Hey guys,

I have an '85 GSL SE (working out some kinks on it haha) and my daily driver '80 SA22C (with a GSL SE rear end conversion). I've been reading a lot about 13b swapped first gens and I want to put the GSL SE 13b into my SA22C. I already have the RB engine mount conversion bracket.

BUT I want to keep all the EFI and stock goodness of the 13b. I literally want to take the GSL SE's engine/engine management and shove them into the SA, while keeping the SA interior. Can it be done?

Some uncertainties I have:

- I read that I should keep the SA22C tranny because the shifter on the GSL SE tranny won't line up. Are the GSL SE 13b and the SA22C tranny compatible? Lots of conflicting literature so I thought I should double check.

- One way I was thinking of powering the swap was just removing the entire SA22C loom and replacing it with the wiring from the GSL SE. Anyone know any problems with doing this? One potential issue could be if the plugs weren't the same across generations (eg for the brake and signal lights or the rear defrost, since the GSL SE loom would have to plug in to the SA connectors). I also read somewhere that the rx7 looms are easy to divide up between engine management and lights/stereo/steering column/interior. Could I make a super-loom with the ecu end of the GSL SE and the interior stuff of the SA22C?

- I read that the GSL SE fuel tank won't fit in my SA22C. Could I just swap the fuel pump over and run a return line?

Any comments are welcome. I'm sure there's loads of stuff I haven't thought of, but I couldn't find documentation of a similar swap anywhere - maybe I missed it?

Roland

 

Only thing I can add is the SE tank won't (easily) fit under the floor since the SA used a full-sized tire cut out which would interfere with the SE tank install...
of course, a Body Guru could likely swap the floors back there for you,since the basic shell is the same.
Loom-wise, if you were to use the SA instruments (I would!) then you would need to conserve the dash harness to some degree. But the control boxes and relay systems the SE uses would still be needed under there, unless you can simplify the emissions, etc that might eliminate some of this? The SA has a rudimentary "Computer" box up under the driver side dash for emissions. Keeping the SA heater and controls would be smart too, rather than the (to me) complex heater control matrix the SE uses.
Having the OE wiring diagrams for both cars will go a LONG way to seeing what wires are needed where.
Someone has done this before, so you are not breaking new ground I think.

'Luck!

Stu Aull
80GS
AZ

 

Remember that the GSL SE loom is designed to go through the passenger side firewall, the SA goes through on the drivers side. The tranny from the GSL SE will not work on the SA. Keep the SA tranny it should work with the 13B. You may will need to use the clutch and the pressure plate for the 13B, so don't even remove if when swapping. I'd leave the SA tranny in place and drop the motor to it.

 

I too have a SA chassis and GSL-SE driveline. First let's talk trannys.
SE on Left SA on right

Bellhousings look identical, except for the 84-85 has a vent on the side. The gearing as far as I understand is pretty much the same (based on mazda part numbers) except for the SE having a overdrive that is a closer ratio to 4th than the SA's optional 5th gear. I plan on using the SA gears with the more efficient 5th gear. If I was road racing, I would choose the SE OD.



over all transmission length remains the same. Please note the difference in shift lever location.

I would deeply suggest that you consider forgetting all about the GSLSE engine management. I would even forget the intake. Get a hold of a second gen 6port intake. From the series four years. familiarize yourself with MegaSquirt/DYI Autotune or Haltech. Build a EFI system independent of the factory wiring. Personally, if I was on a fast track to get this done, I would use a DCOE Weber on the 6port aux actuators and be on the road in no time. Weber people are easier to find than EFI tuners. A weber should give you more power than the EFI. Mazda's fuel injection will give you better drivability of course.

 

Thanks for the tranny info! Pics are awesome too!

Richard, is the main reason you suggest forgetting about the EFI just ease/speed of conversion? The main use for this car will be daily road driving, so I'm not super worried about having excessive power.

