1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Fuel injecting a 12a

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Old Oct 27, 2003 | 04:17 PM
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Fuel injecting a 12a

Hey i was wanting to fiel inject my 12a, i dont have any problems rigging any of it up, but, how do you think i should control oiling, just use premix? if i use premix do you think it will supply enough oil if say i romp on it to 7500 then just let off?

input would be greatly appreciated
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Old Oct 27, 2003 | 11:48 PM
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I really dont think you knw what your getting yourslef into. Fuel injecting a 12a is NOT easy, and there is a reason why practically nobody has done it before.

The 13b has spots for fuel injectors in the intermediate housing, the 12a does not. Even if you were to make an adpater plate to match some 13B manifolds, youd have to wire up a standalone engine management system. And you would still have to find a sopt for two more fuel injectors.

Your talking about thousands of dollars here man, for a 12A! IMO, it just isnt worth it. If you were going turbo that would be a different story.

OK in answer to youu actual question, you will have to premix. The 13b had oil injectors on the rotor housings, and the intake manifold (4 lines) and the 12a had 2 that went to the carb. No carb means no oil injectors. Premix is not bad at all. Most people consider it to be far better than the stock oiling system. Allmost all rotary racers run premix. Premix will allways have enough oil, plain and simple.
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Old Oct 28, 2003 | 12:35 AM
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haha, dude, you think to much like a ricer, im putting the injectors into a custom made intake manifold, useing a megasquirt for the stand alone, and yes im going turbo with it.

this wouldnt be the first car i have injected that was originally carbed. if you have any fab skills you would realize how easy this is, and yes it has been done more than once to a 12a.
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Old Oct 28, 2003 | 12:56 AM
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Go here http://www.speed-technology.com/efi_throttle.html and check out the Rotary section

Slap that on a IDA style manifold and use your choice of ECU, Microtech LTX-8, Haltech etc....ohhhh Megasquirt (just saw that) you are brave. Let us know how it goes...more importantly how much it costs. Good luck.
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Old Oct 28, 2003 | 03:27 AM
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Originally posted by hornbm
I really dont think you knw what your getting yourslef into. Fuel injecting a 12a is NOT easy, and there is a reason why practically nobody has done it before.


It's as easy as buying the right parts (see Nainamo's link) and bolting it all together. It doesn't even require any fabrication. As for practically nobody doing it before, I've seen heaps of injected 12A's.
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Old Oct 28, 2003 | 05:00 AM
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How hard is it to just find a F.I. 12a from another country. I know in some parts of Japan its easier to find the F.I. turbo engine than the n/a 12a
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Old Oct 28, 2003 | 09:40 AM
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rotaryshack.com was selling the 12AT for $800 bucks a month ago. Then i asked about it and the price suddenly went up to $1200. I was going to buy at $800 but not for $1200.
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Old Oct 28, 2003 | 09:44 AM
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12AT

http://12.232.38.41/website/FlashMovie.asp

i believe it is still 1200 yup it is.
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Old Oct 28, 2003 | 09:54 AM
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what makes more power, the 12aT or the 13bT? and which is easier to swap in starting with a 12a N/A
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Old Oct 28, 2003 | 09:56 AM
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Well there is or was a sticky on doing the TII motor into a 1st gen. I m probly going to do the TII motor. The 12at since it is so old probly is going to need a rebuild no matter who i buy it from. And i know that i can buy a TII motor for 800 or less.
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Old Oct 28, 2003 | 10:16 AM
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yea ill keep everyone posted on cost and dificulty

but its a long project, summer isnt back for another 8 mths, so itll b in the garage for quite some time
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Old Oct 28, 2003 | 10:52 AM
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click the picture below in my signature... email the guy doing it... he is making efi kits soon.... from pieces to fully plug in play kits!!! its gonnabe AWESOME!
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Old Oct 28, 2003 | 10:53 AM
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http://www.seriousre.com/megfi fully tune able.....
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Old Oct 28, 2003 | 11:26 AM
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I personally like using a regular 12a racing beat/holley intake with the holley TBI system it works great and it comes with everything you need to install it. It is very efficient for turbo since the ecu is fully adjustable to what ever you want it to be.
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Old Oct 28, 2003 | 01:28 PM
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From: https://www2.mazda.com/en/100th/
the easy way would be to build the 12a with the gsl-se or 12at center plate and put the gsl-se injection on it, with a racing beat dellorto 12a lower intake. boom done

