pp000830

I may have a little shoebox money to improve the quickness of my 96' 993 Carrera. From what I have read shortening up the gears slightly does the trick without resorting to internal engine work. In my mind shortening up 2nd through 4th gears would be ideal and leaving 5th and sixth alone for normal highway driving.

I have read where lots of rennlisters have approached the solution in several ways from adjusting the final drive to replacing a mix of individual gear sets.

For me I would like some feedback from those who have done this and lived with it for a while and have aspects they like as a street car and aspects the do not like so much.

Andy

e9stibi

Let me start with my experience.

I have a 993 convertible with stock US G50 and a 993 C4S with custom-geared G64.

The G64 conversion was done by the previous owner ($$$) by Rothsport with all the right stuff. He used RS gears except for 6 which is the stock 5.

The converted G64 is really fun to drive, particularly if you rev out the gears on the race track and love shifting. However, driving at highway speeds (65 MpH) is a relatively loud affair because the car is running on the stock 5 in highest gear. If you combine this both with some other setup changes like stiffer engine and tranny mounts and a hard suspension, the car is and would not be my preferred street car.

The convertible is more a cruiser and the stock G50 fits this bill perfectly.

mgerber

Hi Andy. I would give you more feedback, but unfortunately I only have 1K of street miles on a re-gear that Steve W did for me three years ago. I wish I had more time to use the car, including getting it out on the track, but I don’t. There are several threads that document gear selection, so I won’t get into that here. Also, please keep in mind that my 993 is heavily modified, so some of the things that might be negatives for street use, like gear whine and chatter at idle, I don’t even notice anymore. My setup includes an RS flywheel and Guard Clubsport LSD (40/60).

IMO the most enjoyable thing about the re-gear is that it transforms the feel of the car. The RPM drop between the lower gears is no longer aggravating, and the car feels very well integrated. The car also feels faster, but given the age and increasing inaccuracy of my butt dyno and memory I can’t do any better for you than “feels faster”. I have had a number of 911s (10+ now), and a handful of mid-engined Pcars, and the re-geared 993 is by far and away the most enjoyable to drive. On the downside, I wish I had done a different top gear. For my build we moved the stock 5th to 6th and it is slightly too short for our roads in the Pacific Northwest. It probably works in an area where top speeds are more restrictive, but driving part of the year in ID, MT and WA I wish I had a slightly longer top gear.

So my conclusion is that it makes the car feel faster and better, and for me was worth the investment. Additionally, my suggestion is that you find another Rennlister that has done a re-gear and ask for some time behind the wheel. I met a friend this way – he reached out for an opinion on my re-gear a couple of years ago and a few days later was behind the wheel for a test drive.

francisluu

I have a 1995 993 and had the transmission re-geared. To my surprise, we found out that it came with the rest-of-world G50/21 gearbox with the shorter ratios instead of the standard G50/20 when the transmission was already sent to California Motorsports in Arizona. We decided to go forward with the re-gear anyways. Generally speaking, you should see similar results with either gearbox, though in my case we started with something with closer and more ideal ratios.

Along with a ton of re-done bits and pieces (as well as going a bit overkill with steel GT3 synchros everywhere lol), we did an Albins 3.00 first gear and an Albins 8:33 ring and pinion. This closed up the huge gap between first and second considerably with a taller first gear, and then shortened everything up with the new final drive. The result is a mad (!!!) rush through the gears. Slight whine in first gear, but it's one of those sort of fun noises to have. I'm definitely shifting way more, but with the Rothsport billet short shifter in there it's so much fun.

Maximum speed in each gear:
1st — 40 MPH
2nd — 58 MPH
3rd — 78 MPH
4th — 98 MPH
5th — 119 MPH
6th — 149 MPH

I'll admit third and fourth are pretty short, haha. But the car is *so* much more livelier. I'm sitting right at 3000 RPM at 65 MPH.

This thread has a lot of great discussion on a re-gear project, as well as some info from others on different approaches — https://rennlist.com/forums/993-foru...mainsheet.html

francisluu

Here are the RPM drops

fatmike

The biggest difference is second gear. The very first time you shift into second you will get a giant smile on your face. Add a lightweight flywheel and lightweight wheels and you will be surprised by how quickly your car's RPMs spin up.

I'm running an un-modified row G64/21, RS clutch and lightweight flywheel and MY'02 wheels.

No doubt others have even better gearing (Francisluu for example), but you don't need to go that far to get a dramatic change.

Compared to a stock US car, there is no downside at all.