 

Example, The SE transmission which would not fit without cutting the transmission tunnel has a switch to tell the computer when you are in 5th gear.I understand it to be part of the closed loop system. By going with a stand alone EFI you get a simplified system. It seems that you have no emissions testing in Alberta and that would be the only reason to use the stock ECU. Remember also that this is a 30 year old computer. capacitors dry out, connections corrode, things just wear out. By going stand alone, you can tune for efficiency. If you do stay stock see if you can have the ECU gone over. at least replace the capacitors.

 

Well, that confirms that you're ignoring all the previous advice about keeping your SA stock as a time capsule...

That said, the SE has a number of improvements that you may run into as challenges in this conversion;

Off the top of my head, recognize that the Fuel Pumps are different (obviously), and an -SE pump is about $380 with the pulsation dampner and fittings. On top of that, the -SE has larger fuel pressure and return hard lines to handle the pressure of EFI - which routinely runs about 40-50psi, and will quickly erode through your low-pressure carbeurator soft fuel lines meant for 4-8psi. If you swap, you're going to want to swap those hard lines, too.

At the rear suspension, the Bottom Link Mounts have been lowered slightly (about an inch) to reduce roll center and help avert snap-oversteer. This a body difference, and while the links will fit, the mount position on the -SE is favorable compared to the earlier cars. This change came about in 84 for all models, not just the -SE, to my knowledge.

The wiring harness swap you're entertaining should (and will need) to include the extra Injection and Computer Fusible Links on the driver's side strut tower. These were added specific to the -SE, and will not be found on 12a cars.

Both cars will have Front Mount Oil Coolers, however, the -SE cooler is designed to sit in front of the radiator, while the SA22 cooler will fit directly below the radiator. Lines are slightly different lengths due to this mounting position.

On the front suspension, the SA has a different strut top which does not rotate, as it relies on the piston shaft to rotate within the shock body. The -SE on the other hand, uses a rotating strut top bearing, which will need to be added to your SA if you intend to install the larger Spindles from the -SE car, which also go along with the larger Brake Rotors and Bearings.

Your -SE has Cruise Control, which is maintained through a control box located in the driver's side bin, and will also need the actuator which mounts on the passenger firewall. The Cruise Main switch is located on the dash in the -SE and may not have a cutout in the SA.

Manual electric choke mechanism on the SA could be removed, as the -SE uses ECU and Thermowax Pellet coolant circuit for warm-up operation.

Those are just a few of the items I can think of briefly, and I'm sure the more I think about it, the more will come up. I owned an SA22C as my first car and kept it running through HS and college, so I know them pretty well. My 84SE is my daily driver and I also feel like I know that car pretty well now that it has 231k miles on it, and an engine replacement about 11-12k miles ago. Both cars have been DIY and maintained by me, which was part of my original assessment to keep the SA22C original and try not to tinker with it too much. There are very few quality SA's out there still untouched, and what you're proposing won't be easy to enact, and will be nearly impossible to undo, should you ever change your mind in the future. Good luck,

 

Thanks for the input! Yeah the electrical/wiring will definitely be the challenging part. I do have an entire working SE car that I can use as a template and pull parts off as I go though, which should help. That's why I want to swap all the factory SE systems over instead of FC bits or an aftermarket engine management system; not only is it a good challenge but I have all the parts and (hopefully) won't need to buy much else.

Does anyone know by exactly how much the SE extension housing should be shortened so the shifter fits in the stock SA spot? It sounds like once the shifter is moved, the SE tranny will fit in the SA, but again I found a lot of confusing/conflicting literature so I figured I'd ask.

Thanks again for all the support!

Roland

 

Its far easier to get an SA tranny. Another other option is to get an 81-83 and swap an SA tail section onto it. The work to modify the GSL-SE tranny is requires permanent modification to the tail shaft. I remember reading about someone doing this on here.

