gslse rear end swap alternative?
05-25-10, 11:12 PM
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gslse rear end swap alternative?
ive looked through the archices on se swaps and im wondering if its possible to just swap out the diff, axles, rotors/calipers, ebrake cable and all rather than pulling the whole rear end if both cars are from the same year. 84/85 have big axles correct? should there be any issues?
05-26-10, 11:17 AM
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im trying to ship an se swap but shipping prices are crazy and id figure all the parts should fit into a gsl rear end, providing i provide the axles, rotors/calipers, diff and wheels and also the front suspension. Im just trying to get around using frieght. I know if i can make it smaller and in pieces i can save the guy a whole lot on shipping.
05-26-10, 12:46 PM
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there are a couple options now.
1. every 84-85 disc brake axle housing is the same, the gsl-se has different rotors, calipers and axles, but the housing is the same.
2. Re speed makes an adaptor that lets you put disc brakes on a drum rear housing. you'll have to double check to make sure they have a gsl-se brake version, as the 12a and 13b might be different.
3. the early gsl-se's are 4.09 geared, but midway thru 84my they switch to the 3.9. the chassis number and date they switched are in the parts fische.
1. every 84-85 disc brake axle housing is the same, the gsl-se has different rotors, calipers and axles, but the housing is the same.
2. Re speed makes an adaptor that lets you put disc brakes on a drum rear housing. you'll have to double check to make sure they have a gsl-se brake version, as the 12a and 13b might be different.
3. the early gsl-se's are 4.09 geared, but midway thru 84my they switch to the 3.9. the chassis number and date they switched are in the parts fische.
05-26-10, 12:59 PM
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there are a couple options now.
1. every 84-85 disc brake axle housing is the same, the gsl-se has different rotors, calipers and axles, but the housing is the same.
2. Re speed makes an adaptor that lets you put disc brakes on a drum rear housing. you'll have to double check to make sure they have a gsl-se brake version, as the 12a and 13b might be different.
3. the early gsl-se's are 4.09 geared, but midway thru 84my they switch to the 3.9. the chassis number and date they switched are in the parts fische.
1. every 84-85 disc brake axle housing is the same, the gsl-se has different rotors, calipers and axles, but the housing is the same.
2. Re speed makes an adaptor that lets you put disc brakes on a drum rear housing. you'll have to double check to make sure they have a gsl-se brake version, as the 12a and 13b might be different.
3. the early gsl-se's are 4.09 geared, but midway thru 84my they switch to the 3.9. the chassis number and date they switched are in the parts fische.
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05-26-10, 01:45 PM
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Man, I can never get a definitive answer for gear ratios for the 1st gen. My John Matras RX7 book, shows all 12a RX7s had 3.909 rear ends, and the GSl-SE had a 4.076 final drive. Then I see Mazdatrix websites list all different oem gear ratios, 4.11, 3.909. I have an 84 and 85 RX7 brochure, it lists all GSl-SE's as 4.076 final drives. They also show the 84 12a RX7 as a 3.933 final drive and the 85 as 3.909. Also, I have mutliple sources that can't agree on tranny ratios. I see some sites list all 12a RX7's have a .825 5th gear, some say that 84-85 have a .807 5th, and GSl-SE's have a .711 5th gear. What is the truth?
just from experience the 12A is the short .825, the 84 gsl-se gets a .758 and then the 85 gets a .711
i think you could look it up in the parts catalog, but i haven't and its a little tricky cause they don't list the ratios, just part numbers, but now that i'm looking there are 3 different 5th gears. 12A, gsl-se up to june 84, and then after june 84
the rear end ratio's are much much simpler, if you look in the parts catalog, they actually just list the ratio's. i actually have confirmed that with reality too, the gears are stamped with the part number
05-26-10, 01:53 PM
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So my 85 RX7 GS should have a .825 5th gear, and a 3.909 final drive?
Sucks, I just picked up a clean GSL-SE rear end, I don't know what year it's out of, I wonder what ratio I have.
Sucks, I just picked up a clean GSL-SE rear end, I don't know what year it's out of, I wonder what ratio I have.
05-27-10, 02:26 PM
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The differences between the diff and 5th gear ratios are very minimal. For most driver's, they won't even notice any performance difference, don't sweat it. If your buyer has a GSL diff, just send all the bolt on parts from the diff and the front struts. Buyer does need to have and 84/85 lsd diff for this to work.
05-27-10, 02:30 PM
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The differences between the diff and 5th gear ratios are very minimal. For most driver's, they won't even notice any performance difference, don't sweat it. If your buyer has a GSL diff, just send all the bolt on parts from the diff and the front struts. Buyer does need to have and 84/85 lsd diff for this to work.
700rpm is very noticeable, especially with exhaust....
05-27-10, 03:50 PM
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if you have a late 84 SE, 1-4 are taller due to the 3.9, but its not noticeable, 5th is pretty tall, but it actually puts the SE engine right at the torque peak @60ish
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