mike
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Old Oct 28, 2003 | 02:15 PM
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if it is premixed it should still get into the engine at the right rate. more fuel = more premix.
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Old Oct 28, 2003 | 04:36 PM
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Originally posted by NanaimoRx-7
Go here http://www.speed-technology.com/efi_throttle.html and check out the Rotary section

Slap that on a IDA style manifold and use your choice of ECU, Microtech LTX-8, Haltech etc....ohhhh Megasquirt (just saw that) you are brave. Let us know how it goes...more importantly how much it costs. Good luck.
WOW I'm dumb. I didnt even think about doing it that way. I thought he was gonna adapt some 13b manifolds or something. It was late... I dont even know why I said what I did.
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Old Oct 28, 2003 | 05:47 PM
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i dont really need a bolt on kit, i was going to do it fron scratch with a megasquirt

was thinking, t2 fuel injectors, t2 fuel pump, new fuel lines, megasquirt for efi

im looking for input on the throttle body sizeing or if i should use 2? (as in 1 per rotor), remember this is on a custom intake manifold, so i dont need to adapt some other manifold to use it
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Old Oct 28, 2003 | 06:37 PM
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How many fuel injectors are you gonna run? I'm assuming four, but you might want to consider using the GSL-SE fuel injectors as your secondaries, as they flow more than the T2 ones.

Putting GSL-SE fuel injectors on the secondaries is a pretty common mod for s4 FC's
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Old Oct 28, 2003 | 07:14 PM
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From: manshank va.
i have one of thosed 1da throttle bodys. its a realy great piece. just havent installed it yet......
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Old Oct 28, 2003 | 08:29 PM
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im going to be running 4 injectors, 2 are stock, the others are 660cc's i belive, im getting them off a friend who is upgrading his t2.
i would like one of those IDA tb's but thats just not in the budget, 575us for one piece, thats like 800 cdn, 800 that i could spend on other efi goodies
i was thinking dual throttle boddies off something like dual cavalier tb's
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Old Oct 29, 2003 | 03:30 PM
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Originally posted by 79+80+84_rx-7
click the picture below in my signature... email the guy doing it... he is making efi kits soon.... from pieces to fully plug in play kits!!! its gonnabe AWESOME!
where is the prices buddy?!?!
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Old Nov 5, 2003 | 01:25 PM
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Originally posted by ToyotaryatGR
I personally like using a regular 12a racing beat/holley intake with the holley TBI system it works great and it comes with everything you need to install it. It is very efficient for turbo since the ecu is fully adjustable to what ever you want it to be.
Ive never heard of this setup before. It always intrests me when i hear of people trying new systems. Which holley system are you using? I went to there web page and there are several different ones.

http://www.holley.com/HiOctn/ProdLin...SFI/FMSFI.html
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Old Nov 5, 2003 | 01:57 PM
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Here is a full rightup on making a FI setup for a rx7. I don't think he says witch engine he is running but it is writen very well.

http://www.sdsefi.com/techinta.htm
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Old Nov 20, 2003 | 03:18 AM
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From: Cloud Nine & Peak of God
As stock the 12AT is not too powerful about 136hp. In comparison the 13BT is 180-200hp depending on the model. A good write up on going efi on a 12A is on Hitmans site. He was acheiving about 220hp on a mild ported engine with good fuel economy. As suggested above he used a 13B centre housing.

Out of interest I costed a rebuilt 12AT with upgraded turbo, ecu and IC to produce 220hp and it came out almost identical to going efi and porting. The only real difference was the powerband and torque curve was far better at the lower end for the efi set-up.
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