ard

I am looking for forum input on re-gearing a G50/20. I have read various threads on the topic and reached out via PM to a few individuals. Regarding the latter, my posting a thread on the forum is not intended to usurp your opinion in any manner. Rather than pestering you with repeated PMs, posting a thread here will allow me to add updates as my decision making process evolves.

The facts

• early 95 993, with stock G50/20, with 2nd gear separable from the main shaft (per my gearbox serial number)
• final drive ratio 1:3.444 (stock)
• I run ~25" diameter tires front/rear
• mostly backroads driving, followed by freeway crusing; no to very little track

The issue(s)

1. I find myself either winding the motor to 6,000+ RPM in 2nd for extended periods of time, which feels unnecessary or just a tad below 4,000 RPM in 3rd which is below the sweet spot in the power bad
2. I want to make 3rd gear more useable for my style of driving without sacrificing freeway cruising
3. I want to achieve the above goals cost effectively - I am therefore leaning toward swapping out 2nd - 5th only, leaving 1st and 6th the stock G50/20 ratios

I am looking for input on the options I am considering - all input is welcome and thanks in advance

My options

For reference here are the stock G50/20 ratios

1st - 1 : 3.82
2nd - 1 : 2.05
3rd - 1 : 1.41
4th - 1 : 1.12
5th - 1 : 0.92
6th - 1 : 0.78


Option 1: swap 2nd - 5th to G50/21 ratios

• that seems to be the most straightforward, and possibly (?) the most cost-effective solution
• the resultant ratios would be

1st - 1 : 3.82
2nd - 1 : 2.15 <-- G50/21
3rd - 1 : 1.56 <-- G50/21
4th - 1 : 1.24 <-- G50/21
5th - 1 : 1.03 <-- G50/21
6th - 1 : 0.78

Option 2: mix and match 2nd - 5th from G50/21 and G97/90 (2007 GT3)

• this further optimizes 2nd/3rd and 3rd/4th spacing
• however, and I admit I don't yet understand all the details, per some threads by Matt Monson, this may either not be possible, or require adapters (on account of a) different ID for idler gears b) different width for gears and c) asymmetrical synchro teeth)
• this seems to be the 2nd-most cost-effective solution (give the cost of adapters, etc.)
• the resultant ratios would be

1st - 1 : 3.82
2nd - 1 : 2.15 <-- G50/21
3rd - 1 : 1.64 <-- G97/90
4th - 1 : 1.29 <-- G97/90
5th - 1 : 1.03 <-- G50/21
6th - 1 : 0.78

Option 3: select from Matt's extensive list of gears

• truly customizable ratios
• top-quality gears
• both of the above probably at additional cost over the previous options
• the ratios would be

1st - 1 : 3.82
2nd - 1 : 2.18 <-- Guard
3rd - 1 : 1.60 <-- Guard
4th - 1 : 1.25 <-- Guard
5th - 1 : 1.00 <-- Guard
6th - 1 : 0.78

Thanks

/alex

NYC993

Would be interesting to see associated cost with each choice and other "while-in-there" parts.
Given that most cost is in labor I would get the best gearing that fits your needs (i.e. fix the gaps)
I have G21 and my issue is more with 1-2 gap. The 3rd is still kind of tall, although I like it for driving around town.
Guards gearing is not far off from G21. I would shorten 3,4.5 more than that, if possible.

os993

Here's my re-gear stack that I did approx 10yrs ago. Guard gears and steel synchro's
2nd - 2.25
3rd - 1.65
4th - 1.286
5th - 1.040
6th - 0.821

I would recommend also switching 6th. I switched it to the Euro Ratio. Perfect now use it almost all the time. Perfect at 70mph and higher. The US 6th is pathetically low.

Have fun!!

sander97C2

Mine is similar to os993. I have an RS lwf and clutch. Engine revs very quick and rev matching down shifts is improved. All my components came from Matt at Guard. I went in for the mainshaft, gears 1-6, and lsd. In my opinion it's one of the best performance modifications one can do to a 993. The car just pulls and pulls, it's truly a pleasure to drive.

1st - 3.500
2nd - 2.294
3rd - 1.650
4th - 1.286
5th - 1.040
6th - 0.854

os993

Indeed! Very similar. And I also did the RS LWF and Clutch. Plus the RS tranny and motor mounts.

A great stack of ratios. Very usable for daily street driving, fun, and great for autocrossing (where you live in 2nd and 3rd gear) and track driving (mine was aligned particularly for Thunderhill, here in the Bay Area, but does great at other locations as well).

