I went to the junkyards and found a good F283 Supra rearend and a W58 tranny out of the same car (86 Supra). The rearend is a 7.5" 4:30 gear with LSD. I'm wondering if this is too much gear for my 85 Celica with a 22RE engine. I'm trying to find out what would be a good rearend ratio for the 22RE. I'm sure the 4:30 gear would give me a lot more acceleration. But I'm not sure if it will cause too much wheel spin and make the engine rev too much. The 4:30 gear seems like it may be too high. Anyone have any thoughts or comments on this. I was thinking a 4:10 might be more than enough. Or even a 3:90 gear. I need some help in deciding what would work well for my 85 Celica rearend swap. I'm doing an auto to manual swap also. So I know the W58 will work. But I don't know what the best rearend gear would be. I going to mod the engine in the future. But I doubt it will ever see more than 150 to 200 horsepower.
Am also very sure that you won't have any wheelspin problems.. Only thing that I can think of, is that you're motor is going to HATE very long trips on the freeway @ high sustained speeds. 80mph, my tach is at 3,600 rpms & it's sucking gas at this point. Several trips from Seattle - Las Vegas have proven this. Now I know that the powerband on a normal 22RE starts to fall off at around 3,500 rpms, but w/ the extra mods you've done, things might be different. I would do a 4.10 ratio instead.
My Celica has a 3.42 rear gearing, and one fo the rear ends i bought was a 3.58. Just thought I'd mention what it was on mine is case you were curious.
Also, out of curiousity, do you have a gt or a gt-s? If you have the gt (live axle), putting in an F series diff will be difficult at best. The axle is built for a 6.7".
My celica has 3.91 gears and they seem fine for most stuff but first gear is almost useless if I really want to get on it. Cruising is passable, 3300 rpm at 80mph. I'll be changing to 3.42s as soon as I get around to rebuilding my diff, that way when I may not top out due to gearing. Being gear limited to 145 is kind of an odd thing. I wouldn't worry about short gears as all the fun of the 22RE is due to lots of torque low down, peak torque is at 2800 rpm and, mine at least, was pointless to take over 5000. My old celica had the 3.42s and while it didn't feel as fast in each gear you don't have to shift much at all, not to mention freeway cruising was great. 2800rpm at 80 in fifth, good stuff.
I've been using this RPM calculator and it works really great. Looks like someone in the Old Celica Club made it for the 3rd gen Celica's and MKII Supra's. Also works with other vechicles. This thing will show you the RPM for any combination of trans, rearends, and tires. Get it here: http://www.home.earthlink.net/~twopapa/gentech.htm#note
Download the program and then you'll need the VBRUN300.DLL Which I did a quick search on the net and downloaded it also. This RPM calculator is awesome to play with.
It looks like the 4.30 gear would be too much for my car. I do like to take trips and cruisin at 80mph would have my engine very tried after a long trips. Like CJSREDPRA was talking about. So I going to be looking for a 3.90 or a 4.10 rearend gear. Since I don't have much HP right now. This should work out good for me. Thanks for the help guys.
There's nothing wrong with my rearend in the Celica. Except it does not LSD and the gears are too low. I got the 6.7" rearend with a 3.58 gear. So I want to get the 7.5" Supra rearend for the LSD and a lower gear. I thinking maybe a 3.90 or a 4.10 would be best. The LSD will also give me better traction. So that's why I want to do the swap.