Close ratio gears for street (G50 3.2)

[Jonny042]

Hello all,

I have nothing better to do in the wintertime than dream of this sort of thing...... I am going to fire up the gearcalc.exe and see what I can come up with.

I am unable to find any real "testimonial" threads from street drivers, just the odd "one of the best things you can do is" statement from admittedly knowledgeable people.

I am going to proceed with my calcs using the following premises:

1st gear is just about right
2nd is too tall but makes for good advertising (0-60) so could be lowered
the shift from 3rd to 4th at redline feels great without too much rev drop
5th gear is way too tall

Personally, I think having 2nd/3rd/4th/5th all lower and closer would make the car a lot more fun to drive, at least at the speeds I drive. I generally don't cruise for long periods at more than 65mph or so.

Anyway, would be interesting to hear others experiences. My understanding is that it's about $700-$800 each (pair) for the gears.

[andyt11]

I'd love to do this but money will stop me!

I've often thought a set of close ratios would be a lot more fun. I rarely need to go much above 70mph but I do like changing gears. Puts a smile on your face in these cars.

I'd be interested to see how the projct works out if you decide to do it.

[DRACO A5OG]

It will be fun for awhile but from what my nuddy told me you will hat eit on the freeway at the higher RPMS

[Nine17]

Jerry Woods (who knows a thing or two about Porsches), told me that he would rebuild a street G-50 around the stock second, raising first to make it more usable to hole-shot out of slow corners and lowering third and fourth closer to second to exploit the powerband better in the 50-80 mph range. He said he'd leave fifth as a freeway cruising gear with a big gap from fourth. He also quoted about four grand...

[porschenut]

I would lower 2, 3 and 4 but leave 1 and 5 the same.

[Bill Verburg]

Originally Posted by Jonny042

Hello all,

I have nothing better to do in the wintertime than dream of this sort of thing...... I am going to fire up the gearcalc.exe and see what I can come up with.

I am unable to find any real "testimonial" threads from street drivers, just the odd "one of the best things you can do is" statement from admittedly knowledgeable people.

I am going to proceed with my calcs using the following premises:

1st gear is just about right
2nd is too tall but makes for good advertising (0-60) so could be lowered
the shift from 3rd to 4th at redline feels great without too much rev drop
5th gear is way too tall

Personally, I think having 2nd/3rd/4th/5th all lower and closer would make the car a lot more fun to drive, at least at the speeds I drive. I generally don't cruise for long periods at more than 65mph or so.

Anyway, would be interesting to hear others experiences. My understanding is that it's about $700-$800 each (pair) for the gears.

Gearing is going to be over $1k per set
here's what you have now, assuming you have a US '87-89 Carrera


You need to be clear as to what you don't like about your current setup and what you hope for in the redone box

[hcoles]

my 2 cents - my G50 seems about right for Thunderhill, at least for my skill level which is not high. I don't have to go to 5th but I get close in two or three places. So you may want to consider what track you usually visit and how the gearing is for that, who cares about anywhere else? ;-)

[KTL]

Personally, I think having 2nd/3rd/4th/5th all lower and closer would make the car a lot more fun to drive, at least at the speeds I drive. I generally don't cruise for long periods at more than 65mph or so.

You should get a 1995-1999 BMW M3. They have a great gearbox!

Bill always does an outstanding job providing feedback on gearing, with charts and graphs and suggested ratios. Do a search a little harder and you'll see he's shared a LOT of feedback on gearing. I diddled with gear charts quite a bit over the years with my '87 G50, trying to decide what would be the best compromise of gears i'd like to have for all occasions.

