big_rizzlah

so i've got my car; 1973 Rx-3 Wagon



I got my front clip



pulled the motor and subframe out of the front clip





Pulled the original 12A out of the wagon







and am now going to put the subframe from the front clip in the wagon sine the bolt pattern on the front clip's suspension matches the bracket at the top of the strut tower in the wagon and then weld some brackets that will accept the bolts that held the subframe to the front clip. the motor is then going in with a series 5 turbo II manual transmission which will require cutting the firewall and rebuilding it with sheet metal. I'm still looking for my rear end (most likely a ford 9-inch with posi and 3.70 gears).



what i need some help with is my ecu. the stock one can't be used because it doesn't work if you don't keep all of the original car's features (auto trans, ac, power steering, emission crap, etc) so i'm going with a standalone EMS (either AEM or Microtech LT12S) i need some advice from someone with some experience with 20bs and either of these ecu's to help me out and give me a reccomendation and hopefully their basemap. any other advice is most definitely welcome and appreciated. Thanks

-ryan

Jeff20B

Ah, you made it here. RETed visits this forum from time to time, so maybe he'll see your post. Of course he's a Haltech type of person. Speaking of aftermarket EMS/ECU stuff, I've got a MegaSquirt that has three ignition outputs that I could use to fire the leading and trailing plugs together with no split right now if I wanted to. I won't though, at least not with three FC leading coils because you should never use dual output coils, such as the FC leading coils, on the same rotor housing, ever. Fellow forum user heretic could explain it more eloquantly than I could. Anyway, late leading is possible (each leading plug spark once at TDC and again at 180°, seperated by 120° per rotor) but the code writer wants me to test the code in single spark mode to make sure it works before he'll put the time and effort into modding it. My modded dizzy already has late leading, so I've got it to fall back on.



The MS can work with a Mazda CAS, but currently supports 12-1 (one VR sensor and two teeth shaved from the 24 tooth wheel). It could support the CAS' stock 12+1 signal with a little work, and it does other cool stuff too, but I don't want to fill up your thread with my ramblings.



I had to cut the firewall in my 20B project too. So far I've tried welding individual pieces of sheet metal back in, but it's not a very fun process. How do you plan to rebuild yours?

Robbomaz

Great project! 20B Rx3 will be a missile!

No-brainer in this part of the world: M-Tech LTX12s

ECU has ignitors built in and kit comes with 6 coils.

big_rizzlah

to Jeff20b:



For the firewall, I'm gonna do the same thing as you it sounds like. completely remove it, and then rebuild with pieces of sheet metal welded together. the only other option that i can see, is using the firewall out of my frontclip and trying to mate it into the wagon. . .i'm not sure if that would be more or less work, either way doesn't seem to fun, but must be done nonetheless. Thanks for the input on EMSs, i commend you on your work with the MegaSquirt, a little too involved for me, code writing and testing is a little more than i'm trying to get into. . .the biggest electrical headache i'm in the market for is wiring up an AEM. nobody using the aem seems to want to help me out with any of their basemaps or stories on wiring it up. i don't think it should be too hard, but i wish someone could just confirm it for me before i drop $1400 on it.



to Robomazz:



I'm interested in Microtech because they come preprogrammed for the motor, but i don't want to have to go that far for tech advice if i have to. as for the LTX (X being the models with internal coils), i've heard that they run much too hot for the 20B and end up no being able to handle the load. if i was gonna go microtech, it would just be the LT-12S and use the stock coils for now since i'm leaving everything else stock initially. Are you using the LT-12? if so, how's that working out for you. like i already said, i know they come programmed and they come with a wiring diagram as well. i am just looking at the AEM because it has more features. . .the dual knock sensors, the two-stage launch traction control, TONS of extra outputs for anything you might need, etc.



Thanks for the input though. . .i really appreciate any advice on any aspect of this project, especially since it's my first 20b

Jeff20B

That's a lot. I only dropped $140 on the MS (I also got a stimulator kit which came to about $188 total for everything), and there are tons of stories out there, well stories of MS installs on other engines, including two rotor engines. Mine will be the first 20B as far as I know.



I'm going to need to finish my firewall before I can mount the MS in the car. Then it'll be test and tune time. I'm very nearly done bench testing the MS right now. The hardware mods I performed are like preschooler-simple according to most of the MegaSquirters on the msefi forum. Pull-up resistors and the like are not hard to solder.

Rub20B

The coils aren't built in, the igniters are, and why should they run hot? You can use whatever coil you want, (without built in igniter) you can choose for the morge stock Microtech one's, but you can also buy MSD coil packs...

big_rizzlah

My mistake, i mispoke. as to why they would run hot, i'm not sure. . .i would assume just form the spark needed for rotaries, i wasn't given an explanation why, i was just told that that was the case. . .

Rub20B

I thought microtech is specialized in rotaries as they have all the basic maps for 13B and 20B's ready... but I don't know for sure, does anyone has problems with the built in igniters?

Rub20B

Another question, when assembling the 20B you need to screw the thick middle plate to your engine stand, is it healthy for the plate when the whole stack hangs only on the 2 bolts of the thick middle plate..?



I don't want to break the bolts of or so..

RX-Jesus

an other question about this

what kin of ingniter/coils can we use whit the LT-12s model?

just becuse the ecu is cheeper than the LTX model

thx



P.S. nyce swap! need more pic!!!