im looking atcually for the best 12A- 13B ever built im thinking its the 1989-1990 because of the compression of the rotors, but the 1984-1985 4 ports are the best housing for modification, i need to know if this is true and if so can i mix parts like 89-90 rotors into 84-85 housing then if soo stock no ports should give me around 155-160hp, 5-10hp less than the 6 port.........need back up ans. asap

 

The frist two years of the fuel inject 13bs the oring groves are in the rotor houseings, after that they are in the end houseings. The E shaft and rotors you can do any thing you want. 2mm 3mm late E shaft or one out of a 75 to 78 13b can be swaped any way you want to. I know some peaple out there are going to say I dont know what I'm talking about, but then what's that undre the hood of my 76 RX4. 76 E shaft. 85 rotor houseing, becouse it has the oil injection nozzles, and then what ever year the 2mm rotors had the high compression. With two turbos and K fuel injection, lots of porting.

 

just going by pics i've seen, all rotarys after '85 have the O-ring grooves in the intermediate housings. these grooves were moved back to the rotor housing in the rx8 engine.

now the engine i built for my rx3 is from a '74 rx4. the intermediates had the streetport and were reused, rotor housings were replaced with used ones, simular year and already ported, rotors were also replaced with simular year, e-shaft is from early 2nd gen '86-'88, not really sure, as is the wp housing to keep the alternating theme, aluminum, steel, aluminum, steel. i chose to use that particular housing to alow me to keep the two bolt steel outlet neck.

 

Toughest of all the turbo rotary engines is easily the 12A turbo from the HB Cosmo & SA RX-7 (series-3).

They will take 10 times more punishment than a 13B turbo & are good for over 200,000km if well looked after.

Series-4 (86-88) 13B turbo is ok
Series-5 (89-91) 13B turbo is much stronger
Series-6 (92-95) 13B twin-turbo is ok
Series-7 (96-98) 13B twin-turbo is better
Series-8 (99-02) 13B twin-turbo is much stronger

 

well i looked up the compression of the 89-90 13B N/A the rotors are the lightest and the compression is 9.5 and the lightest of rotors. close to the 10 compression on the R26B but the housing on the 84-85 is the best for modification so im gonna go with a 84-85 housing with a 89-90 rotors for N/A power but i donno if it ill be good for turbo????