Did some searching and came up empty handed. Lots of swaps for other things etc but not this:

I have a SE parts car with the EFI setup.

How would a SE EFI work on a 12A?

Yes, I know it wont "bolt on." That's not my concern. I'm still not certain if the FB 13B is 6 port, if it is, I'll adapt the intake and work around it.



I'm wondering if anyone has done this, and what issues they came up with from a tuning standpoint.

I can make it fit. No problem. The parts car has a S5 engine that's dead. My '82 GSL has a nice clean 40k mile Pineapple Stock 12A w/ my exhaust work. I'm tired of carbs, poor milage, chokes, needle/seat problems.

And last weekend when I was up on some mountain roads, I was cornering hard enough, that even though the float levels are dead on, fuel was sloshing out of the carb and I was getting a gnarly fuel smell.




If the Mazda computers are anything like Nissan I should pretty much be able to bolt on and go. Maybe a little rich in open loop? Kick the fuel pressure down a little? A 12A and 13B can't be that much different in stock form as far as fuel consumption.

I want turn key, ready to go, reliable induction. Figure this will iron out alot of kinks for my TII swap in the future, (IE fuel system, basic wiring)


Thanks for any and all input.
-Paul

 

i thought about doing this back in the 90's, i think it would work really well. actually this intake works really well on a 13B, but on a 12A it should have better top end.

you only need 2 parts, in addition to the stock GSL-SE stuff to install it properly on a 12A. you need to rebuild the 12A with the gsl-se center iron to get the fuel injector bungs. RB sells a lower intake that will work with the GSL-SE upper http://www.racingbeat.com/RX7-1975-1...ake/18111.html.

after you do that, the rest of the GSL-SE injection just goes on like stock. i don't know about the wiring, i'm assuming since most of it is on the engine harness, that you only have to hook up powers, grounds, and the tach/clutch switch/trans sensors. probably like 6-10 wires?

the FB 13B is a 6 port, but it doesn't matter. in my experience a GSL-SE with some air flow mods, exhaust etc, the GSL-SE actually runs on the lean side anyways. this is also where the MPG comes from, if you're cruising down the street the closed loop is just turning the engine on and off....

 

I guess I should start digging into the parts car for the setup.

I have never touched EFI on a rotary. Lots of experiance on piston engines.

There are a set of injectors that go into the housing itself? Any possible way around this? I don't want to take the 12A apart.

 

You could weld two injector bungs to the manifold. Cheaper and easier than opening up your 12A.

 

How do these two get fuel? Will I need to mod for a fuel rail, or is it some kind of hose attachment to the injector?

https://www.rx7club.com/showthread.p...ousing+compare

This guy used an S4 intake and deleted the aux injectors? Is that an option?

 

Twilightoptics....check out my FS thread....I'm selling just the 12A LIM you need.... Hit me....I'm motivated to sell!

 

all of the EFI rotaries have the primary injectors in the center housing, and if you use that center housing the stock fuel rail just bolts on. which is why i never did it in the 90's, too much work!

you COULD add injector bungs to the manifold, like DF says, mounting a fuel rail becomes custom.

the FC manifolds are possible, but they have a different bolt pattern between upper and lower, so you can't use the RB lower piece, which means you'd need some custom adaptor somewhere, which again is too much work.

 

Figure changing manifolds and my Lincoln Tig Welder is pretty easy for me.

What's the point of the FC manifold if it too runs the secondary injectors in the center iron?
Looks like they have 4 injectors up top and two below?


It would be pretty easy to put injector bungs on the intake for me.


Patmac - Sent you a PM.

 

SE and FC 13B have primary injectors in center iron and FC on up have added secondary injectors in the intake manifold secondary runners.

 

If it were me, I'd make a thick adapter plate to fit between the block and the LIM. Then put the injectors in the plate. The adapter plate can then be shaped to give you better flow from the LIM into the block. Otherwise, you're going to be doing a whole lot of grinding and filling. You probably will be anyway, though.

