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-   -   Update on my supercharger project! (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/update-my-supercharger-project-381931/)

gold87na 01-02-05 04:25 PM

Update on my supercharger project!
 
Http://pissuoff.gotdns.com:81/rx7 sorry about it running on port 81 my isp blocks incoming port 80. It's nowhere near done. I still need fuel/engine managment upgrades, and a lot o dyno time.

scathcart 01-02-05 04:37 PM

Some of the specs. on the charger are 1.4L/rotation & 10,000 pulley rpm redline. That leaves easy math :-) A rotary engine takes 1.3L/3 crank rotations. This should yeld about 14-16lbs boost.

Might want to rethink that math... or even your conception of how a rotary works.

drago86 01-02-05 04:48 PM

its 1.3 every 2 rotations...

scathcart 01-02-05 05:06 PM


Originally Posted by drago86
its 1.3 every 2 rotations...

Wrong again.

Combustion chamber is 654 cc's. In two crank revolutions, we have fired on two rotor faces, on each rotor. 2 x 2 x 654cc's is 2616 cc's, so the engine moves 2.6L of air in 2 revolutions, given 100% volumetric efficiency. In one engine revolution, we move 1.3L, is 3 engine revolutions, we would move 3.9L.

This has always been the big argument... our engine moves twice as much air as its rated displacement in two revolutions whereas a piston engine moves its rated displacement in 2 revolutions.

gold87na 01-02-05 05:18 PM


Originally Posted by scathcart
Wrong again.

Combustion chamber is 654 cc's. In two crank revolutions, we have fired on two rotor faces, on each rotor. 2 x 2 x 654cc's is 2616 cc's, so the engine moves 2.6L of air in 2 revolutions, given 100% volumetric efficiency. In one engine revolution, we move 1.3L, is 3 engine revolutions, we would move 3.9L.

This has always been the big argument... our engine moves twice as much air as its rated displacement in two revolutions whereas a piston engine moves its rated displacement in 2 revolutions.

Thats a good fact. I did not know that.

Thanks for finding the bugs, keep it up! I made this page from start in the past 2 hours. :)

scathcart 01-02-05 05:22 PM


Originally Posted by gold87na
Thats a good fact. I did not know that.

Thanks for finding the bugs, keep it up! I made this page from start in the past 2 hours. :)

Are you positive that your supercharger moves 1.4L of air per revolution of the supercharger?

None of your pictures load for me, so I can't really offer comment on much else.
You might want to consider a small intercooler... an TII intercooler would work very well front-mounted for your application.

BlaCkPlaGUE 01-02-05 05:28 PM

That supercharger mounts directly to the block, how are you going to fit an intercooler in there?
Do you mean cool the intake air with an intercooler before it meets the supercharger?

gold87na 01-02-05 05:33 PM

no the outlet of the supercharger is going to go into the intercooler then into the throttle body. It will have a BOV right after the supercharger. I'm going stand-alone haltech e6x so i wont have a MAF. then i would be able to relive un-needed boost. It's not done by the books, i already know this. I'm just having fun. :)

gold87na 01-02-05 05:34 PM

the toyota sc-14 has a 2 1/2" inlet and a 2 1/4" outlet.

gold87na 01-02-05 05:38 PM

http://homepages.tig.com.au/~ovlov/technical/blower.htm Thats the best info I could find on the blower.. that claims SC-14 = 1420cc displacement

SonicRaT 01-02-05 07:01 PM

It's efficiency is it's big downside, and as far as boost psi, forget about it. 16psi is a useless number. The things to worry about are CFM and temperature. That thing is going to create some impressive heat due to the port design on it, and once it creates heat, up goes the PSI, but it doesn't do you much good.

Evil Aviator 01-02-05 10:17 PM

There are several reasons for the excessive heat:
1) That supercharger was designed for a 2.0L 4-stroke piston engine, which only breathes roughly 1.0L per crankshaft revolution (ignoring volumetric efficiency). You will need to run the supercharger about 30% faster to create the same boost level in your 1.3L rotary engine. Like most things, superchargers tend to run hotter when their rpm increases.
2) Roots type blowers are the least thermal efficient form of forced induction used on modern vehicles.
3) Roots type blowers compress the air in the intake manifold plumbing, not in the supercharger itself. Your plumbing is incredibly inefficient, which is going to increase the heat produced upon compression. I suggest that you re-make your plumbing out of metal with few bends and gradual flares. Since you want the intake pipe as short as possible, it is not a wise idea to use a front-mount air-air intercooler. It would be better to integrate some type of cooling system with your custom manifold intake piping. See here for ideas:
http://www.superchargersonline.com/p...rcoolers_water

BTW, your supercharger mounting brackets are too thin, not reinforced, and they look misaligned. Corky Bell's "Supercharged!" book shows how to make good brackets, and will also explain MANY other aspects of supercharging your engine.
http://www.walmart.com/catalog/produ...est=9999999997

gold87na 01-02-05 11:01 PM

thank you for the tips. i'm definatly goingto do some reading.. if i don't like it i will have the fuel injection already built and ready for any other forced induction setups.. i do have a turbonetics t04b with a blown oil seal lying around. i just wanted to use the supercharger..

digitalsolo 01-02-05 11:36 PM

I've built SEVERAL roots supercharged engines (non-rotary) and I can tell you right now that an A/A intercooler is going to hurt you on that. On the same note, with the stock pulley, I'd expect more like 4-5 lbs of boost, not 14 lbs. Did you fully calculate your pulley ratios on that setup?


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