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

12a fuel injection

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Old 01-19-08, 12:21 PM
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12a fuel injection

I have a stock 85 12a and I want to make it fuel injected. I know its possible I have seen one. Also mazda made the sa22c. An rx7 12a turbo with fuel injection. Any thoughts?
Old 01-19-08, 02:05 PM
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my only thought is confusion
Old 01-19-08, 02:19 PM
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there are aftermarket throttle bodies that you can buy with harnesses that look alot like Webers. ive seen a few in the for sale section
Old 01-19-08, 02:26 PM
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I'm doing a turbo 12a build now using a gm tbi. I'll let you know how it goes.
Old 01-19-08, 07:38 PM
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To get a fully complete,factory EFI 12AT in the states is a tough job.
All the stock 12AT EFI components are pretty hard to find, since we never got that engine here.
If you need a smog legal EFI 12A,then your pretty much outta luck.If you dont need to smog it,then fork over the big bucks and build/tune a custom EFI system using any number of individual throttle body systems that are out there.Most use common carburetor intake manifolds and are quite simple to install.Most of the work involved is getting the fuel delivery system setup to handle EFI pressure/feeding, and the dyno tuning of the ECU.
Old 01-19-08, 10:08 PM
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...have to run an ECU

ECU= Pain in the

but good luck!!
Old 01-19-08, 10:34 PM
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Originally Posted by 680RWHP12A
my only thought is confusion
+1


Shoalin, you came out of the monastary before your rotary courses were completed. SA22C is the designation for all USDM Series 1 RX7s. What does that mean, it means all 79-80 models. Worldwide, it's the designation for all 1st gens made.
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Old 02-22-08, 12:24 PM
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Budrud, I have thought about using a chevy tbi setup also. I have a roommate with the software and equipment to burn chips for the chevy computers. The same roommate can also make me manifold adapters and flanges on a cnc machine at school. If you have any info on doing this let me know.
Old 02-22-08, 12:38 PM
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Originally Posted by shaolin
I have a stock 85 12a and I want to make it fuel injected. I know its possible I have seen one. Also mazda made the sa22c. An rx7 12a turbo with fuel injection. Any thoughts?
My thoughts are that you need to read more.

SA22C refers to any Rx7 produced between 1979 and 1985 because outside of North America the VIN for all those years starts with "SA22C..."

But more commonly, the SA22C (or just "SA") is used to refer to the 1979-1980 Rx7s because those two years held VINs starting with "SA22C..." in North America. After 1980 they changed the VIN to comply with changes in American laws, so all north american Rx7s from 1981-1985 are referred to as "FB"s because their VINs start with "JM1FB33..."

Check the FAQ, you'll find more info on SA, FB, FC, FD etc... there

The 12a turbo was only available in Japan. They got that and we got the GSL-SE instead. It was fuel injected, but good luck getting your hands on any parts from them. They're extremely rare especially on this side of the pond.

The most common way to fuel inject a 12a is, as mentioned by bugman, is to use the FI throttle bodies that look kind of like 2barrel weber carbs do. If you keep your eyes open they sometimes become available in the for sale section or on ebay. Since FI uses higher fuel pressure than carb and needs more flow, you'll need to change to an FI fuel pump, run new fuel hoses, and of course you'll need some sort of computer control from a standalone ECU.

The question you have to ask yourself is why are you doing this, and what is your budget? Just switching from carb to FI isn't going to give you a lot of power, and it is very hard to make an emissions-compliant standalone FI setup for a 12a if that's a necessity in your area. It will cost quite a bit and not be a simple "bolt-on" swap.

If you're just looking for increased performance, look towards aftermarket or performance carb options such as sending your Nikki to Sterling for a complete overhaul and rebuild.

Jon
Old 02-22-08, 12:44 PM
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Carbs 4 the win!
Old 02-22-08, 12:56 PM
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I think you'd be better off to try to put in a 13B engine that was designed to be fuel injected.

It would certainly cut down on the PITA factor...
Old 02-22-08, 01:21 PM
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Theres this option but its very expensive. http://www.atkinsrotary.com/store/pr...cat=589&page=1
Old 02-22-08, 10:50 PM
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Originally Posted by Vashner
Carbs 4 the win!
I used to say the same thing, in the contemporary vernacular.

Since that time, I've driven some rather "built" cars with EFI.

Here's a pic of my car as of today:



Yeah... carbs? They're OK but EFI is way bitchiner.

edit: And the awesome part. When I get bored with the stock -SE engine and put something radically ported in there (maybe the P-port 12A will go another round, maybe an extreme streetport FC engine for N/A non bridge braggin' rights... I can reuse almost all of my investment. The initial cost is a little steep, but it's still on par with a *decent* aftermarket carb... and when you change setups, you don't have to buy $50 in jets.

Last edited by peejay; 02-22-08 at 10:56 PM.
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