Actually, if I were going to do a fuel-injected 12A, I'd add some injectors to the stock 12A intake (probably feeding into the primary runners from the passenger side, where the ACV used to be), and use the Nikki as the throttle body. Then I'd control the whole thing with a MegaSquirt in MAPdot mode: no need for a TPS, just a vacuum line and an IAT sensor. If you wanted to, you could even keep the fast-idle part of the choke mechanism to function in the place of an IAC valve for cold starts. Bonus: then you'd have a fully functional standalone for when you do your TII swap.

 

Never had alot of luck with megasquirt. The software is too convoluted and I haven't had anyone knowledgable that can get me up to speed on it. FAST, Holley, ECMLink, Nistune all pretty easy to get a handle on if you know what the sensors do.




This is going to happen. Time to pull the wiring schematic and have a look see. I'm reading that the SE computer only controls fuel?

Anyone know if the dizzy has a different curve to it?

 

Correct, the ECU is fuel-only.

And yes, the dizzy is a bit different. As I understand it, it has both a faster advance curve and more total advance.

 

Easy enough.


I think I'll try getting the whole setup running on the unknown motor, on the engine stand. Just to verify all sensors and ecm works before swapping out my stuff.

 

yep. its not really enough different that its worth changing distributors for though

 

Even in the epic quest for MPG? :O)

 

Exactly what I was thinking.


-billy

 

So with this 12a RB manifold I've got coming... Just copy the gasket into 1/2" aluminum plate and drill a couple stepped injector holes in the middle. Should be easy enough. Might even be able to utilize the fuel rail mounting....

 

the distributor curves aren't that different and they aren't that great. you'd be better off re-curving your stock one

 

There's so little to the wiring on the SE EFI. It's rediculous. I guess I'm used to Datalinks and 8 computers at any given time LOL.

So, how easy, if at all, will the intake STUDS come out? IIRC there are studs in addition to the bolts. Clearly those will need to be elongated.

Pictures coming shortly.

 

I'm very interested in this as well. Can't wait for the final result.

 

So I'm currently searching, but figured I'd post here for information under this heading.

So I pulled the engine from the parts car and got a closer look at it.

My concern now..... the omp stuff. I'm so used to 12A and carb... this thing has 2 oil lines going to the rotor housings, and 2 going to the intake manifold passages. There are vacuum lines going to the fittings.

How do these work? Can I put the 2 from the rotor housings to into my custom plate? Or can I just use the 2 from the 12A OMP and run them to the intake manifold fittings and call it good?

I really don't want to run pre-mix.


And this is a bit of a bastardized setup I pulled out. Previous owner deleted the ACV and swapped in a S5 13B. The GSL-SE 13B only has 2 injectors total on this setup... Is that correct?

Thanks guys
-P

 

Just tee the lines together and run them both into the intake manifold.

Yes, only two injectors on the GSL-SE engine.

 

adapter plates to readily convert the 12a to use s4 or s5 turbo inlets are readily avail in aus
( tweakit etc )
for ex carbed blocks , the norm is to add injector bungs to the adapter
if you use the mazda injectors then then you can select a type of weld on injector bung that holds the injectors down with a clamp on a rubber sitting around the belly notch
( the injectors fed from hose tails from an external FPR )

else you need to be creative with the injector rail

 

Excellent about the OMP lines.

Do I Tee the vacuum section of the lines as well? Or just the oiling lines.



I guess my next question about it, can I use the stock 12A OMP with the two lines and just run them to the intake fittings?

If not:
Will the SE OMP bolt to the 12A Cover? Or do I actually need to swap covers/oil pan to use the SE OMP.

Thanks!!!!!

 

I haven't directly dealt with a GSL-SE engine, so I'm not positive how the lines are routed. However, if it's like the later engines, those lines don't see vacuum at all. They just connect to a filtered air source. I guess they act like atomizers for the oil or something. Just cap off the ones for the rotor housings and you're good to go.

Edit: scratch that, 12A and GSL-SE OMPs aren't interchangeable.