 

Look up my build on my 1980. It's not too hard to get it to fit and run within the stockish SA chasis. If I remember right the main things I had to do was tap into a keyed power source in the black CPU in the left kick panel and the ignition switch harness for 12v to fuel pump relay. I ran new fused power from the battery to the ECU switch by one of said relays. Youll have to custom build your exhaust. I have a 12A 1980 RB power pulse exhaust from the pre silencer (with custom aux port pipe) to muffler, and a GSLSE header with like 6 inches extended to reach the presilencer. I "L" slotted the stock 12A front mount bracket. I used the 12A water pump, fan, radiator etc.

I still have stock rear end and transmission holding up to a few years of abuse with 160-170% power increase over stock. and lightened flywheel.

Elwood made me a custom internal surge tank for fuel supply welded right into the stock SA tank. Basically a small tank with lift pump supplies a constant level of fuel to the GSLSE fuel pump. I also increase the return line from 1/4" or whatever it was on the SA to 5/16".

 

Something else to think about that came to mind; the SA cars have a Voltmeter built into the Tachometer that operates when the key is in the Accessory position. The SE will have a separate voltmeter, and getting the SE wiring harness and ECU to operate the SA Voltmeter will be interesting. You'll probably have to keep both parts of the wiring harness for that to work properly.

Not to rain on anybody's intention here, but putting the -SE guts into an SA just seems like the wrong approach. You could put a 13b in an SA much more easily, but once you want the EFI components, it gets a lot harder. Good luck, either way,

 

My volt meter works perfectly and I did nothing special with my swap. I still have the stock wiring on the alternator (although it is S4 80 amp), stock-ish wiring for the coils, stock SA CPU in the left kick panel, and stock GSLSE ECU under passenger floor board. Doesn't the volt meter get its info from the ignitors/coils? I can't remember...

 

A little late to this party, but I ran across this thread because I'm about to do something similar. Long term, I plan to use a MegaSquirt, but I'd like to get the engine running properly first with the stock ECU. I blew the engine on my SA 10 years ago, and it's sat like that. I recently sold the blown engine (oil control seals about gone) and a previous dead 12A (rear apex seals), and I have a GSL-SE that's in "meh" condition.
It would be easier to refurbish the SE, but I literally don't care about that car. My '79 is my first RX-7, and thus, it gets all my love (after a dalliance with a '90 GXL for the last decade.) I also prefer the steel bumpers and rear treatment on the SA. The SA already has that GSL-SE suspension in it.
I want a 13B, and I want EFI. Carbs suck.

I think a lot of the questions were answered, but on the subject of transmissions, an FB trans *will* fit *IF* you cut the transmission tunnel back several inches to clear the shift tower. Before I pulled the engine, my SA has a, '84 SE transmission in it:


These were from a couple of weekends ago, just before I dropped the trans.

Mods to the trans tunnel and FB shifter boot plate I did are here:
Mods for FB transmission in an SA

I did this back in '06, so please excuse the ancient digital camera images.


An additional twist in my case: I discovered that the engine in my SE is actually an FC engine (EGR on top, different EGR ports at the intake mounting), and the transmission as well (ribs on the bell housing). Someone took the time to switch the shift rod and tower from the FB trans to the FC unit.

Regarding the SA Voltmeter, mine didn't work right to begin with, since a previous owner had swapped in an FB 12A, along with the FB engine harness and internally regulated alternator, which really freaked out the SA external regulator, which triggered the voltmeter priority. Basically, any time the "ALT" light should be on, the tach shows volts, so in my case it was on all the time. I just disconnected the feed for the voltmeter on the back of the tach at the time. I put in an SA harness, but rewired for the internally regulated alternator, and never reconnected the tach voltmeter, since I had also installed aftermarket volts, temp, and oil pressure gauges. As far as I know, as long as the alternator is wired correctly, the volts gauge should work as factory. It's easy to disable if needed, though. The external regulator is pretty easy to bypass as well. As I recall, I just had to jumper a couple of pins on the connector that used to go to the regulator.