I have the stock US gears in my 97 993. Assuming there is a Santa Clause I want to see if I can change over to close ratio gears. Since I race in stock PCA I need to use one of the factory selections for my car (RS,CS...) . The most cost effective would be to do the following:

leave 1st & 2nd gears as is
3rd gear change to 25/38 1.520
4th gear change to 33/40 1.121
5th gear change to 37/38 1.027
6th gear change to 35/31 0.885 or leave it stock

Any thoughts on this set up?

 

What happens if you go the euro route, G50/21 style? This changes your 2nd through sixth....

If I wasn't concerned with PCA racing, I would do the following:
1st: stock
2nd: 2.250
3rd: 1.650
4th: 1.286
5th: 1.040
6th: 0.821 (euro 6th)

New steel synchros all around, except where it's extremely cost prohibitive (1st, I think) and just put in a fresh standard synchro.

Change bearings, inspect shift fork for damage (replace with Paul Guard's beefed-up version..)

Replace disks in your factory LSD, or go *****-out and get a Guard LSD (no affiliation with Paul Guard, but just hear his stuff's the best..)

Throw on a RS LWF, install some RS motor and tranny mounts....and HO HO HO Merry Christmas for you!!

 

Bill I'm confused. If you need to use the gearing offered in a factory car, how do you figure the gears you show fit the criteria? By reusing your existing 1st and 2nd, you violate this rule.

The stock 1st and 2nd from the G50/20 have lttle in common with the other G50 transmission options.
The /21 shared 1st but 2-6 are different and the /31 (RS), /32 (RS CS) or /33 (RS or RS CS in Switzerland)all differ from your listing. I'll email the info I have on what was offered. It covers all the G50 possibilities through the G50/54 (GT 2) and the G64 options as well. The spreadsheet allows you to see the rpm drop as you shift gears.

I assume you want to retain 1st & 2nd as they are to avoid the extra $1500 to replace the mainshaft that has both 1st & 2nd fixed on it?

On a related note, I was counseled to save my money and not to go with steel synchros unless I planned to use the car in enduro races. I was told the normal brass syncho are fine unless your gearbox gets really hot (which takes more than a 20 minute session).

 

Bill, if I remember correctly G50/32 is what you are aiming to copy, so... Go with a g50/32 1st, stock 2nd, G50/32 3rd, G50/21 4th, G50 21 5th and a G 50/32 6th. That will give you the ratios you need to be almost identical to a g 50/32 and save you some $ on 2 gears(about half the cost of the G 50/32 gearsets. Go with the billet 1-2 shiftfork, and use steel syncros for 3-6 with stock syncros for 1-2. I would absolutely recommend Brian Copan as the best and most knowledgable on 993 boxes( also extremely reasonable) that I am aware of. I know there are also some other very good builders out there, always ask for multiple references... You will need to alter the width of the gearstack spacers when you do it this way. The RS gears(narrower gearstack spacer) have a wider center hub than the stock 993 gears(wider gearstack spacer). Hope that helps! Gert can order the gears for you, PN's are easy to get, let me know if you need them.

 

Bill:

Find a wrecked 993 and swap for a tiptronic. That way if you still have the car in 40 years you can be competitive in the Historic Seniors category even after a total hip and left knee replacement.

Plus, from what I hear you are getting too fast. This will help me keep up.

Chris Brown

 

Bill,

I will mail you a spreadsheet with some options have seen from the rennlister's.

 

Bill,

Check this site for all the gear ratios for the various 964 and 993 boxes.

<a href="http://www.porotto.com/deutsch/G50.html" target="_blank">Factory Gear Rations for 964 and 993</a>

I will second the recommendation to contact Brian Copans to do the work. I recently had him repair my C4S transmission (a minor dowel pin became mislocated) and at the time had him regear 3-6. Brian can advise you on the best ratios for what you want to accomplish. He has most of the ratios in stock in additiona to all the other misc. parts and tools. You can choose between Paul Guard or Porsche Motorsports.

1rst gear is actually machined as part of the main shaft and 2nd is permanently attached, I think by electron beam welding. So changing 1 and 2 is VERY expensive. I believe 1rst and and 2nd gear syncros are multipiece and VERY expensive.

I opted for new 3-6 gears. 3-5 are the same as the CS gearbox, and 6th is slightly shorter than the CS. I opted for Porsche Motorsport gears sets, and steel synchros for 3-5. Brian suggested that a new brass 6th syncro was good enough for a street or club box. If you're going racing, it might be a different story.

Bottom line, Brian will advise you on what you might need, and build whatever you want. You're going to find that this is NOT an inexpensive exercise. Gears sets run $800 - $1000 each depending upon the source.

Good luck.

If you do go the CS ratios route I can tell you that after you make the 2nd to 3rd shift you will soon be long gone............

Fred R.

PS. You might want to go with the RS LWF while you have the transmission and engine separated. You can add it for the cost of the parts (Gert has the best price) and very little extra labor.

 

Thanks for all the feedback. The gears I listed were taken off the factory euro list. I stayed with the US 1st & 2nd only to save the bucks and I see no need to change them. I am running as a RS so I have made many of the RS changes but still have the 3.6. Flywheel, weight, gears(soon), spoilers are RS.

Chris, Sebring has a NASA BMW/Porsche race late in January. Looks like a great event. Bring ole blue down!

 

Bill,
There is a new 993 RS trans on e bay G50/32-2
I dont have the link but search for 993 RS and it will pop. Dont know anything about it but thought I would give you a heads up

 

I saw that RS gearbox on eBay. If I had permission from the CFO (wife), I would buy it and sell my current 6speed. I think it would be less out of pocket if one were going that route for a ratio change. I wonder what his reserve is? Then I wonder what my gearbox would be worth (42k miles LSD)?

I can dream cant I?

Chris

 

I bid on that box last week up to 5K and did not hit reserve. There was another buyer who had the highest bid and the auction ended without the reserve met. The seller re-listed the item with a lower buy it now price so I must assume that he will take around 6K for it.

On another note would a switch to a G50/21 take you from D-stock to C? I read the new rules and it is not very clear. Furthermore I have seen D class 993's running with RSCS spoilers and RS flywheels! I thought these stuff would bring you up to C? <img src="confused.gif" border="0">

 

[quote]Originally posted by DJF1:
<strong>On another note would a switch to a G50/21 take you from D-stock to C? I read the new rules and it is not very clear. Furthermore I have seen D class 993's running with RSCS spoilers and RS flywheels! I thought these stuff would bring you up to C? </strong><hr></blockquote>


DJ,
I guess that could be open to debate, but to me it looks like a /21 box would move you to C. Here is the first paragraph to the rules.

"Any vehicle in the stock classes, including “prepared” vehicles, must compete with full road equipment and, with the exception of exhaust/emissions, be street legal as designed by the factory, capable of being registered for street use in the condition of the car when presented at scrutineering, and capable
of being driven to and from the event. “Euro-spec” cars will automatically progress up one stock class."

The front splitters the scruitineers aren't too hard on in my experience. Any rear spoiler with a raised element/wing should move the car up a category. The RS flywheels should move the car up a level also but it is harder to determine if a car has one just by looking. I think the LWF should be free since the dual mass one is not known for its longevity.