Not the cheapest thing to do (did it before kids when there was more disposable income, haha), but as noted, a GREAT upgrade that is immediate and justifiable.

Keep up posted on your decision.

GTgears

Hello Alex,

Got your emails. Still digging out from long weekend and stopped by rl on my lunch. I'll answer you this afternoon and you can paste and post whichever pieces you feel are useful for others as youceducate yourself.

Regards,

Matt

ard

I definitely will - I have reached out to Sunset and Matt to get input on availability, feasibility, gotchas, etc.

Agreed on cost likely being a bit "gulp-worthy" but OTOH, better performance without jeopardizing passing emissions (a must here in Kalifornia) feels like a win to me.

Jlaa

In this link https://rennlist.com/forums/993-foru...mainsheet.html you will find some analysis on this stack of ratios, along will Bill V's usual comprehensive force plot graphs. About two years ago I set about finding an optimum set of ratios for casual street driving --- there is a survey of various Rennlister ratios in that thread (unfortunately Sander's ratios weren't reflected in the survey). I ended up basically copying OS993's ratios and added Matt Monson's excellent 3.500:1 mainshaft, and I strongly agree with the sentiments expressed in this thread.

Analog Theory

Hands down best money spent on my car. Big bucks obviously but the car is completely transformed.

INTMD8

Well basing it on my F355 which I feel has perfect gearing I went with option 3 and chose each ratio to what I thought would be ideal. (just a bit shorter due to less rpm and power) Ended up with-

1st- 3.167
2nd- 2.25
3rd- 1.65
4th- 1.28
5th- 1.04
6th- .867

That would be ideal for me personally. Only question is cost and how loud are the gears?

Oh, chart of the F355 vs above re-gear if interested-

JM993

I agree that the 355 has perfect gearing. OP, just keep in my mind that we have almost extra 2000 rpm to play with the glorious 355 engine (8500 RPM redline)

I have a g50/31 in my car and love the gearing. I wouldn't change a thing. It's perfect.

Jlaa

Argh. I'm missing the option where I have an F355 parked next to my 993. What does it take for me to get this option? Does Sunset offer a discount?

:-) :-) :-)

Martin S.

it has been working for me for over 2 years, since early 2015. I never really jump on the car in first gear so I had an impossible time talking myself into a mainsheet where I could gave 1st and 2nd gear crafted for me
1st 3:818 Stock
2nd 2:048 Stock
3rd: 1:560 G50/21?...1:522 is g50/31
4th: 1:241 G50/32
5th: 1:094 Porsche Factory Gear set, do know its origins
6th: 0.912 Porsche Factory Gear set, do know its origins

Final Drive: 3.4444

I had it built for me by Lance Aspesi in Van Nuys, CA. KI also have in conjunction:
1. RS Fly Wheel and clutch
2. RS Motor mounts
3. RS Tranny mount
4. Factory SSK
5. FDM Golden Rod, actually Platinum Rod from FD Motorsports, NLA
6. All steel synchs
7. Forged 1-2 & 3-4 shifting forks
8. "While you are in there" bearings, etc.

Now I have the proverbial "hot knife through butter" shifting experience and incredible performance across the power band. It was there all along, I just couldn't revel in it with factory gears. Don't overanalyze, a re-gear works, and because you are always in, or very close to the power band, it feels like added HP, of course it isn't, but regardless I love the feeling. Since you are in NorCal, drive on down to Paso Robles and I'll take you for a little ride. Post ride, you'll have your check book** out.

**Who and the hell even has a check book in this digital age. I have one, but never use it. I use Chase Money Transfer and Pay Pal. Not so much Pay Pal anymore..they have *&%$ my pass word and I can't get on.

ard

(tongue-in-cheek comment) NONE of you are doing anything to stop me from sliding down a (steep) slippery slope

Very useful information and the ranges of ratios posted seem to reflect individual preferences.

@Martin - I come down to Santa Barbara occasionally so thanks for the offer - I may well take you up on it.

Couple of questions

1. @ 51K miles, not ham-fisting the gearbox, what else should be replaced "while you are in there"?
2. I have generally hewed to an OEM-or-better philosophy when doing R&R but do I really need steel synchros? What do they do better than the stock synchros?

Thanks again

/alex

Jlaa

A new gearbox for your 993 is the responsible thing to do. It is much, much cheaper than buying an F355 anyways. You don't really have to buy a whole new Italian car just to get some desired gear ratios ----- just buy the gearbox itself.

There! A new gearbox is the cheap option. :-) :-) :-)