'85 GSL 302

Well, unfortunatly the GRM myth is just that. There's no way to make the Miata suspension fit under the RX-7 unless you move it back about 6". The problem is the frame rail starts to drop down imediatly after the axle, but the miata subframe continues for another 6". There's no way to make it fit without some major fabrication.



With that said, I'm extending the frame of the car, and I'm going to bolt up the miata suspension anyways. I'll try to take some pictures of the RX-7 project and start a new thread in the next couple of days on the progress. I have the car about 96% stripped right now. Still need to get the fuel lines, brake lines, and a few minor parts. Once I finish the fame modifications I'll get the cage installed. Stay tuned....

Manntis

You have to modify the c-channels and unibody rear anyhow to provide mounting points for the subframe. Pretty much all live rear axle cars have that arc of 'rails' over the axle whereas IRS have a flat spot.

TurboIIGuy

What year is the miata rear axle from?
There is a specific group of years of miata that will fit almost as bolt in. It probably isin't the IRS rear though. I know that the earlier years of miata have rear gears that fit a series 3 (1984-84) rx7. I know that Racing beat in Anaheim has a welth of knowledge regarding this. Try giving them a call if you need more info. www.racingbeat.com

82transam

iTrader: (18)

we had a 93 miata in the shop (gas station) the other day and while it was on the lift I was poking around under there taking measurments etc. And what you say is true, it sits a bit too far forward. As stated earlier you'll have to modify the curved portion of the frame rails. As long as you brace everything properly it should work fine. Have you given any thought on you're going to attach the coilovers? Also how do you plan to recreate the brace that goes from the trans back to the rear end? I can't wait to see some pics, cause ever since i saw under that miata the gears have been turning in my head on how to put its suspension in my project car. The front suspesion sub frame looks like it could fit with a fair amount of fabrication. Man the thought of a fully independant double wishbone first gen makes me drool...

'85 GSL 302

I'm using a '00 Miata rear end. All miata's had the IRS, although the older ones may have had a different design. I can't imagine it would make enough of a difference though and I highly suspect it's the same frame.

I have no intentions of including the PPF brace. The engine/tranny will have solid mounts, so they won't be flexing in the chassis. As for the spring/shock mount, they nearly line up with the factory RX-7 spring pertch, so I'm planning on cutting that out, and welding in some mounts for it. I'll probably integrate it into the cage, but it's not necessary. As for the frame, I'm going to cut into the passenger compartment and extend the rails. I've also thought about just installing a tub frame rear, however I'll probably avoid that purly on cost. I suspect it'll be some place in the middle as far as fabrication goes.

As for rear ends, I'm going with a T-bird 7.5" IRS, a custom driveshaft, and custom axles. It's what all the monster miata's run with their V8 swaps. Hopefully I'll get pictures up today or tomorrow.

The origional plan was to run "A" arms in the front off a circle track car, however I'm just going with the FC front instead. The amount of fabrication involved isn't worth it. In all honestly, struts are awsome designs. The Evo's are struts, STi's, most 240's, you get the idea. There's a point of deminishing returns, and I can accomplish all of my goals using the FC front suspension I believe.

But yes, quad "A" arms would be sexxy....

82transam

iTrader: (18)

being the newer gen Miata, its possible that the suspension differs on the 2000. I'll have to poke around my boss's car next time its here to findout. As for what you said about using a fc front end I agree, it should do nicely, I still may try to use the miata front someday. I'll have to add that to the wishlist for my future project.

christaylor

The 2000 is the newer gen Miata. M1 goes from 90-97, while M2 goes from 99-present.

EDIT2: I'm a moron, you're right. I need to quit staying up late at night..... :sigh:

j9fd3s

iTrader: (3)

the rear suspensions from the miata's are basically the same from 90-now, theres a couple small changes but nothing important.

they did change the diff in 94 to the fb style unit, but thats seperate from the suspension anyways