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Chassis Design for 1st gen RX-7
jestre - 26/10/04 at 09:56 PM

getting my steel tomorrow ($100usd for 300ft, it is a take all / none offer) and I need to know if the book chassis will take an RX7 rear end, engine (12A), and transmission. If not what needs to be changed.

I would like to know before I start cutting.

Thanks


Hugh Jarce - 27/10/04 at 04:05 AM

I'll jump in here as no one else has yet.
AFAIK, no one else has attempted that particular combination, which is probably why you havent had a useful response.
Hopefully somebody will prove me wrong.
The forum's search engine isn't much use, but maybe give it a go and see what turns up.


derf - 27/10/04 at 12:28 PM

Ok, good news for you, I have a 13B in my book chassis car, the 13b and 12a are rougly the same size (13b being slightly larger). he associated RX7 tranny will fit fine in the tranny tunnel, just watch out for the starter motor (I'm assuming that it's on the drivers side) which could make the drivers footwell a bit small. Leave the tranny tunnel and all the inner tubes until you are ready to mount/or have mounted the engine. You will have an easyer time than me mounting the engine as the engine mount for a 12a is just bolts to the front of the front housing, you can buy a solid mount from racing beat which will make your life real easy. the tranny mount is a bit trickier (again same as 13b?) I just ran a plate across 2 lower tranny tunnel tubes, and used some polyurethane mounts I picked up in the local store, then bolted the tranny to the chassis.

I couldn't tell you about the rear as I used one from an S10, but apparently it is possible to use the 1st gen rx7 rear, Mcsorley did it:



Also, thats a good buy $100 for $300 ft. I paid $1.26 for mine per foot, thats a real good deal.

Where are you located?


derf - 27/10/04 at 02:27 PM

I actually just found this, I wish I had found this Idea when I built my tranny tunnel, it would have given me much more foot room, just a simple cutout for the starter...



pbura - 27/10/04 at 05:37 PM

An advantage you have with the 12A motor mounts is that it's possible to shorten the sump, which may be just enough to use a CMC nosecone and still have adequate ground clearance.

Dave Disney used a 13B, but with a 12A front cover, and shortened his sump. Here's his website:

http://locost.voodoobox.net/

The 1st Gen axle is quite popular in the US, often with cars that are slightly oversize (up to 4" wider) though Jim McSorley has mentioned that he would have been a bit better off with +3" instead, to give a bit more room for the trailing arms, not to mention tires. With a book frame, you could use up to 245mm rear tires with no problem.

Pete


jestre - 27/10/04 at 07:07 PM

Derf, I'm in West Michigan. ( got a truck load of steel today to ) they actually gave me closer to 350ft of steel

[Edited on 27/10/04 by jestre]


derf - 27/10/04 at 08:02 PM

Michigan? 350 for $100? Bite me.

Actually I have found through talking to others that the farther west you go the cheaper steel is, sgraber is out in arizona and he paid something like $0.36 per foot. slightly more than what you paid, but compared to here, I got a deal, there were some places that steel 1"x1" 16g steel tube is over $2.

keep us updated, it's good to know that there are a bunch of us US'ers on here.

I used a CMC nosecone with my 13b, and my hood rests on the intake manifold, I am going to try to experiment by beating a small dent into the hood tyo see if I can clear it.


jestre - 27/10/04 at 11:32 PM

I posted a "Want" ad on the local group of Freecycle.org, and was contacted by the seller with on offer. They had bought a large amount of this steel and this was the leftover that had been sitting inside for 2 1/2 years.


Louis M - 28/10/04 at 07:51 PM

do you know anyone who did IRS on a 2nd gen?


jestre - 28/10/04 at 07:57 PM

groups.yahoo.com/Locost_north_america

look in the photo's for Oddbritt for a 2nd gen setup


Louis M - 28/10/04 at 08:04 PM

he uses a de dion


mranlet - 3/11/04 at 02:40 AM

AFAIK, the FC RX-7 rear end uses the same houseing as the Miata (semi-trailing arm rear suspension, which could most likely be adapted with very little variance from the book chassis).

I didn't catch what model your RX is, but from what I understand, the Turbo II's came with a LSD (although it probably in dire need of a rebuild by now, almost 15 years after production)

Hope this helps, and that I'm not giving you bum info