DaveK

Hi,
This is just a thought - but since I ruled out the idea of a supercharger last year......

How easy would it be to have the gearing changed - and is it even possible? I might be willing to reduce my top speed by say.... 20mph.... if I saw big improvements in acceleration. Not something I'd do just on it's own - but I figure I'll need a new clutch soon and since the engine would be out anyway.......

Anyway - just a thought. Is it possible, and is it practical?

Ruairidh

Dave

It is possible and, if you can afford it, practical in the sense that it doesn't require other adjustments (like the loss of a heater!).

A couple of years ago a Rennlister who had a 3.8RSA which had been regeared told me the following

"It was kind of fun playing around with a gear chart but in the end I relied on the supplier for the proper gearing. I purchased them through PowerhausII but I hear that Guard is also good. They both advertise in Excellence and Panorama.
The only downside is the cost. I think it was $600/gear+install. Around $3200.
It was a significant difference in performance though. Great pull 2-3 and 3-4. Very obvious to other C2/C4's at the track where I can accelerate out of the corners so much faster. More fun around town too."

You do lose the top end speed - I too thought a 20mph reduction in max speed would be a price worth paying for making my cars acceleration in 3rd and 4th feel like it does now in 2nd.

I'm still mulling over doing this, just want to wait until (a) I make my mind about what I'm going to do to my car and (b) I don't like doing extensive changes when she is running well, I'd rather wait until work needs doing and then tack it on then.

Many of the US 993boys have changed the ratios of their gearboxes - often to Euro spec.

DaveK

$600 / gear + install? Wow - I was thinking that if the engine was out anyway, this would be a fairly cheap option. Perhaps not!

Phil Raby

Interesting idea, Dave. I'm sure you must be able to get the gears for less than that. Might be worth talking to Neil Bainbridge at BS Motorsport - www.bsmotorsport.co.uk.

Cheers

DaveK

Don't seem to get anywhere with that link?

robmug

Presumably you are referring to changing the diff final drive? How can it be so much $ for fitting?

(interestingly, I did exactly this modification when I was 17 to my 1970 Mk3 Mini Cooper S - cost nothing like $3200!)

DaveK

Well - although it's not quite the same..... if you can remember back that far, what sort of difference did it make?

Phil Raby

Funny, that is the correct URL - try this http://www.bsmotorsport.co.uk/

DaveK

Thanks - that works. Was clearly my stupidity....

Phil Raby

No, I clicked on the link in my post and it didn't work for me either. No idea why.

tonytaylor

Fitting a second hand 993 box really helps mid range ( 70 - 140)acceleration as its a 6 spd. Probably about £2k fitted.

DaveK

It's really the lower range I want the boost - maybe 0-80mph. 6 speed is a nice idea though, and 2K doesn't sound too bad.

Cay

you can also look for a 993 gearbox from a accident car - fits nearly perfect.
had this modification in my speedster (tuned up to 300 HP) and paid 6K for box and install. it was a box from a 993 from end of 96 (long version). it sucks and i regret
making this. 6th gear is by far to long and I have the feel that shifting points on my stock 5 gear wtl 64 been better. but 993`s before mid of 96 are shorter in gears - maybe this box will work better.

but you get also the "kegeltellerrad" (dont know english word - i mean the main wheel in the gearbox) from porsche motorsports in 3 different settings. this item costs aproxm. 2.5K.

johnfm

Dave

as rob mug mentioned, changing the final drive may be a more economic alternative, though this will not change the 'spacing' between the ratios, just make them all a bit shorter.You could comine it with an LSD install, as I expect you need the diff out to change the final drive gear.

Tom W

I re-geared my 993 and it made a profound difference in acceleration. I had a number of guys ask me why my car was so much quicker than stock at an autocross school (they made this assessment by just watching my wife and I and comparing to other 993s).

It is anything but cheap to re-gear. $600 per gear is lower than I've heard (or paid), in the USA a good estimate is $1000 per gear using brass synchros plus about $1000 to remove and replace the transmission. A Euro /21 gearbox is nice is you can find it, in the USA these are closer to $3500 if you can find them. Steel synchros are nice for track use but the one for 2nd gear is about $1500 by itself (others are cheaper).

I'm not sure about 964s but one issue on 993 is if 2nd gear is fixed to the main shaft (probably in Adrian's book, but that's at home). If it is and you want to change it, it's another $1500 or so.

Since I paid all the money to have my transmission removed (it had 'broken' and needed to be fixed), I had the RS light weight flywheel and clutch added, re-geared 2-6 (re-used 5th as 6th in the revised box), and added a LSD. Great difference, more fun, but $11k.

If you want an Excel spreadsheet with the standard G50 ratios and a calculator to show what happens to mph as you change gears, send me an email at home .