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Best gearbox and diff for RB26


Guest MickieB

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Guest MickieB

Hey guys,

 

I'm doing up the budget for my conversion and i'm figuring out what diff and box i'm going to be using. I've got a 1975 260z 2+2, and i'm putting in an RB26DETT. I was thinking of the supra 6-speed cause the extra gear will come in handy for the highway travel i'll be doing to save some fuel. I honestly know nothing of the diffs out there that will fit or whatever, but i'd like an easy to find LSD. Also will this mean a custom tail shaft?

 

Any info on this much appreciated!

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Your "cheapest"/easiest tranny option is the RB25 tranny. These are RWD trannies, and the internals are VERY similar to that of the 300ZX (Z32).

 

If you're serious about the Supra tranny, there are two options:

 

1. have a VERY VERY competent shop weld the bell-housings of the supra and the RB trannies together. . . this method is expensive, and is not guaranteed to work.

 

2. your easiers, albiet not the cheapest, would be to get the Skyline R34 Getrag tranny (uber expensive), get the Supra Getrag tranny (not too cheap), and bolt them together.

 

The second one has been done before in Japan a couple of times, since it's not that hard to find an R34 tranny. We're talking about doing something like this in one of our shop cars, but nothing's set in stone.

 

If you're interested in the second option, we have a couple of R34 trannies laying around. We're also getting the Supra 6 speed comming on a container in a couple of weeks. I will warn you, though. . . it's not going to be cheap. I'm guessing the total cost of obtaining the trannies will cost around $4k.

 

All that just for the extra cog? I don't think it's worth it. . .

 

Get the RB25 tranny. The going price for those are around 800-1000, and can handle a good amount of power.

 

. . . oh, by the way, there are several companies making mustache bars w/ provisions for the R200. This diff should hold up just fine. The R200 is the diff that nissan used on many cars, and the gearing options are practically limitless, and the chance you're going to break is not too likey (depending on power levels, of course).

 

I seriously doubt that you'll be breaking either one (RB25 tranny or the R200 diff). The Z is such a light car that the strain on those parts will be minimal. Besides, you're going to have to worry about other stuff breakig at that power level.

 

-Kenny

http://www.rbmotoring.com

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Guest MickieB

Yeah i'm looking at making the car say about 400hp. Nothing too extreme for the RB26, but nothing too stock either. But that's way down the track, i just want to start off putting on parts that will take thr strain if i do decide to max out the power a lot.

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If you're going to max out the power "a lot", and want the drive train to live, be prepaired to shell out $10K for a dog box from Hollinger or GForce. If all you do is drag, you could go with a GM Powerglide auto with adapter for about $4000. The rear end will need a live axle from Ford or GM. 700hp will make a quick lunch of the R33 tranny and the R200. Stub shafts for the diff will go way before that.

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Guest MickieB

Nah realistically "a lot" will mean about 500hp i'd say. If i do race it it won't be drag but curcuit, and in particular hill climbs! Thanks for the info guys i'll look in to it all! :)

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The R33 RWD tranny can take over 700 ft-lbs of torque relaibly, I have seen many skyline's and swapped 240SX's with this much power and stock transmission. As for hard drag launching, it will hold up but for how long I am not sure. I know it will last at least a few passes and can handle enough power to run a low 10 @ 145 mph. I wish I could say it was my car but it was a 350Z drift car with a RB26 and RB25 RWD tranny (heavier then a 240Z). They were doing a magazine article about this car and launched it pretty hard for a few passes.

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Guest MickieB

Yeah a couple of passes is all i'll want, just to figure out what time i'd run. After that it'd be mostly streeting it and races.

 

Thanks guys! Given me lots to think on. Oh one more thing for aussie guys, where might i find an r200 diff? Wreckers have them? I know a few companies i can source the gearbox, but yeah not the diff. Thanks.

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