On the street 2nd is great. I don't think it's too tall. I think 1st is too short! 2nd is a pretty good ratio that gives good acceleration at low-ish speeds. At my local tracks where i've run the car, I have found the stock 2nd has always been too short. Meaning, you run out of revs in most places, with the exception of the slowest of corners, and therefore can't use it effectively. Quite often I short-shift to 3rd in order to avoid hitting the rev limiter in slower turns. Then the large drop between 2nd and 3rd rears its head and sometimes the engine is slightly outside the powerband. However 3rd-4th is pretty good. Engine stays in the powerband quite well due to the rpm drop being much less than 2nd-3rd. Then you grab 5th and the rpm drop stinks. Clearly the overdrive 5th is for reduced rpm cruising.

My thought for a street-used G50 5 speed, that would see regular track driving, was to pick a taller 2nd and leave it at that. A 1.90 or 1.94 2nd gives your 2nd gear some longer legs and a lesser rpm drop for 2nd-3rd. That puts you right in the sweet spot of 3rd on a redline upshift. I agree the 3rd-4th spacing is nice as is. I don't think a shorter 5th is really needed. The overdrive 5th is very nice to have if you drive on the highway frequently.

Jerry Woods idea about regearing is good. Stock 1st is really nothing more than getting the car moving easily from a dead stop. It's basically useless for any sort of sporting use IMO. A longer 1st gear would be great for rolling starts or very tight corners. However a new 1st gear requires you to replace the mainshaft (expensive) because one gear is welded on the shaft. Stock 2nd is good for slowish corners. Revised 3rd & 4th can give the car the longer legs it needs and a stock overdrive 5th would cover highway driving or very long high speed sections.

[porschenut]

Are there any options to change the final drive ratio on a G50? I believe it uses a 9:31. Using a shorter ratio wouldn't fix the big 1st-2nd drop but it would make the car faster and more fun on the street. And I would assume it would be a heck of a lot cheaper than swapping gears.

[KTL]

Yep. Places like Guard and California Motorsports have a 8:32 ring & pinion.

California Motorsports Porsche G50 5 speed transmission section

[Deadeye]

A new 8:32 R&P will run you about $3K just for the parts. There is also a higher wear factor with that ratio as you have less tooth to tooth contact. New gear sets are closer to $1,100.00 currently and if they are aftermarket, you will have to buy sleeves as they are being made for the newer gear boxes that use larger diameter shafts. I just had a box done recently by a reputable shop and it was $$$

Good used gear sets are out there if look, I have a few left over after making one good box out of two. Also good case parts if anyone is looking

[Bill Verburg]

Originally Posted by porschenut

Are there any options to change the final drive ratio on a G50? I believe it uses a 9:31. Using a shorter ratio wouldn't fix the big 1st-2nd drop but it would make the car faster and more fun on the street. And I would assume it would be a heck of a lot cheaper than swapping gears.

Again it depends on what you want from the trans, but changing to an 8:32 cwp doesn't do a thing to help the drops and severely limits the range of each gear.
here's thsame g50/01 shown above but w/ an 8:32 cwp instead of a 9:31

[Bill Verburg]

here's a g50/01 regeared w/ a shorter 3,4,5. Note the drops between gears. A reduction of 6mph from stock may not seem like much but it makes for a big difference in the feel of the car.


when you go to short the range of each gear is limited too much, you end up spending all of you time shifting.

If the car is used on the street too short a top gear leads to very high rpm cruise, JMO but I like ~160 or in these charts for a top gear max rpm, hard to do w/ a 5 spd though
Just some food for thought, the g50/30 used in 993Cup and RSRs is just about perfect for a dual use car w/ a stockish engine w/ ~7K rev limit, the gearing is low and tight enough for track but not so low as to preclude street use.

[Jonny042]

Lots of great info here to digest, but no time at the moment to reply - but thanks to everyone especcially Bill.

I use a quaife gear calculator that produces simplar charts and graphs to what Bill Uses.

[Jonny042]

Originally Posted by KTL

You should get a 1995-1999 BMW M3. They have a great gearbox!

I had one!! Sold it to buy the 911. Wish I'd kept it but now I'm a little more flush I'm thinking of an E46 for a dd.

