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-   -   12a BP vs 13B 6port SP? (https://www.rx7club.com/1st-generation-specific-1979-1985-18/12a-bp-vs-13b-6port-sp-944657/)

Jobro 03-08-11 10:06 AM


Originally Posted by 80's old school (Post 10505600)
OK, OK.... so will this work???

12a irons, 85 and older 13b housing, any 13b E-shaft, S-5 high compression rotors???? Will this work??

Then do I use a 4 port 13b manifold for a side draft weber???

As you can see.... I am trying to build my dream motor!!!

Also.... please advise from folks who have done this.... Not just dreamers and guessers!!!

The best (and still somewhat affordable) way to do it is as follows.

S4/S5 turbo rotor housings
S5 NA rotating assembly (have to find a rear counterweight from an automatic turbo model)
S4/S5 turbo front and rear faceplates
12A tall port centre plate
S4/S5 turbo to IDA downdraft manifold
55mm twin tapered bore bodies (efihardware.com sell them)
S4/S5 crank sensor in the front cover.
FD oil pressure regulator (rear).
New FC turbo oil pump

If you use an early gearbox you can just use a 8.5" lightweight steel flywheel. 4 puck unsprung button clutch. Match that with the right rear end ratio and a LSD and you'll be keeping up with poorly setup turbo cars (which is most of them :lol:)

Have the intake ports all matched up. The only non standard thing about that build is the missing water seal groves on the 12A centre iron which is machine time.

flight_of_pain 03-08-11 10:11 AM


Originally Posted by Jobro (Post 10506523)
The best (and still somewhat affordable) way to do it is as follows.

S4/S5 turbo rotor housings
S5 NA rotating assembly (have to find a rear counterweight from an automatic turbo model)
S4/S5 turbo front and rear faceplates
12A tall port centre plate
S4/S5 turbo to IDA downdraft manifold
55mm twin tapered bore bodies (efihardware.com sell them)
S4/S5 crank sensor in the front cover.
FD oil pressure regulator (rear).
New FC turbo oil pump

If he has a 12a for irons and an -se for housings, there is no point in going with all those 2nd gen parts.

Yes, 80's OC, what you posted will work, and work quite well. The older style 4-port weber intake is fine, or the rx4 intake. The rx4 intake will flow just fine for what you want to do, I have been running one for years.

Isaac

rotarycrazy 03-08-11 12:22 PM

well i guess i need to try and track down someone that has a rx4 mani then if not i guess the rb bridge port one will have to do but dam things are like 315 bucks.

orion84gsl 03-08-11 01:04 PM

^ Gotta pay to play. This isn't a cheap game. RX-4 mani's are going to be hard to find, and especially for a good price. I got lucky. 84stock got a hold of one and was willing to sell it to me for a fair price. Getting my hands on it is actually what decided the direction of my build for me.

flight_of_pain 03-08-11 01:45 PM

I have seen several for sale on the boards here in the last few months. Ask in the Other rotary section.

Isaac

84stock 03-08-11 05:12 PM


Originally Posted by orion84gsl (Post 10506807)
^ Gotta pay to play. This isn't a cheap game. RX-4 mani's are going to be hard to find, and especially for a good price. I got lucky. 84stock got a hold of one and was willing to sell it to me for a fair price. Getting my hands on it is actually what decided the direction of my build for me.


Being a parts hoarder I am still kicking myself for selling it, lol. It's like seeing the clean bare spot on the wall of a museum where the Mona Lisa used to hang. :blush:


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