Here for the tire tech threads
09-17-2017, 05:16 PM
#1
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Here for the tire tech threads
Hello,
I have an '83 RX-7 that's now 90% non-Mazda, I did all that work, with paint, noone liked the results, then trying to trade it I seized the GM V6 because I forgot the oilpan leaked. Anyway, I adapted an FC IFS to this FB, with my own BBK, and managed to mostly tuck a set of 15x7 +40 with cheap 205/50s that are more like 185/55s.
As I've followed Roadkill's Rotsun, and failed to get my 4.8L version of the LS swapped into anything else, I've been thinking of making ReX into a drag car, except that the T5 and axle I went with aren't that strong.
I could probably tuck 9s under the rear without flares, but the front will need flares even if I just get RE-71Rs, so I was considering some R-S4s in the 245/40 size on some zero-offset 15x10s up front, and maybe narrowing an 8.8" for the rear. 15x12s w/ 4" backspacing, finalize axle width to suit.
I did a three-link with Panhard in the rear, couldn't fit a Watt's Link, but it's great at canyon carving anyway.
I lengthened the trailing arms when I had 225/60R15s on the rear, since changing sizes the arms seem slightly too long now. But I'll leave them until I get to a stronger axle and wider wheels. I may have to get the driveshaft shortened and re-balanced anyway. I used to do that, but no longer work at a driveshaft shop.
More later
I have an '83 RX-7 that's now 90% non-Mazda, I did all that work, with paint, noone liked the results, then trying to trade it I seized the GM V6 because I forgot the oilpan leaked. Anyway, I adapted an FC IFS to this FB, with my own BBK, and managed to mostly tuck a set of 15x7 +40 with cheap 205/50s that are more like 185/55s.
As I've followed Roadkill's Rotsun, and failed to get my 4.8L version of the LS swapped into anything else, I've been thinking of making ReX into a drag car, except that the T5 and axle I went with aren't that strong.
I could probably tuck 9s under the rear without flares, but the front will need flares even if I just get RE-71Rs, so I was considering some R-S4s in the 245/40 size on some zero-offset 15x10s up front, and maybe narrowing an 8.8" for the rear. 15x12s w/ 4" backspacing, finalize axle width to suit.
I did a three-link with Panhard in the rear, couldn't fit a Watt's Link, but it's great at canyon carving anyway.
I lengthened the trailing arms when I had 225/60R15s on the rear, since changing sizes the arms seem slightly too long now. But I'll leave them until I get to a stronger axle and wider wheels. I may have to get the driveshaft shortened and re-balanced anyway. I used to do that, but no longer work at a driveshaft shop.
More later
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09-19-2017, 08:21 AM
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09-19-2017, 09:53 AM
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In a car that light the 7.5 may be ok. But you can also get an 8.5 from an s10 that should be a direct swap (sans your weird axles for that 4x108 pattern, the splines may both be 28, I just don't recall) for the 7.5 you have, assuming you didn't move perches around or whatnot. The 8.5s aren't common but they can be found.
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09-20-2017, 07:35 AM
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I entered it in the Cashe Valley Cruise-In, one of the biggest car shows between Denver and Hot August Nights in Reno.
It looks ok for what it is, it drives great for a solid axle car, but no interest in a non-v8, no interest in such narrow tires, little interest in non-American, non-BMW build. And it is weak, except from 15-50 mph in first gear. But even with that 3.75:1 first, it can't spin the rear tires.
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09-20-2017, 07:42 AM
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I know about the ZR2 axle, and you'd be right about it being the easiest upgrade, especially since I did end up 5 lug by the end of the thread, except I figure that deep dish wheels with a narrowed axle is less weight (unsprung, too!) than a wider axle with positive-offset wheels, looks be hanged.
I have nearly 2" more useful under-fender width in the rear than the front, unless I add wider front fender flares than rear fender flares, which I won't, because of the FC struts, but I'd change the struts to short-coil adjustable coilovers if I could find affordable wheels with enough positive offset. Right now the front is at 5.57" backspacing, and without mods it can't go to 6".
I have nearly 2" more useful under-fender width in the rear than the front, unless I add wider front fender flares than rear fender flares, which I won't, because of the FC struts, but I'd change the struts to short-coil adjustable coilovers if I could find affordable wheels with enough positive offset. Right now the front is at 5.57" backspacing, and without mods it can't go to 6".
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