I had a completely stock 1983 FB with a 12A with a 4 barrel. It seems the best way to make power is get a 13BT for it, but everyone does that! I have decided to build a 'muscle' 12A and use my car for experiments. Plus the 12A should be lighter.



I started trying to add power by sealing off the air cleaner with a K&n filter, and routed it to suck air in underneath the windsheild. Like a cowl induction effect. (Yes I cut into the firewall) Later my friend gave me a cone K&N filter (as oposed to the ring one I had) I thought this might flow more air, so its now mounted directly atop my carburator. It feels like this added 5-10 HP



I removed the Air Pump, and the car sounds really cool without that thing. Here is a list of my Ideas for 300 horse to spin at about 10,000rpm, and yes its mostly experimental.



It seems the Weber makes a bit more power than Holley with porting, so

Weber 52 Ida and intake manifold (runners)

Street Porting

2 MSD Ignition Blaster coils

MSD High Energy spark amplifier

Bosch +4 plugs

Header & hi Flow Cat, Low restriction muffler.

OR just straight piping from the header if '83 doesnt require emissions.

Or perhaps a Hi-rise intake, and a ring type K&N under a Cowl scoop

Lightened Flywheel



What are your thoughts on this, people?? Has anyone tried anything simular yet?

Also does anyone know the PROPER way to remove the right emissions? ITs hard to know what to plug and to leave open...



Thanks

 

I pretty much have the same setup on a 86' 13B with a Bridge Port and a Holley. I am only making 225hp. I would say you need to go fuel injection and P-Port 12A to make that kind of power.

 

You won't make that kind of power on a 12A street port NA.



300whp on an NA will definately call for a good bridge or p-port motor. Judge ITO just made 330+whp w/ a bridged 13B w/ cosmo rotors, etc. It was setup for NOS, but w/out spray it made 330+ his info is in the dyno forum.



My roomate has a pport 13B that was in a toyota starlett that supposedly made like 290-320whp...



I just know that a 12A streetport with the right carb setup will probably only net you around 200-225whp.



Go EFI and large porting to make those numbers...

 

I have a 12a with a half bridge. Bridgeported secondaries and a large streetport on the primaries. I race ported the exhaust ports. We grinded out the intake to match the irons, machined the primary and seconday venturies out and drilled the jets on the factory carb. I have a racing beat header and a straight piped exhaust system. Off this I'm hoping for 180-200 rwhp. I have a line on a set of 48 IDA weber and racing beat intake, and off that i'm hoping for 225-235 rwhp. The 52 IDA webers will be too much fuel for your streetport 12a. The 52 IDA's are really suited for a p-port engine.

 

factory had 3 PP motors



early round port 250hp

79+ D port 270hp

80+ injected dry sump engines, 280hp



those are all flywheel numbers too. i would bet 26 years later you can squeeze 300hp from a PP 12a, but everything has gotta be spot on

 

Thanks for your replies! I just had my stock clutch go out, now would be the time for rebuilding the motor / tranny. So Im definetly going to order the Bonez racing clutch $329 which 2x stronger good deal on rx7.com.

Now would definately be the time to pull the motor for the P-Port and rebuild everything. Im assuming to make 300 horses on a 12A it would be up around 8 or 9000 RPM

Now a couple of questions.



Im wondering if $500 is good for a 8.5lb aluminum flywheel? (stock is 20lbs)

Does anyone happen to know What the best exhaust header / Diameter would be for high power, flow and heat?

Also, Are the LSD Diffs, Full time posi until one wheel needs to spin faster? OR is it an open diff till one wheel starts to slip, then it locks? I know on GM vehicles, they have both types, So just wondering about an RX7's

 

Also the Supercharger for the 12A seems like its worth saving up for. What does anyone know about using a Supercharger and Porting together??

 

300 horses on a 12a would be up around 11-12k.... that flywheel prolly isnt good enough, and there isnt an off the shelf exhaust that will work for a 300hp 12a. it would be custom

 

300 hp on 12a NA tall order. It must be a PP. For the money it will cost for the housings, ida + manifold fuel pump reg ,flywheel ,rebuild why not turbo a 12a extend port with one of those ebay t70s use an adaptor plate and use s4 intake manifolds and injectors and a cheap ecu like microtech. Not only will it meet or exceed you hp goal the extra torque will make it.

 

With a good conservative tune, it will last a whole lot longer as well, in addition to being a lot more pleasant to drive in town. A car that is is pleasant to drive will be enjoyed more often.



With an improper or hairy edge tune, it will break rapidly, as the old style rear side housings are not very strong and do not tolerate abuse. Rebuilding every week because of a poor tune is also unpleasant and prevents enjoying your car.



Fixating on dyno numbers is one of the quickest ways to get a hairy edge tune...