geordie

There is an interesting thread over on the 993 board about changing the R/P. The OP was hoping it might help as the USA 993 'box ratios are less than ideal.

My USA spec '94 964 C2 has the 3.333 vs the ROW 3.444 and I've often wondered about lowering the rear end (ie numerically higher) to generally aid acceleration & perhaps benefit (the some way off) DE driving I've been longing to do.

Any ideas on cost ?
do instruments need to be re-calibrated ?
is there a 3.5 R/P option ?

TTFN

race911

Did you see my post over there? I believe the unit available way back when was a 4:1. Made 2nd unusable, and 3rd and 4th too short for everything but maybe Laguna and one Buttonwillow config. Could run the same lap times with a stock box.

geordie

Thanks Ken, yes, I did see your post.

I certainly don't have the know how/understanding that you have. What I'd be interested in, is a (relatively inexpensive) change that whilst obviously lowers 1st, doesn't make it redundant and allows greater use of 2nd-4th for "fast road"/spirited driving.

I'd be happy to swap the trans (and motor) from the Zonker into my car, purely in the interests of furthering my understanding

PS a kazillion years ago I had a 99% correct '66 Shelby GT350 clone (built by the PO on a correct K code fast back) that I recall had a 4-sp Top Loader w/ Detroit Locker back end & 4:10 (or thereabouts). Lots of fun .... in a straight line ....

crg53

Gordie, just out of curiousity, is your avatar a picture of your car, if so which type of oil filter is that? Does not look like the correct type.

geordie

Good eye Steen!

That picture was taken on the day I collected the car. I don't recall what brand it was; it was immediately replaced with a Mahle filter.

race911

Come drive the car. There's no cheap/free lunch on regearing these transmissions, either in the gear sets or the final drives. Nice when they're done; no way would I pay for it. Even though I can do it myself.......

(Further comment about the oil filter, it's just a generic and probably fine. Was SO glad there was one in stock at the Willows Walmart last year when I drained the oil out of the RSA and thought I had filters in the garage at the track. Grr. But 1 year and probably 200 miles later, it works fine.)

geordie

Next time I'm in the Bay area I'd love too!!

Going back to my original enquiry, any ideas on cost? the need for instrument re-cal? 3.5/3.6 R/P availabilty ?

race911

15 years ago it was about $2K for the ring and pinion. It was an 8:32 unit aka 4:1. Don't need to recalibrate anything as you're not changing your tire diameter.

geordie

Cheers.

I think I might try and fit those old 10" Minilites from my dearly departed Mini Cooper as a budget measure to lower the gearing. Failing that, where did I put my old Z-Flex skateboard .....

Bill Verburg

totally different issues wrt to the 993 and 964 transmissions

here's a stock 964 g50/05 compared to 2 different cwp variations and true 5 spd race trans, note the reduced drops between gears and as you progress through the gears in the race trans

geordie

Bill,

I'm aware of the g/box differences between the two models & what the owner of the 993 was trying to achieve.

Thank you for posting the data chart, it makes for interesting reading. I'm already dreaming of West Coast mountain road blasting with the 4.00 rear end. I suppose the decision for me is a) cost based & b) can I live with 3400rpm/70mph cruising. When I get the chance I'll try a thirty (plus) minute 4th gear/70mph run to see what that might feel like.

993PET

I had an 8:32 Ring & Pinion grenade on my RS America at Watkins Glen last year taking most of the transmission with it. Tranny rebuild was well north of $7k. I was advised during the rebuild that the 8:32 ring and pinion is much weaker than the stock and should be removed and inspected every 30-50 hours in a track car.

Geoffrey

Its not that the 8:32 is weaker. My opinion is that since the 8 teeth on the pinion match every 4 revolutions with the same tooth on the 32 tooth ring gear they begin a wear pattern. An 8:32 R&P will last in the 100hr range in a race car. I don't know how much in a street car, but certainly much less than a stock R&P. My advice is to replace 2-5 and retain the stock R&P.

Bill Verburg

That is the issue when the tooth counts are evenly divisible, the Cup cars w/ 8:32 are inspected very often because of this issue.

Just from my experience I wouldn't want a trans for a dual use car that has a top of less than ~160, a lot of the 993 guys move their 5 to 6 giving a top of ~157.

If you regear it's not cheap, in the neighborhood of $900/gear set, you'll notice that on the race box he only changed 3, 4, 5 but unless you are a drag racer you would want a 1 that goes to ~46. Then fill in between w/ gear sets that have progressively smaller drops up to ~160, the race box would probably find a little taller 3, 4 useful

it's surprising how even a small change in mph/gear can make a big difference in the feel.

geordie

I really appreciate the collective wisdom of you fella's. If I'm understanding this correctly, a relatively cheap, quick fix for my scenario would be the installation of a ROW 3.444 R/P.

Of course, when I get my car back to the UK & visit Colin's (Belton) for servicing, all bets are off when he casually mentions he has G50/21 available to compliment a R/P change.