing this without moving the throttle body. What you can do is get a large vacuum activated valve. There are a bunch out there, not very expensive either. When there's vacuum, it's shut. When there's little vacuum it springs open. Put this before the supercharger.

Between your SC and your TB you put a bypass valve that is open during vacuum. This will give your engine air when cruising/idleing. this way cruising down the highway at 65... you can keep your SC in a vacuum state and get good gas mileage.
This is nice in that it keeps you from having to move your throttle linkage and etc. around.

Personally, I think the m90 is a good cheap starter for a boost application. Use it to learn the ins and outs of boosting your engine, then move on to bigger and better things. I don't why these threads turn into wars. It's quite simple, people are doing something, they want to do it cheap, and they want to learn how to do it so that when they go bigger, they know more. Better to learn cheap than to learn expensive and blow your **** up.

 

The m90 SUCKS. It blows more hot-air than it's worth to make anything even resembling power on an FC. And doing it cheap is exactly that, cheap. And generally, learning cheap leads to being more expensive than doing it right the first time.

 

And wtf is with these damn posts from forever being bumped?

 

Here's a twin blown Miata.


More: (56K, go make a sammitch.) http://brpforum.infopop.cc/eve/ubb.x...ColdFusion.wmv


Another pissed off Miata, just because.

Chech out the little details like the dual K&Ns in the cowl.
22psi = 340+ whp!
More: http://biggulp.home.att.net/Aboutbig...Gulp%208/29/04

 

how can you estimate the speed ratio (crank:SC pulley) for a wanted boost value, created with a supercharger?

say you have a 13B, with a positive disp 1200cc/rev supercharger, and want to boost max 6-7 psi

 

bump

anyone?

 

"rotary engine displacement ??"
https://www.rx7club.com/showthread.p...81#post4324081

Rotary breathes like a 2.6L 4 stroke engine or 1.3L/rev.

1.3L * (psi +14.7)/14.7 = 1.2L * crank ratio

1.5 times crank speed for 6psi.
1.6 times crank speed for 7psi.

 

how would this be set up? is it like the sequential turbos the FD has?
that'd be nice to minimize turbo lag.