Leland Pate

Alright, as some of you know I’ve just finished doing a considerable amount of work to my C2. After pulling the engine I installed a LWF/RS clutch, slave cylinder, RS Motor mounts, and a close ratio G50/34 built by Chris Cervelli. Because I made all of these modifications at the same time, I cannot attest to the difference created by each modification. What I can give is my best description of the benefits of the changes I have made.

First a little background: I have a ’95 C2 with approx. 60K. Other than the items listed above, I have only added a Rennsport Systems DME chip and replaced basic maintenance items (plugs, wires, caps/rotors, etc.) The car was otherwise, bone stock in the power train department.
Here is the thread I started that details the removal of the engine: Engine Removal

Here is a breakdown of the work performed by Chris:
Ratios:
_________ratios______teeth___manufacturer part # synchro
1st 3.154 41/13 Porsche 950.302.901.16 950.302.611.11, 950.302.613.11, 950.302.617.11
2nd 2.000 42/21 Porsche 950.302.611.11, 950.302.613.11, 950.302.617.11
3rd 1.522 38/25 Porsche 950.302.903.47 928.304.211.31
4th 1.242 41/33 Porsche 993.302.904.40 928.304.211.31
5th 1.031 33/32 Porsche 950.302.955.11 928.304.211.30
6th 0.857 30/35 Porsche 950.302.956.00 928.304.211.30
Final: 3.444 31/9 Porsche 950.302.911.13

Notes: 3rd and 6th are GT2/RSR gears. 3rd/4th synchros are new old stock of superseded 928.304.211.31

Shift assy:
Detent bore: RSR detents with ball bearing
selection shaft: G50/32 950.303.035.06
shift forks: G50/01 3rd/4th fork 950.303.113.04
Lateral shims: 2mm each side
detent shims: RSR aluminum top hats

Ring and Pinion setup:
Desired pinion depth: 61.05 mm
Desired backlash: 0.12 mm
Measured pinion depth: 61.02 mm
Pinion shims:
Measured backlash: 0.14 mm
S1, ring gear: 2.2 mm
S2, case: 4.1 mm
Stot: 6.3 mm
Differential type: 993 RSR, 950.332.083.30
Notes: 4 plate motorsport LSD
Built with ERP billet side cover
Installed used RS trans mount.



The install went very smooth.
Here are my driving impressions with the new gearbox and LWF/clutch:

Firstly, anyone who says the 993 is too cushy/undemanding/quiet/posh, or removed from what a real 911 should be needs to perform these modifications. The car now feels more edgy than my old lightweight SC coupe. The only area that the older cars still have the upper hand is in the steering department. Power steering just robs these cars of that connected feeling you get from older 911’s. Anyway, back to the modifications.

The engine revs much more freely. In fact it took me by surprise during one of my downshift “blips.” I love it. The clutch is so easy I may as well be driving a Honda Civic DX or something. I have no way of knowing if this is from the replacement of the slave cylinder or if it is due to the new pressure plate. It did take some getting used to. I almost stalled the car a few times in the first few days. The clutch also engages much closer to the floor now. Again, it took some getting used to, but the end result is great. I also noticed a huge benefit in the shifting department. This was surprising because Chris had warned that steel synchros required more effort than the stock units. No one told me a Porsche could shift so smoothly.

The gearbox is simply phenomenal. For the life of me, I cannot understand why they didn’t install these at the factory. Every 993 should have come with these gears!

There is no real way for me to describe the feeling of close gear ratios, but I’ll try.
You know how you punch it in 1st gear… and the revs climb until you are at your shift point. When you slip it into 2nd, the rpms drop and you lose that groovy power band. Then it takes a while to get the rpms back up to the 4K region where the motor starts to scream again. Well, with the close ratios, you are already in the “meat” of it after EVERY shift. THAT is a great feeling.

BAM!!!!

Idea #1:
Here’s what I want to do: One of you with a ’95 C2 (stock) needs to find a buddy and a digital camcorder. Get them to sit behind the driver’s seat with a camcorder videotaping the speedo and tach. Do several runs and film the speedo/tach. I can do the same and we’ll get someone to host a pair of video clips of the two for comparison. This will give those of you who are curious about the differences. Hell, if someone wants to get real technical, we could integrate a digital timer at the bottom of the screen or something to time the runs to 60/80 mph for instance. That’d be cool.

Anyway, I cannot stress enough how these modifications changed the character of the car.
The motor vibrations (motor mounts) are more notable. I think it makes the exhaust seem louder, but in reality, it is the vibrations being transmitted to the body through the mounts. The gear chatter is also much more notable. The gears on a transmission like this are going to make more noise. The LWF also adds to this. It is important to note that the LWF itself does not “rattle.” Rather, the LWF does not dampen/suppress the noises that were always present like the DMF did. So, yes, there are some rattling noises at low rpm. And those race gears do sound like a muffled paper shredder with the clutch engaged and the gearbox in neutral at red lights. At first, I wondered if I would be able to get used to the added noise. But within three days, I had already forgotten about it.
Bottom line: I need to get my personal plate changed to “RAPDAPE” or something similar.
I could not have asked for anything more.

