Kenku

Okay. I need to figure out if it's at all possible to mount a 12A to a 2nd gen front subframe. I know it's not a bolt up swap at all, but can anyone think of any aside from something like taking apart the engine to put a 13B center housing on to get the mounts?

... the reason why I'm asking is because I went to a junkyard today and finished my acquisition of a complete 2nd gen front suspension. Subframe, rack, springs and struts, hubs and *4 pot calipers* with the corresponding 5 lug wheels. And this is going into my 1st gen.

Only... well. I have a 2nd gen 13B sitting around. But it's not ready. It needs to be ported and it needs to have an intake manifold fabbed, and lots of other things. So I'd *LIKE* to get the subframe swap figured out, and running with a 12A on a temporary basis.

Any help would be appreciated; or even ideas on where to look. Thanks!

Pedestrian X

WOW! I'm sorry i dont think i can help you with any of that but i wish you the best of luck. Keep us updated on the progress aswell.

Kenku

Yeah, I'm planning to heavily document the whole thing. I've heard rumors of other people doing this but... never seen any pics. So thus, I will provide pics!

Kenku

Argh, stupid double post.

moremazda

iTrader: (4)

There is no practical way to make this happen. The second gen 13b mounts through the oil pan to the center plate and off the driver side of the front plate.

Number one, the 12a is 10mm shorter than the 13b between the two mounting points.

Number two, you can't put a second gen center plate into a 12a, due to the water seals needing to be in different locations.

Number three, if you jump the previous two hurddles you will then need to fabricate an oil pan to fit the subframe, the engine mounting locations and most importantly the 12a oil pan bolt pattern (since the 13b oil pan will not fit the 12a).

Good luck though

Ryan

moremazda

iTrader: (4)

Oh yea and don't forget that you will need to move the entire engine towards the rear diff. by 20mm (since the 12a is a total of 20mm shorter than the 13b) to keep the tranny aligned properly with the chassis.

Ryan

Kenku

Dohyeah, *that* one I forgot about. I know the 13B is longer, and the 2nd gen engine bolts up differently but...

... well hmm. Looks like I have to be creative again.

anthrax

Man no help here, but good luck with a vary ambisous project.

Blitz0309

sell the 12a for a running 13b?

Granted thats not what i would do. But it would probably be the easiest thing to do. Its that or a whole lot of custom fabrication.....

13B4port

one question. why are you puting the 2nd gen front end into your 1st gen?

i would be willing to bet the spring rates are different. so if you only do the front end wouldn't that mess up the great handling that a rx7 is known for. so too keep the handeling wouldn't you have to put the 2nd gen rear end in to.
and if you do that you have a 2nd gen engine, 2nd gen front end, 2nd gen rear end. with a 1st gen body and interior. why don't you just go buy a 2nd gen?

maybe i'm all wrong about that but it seems like a lot of wasted money. but if you do go and do this i wish the best of luck.

Kenku

Well, the reason I'm putting the 2nd gen front end into my 1st basicially boil down to getting a rack and pinion steering, bigass brakes, better suspension geometry, and 5-lug wheels. Well, that and it looks like it's going to be as close to a direct bolt up swap as I could hope for.

Spring rates being different I'm willing to bet you're right about. The 2nd gen is a heavier car after all. *HOWEVER* that's not all bad, again in theory, because stiffer spring rates are what's moved towards for better handling anyway. In practice, I don't care too much what the 2nd gen spring rates are because it just happens to look like the upper and lower spring perches are exactly the same size... meaning the springs are the same diameter, meaning I can swap in the aftermarket springs we pulled off of our race car when we went to coilovers. Meaning I have springs with rates and heights designed for a 1st gen.

And no, I have absolutely no intention of putting the 2nd gen rear suspension in. Period. From everything I've researched about it, it's a pretty poor design for independent rear suspension. Mind ye, the live axle rear of the 1st gen has problems too, but those are easier to fix.

