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Gearing Woes

I was informed yesterday by a local 914teener, who also works on and races/rebuilds them, that if I go with my proposed V/8 conversion I will run into a gearing problem. Now, here are my two questions. First, do they make taller gears for all five gears? I know that they make them for 3,4,5 but was curious what about 1,2? If so, does anyone know a price for them? Second, he told me how high the ring and pinion ratio was and my queston is this. Do they make a lower ratio tht would be more well suited for the V8? Again any info on pricing and where I can get them would be appreciated. However, this brings up a concern. If I opt for the lower gear ratio, wouldn't that place all the undo stress from the bigger V8 directly on my gears? Just a little mind boggle that I had.Look forward to the responces
Old 10-03-1999, 03:45 AM
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I guess you can solve the gearing problem by swapping gears around. I saw a thread somewhere about it. There is a solution.
Old 10-03-1999, 05:23 AM
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Yes, other gears are made for the 901 tranny. The following page has a list of most or all of the ones available, with their ratios and some speeds (assuming a given tire size).

http://www.geocities.com/SiliconValley/2499/901gears.html

Some of them are pretty uncommon, and you may pay a good chunk of change for them.

You can also change the overall gearing by changing wheel and tire sizes. Have you considered that as a possibility? Going with 17" rims would make the gears all a good bit taller, depending on the choice of tires.

--DD
Old 10-03-1999, 12:43 PM
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I've heard that the rear part of the 1st gear shaft is pretty much unsupported, so putting a different 1st in won't help durability (from what I know anyway). Also most people with a high torque motor like a domestic V-8 don't even use 1st. Just treat 2nd as your 1st gear.

Anyway you look at it, you are going to tear the 901 up if you abuse it with a V-8. Maybe look into rebuilding the whole tranny to support the power, not just swaping gears. Either that or buy a few extra 901's to swap in when the first one blows.

Also a LSD would probably help more than gears, you can have all the gears in the world, but you ain't going nowhere with a "one tire fire".
Old 10-03-1999, 03:07 PM
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What is a LSD ? I am planning on a full rebuild of the transmision, but was curious about the gearing. I want good mpg's on the highway and I don't want to redline my motor doing 85mph. A typical ratio for a V8 sports car is 3:83. However the porshe's ratio is much higher 4:64 ( I think thats what he said ) So, you can see my problem I'd face. I was either hoping for larger gears and/or lower ratio. I thought about using 17" tires but the price is what's killing me. I would rather use 16" if at all possible. If anybody has seen or know of this problem and a solution let me know please. As always happy motoring

[This message has been edited by Dane (edited 10-03-1999).]
Old 10-03-1999, 07:00 PM
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An LSD is a Limited Slip Differential. An LSD, easy definition is a posi-traction rear end aka as two-wheels-burnin' as opposed to just one. The theory is that you get a better launch/traction with power to both wheels.

The down side is, tire wear, drive train wear and massive tickets... 8^).

FYI- The rule on V8 conversions is to lock out the 1st gear, 1st, it is worthless...too low and.... 2nd unsupported on both sides so as to be weak link...

My low power 6 conversion CAN get side ways in second but, I still use 1st. A V8 obviously will have a different result.

Good Luck....
Old 10-03-1999, 08:10 PM
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The stock 5th gear on the 914 is pretty tall, mostly for fuel economy. Redline on the stock four-cylinder (5600 RPM?) equates to about 135 MPH. If your V8 only spins up to 5000, that's still over 110.

And that assumes 165/78-15 (or close, like 195/65-15) tires. If you go to something with a small but actual chance of not spinning, and 16" rims.... Say something like a 245/60-16. That'll get you a fair bit taller than the stock stuff!

Stock is 25.1" diameter; the 245/60-16 is 27.6". (Nominal, that is. Actual tires do tend to differ...)

--DD
Old 10-03-1999, 09:38 PM
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This is why I love PPBB. Thanks everyone. I am planning on locking out first, I just didn't know what to do about the rest of my problem. 245/60/16 sounds good enough for me. Come to think of it i believed that we just installed those same tires on our vette, I'm gonna go out and measure them tommorow. Any more hints or suggestions are always welcome. Thanks again.

P.S. How expensive is a limited slip and where can I get one?

[This message has been edited by Dane (edited 10-04-1999).]
Old 10-03-1999, 11:43 PM
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A limited slip is pretty hard to find for a 901 transmission. It is almost better to do a complete conversion to the 915 tranny(I think that is the number). There seems to be only one importer of the Quaife lsd units, Autotech at: http://www.autotech.com/ and the price is about $1300 or so for the 901 version, figuring a few hundred more to get it put in, the estimates I get are around $1600 to $1800 as long as no expensive parts are needed inside. There are some used ones but they are really hard to find.
Old 10-04-1999, 06:14 AM
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Contact RENEGADE HYBRIDS they regear the 901 trans for V8 conversions. They cost about 900.00 exchange

[This message has been edited by davew (edited 10-04-1999).]
Old 10-04-1999, 04:48 PM
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