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-   -   Which Supercharger? (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/supercharger-416758/)

springsracer88 04-18-05 09:22 PM

Which Supercharger?
 
i am looking into buying a supercharger soon... and i am just wondering which 1 i should buy for my 91 N/A... (yes i searched and after looking thru the first 3 pages with no result i gave up) thanx

SonicRaT 04-18-05 09:24 PM

Unless you feel like custom making everything to do it, you're pretty much SOL. The camden kit isn't worth the effort, and at the moment there are no other kits available.

springsracer88 04-18-05 09:30 PM

so if you were me....(and i want either to supercharge ot turbo my car) what would u do?


(btw....the kit that you ar making....when will it be ready?)

springsracer88 04-18-05 09:37 PM

so if you were me....(and i want either to supercharge ot turbo my car) what would u do?


(btw....the kit that you ar making....when will it be ready?)

PureSephiroth 04-18-05 09:43 PM

he'd do both obviously. ;)

There was a thread a long while ago about fitting a T-bird supercharger on an NA FC. Search for that, you might find what you're looking for.

classicauto 04-18-05 09:49 PM


Originally Posted by springsracer88
so if you were me....(and i want either to supercharge ot turbo my car) what would u do?

turbo it

bingoboy 04-18-05 09:53 PM

the tbird eaton m90 doesn't flow enough air for the 13b.

SonicRaT 04-18-05 09:57 PM

It does, just not for much power.

I've done both, turbo and supercharger already. And in all honesty, I'll say unless you've got 4k+ to dump, a turbo is the better bet. Check the thread for kit status.

Jezzder 04-18-05 11:43 PM

use the eaton supercharger off a jaguar xjr... and i am all with you on the supercharger bit... i dont really like the whole turbo idea...

really what you want is a positve displacement supercharger.... that will pump enough down there.... :)

SonicRaT 04-18-05 11:48 PM

An eaton m112 still isn't good enough for much of anything. They're so innefficient at low boost and expensive to install it's not worth the effort.

BrianVFR 04-19-05 12:17 AM

SonicRat, are you saying that the 13B breathes more than a 5 liter piston engine? I can't figure out how to calculate total CFM on this twin triangle thingy!

SonicRaT 04-19-05 12:22 AM

I'm saying that the eatons are inefficient over 8-10psi of boost unless you port the shit out of the charger and put every single peice of hardware you can find (custom plenums/air-water intercooler/etc), and they're STILL not very good at high boost. So, you figure in it's volumetric efficiency, then you figure it's adiabatic, and then you look at the max boost you can squeeze out of it without creating some insane heat, and you'll find on a rotary it doesn't do much good. The thing about it on a 5liter, is it can move air for 8psi, but still be somewhat 'ok' in efficiency because it's not actually *over* 8psi and forcing air back through the blades and so forth, where-as with a rotary, we require not much air, so we hit 8psi pretty easily while moving a rather small ammount of air, but the more you force feed it, the more inefficient that charger becomes.

I generally size things around a 2.6L to go with the rotary.

BrianVFR 04-19-05 11:49 PM

So, would it be better to go with a twin-screw type, like the AutoRotor that I put on the 928?

bingoboy 04-20-05 12:01 AM

we got an M90 on a six port engine and rev'd the snot out of it and it's making 5lbs of boost running off of the crank pully that runs the water pump/alt with a serpentine belt. this is with the smallest pulley you can get on the M90. as compared to their webpage i think we've already run the M90 out of the rpm range listed for their specs on cfm/boost etc.

RoadRaceJosh 04-20-05 12:02 AM


Originally Posted by BrianVFR
So, would it be better to go with a twin-screw type, like the AutoRotor that I put on the 928?

I would have to say so. For those in the US Whipple is the place. Roots type blowers are just that, blowers. They have no internal compression so they are pretty inefficient. The Lysholm types, like the Whipple, are internal compression superchargers and are much more efficient. A good centrifugal compressor like you find bolted to an exhaust turbine can be more efficient, but you don't get the broad boost range of the Lysholm compressor. The only thing I know of that came to the US with a Lysholm compressor was the Mazda Millennia S.

SonicRaT 04-20-05 12:02 AM

Yes, a twin-screw is better, though rather costly. :)


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