/

NYC993

After running on the track with a few re-geared 993s, I think it's a waste of money. I have stock C4 gearbox, which I understand has better gearing than C2. The difference in re-geared cars pulling away is so immaterial. Now if I had to open gearbox for other items, then I'd def consider re-gear or shorter final drive.

race911

But that's it--on the track. As I've said numerous times, what's almost perfect for Sears Point and Thunderhill is a two second penalty at Laguna. (1:50 and 2:00 v. 1:40--should be 1:38)

Staying with what the OP wants, it's all about a 15-20% "invest" into the car. i wouldn't sweat it; I pretty much take street cars for what they are. But many here are very pleased in street applications, so I'd put more weight on their opinions.

Paddy

I tend to agreed that it's probably not worth the expense for a street car. But for a track car it's totally worth it, not to mention a proper LSD and steel syncros make it a wonderful combo. My swap from the stock G50/20 to 3.8 Cup G50/30 at VIR was good for nearly 4 seconds a lap. Also, the gearing of the 3.8 Cup box keeps the revs in the meat of the torque range. Albeit, I'm very busy shifting it's a f*ck load of fun.

Also, NYC993, last time at WGI you couldn't keep up

Here's an older video at WGI with the G50/30 box: https://vimeo.com/131612030

francisluu

It's also an eff load of fun being very busy shifting on the street

race911

Just another track data point--ran into Mike Orsini last Saturday, he being Boston transplant and now having the nearly non-existent stock class 993 racer in Northern CA. On R7's he was running a 2:00 (bypass--add 2 sec for the full track), which is what I can do with the faux RS on less-than Hoosiers. So, pick where you want to spend the money, or under what rules package you care to run.

NorthVanSlowLane

Hmmm. A bit of food for thought here.

I took my "new to me" 993 C2 for a first drive three weeks ago. Pulling in 3rd gear up a long hill my first thought was that the car was slower than my 964. I didn't notice this in 1st or 2nd. My mechanic pointed out the taller gearing and it became apparent I was going faster - but it felt slower.

I wonder if you can drop the gearing for street use in 3rd or maybe 2nd and 3rd and leave the rest as is for your highway cruising?

NYC993

Hahaha I remember it and have it on the video you flying by when you got out in a green session. And my point is that I could not keep up not because of stock gearing. If we swapped cars, I would have not been able to keep up.

But happy to report a few things changed. That was my second DE and first time at the track on street tires. Back then I was running high 2:40s. This year I managed a few 2:17s with NT01 and still street suspension and full interior. At the glen I would love better gearing, no question, but when it comes down to the purpose and value of it...I'm not sure. Like I said, If I had to open tranny for other reasons, I'd consider it.

Paddy

HA, just giving you a hard time. Happy to hear the laptimes are down. Would love to see that video too!

Matt Lane

I had my 1997 done about 4 years ago by Copans and did a ton of research prior. Bill V. has helpful, as always, running ratio charts. Made it very easy to visualize the changes vs. stock and some of the other factory RS track options.

Was into it already for R&P.

I love the end result, and yes it was worth it to me.

A few observations:
- 1st and 2nd are fixed on the later mainshaft - mine is a 97 - so the long shift from 1 to 2 which bothers so many in street driving is NOT easily improved doing this. Personally, I never found this an issue as I don't drive the Stoplight Daytona, but something to be aware of. On track, this is completely irrelevant.

- In checking out ratios and options, Brian recommended a new 6th instead of machining 5th to fit - in his opinion the former option is doable but a compromise.

- I ended up with a combination of new and mildly used 911/GT3 gears for 3-6, steel synchros, and a few other wear items pre-emptively replaced and upgraded.

- On street, the shifting once rolling and into 2nd and beyond, is sublime and pulls just right from shift to shift – perfectly in the power band. This is what the whole thing is about.

- On highway, my new 6th is a bit short (maybe just a Bit taller than stock 5th)

So, you need to be honest about how you will use your car:

Street: I don’t cruise continuously above 75, so I can live with a short 6th (running at about 3K RPM). If you do tons of highway and want to roll at 80+ continuously – never mind driving as intended on German highway – then no reason to change 6th , but it then remains a compromise overdrive gear which as least in North America is a waste (to me). I don’t drive mine as a highway hyper miler.

Track: Short ratios between 2 and 6 are sweet. You can grab an upshift dropping to 5K RPM all day. That said – the advantages are track-specific. Some corners you will be faster, some slower due to an extra shift. It may in fact be a wash on a given track when you factor in time to execute a few extra shifts per lap.

Coming full circle, I like it a lot. Just need to be realistic about what you will personally get out of it and what the cost is.

Glad to clarify further or answer any questions.

Cheers

Matt