I'm not trying to keep the handling exactly like it was from the factory. I'm going to be trying to tune it to where I want; *BETTER* than factory. Well, at the expense of some ride harshness, but I don't mind that at all.

There's a couple reasons why not getting a 2nd gen. First and foremost, I don't like them. They're a lot heavier and they look like a Porsche 944 ripoff. Second of all, even if I wanted one, this is Wisconsin. Rust free cars are incredibly rare, and 2nd gens aren't common either. Mind ye, 1st gens are only slightly more common, but I got a great deal on a New Mexico car.

A final point is what "all that money" amounts to. I got the entire front suspension from that 2nd gen for $180.

hornbm

yeah, by the time you figure out how to correctly mount that 12a in there you could have had your 13b done 3 times over. Its not worth the time.

Kenku

*muttered expletives* Okay, instead of another "this is a deleted double post" comment, I'll change this to replies.


Well... not a bad idea really. And I have a 13B but... while this may be me being an engineer, I don't want to put it in the car until it's built the way I want. I mean, originally I was going to get the 13B done first before trying any of this silliness but... well. Price was right on the subframe. Custom fabrication really doesn't scare me at all, and it's looking like that's the way I'm going to have to take.

Well... not really. What I want to do to the 13B should be interesting, but it's going to involve a lot of custom fabrication. And getting an EFI system from... somewhere. I don't like talking about my plans for the 13B too much because I keep thinking that people would find them ridiculously overcomplicated and impractical, and I'd rather just be able to have the finished engine done and explain then.

I figure worse comes to worst, it shouldn't be that hard (by my standards) to come up with a new front cover crossbar thingie that extends farther back to pick up the mount holes on the 2nd gen subframe. So that looks like what I might have to do. Dunno exactly yet; haven't tried test fitting everything and probably won't get a chance to until next week.

13B4port

ok i got a solution to your problem. just wait till the 13b is done then do all the work at once.

hornbm

Your 13b plans aren't going to be as "rediculously overcomplicated and impractical" as your plans for putting in that FC subframe are. Tons of people here do 13b swaps, but how many people do FC suspension swaps?

Again, you should just wait and put the 13b in there instead of trying to figure out how to get a 12a in there, you'll have the 13b done 3 times over before you figure out that 12a mounting problem.

excitingleopard

Good luck learning to spell ambitious.

Juuuuust kidding...heheh

79+80+84_rx-7

https://www.rx7club.com/forum/showth...hreadid=156545








https://www.rx7club.com/forum/showth...59#post1764359



hope that helps...


I will still love to see your right up...

well i hope i didnt burst your bubble, keep on keeping on!

peace!

Kenku

Well... yes, they are. For one example, I'm making my own damn intake manifold, and I full well expect that to take several tries. To say nothing of debugging the code for the EFI system to get it to control everything I want properly. Why am I making my own intake manifold? Because the stock manifolds don't have all the ports that I want. And I hate how the stupid 5th and 6th port actuators work, so they're going to be solenoid driven ball valves controlled by the EFI system.


... really though... you're kind of right. I *should* put the 13B in there. But... I'm impatient. I'm going to be happy if I get the 13B done by the end of the year and I want the car driving before then. Besidess which, I did all sorts of neat things to the 12A; Sterling's mechanical secondary mod to the carb, plus an RX-2 air horn and intake manifold. Actually, I should post pics of that in another thread. But yeah... it just sort of seems like a waste... and I think I figured out how to get the 12A mounted in there with only ruining at most one subframe. And I've got a spare 1st gen subframe.

Kenku

Ah *HA*! Huh, 'tis okay, just hadn't seen those before. Last time I remember searching, it was one of those things like the Loch Ness Monster... lots of people claiming to have seen it but no proof.

... well, I'll be the first to do it with a 12A? This doesn't mean I'm not going to do it anyway... oh ho ho ho ho ho...