Hey guys -

I bought an '85 GS as a project car knowing that the original 12A had problems. When I tore it apart I found that the rotor housing are shot. So now I'm turning my attention to the 13B that came with it. Can you tell from the attached photos what year car this came out of? It has the oil cooler that mounts below the radiator. I think you can disregard the distributor...I think the previous owner stuck it in there, because there is a crank angle sensor in the box of parts that came with it. My guess is that it's from an 86 - 88. I need to know so I know which wiring diagram and layout to use to try to figure out how to connect everything for the fuel injection. My assumption is that I can use a Megasquirt to control everything, right? I know I need to move the front cover, front motor mount and oil pan from the 12A to the 13B. Anything else I should know to do this transplant?

Please don't tell me to search. I've done some searching and I've been watching this forum for a couple of months now, and it's really difficult (and time consuming) to piece together various posts to arrive at the proper answer.

Thanks,
Rich

 

if all those parts are original, then it's more likely 1989-1991 because that's the intake manifold from those years. you can check the OMP to confirm, but there's nothing to say that someone didn't transfer parts from a newer engine to a 1986-1988 engine - just something to keep in mind, but if wiring is your concern it doesn't matter.

just an aside ... dude, it sucks to search, i know, but everyone's time is precious to them. i've stopped telling people to search simply because i've come to realize that it takes no more time to type answer if i know the answer or move on to a different thread if i don't. anyway ... just wanted to say that ...

you can't transfer a 12A oil pan to that engine. you'll need an SE oil pan.

 

Thats a S5 N/A engine (89-91).Probably the most fun non-turbo 13B made,its got the lightest rotors and the highest compression of any N/A rotary.
Definately a good score,but you wont be able to run the factory EFI easily in a 1st gen.To use the stock EFI,you have to retain the electric oil metering pump which wont bolt to a 1st gen front cover.If you run a Megasquirt,that wont be a problem,however youll have to figure out how to activate the variable dynamic chamber valve and the aux port actuators.Its basically a rotary form of V-tec and is responsible for the nice,flat torque curve of the FC N/A engines.The stock ECU is the best thing for coordinating all that stuff,but the big electric OMP has to be retained in order for the EFI to work.
2 options that will work for you are....
Bolt on a GSL-SE front cover and mechanical OMP.Plug the electric OMP into the ECU and tie it off to the side of the engine bay.The SE pump will feed oil to the engine and the electric one will keep the ECU happy.
Or,have an SE front cover machined to accept the big electric OMP.Thats what I did for my S5 TII swap.Wasnt too hard,although it requires a knowledge of aluminum welding and a machine shop.

 

In theory, couldnt you get an S4 ecu, injectors, and sensors. Run it with all S4 electronics and the mechanical OMP...

Aren't hte Aux port actuators run off of exhaust backpressure (And can be modded to run off the air pump)

 

same question i had

 

arent the s5 actuators run of the airpump stock?

 

hankis for all the info guys! Looks like I have some work to do. Any suggestions for a source for the GSL SE front cover and oil pan? Someone previously suggested Mazda Motorsports, but it looks like they only sell to racers, and I don't race.

Thanks,
Rich

 

hankis??? Sorry...I didn't do a very good job of proof-reading. Obviously, I meant "Thanks"...

 

Yes,you could run the S5 engine with S4 controls and mech. OMP.Thats what I did with my S5 TII engine for a short while.But,that would negate some of the advantage of the full S5 engine,like faster ECU processing,better AFM,a real check engine light/codes,and the improved intake system.
The S5 aux ports could be switched to run off exhaust pressure(S4 style),from the factory,S5 are run by the airpump.The S4 ECU doesnt have provisions to activate the variable dynamic intake valve, however.

 

Also, is there a decent source for the S5 ECU?

 

What if I stick a Racing Beat Holley on this motor and use a standard 85 distributor and coils? Do I even need the ECU then? Seems like that would be easier. I could then use the 12A front cover and the mechanical OMP. The mechanical pump only has 2 outputs, while the electric pump has 4. Am I going to be ok if I just use 2? I could always premix too.

What do you think?

Thanks,
Rich

 

Yea,you could run a carb and pitch all the ECU and wiring stuff.The 4 hose OMP engines have oil nozzles on the rotor housings,so you could run a 12A OMP directly to those two ports and you wont have to run oil lines to the carb.The 3rd gens are setup this way,with oil metered to just the rotor housings.

 

Easiest route would be your last post. Carb, dizzy, premix. No fuss, no muss, mo problems.

However, a Megasquirt would be more tunable, flow more air, and make more power. It would be more of a challenge, but likely more rewarding. I can't remember if the megasquirt&spark is out yet, so you would need to keep the distributor regardless.

Where it me... Megasquirt, custom intake, DLIDFIS, which I am officially renaming GFS, for the sake of brevity. (Good and Spark are two of the words...)

 

I'm doing MegaSquirt and TLIDFIS.

GFS = God Farts Sweetly? Heh.

 

I like the idea of going with the stock EFI and ECU, but I have a few big problems with that. 1) I am totally unfamiliar with fuel injection (identying all the sensors and components and figuring out what gets connected to what) 2) Modifying the front cover to accept the electric OMP. 3) Coming up with the wiring for the ECU (I have a couple of feelers out looking for this).

Are these valid concerns? I'm very good with electronics, so working with the various pieces is not a problem. It's just a matter of getting familiar with the system.

Thanks,
Rich

 

But then again, if I can use the mechanical OMP with the carb setup and just use the two nozzles on the rotor housings, why can't I do that with the EFI setup? Just not use the other two nozzles...

Thanks,
Rich

 

You cant run just a mech. OMP with the stock S5 ECU.The S5 ECU is smarter than previous years,and must sense the elec. OMP is in place and functioning correctly.
You either have to modify the front cover to accept the elec. OMP......
..or leave it plugged into the wiring to satisfy the ECU,and run a mech. OMP on the engine/or premix.

 

it can be done with the GSL-SE font cover. You have to drill a couple holes, but it does fit

 

**COUGH**RENESIS**COUGH**

 

Yea, I figured that out after I made the post...thanks.

I'm getting close to deciding to go the carb route. The fuel injection system that came with this motor is nowhere near complete. There are many missing parts and sensors, not to mention the wiring. Just seems like more time, trouble, and money than it's worth.

Rich