livetoroll

I just bought a 1983 rx7 at a good price I want to make it about 250 hp with out the help of a turbo or supercharger, I have a 13b motor but i would like to keep the 12a, Please help me find the parts i need to reach my hp goal.

nevarmore

Go to the firstgen forums and start reading, but you don't need parts so much as labor. You're more than doubling the power of a stock engine (101hp/106tq).

The 'free' mods for the 12a are an electric fan, emissions removal, and timing. Good for anywhere from 10 to about 30 ponies IIRC. Weight is also free, however you have to decide how much you can live without and there really isn't much left to take out.

Streetporting, a good carb (sterling, holley, weber, etc), and an exhaust (RacingBeat is highly recommended). You're looking at $200-$1000 for the porting depending on engine condition and your skill, $500ish for the carb and intake setup, and about $600-800 for a name brand exhaust $200 if you DIY.

It is possible to get near your power goals with only exhaust and intake, but you need a good tuner.

diabolical1

iTrader: (3)

dude, this underlined part can't be right - not without a damn near flawless exhaust system and some carburetion mod and i'm assuming that you mean without them because you mentioned them in your next paragraph. if i'm wrong feel free to correct me.

as for the original post ... you're probably not going to pony up much more than 180 to 200 HP (flywheel) without forced induction - this would be a "good" streetport with all the trimmings and utopian tuning.

you can attain your 250 HP goal if you go bridge or peripheral ports, but if this is your streetcar i don't recommend that route (just my opinion).

The Wankler

iTrader: (14)

diabolical1 is very right. 250 is my goal as well, and here is how I intend to reach it.

Rotaryshack jspec 12a streetport w/s5turbo & manifold
Weber sidedraft
3"exhuast, no cat
Wallboro Fuel Pump
great spark, not sure yet which one.
Electric Fan
Intercooler
no emissions!


That should get me/you close. Consider those options.

good luck

Fire85GSLSE

iTrader: (29)

250hp...... good luck with that goal. If you hit it please post it.
I don't think you can get a 12a to 250 hp without going turbo/supercharger.

I hope to be at 200 with all of my mods and I am running a 13b.

nevarmore

Yea I wasn't really sure on the exact figure. My benchmark was a friends FB with only timing and an iffy homebrew exhaust, my butt-dyno might be calibrated a bit too high. Also, some of the numbers I read around here may be inflated or not verified on the dyno. Thank you for calling me on my mistake.

My overall point still stands. The people who really know what they're doing or those willing to learn on thier own, can make a damn nice motor without having to buy as many parts. On the other hand, you can know the basics and go buy and install parts and get the same result.

813KR$

A good street port with headers and Micro tech EFI produced 258hp at the flywheel on a dyno. That was a friend of mines 6 port 13B in a Dune Buggy that ran low 8's in the 1/8th mile sitting on 20's ! ! !

Check it out:

http://artisticperformance.com/v-web/gallery/dsktp/20in

kleinke

Yes of course it's possible. Even >300bhp. However, do you care about the fuel consumption or driveability?

hiboost7

ummm...why not go turbo or supercharged? my 12a turbo should be good for about 300+ hp. getting an N/A 12a past 200 is a hard thing to do with out sacrificing alot of driveability, and with gas prices up so high you'll never drive it...

813KR$

Whoa, whoa.

My boys Street Ported 6 port pushes 250hp with only headers and Micro Tech EFI. This thing runs smother than a babies *** ! ! ! You cant tell it is street ported! Driveabilty is like stock but with ***** and is very quite, with extremely good MPG, I think it is in the high 20's, 26-28 someting like that. It is alll about the tunning!

nevarmore

Turbocharging costs on fuel as well, you have to burn something with all that extra air.

In general, turbo or supercharging increases maintenance costs and can lead to reliability problems. For many setups those costs are simply from having more parts. For very powerful setups and/or poorly done rigs -charging places too much additional strain on the engine. Thats not to say that a powerful NA setup won't do the same, but its easier to overstress something while boosting.

hiboost7

so your trying to say that a P port or bridgeport saves more gas and lasts longer than alittle boost on a 12a?

diabolical1

iTrader: (3)

this is only partially true. actually, RPM does just as much damage to engines as running crazy boost levels - and the bottomline is that you MAY be able to match power figures (to a point) with an good, tuned N/A build, but you have to turn RPMs to do so. it's a trade-off.

i can't speak on supercharging ... BUT ... if you keep the boost down to reasonable levels, turbocharging can actually be easier and more efficient than high RPM N/A engines. of course this is NOT a matter of just slapping a turbo on an engine, you'll need the right porting, oil mods, cooling, etc.

t-von

iTrader: (8)

Does this person post on this forum?

813KR$

No, he does not poston here, that I know of.

MazSport out of the Tampa area built the engine. I think the guys name is Jeff? He is the owner and has a really nice 3rd gen with turbo and juice!