rx7anator

i read it somewhere when searching about efi 12as but wasnt sure if it were ture.

could i use the 13b center housing with my 12a and somehow get a efi intake to mount and actually work (using a stand alone fuel system)

yes i understand it will prolly cost a arm two legs but oh well.

so anyone know? done this? tried?

thanks

Brad

mazdaverx713b

iTrader: (91)

no, because the 13B housing is wider

flight_of_pain

the 13b rotor housings are 10mm wider, and the center irons are the same IIRC. so you would end up with 20mm of "ahhhh....damn, it doesn't fit"


isaac

rotary emotions

the center housings of a 86 onwards 13B DO NOT fit a 12A. The water seals are moved from this year on. You can use pre-86 side/center housings, but that ain't needed.
You CAN make this work (13B efi on 12A) but you'll need an adapterplate. A 12a has smaller rotorhousings (side and center housings are identical in size) so to make a 13B intake fit, you'll need a plate that fits in between. I believe this has been build in Australia.
An easier (but even more expensive) option would be to use a sidedraught intake (for Weber carbs etc) and use weber-style throttle bodies. That's and expensive but very good option.

REVHED

Who cares about the rotor housings. He's simply talking about using a GSL-SE centre housing for the injector bungs. The answer is yes it can be done.

I agree with rotary emotions though. The best option would be to use a either an IDA or DCOE style throttle body and manifold. Check out www.injectionperfection.com and www.efihardware.com

peejay

Port EFI is better than those IDA/DCOE abominations. If you want something craptacular like that you can save money and just get a TBI unit from a junkyard (get something off of a truck) and adapt it to the existing intake manifold. That would work about as well and for a lot less cash outlay.

turborotarypower

another option would be to buy a Racing beat intake manifold for a holley carb, then buy an EFI adapter like the Accel throttlebody or Pro-jay throttle body adapter and i know puerto rico has a version also. after you get these parts together buy a standalone ecu, injectors etc.......

moremazda

iTrader: (4)

What about building the 12a with the GSL-SE center plate? So you have a 12a, with a place for the fuel injectors.

Then use the Dellorto/Weber lower intake manifold made by Racing Beat, and installing the GSL-SE upper intake manifold, and electronincs.

Now you have an economical fuel injected 12a.
Easy, no???

Ryan

peejay

Say that's my idea.

The only potential gotcha is that alternator clearance with the plenum might be nonexistent. It's been a while since I've seen a complete GSL-SE underhood, and when I did I wasn't paying attention.

If there's room for the alternator to be 10mm closer to the intake manifold, on a GSL-SE, then there'd be no problem. If not, then ya gotta dig out the fangle gear.

rx7anator

someone go measure...!!!

i KNOW thee has to be some other problem other wise everyone would do it.

so does everyone have the same idea...center gls-se housing...rig on a lower manifold...and rig on a upper manifold from some efi rotary (i like the FD intakes...how they go to the left instead of the right)

would all this be possible???

wwilliam54

thats a really really good idea
i can get GM TBI setups for next to nothing all day long, that would be the absolute cheapest way to go with a better than stock setup

it needs to be MAF tho RIGHT??

wwilliam54

you can put a 12a plate in a gsl-se engine for a 4-port 13b, i dont see why the reverse woulndt be true

rx7anator

ok....im gona try it. i think.

which is it the holley or the webber lower manifold that lines up with the upper intake???

are there any preprogramed stand alones?? that dont cost my first born child?

anyone have any good links of info of the efi on the gls-se?? i need to read up on it (never did...always planed to go carb)

anyone else want to try?? two brains are better then one.

Brad

wwilliam54

megasquirt is always the cheapest

but for a 12a up to a bridgeport i dont see why the stock 13b efi ecu,AFM,Oxygen sensor and so on wouldnt be good to go, but thats just my opinion/idea

rx7anator

EXCATLY what i wanted to hear.

what year you think would be the best?

wwilliam54

???
i think 84/85 are the same

but other than that, i have no idea

rx7anator

i was thinkin....fb, fc, fd? they all would work right ?

wwilliam54

yeah sure, i dont see why not

let peejay chime in and answer that
(he'll bust my ***** if im wrong)

rx7anator

and it wouldnt be that much of a pain in the *** to have the ecu just run the efi right....kind of a stock stand alone.

i dont like wiring...i wanna plug some stuff together...tuen it with my lap top..and haul ***... just wish everything was that easy

Brad

wwilliam54

ask the 2nd gen forum
IIRC they can use a dizzy, so you might be able to do exactly that

peejay

FC computers need the CAS. So do FD, but FD use an inferior (for our purposes) MAP sensor based system ("speed-density") which calculates airflow based on programmed-in assumptions, like assumptions for VE. Alter the VE and the airflow does not coincide with what the computer is calculating.

For modifying engines with stock injection, AFM and MAF type systems are the ****. They physically measure the airflow, no programmed-in guesswork.

The best setup to use would probably be the FC N/A computer and T2 AFM and injectors. j9fd3s told me that the T2 and N/A computers use the exact same fuel programming, just the T2 AFM and injectors are larger in proportion to each other. In theory the N/A stuff should be good to 250. (Flywheel) I forget the calcs but the T2 injectors should be good to ~300-320 or something like that. More than plenty. A piggyback is highly recommended for anything using an FC computer since they run insanely pig rich (like 10:1) when in open loop. A friend of mine had a Power FC, or whatever the unit is with the little dials on it. His stock FC got WAY more powerful by leaning the high RPM sections as much as -8.

The GSL-SE AFM and injectors both run out at about 200hp (again, flywheel), but the computer, being analog, is still more tolerant of doing weird things to the engine. I keep thinking of how neat it'd be to use the -SE "computer" (really, fuel injection module) with a second AFM just sitting there dividing the airflow the computer sees in half. Then using an external injector driver to drive another pair of -SE injectors in sync with the standard ones. I dunno how well an engine would idle with two 680/720cc injectors per rotor, it'd be the equivalent of roughly one 1400cc/min injector per rotor, since this method would not involve staging.

Or you could use MegaSquirt. It has the dumbest name ever, but it's cheap, it's available, and it works.

rx7anator

thanks...im doing some reasearch on the fc ecu and cas and all that

iv read where one guy wasn gona stich over to a 12a dizzy...inwhich case it HAS to be possible to make the ecu run the efi on a 12a....right?

peejay

Eh?

The FC system *needs* the CAS. Period.

There have been other-market FC's that used distributors, and thermal reactors (yes, you read that right). I don't know if they use a GSL-SE type system or if they have the CAS-type trigger wheel buried in the distributor. My guess is GSL-SE type system, since the pictures that I saw showed a vacuum advance can on the distributor.

rx7anator

ok...so what if i got a MS system to contol the efi....does anything else need to change? would it be just...plug in, tune, drive?

rotary emotions

A European spec FC has a Fuel only computer, the ignition is run through the distributor. It has the same coils as any SA/FB, and the ignition setup is just like a S2/S3. The ECU only controls fuel and calculates this by signals from AFM, RPM (coil negative) etc.