cbro

iTrader: (3)

hey fellow Rotards I have been lucky enough to come across the purchase of a paxton supercharger for my vert street ported 13b na I would like to know of anyone who has the same mod and is one of the very few rx7 with one i would love some insight on how to get the max hp out of it and what kind of things i should take into consideration when installing it can i get it rebuild if necessary and would i have to out sourese since paxton no longer makes them thanks allot rx7 club

Aaron Cake

iTrader: (1)

Luck may be variable considering.

The Paxton kit was fairly terrible. The compressor is mismatched such that it provides very little boost down low (typical of centrifugal superchargers) but by the top end, is being overspun.

I believe the original kit used a rising rate FPR to add fuel as necessary. While fuel can be taken care of easily, the NA ECU is still commanding 30+ degrees of timing at WOT in the mid to high RPM range. That's what will blow the engine.

cbro

iTrader: (3)

Hey aron cake thanks for the respond ive seen your youtube vids great stuff man
Anyways as for the paxton i was planning on pickin up and haltech during instalation now for the overspinning can this be avoided
Can i increase the low end boost with a proper tune?

roe-tah-reeeeE!

cbro

iTrader: (3)

Reson i ask is im not looking for more than 300 hp on a mild streetported s5 13b

roe-tah-reeeeE!

misterstyx69

iTrader: (142)

you wouldn't likely get it anyways with that,so you have,in reality, already achieved your goal!

Evil Aviator

You can install a larger pulley to avoid the overspinning. See these two websites:
Roadrunner's RX-7 Page
Phil Garrott's 1988 RX-7 GTU Supercharged

No! Centrifugal supercharges are basically a centrifugal turbocharger that is spun via engine rpm rather than exhaust gas. Centrifugal compressors produce boost at the square of rpm. The only way to increase boost at lower engine rpm is to use a different gearing or pulley ratio. The problem with this is that the compressor redline will be reached at a lower engine rpm, which is exactly the problem that the Paxton suffers from if you use the original pulley.

In other words, a centrifugal supercharger is more or less a turbocharger with massive lag. The advantages of this is that the boost rises at a predictable, constant geometric rate, making the car easier to drive, especially on slippery surfaces or when precision work is required such as in autocross or drifting events. The disadvantages are that there is little low-end boost (although as mentioned above this may be an advantage), and engine output is reduced because it takes horsepower to drive the supercharger. Given the same boost level, a supercharger will produce less horsepower to the wheels than a turbocharger. This is primarily why the kit was never very popular.

If you want low-rpm boost then install a Roots or Whipple (twin-screw) type supercharger. A Roots is designed for 8-12psi max boost, so if you want more than that you will need to go with the more expensive Whipple. Another option is a V8 swap, in which case I think that you are better off simply selling your RX-7 and buying a Mustang, Camaro, Corvette, or other V8 sports car.

Good, because you will only get about 250bhp with that setup.

Customisbetter

The amount of money spent making that old thing work is much better spent on custom fabbing a better supercharger.

I personally am going roots style although you must take my words with a grain of a salt as I have only done the math and not the whole process yet.. The only roots type blower that is worthwhile is the M112 from the ford Mustang cobra and SVT Lightning or a high end TVS or twin screw.. If you go centrifugal you might as well bolt on the already easy as hell and cheap turbo set up.

cbro

iTrader: (3)

Wow this is allot of info in a very short time thanks guys well i have the supercharger still are any of you guys interested in buying it
Its in perfect working order and its deff a raRE find also the mounting bracket is the right one and as for the pulley i have the right size one that said not to overspin
Plus i might aswell just tune my na to that 240-250 tips mazda trix has done also on their vert their right up the street from me

roe-tah-reeeeE!

Customisbetter

Its takes a lot more than a "tune" to get that much power. We are talking totally custom headers and fabricated intake. Plus really nice porting and other engine work in addition to a well tuned stand alone ECU. $$$$

cbro

iTrader: (3)

Hey custom is better

Well im on a freshly street ported na saving for a haltech re any tips
Can i get the na higher than with the supercharger or nab

roe-tah-reeeeE!