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Pete

You were there. That was the Sunday course. I'm about three miles away from the turnaround which means about fifteen feet from the starting line. Didn't want to shift up then down then up because my trans shifts like shit so I just kinda soft pedaled it until the turn around, which is a decent chunk of why my times fell so far back.

Now, if you were to compare to the kind of courses we run in Ohio, especially the National Trail site like where we're holding an event this weekend and you'll probably get 900-1000 seconds of run time if you show up, or the "Duel" happening on the 7th because pursuit racing on dirt is AWESOME, our speeds never really go that slow so short gears where you are going between 2nd and 3rd (which are always a lot closer than 1st-2nd) makes more sense.

So, what do you want the car to do? Always the first question to ask yourself before looking for an answer.

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john vanlandingham
Which means we know we can't really go much shorter than 4.3 before 1st gear becomes so short that its useless (you dig holes on starts and go down rather than forward---and the car goes 1-2 car lengths before first is revved out---not a good way to start..

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RDR

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john vanlandingham

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RDR
Actually, Weir seems to offer some cool ring and pinion kits for not a ridiculous amount of money.

Choices include 4.56, 4.88, 5.29, and 5.71:1 ratios. I wonder how short is too short. I guess I'll have to do some trans research and figure out the available speed ranges.

You know, there are some here who have been doing this modding gearing stuff for like 45 years...
You could have a dialog with them and probably get a better answer sooner that researching on your own. (since in North America among those that write for magazines/fanzines/"the web" generally are among the most ignorant people not under restrained medical care, and thus unlikely to consider/ask/discuss gearing---since its not shiny.)

A fair point; that's why I'm here - to learn from other's experience, and maybe someday if I'm lucky, be able to contribute something!

So let me be more direct. It seems like there are several choices for much shorter ratios than what I have (which I believe is about 4.1:1). The car is responsive, but the Tacoma truck engine (3RZ-FE) only revs to about 5500-6000 rpm. It has a nice fat torque curve, which is good, but I could certainly take advantage of a greater multiplier.

How short is too short? If I were to do this, should I go as low as possible and grab the 5.71 set? The car has the stock 83 Celica GT-S trans. Any guidance is welcome and appreciated.

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john vanlandingham

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RDR
Actually, Weir seems to offer some cool ring and pinion kits for not a ridiculous amount of money.

Choices include 4.56, 4.88, 5.29, and 5.71:1 ratios. I wonder how short is too short. I guess I'll have to do some trans research and figure out the available speed ranges.

You know, there are some here who have been doing this modding gearing stuff for like 45 years...
You could have a dialog with them and probably get a better answer sooner that researching on your own. (since in North America among those that write for magazines/fanzines/"the web" generally are among the most ignorant people not under restrained medical care, and thus unlikely to consider/ask/discuss gearing---since its not shiny.)

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jrally
Or really cheap, most all of the Toyota vans, with the 7.5" axles, came with 4.30:1, if you needed just a little more gearing advantage. Not really important to this post, but it's possible (Weir sells a kit) for installing the Supra 7.5" LSD into the live axles. That's how I set up my live axle Celica.

-Jon

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RDR
Actually, Weir seems to offer some cool ring and pinion kits for not a ridiculous amount of money.

Choices include 4.56, 4.88, 5.29, and 5.71:1 ratios. I wonder how short is too short. I guess I'll have to do some trans research and figure out the available speed ranges.

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john vanlandingham
Going to swap final drive? That thing would go like stink with a 4.88.

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noypiesky
Look for a plate on the firewall that contains information about the vehicle. The differential section should have a 4 alphanumeric code. For example: F293, F=7.5" ring gear, 29=4.1 ratio, and 3=2 pinion LSD. Google for Toyota axle codes.
http://www.toysport.com/technical%20information/toyota%20differentials%20identifications.htm

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RDR
So the 1983 Celica I picked up recently has a rear subframe from a Celica/Supra of similar vintage, meaning that it's equipped with a semi-trailing arm setup instead of a live axle.

I have two differentials for the thing that reputedly were both LSD-equipped. However, when locking the input shaft and spinning one output, the opposing shaft rotates in the other direction. I believe this indicates that the LSD is no longer functioning in either diff.

What I'd like to do is continue to run with the differential that's currently in the car, and rebuild my spare in the mean time. I've attached (or tried to attach) a couple of photos below. The thing doesn't seem to have any tags on it, except for a '3' on the rear cover. I'd say the ratio is a little over 4.0:1 based on spinning it by hand.

Can anyone help me identify the diff? Are these clutch type differentials? Do we know of any resources to rebuild these things? Are these the same diffs you guys seem to love for Merkur builds?

Photos: http://imgur.com/a/T2Bvp

Thanks!