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-   -   Rotor Housings interchangable between 1st and 2nd gen? (https://www.rx7club.com/new-member-rx-7-technical-256/rotor-housings-interchangable-between-1st-2nd-gen-1092819/)

tbauerc4343 11-29-15 10:47 AM

Rotor Housings interchangable between 1st and 2nd gen?
 
Is it true that I can use 1st gen turbo rotor housings with 2nd gen irons and rotors?

RotaryEvolution 11-29-15 11:27 AM

if this is a 12A Savanna, no. if it's a swapped car, no friggin clue what you have so i can't answer. the only other 1st gen that was turbo was a conversion kit done by pacific avatar which was also a 12A, and answer is still no.

the next question is why?

many earlier cast irons actually have more meat to port LARGER than a second gen can be ported to. the early B casting truck 13B irons, and the R5 for example are great for hogging out.

the issue isn't the ports though, it is how mazda moved the coolant seals after 1986. you could have the rotor housings CNC cut for coolant seals, but again what is the real purpose? you would then have to use the FC water pump with an early front cover.

if you're building a turbo motor, use a turbo motor and just swap the front cover and GSL-SE pan versus tossing a buncha random parts together. otherwise just run what you were given til it blows, then swap motors.

tbauerc4343 11-29-15 11:44 AM

Well, I am sure it's my poorly worded question. I was referring to the s4 and s5 version swaps.... I was told that you can make more power using the s5 rotors with the s4 housings, or vice versa. Also there was swapping an upper manifold using the other lower etc etc. Sound familiar? That's why I am here in the short school bus side, so don't beat me up, I can pull it up somewhere I am sure. But when a bet is made we want the answer now.....lol

RotaryEvolution 11-29-15 11:55 AM

S4 is low compression, S5 is high compression. S4 can run higher boost, so more horsepower, S5 has more down low torque but cannot run high boost so more torque and less horsepower.

S4 rotor housings are made of swiss cheese similar to what the FB originally came with
S5 rotor housings have a superior plating, just short of the FD 3rd gen housings which also can be used in any post 1986 engine, these all must be used in pairs.

so if you want to swap engines, id say S5/FD are superior unless you are building a drag racing engine, but i doubt that or you wouldn't be asking such a simple question. :)

1970-1985 9.4-9.6:1 compression
86-88 non turbo 9.4:1
86-88 turbo 8.5:1
89-91 non turbo 9.7:1
89-2002 turbo 9.0:1
2004-2011 renesis non turbo 10:1

9.4:1 is marginal for turbo engines, 9.7-10:1 i consider not good for use with a turbo/forced induction with regular pump fuels(E85 being an exception).


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