FWD rotary conversion

[Damkid]

I'm posting this here simply because i don't know what car i will put this engine into, so i'd say this is a Build thread on the FWD conversion only, once i figure out a car to drop it into, i'll start a separate thread

Ok so i know rotary's never came FWD, but i think it would be cool to have a FWD rotary setup, so here is my little side project

So i'm sure some of you have seen the KL powered Miata, they use an adapter plate and an RX7 tranny mated to the KL, so that tells me the flywheel/starter situation works with that setup, so why not use a KL tranny on a 13B?

A friend of a friend is a tool and die maker and he has his own CNC plasma cutter and is very good with CAD drawings, if i am not able to locate a CAD drawing for both the 13B and KL bellhousings, i will get him to make up the CAD drawings using any of my spare components and then cut out an adapter plate for me, if the adapter plate is too big for his CNC plasma, then there is a local laser cutting shop that i can have the plate made at

I figure the starter placement on the KL trans should work nicely on a 13B, and since i have a couple spare KL tranny's, the first step is to get a 13B to mess with

I know the biggest hurdle i will run into is the exhaust manifold interfering where the axle will go, my plan is to make a custom manifold for it to clear, worst case senario, i can "clock" the engine a bit the help with the clearance

$200 later and here i have a complete setup from an 89' RX7, wiring harness/ECU etc. (tranny will be F/S later on after the adapter plate is made)

And i started taking a few things off the motor to get an idea how its built

The clutch looks pretty similar to the KL clutch and the spline count matches the KL clutch which is awesome cause i won't need to mix-match components to line things up

Now I do understand there will be a bunch of custom work for this setup to work, but that just adds to the cool factor if i manage to pull it off, this will most likely be a very slow build as well since its not my priority build, i still have a festiva to finish turbo'ing and a 323 that needs a new engine, but i will update this thread as i make progress here and there

Anyways, wish me luck lol

 

[fishdonotbounce]

Sub to see how this turns out. Good luck.

 

[caidoz]

only issue I could think of right off hand would be finding a tranny to handle the high RPM's.

 

[Damkid]

only issue I could think of right off hand would be finding a tranny to handle the high RPM's.

I'm slightly confused, why couldn't a KL manual tranny handle the RPM? like i know rotary's can rev like a bastard, but i shift my KL festiva at 7500rpm, and since its a manual, it's only gears spinning inside

Worse case though if the KL trans has too short of gearing with the 4.38 final drive, i can swap it for a MX-6 trans which has a slightly lower 4.11 final drive, which would help it out

 

[Damkid]

so today a buddy came over and we tore down the 13B to the block

Then figured to try test fitting the KL trans on it, didn't go so well since the 13B flywheel is bigger then the KL's and it doesn't really fit in the KL bell housing

So we figured pull the flywheel and see how it mounts to compare it to the KL flywheel and well this is new to me....

So since I don't have a 2-1/8" socket, I couldn't get the flywheel off, either way I gotta get real creative in order to make this happen

 

[mymmeryloss]

U will be my new hero if u pull this off!

Im rooting for ya over here! Glwb!

 

[eprx799]

good luck getting the flywheel off its torqued to about 300ft/lbs. you better have a good impact gun.

 

[Damkid]

Yes I do have an impact gun (electric) but until I can locate a socket I'm at a stand still, but also I'm not in a hurry either since I have a different engine swap coming up

 

[eprx799]

If your only going to remove the nut once, than just take it to a mechanic and have them remove the nut and the flywheel and put the new one on for $10-$20 your still ahead of the game the large socket is about $25-$35 .
Plus your electric impact probablly doesn't have the torque needed to remove the nut.

 

[Damkid]

Your probably right that my impact won't take off the nut, but I have friends who work at shop's so I have access to the necessary tools lol, it just hasn't been a priority to me yet lol

 

[ajkulish]

interesting sub

 

[BRIAN_MP5T]

Why? SUBS

 

[ajkulish]

because race car.... and because mazda heritage.

 

[BRIAN_MP5T]

No, the Why was directed at the OP... Not you..

More of a general "Why FWD"

 

[ajkulish]

i know who it was directed to...... it was a joke.

 

[Damkid]

Why?? Well I've basically been around festiva's since I started driving, which turned into mazda's in general, and I've seen many many threads on the forums about if a FWD rotary swap was possible, so this project is to answer that question once and for all, if I can pull it off, there could most likely be members on clubprotege.com that would try a rotary swap in there protege's, 323's etc

So I guess you could say I'm being the guinea pig for all of it, worst case scenario, this conversion turns out to be a bust and I sell the engine/trans for what I paid for them

 

[ajkulish]

i say why not. its not like a na 13b is that powerful. plenty more powerful than the stock motor but i think it would be a good fit for its application and would be really cool to be seen done.

 

[magnumP5]

Subbing for a possibly interesting build. One item to point out is that engine is not out of an '89. The intake manifold is of the S4 ('86-'88) design. No big deal, it just produces 146 hp instead of 160 hp. What I'd almost be more worried about rather than fitting the FWD is getting the auxilliary ports working on the engine. If you leave them open low-end power will suffer significantly (below 5000 RPM).

 

[Damkid]

Hmm good info, thanks...... i can say that the engine did come out of an 89' for sure, however i don't think the engine was original to the car (which could explain the older style intake) if you look close at the pic of the flywheel, there are air chisel marks on the nut to suggest the flywheel was off at one time, and personally i only take flywheels off for either re-surfacing or changing the engine

 

[magnumP5]

The manual RX-7's have the rear counterweight integrated with the flywheel so if one was simply swapping an engine from an S4 car to an S5 car the flywheel wouldn't have to come off. However, there are some very significant differences in the control systems between the S4 an S5 models so I'm curious what all was done. It's rare to go from and S5 to an S4 engine because of the drop in power. You could have an interesting engine on your hands so are there any plans to pull it apart and rebuild?