Three cheers for Steve at Rennsport Systems who provided tons of great advise, support, good conversation, and the clutch kit.

The same goes for Chris Cervelli at Premier Motorsports who built this great box, and gave me a 2 yr warranty to boot. He followed through with emails, timelines, and it resulted in a great product and happy owner.

And I also want to thank the other members who chimed in when I got stumped. Chris, Jason, Mike, and others, you really helped me make this happen. I am not wealthy, and live nowhere near a dealership (I wouldn’t let them have all the fun anyway) so this site is an invaluable resource for me. I simply would not be able to own this car without you guys.

And for the record, I would be out driving instead of writing this if I hadn’t ordered the wrong size valve lifters. The car is down until I can identify and order a new set.

chris walrod

Leland, great review! Thorough and all. Just when one thinks the 993 cannot be improved, walla! And as you and Emeril say....BAM! Gotta love that one.. It says it all..

Tom W

Steel Synchros? Is all this for a dual duty (street/track) car or just for a fun street car? I have close ratio gears in my 993 (close to the initial Euro transmission) and it is a lot more fun to drive and a bit quicker (I also have a LWF).

I think the better clutch feel simply comes from the new clutch. When I did my transmission work and LWF I had a clutch that required great strength to depress to shift. After the work was done (same slave) it was much, much easier to depress and shifting was smoother. The same was true when I added the LWF to the 964.

Glad you are having fun.

Jim Morton

Leland:

Great write up. Enjoy the gears !

I did not go quite that far, but even with less gear changes with only thr euro ratios and LWF/Clutch, I second your observations !

K24madness

Jim,

What are the euro ratios?

Terry Adams

Glad to see your project turned out successfully, even farther down the slope than just the LWF/RS clutch. The butt-o-meter tells the story as well as any dyno.

c993k

Great mods Leland, I feel gear ratios are always the the best thing to do first.
It just changes the whole attitude of the car. Chris

Feehliks

I have the Euro G50-21 and whenever I go into the mountains and face hairpins I curse this transmision and wish I had the RS ratios, as first gear is too short and staying in 2nd robs you some power when negotiating a hairpin. The RS ratio of 3.154 vs. 3.82 is quite an improvement there.

Porsche made the 1st short on purpose: to save clutch life and increase driveability in town. Well, the longer 1st gear of the RS box might rob you some traffic light starting power and a little bit of clutch life, but that's irrelevant in my eyes.

Best regards,

Felix

Monique

Sounds great. Note to self... check your gear ratios against my own

maurice97C2S

Monique, your box should be the same except for 5th and 6th (assuming /31). I guess Leland's designation of /34 is because Porsche didn't do this exact combination, the closest is the /32 Clubsport box. Leland's 6th is a little lower geared (higher numerically).

Exactly what I want to do, when (if ever) the gears / clutch need attention ...

Well done Leland ! cheers, Maurice

Glen

Leland,
Congrats, glad it went well and you are pleased!....heh heh ...told You so...lol

Leland Pate

Yeah, the /34 designation is not totally correct, nor is /32. I guess I call it a /34 because of the gears and the RSR LSD.

Here is a chart of the ratios available from the factory (Courtesy of Bill Verburg):

__________Mine_______G50/20__________G50/31 RS___G50/32RSCS
1st________3.154________3.818____________3.154_____3.154
2nd_______2.000________2.048_____________2.000_____2.000
3rd_______1.521________1.407_____________1.521_____1.522
4th_______1.241________1.118_____________1.242_____1.241
5th_______1.030________0.921_____________1.024_____1.031
6th_______0.857________0.775_____________0.821_____0.829

all have 3.444 cwp

DJF1

I got similar feelings with the Euro Box I installed. there is simply no comparison. Back when I installed it , I reported 50HP on the dyno butt Simply a great bunch of upgrades...
The only downfall on the Motorsports LSD is the increased understeer at turn in, but everything else are sooo worth it!
Great report!

Leland Pate

Tom, the car only sees about 2 track days a year. As soon as I can move from the deserted frozen tundra, I hope to change that. The steel synchros are overkill for my application. But... ...I like overkill.

I don't have the ratios for the G50/21 euro box so if someone sends it to me, I can add it to the chart above.
As you can see the RS and RSR gears are damn close. The only difference is my 6th gear. Speaking of sixth... I am so happy that I can still cruise on the interstates up here @~80mph around 3K rpm. I was a little worried the gear selections would make long distance driving less pleasant, but Chris is good at picking ratios!

Jim Morton

Tom:

If you do a search, there is a great spredsheet on all G50 gear ratios. If it does not get posted, or you don;t find it, I'll post it tonight, when I get home.