[Canada Kev]

It might be a bit more financially feasible to get yourself a whole transmission from another market (Euro G50/00 or Switzerland G50/02). I know that having that little bit taller first gear actually makes it useful on really tight corners. It makes the difference between being able to blast out and lugging away in second. I don't encounter a lot of slow corners like that, so for just first gear, it wouldn't be worth it for me to make that kind of change. However, having the first four in a nice tight bunch may be for certain tracks.

I asked a question about gearing on my Swiss market car and Bill kindly posted this gearing comparison chart.



Bill, what are you using to create your newer charts? Would it be too much to ask that you post one for the G50/02 so it would be a bit easier to compare apples to apples with mine and the others on this thread?

[Matt Monson]

Originally Posted by KTL

Yep. Places like Guard and California Motorsports have a 8:32 ring & pinion.

California Motorsports Porsche G50 5 speed transmission section

I don't have any of them. Demand has fallen off in recent years with more people realizing that re-gearing is both more cost effective, more performance, and more durable. If demand ever returns I'll make a run of them, but for now it's just not a viable product in the current economy.

Regards,

Matt Monson
Guard Transmission LLC

[boba]

Originally Posted by Bill Verburg

Just some food for thought, the g50/30 used in 993Cup and RSRs is just about perfect for a dual use car w/ a stockish engine w/ ~7K rev limit, the gearing is low and tight enough for track but not so low as to preclude street use.

Not to hijack this thread but to comment on Bill's reference to the the G50/30. I was sourcing a G50/31 for my 964 and found that now if you do not have a like core they are unavailable, not to mention that the price has gone through the roof. I then went to the re-gear a G50/20 option. Looked at the R&P change but that does not address the spacing. The plan evolved to tall 1st, stock 2ed, short 3,4,5, and stock 5th in the sixth slot. This was still not quite what I was looking for so we made a change to second as well. I do not have the software on my PC to do the charts but what we ended with was the following.

First.................3........................... RPM Drop at 7000
Second............2.133........................... ....2023
Third................1.65......................... ........1585
Forth................1.333........................ .......1345
Fifth..................1.1........................ ...........1224
Sixth.................0.9211...................... .......1138

With the 3.6 this should be fun and still livable at freeway speeds.

Bill, what would this look like on your chart? BTW we used a 25" tire if that makes a difference.

[Rob H]

I have a 1989 euro G50 3.2, it being my only car, I drive it every day and do the odd track day and tight hill climb. At the track I don't get into fifth and at the hillclimb I haven't managed third gear yet it's so tight.
I bought some 15" rims with 205/55/15 and 225/50/15 track tyres thus lowering the overall gearing by about 6%. This is a fairly cheap and easy way to improve your acceleration, lighten your wheels, improve your grip and lower your centre of gravity for track days or spirited driving. The standard 16" wheels are great for normal cruising though. I would love to have the close ratio gears you suggest, but the wheels are a cheap alternative.

[Bill Verburg]

Originally Posted by boba

Not to hijack this thread but to comment on Bill's reference to the the G50/30. I was sourcing a G50/31 for my 964 and found that now if you do not have a like core they are unavailable, not to mention that the price has gone through the roof. I then went to the re-gear a G50/20 option. Looked at the R&P change but that does not address the spacing. The plan evolved to tall 1st, stock 2ed, short 3,4,5, and stock 5th in the sixth slot. This was still not quite what I was looking for so we made a change to second as well. I do not have the software on my PC to do the charts but what we ended with was the following.

First.................3........................... RPM Drop at 7000
Second............2.133........................... ....2023
Third................1.65......................... ........1585
Forth................1.333........................ .......1345
Fifth..................1.1........................ ...........1224
Sixth.................0.9211...................... .......1138

With the 3.6 this should be fun and still livable at freeway speeds.

Bill, what would this look like on your chart? BTW we used a 25" tire if that makes a difference.

It's really difficult to do the full chart w/o toothcounts, max rpm and specific tire size(specific tire helps too) as I use the loaded radius not the usual tire height supplied by the manufacturers