The g50/31 Experience
10-04-2009, 07:43 PM
#46
Three Wheelin'
Same advice I got on the 993TT forum when I asked the same question over there.
10-04-2009, 08:08 PM
#48
Rennlist Member
I have been following this upgrade for some time, and the $$$ continues to hold me back. I am wondering, for my use, if a "simpler" re-gear of 3,4,5 and moving 5th to 6th wouldn't be more cost effective.
I read the original observation below, and do not really feel this is a major impediment to my driving experience/enjoyment. I don't accelerate at full throttle from 1st gear to redline as it is, so perhaps offline performance is not that important for me...
As for track use, I don't use 1st as an active gear anyway. I guess the 2 questions I need to consider are:
1. How much money can be saved rebuilding a stock transmission while changing just 3,4 and 5 vs. an RS box outright; and
2. Will having stock 5th gear doing duty in 6th be too much an impediment.
Answser to #1 should be pretty definitive.
Question 2 probably has more to do with how fast you want to cruise on the highway (fuel efficiency and increased engine wear) and how likely you need a higher gear than stock 5th on the track.
Any thoughts? Am I at least analysing the options correctly?
Best,
Matt
I read the original observation below, and do not really feel this is a major impediment to my driving experience/enjoyment. I don't accelerate at full throttle from 1st gear to redline as it is, so perhaps offline performance is not that important for me...
"...but the gearbox allows you to always stay in the meat of the powerband where the car pulls the hardest. This was impossible with the /20 as the gaps were simply too wide. A good example is the 1st to 2nd shift. With the /20, the car always felt "off cam" after the shift, no matter hard high it was revved in 1st. This is no longer a problem now."
1. How much money can be saved rebuilding a stock transmission while changing just 3,4 and 5 vs. an RS box outright; and
2. Will having stock 5th gear doing duty in 6th be too much an impediment.
Answser to #1 should be pretty definitive.
Question 2 probably has more to do with how fast you want to cruise on the highway (fuel efficiency and increased engine wear) and how likely you need a higher gear than stock 5th on the track.
Any thoughts? Am I at least analysing the options correctly?
Best,
Matt
10-04-2009, 08:29 PM
#49
Someone should open a shop in Detroit to manufacture high-quality replacement gearsets and retrofit gearboxes.
I just can't justify 30%+ of the value of my car for such an upgrade, at least not until I'm forced to open it up.
I just can't justify 30%+ of the value of my car for such an upgrade, at least not until I'm forced to open it up.
10-04-2009, 11:06 PM
#50
Burning Brakes
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10-05-2009, 12:52 AM
#51
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Matt,
It depends on your application. When I had my /20 re-geared, it came out to about $1500 per gear (don't forget to add the cost of the new clutch and LWF too - why re-gear if you are not doing that?). You might be able to save some money by not doing 2nd, but you would need to determine if it was going to save all that much given the cost for the labor. And why would you want a poor 2nd to 3rd transition? I eventually bought the /32 just because I lost too much ground to others in slower corners given the 2/3 transition in my /05. For a track only car, especially one raced, steel syncho's are very nice. You have to remember that closer gears mean a lot more shifting and if you can't shift quickly, it will get old fast. My /32 allows much faster shifts than my /05 would every permit, especially the 2nd to 3rd shift coming out of a corner.
Look at Bills spreadsheet and try to determine what gear ratios would actually work well with not doing 2nd. I don't think you'll find any that make it worth the expense. Save money by not doing 6th if the tracks you normally run don't have a long enough straight that gets you into 6th to begin with. It takes a lot longer to get through the higher gears, even with close ratio's due to the wind resistance and a stock 3.6's relative lack of horsepower. I've never used 6th at the tracks I normally run at.
It depends on your application. When I had my /20 re-geared, it came out to about $1500 per gear (don't forget to add the cost of the new clutch and LWF too - why re-gear if you are not doing that?). You might be able to save some money by not doing 2nd, but you would need to determine if it was going to save all that much given the cost for the labor. And why would you want a poor 2nd to 3rd transition? I eventually bought the /32 just because I lost too much ground to others in slower corners given the 2/3 transition in my /05. For a track only car, especially one raced, steel syncho's are very nice. You have to remember that closer gears mean a lot more shifting and if you can't shift quickly, it will get old fast. My /32 allows much faster shifts than my /05 would every permit, especially the 2nd to 3rd shift coming out of a corner.
Look at Bills spreadsheet and try to determine what gear ratios would actually work well with not doing 2nd. I don't think you'll find any that make it worth the expense. Save money by not doing 6th if the tracks you normally run don't have a long enough straight that gets you into 6th to begin with. It takes a lot longer to get through the higher gears, even with close ratio's due to the wind resistance and a stock 3.6's relative lack of horsepower. I've never used 6th at the tracks I normally run at.
10-05-2009, 01:18 AM
#53
Banned
Thread Starter
Agreed. The "price" will be about the same. Except you wont have a Porsche Motorsports LSD, a 2 year warranty, and a used $5K g50/20 gearbox to sell when you're done. Note that the extra wide ratios of the g50/20 are much more suitable for the big V8s the Factory Five guys use in their cars - which is why they are sought after.
Last edited by JM993; 03-28-2011 at 05:18 PM.
10-05-2009, 02:57 AM
#54
Rennlist Member
OK...all good points...
The best possible configuration, with no consideration for price, had got to be the G-50 993 RS tranny with LSD, either PMS or Guard.....no argument form me on this. I just dont want to spend the money....
For us cheap guys, Ring and Pinion is about $2,500...about $1,000 in labor to install it.
To do a tranny right with LSD and 993 RS gears and steel synchros + steel shifter forks, steel synchros...about $10,000.
It's all about what one is willing to "invest". With the value of the 993 between $25,00 and $30,000 it doesn't make a lot of sense to me to invest 1/3 of the value of the car into the tranny.
With 04 - 06 GT3 prices down around $50,000....do I put more money into the 993, or sell it for $25,000 or so and cough up the delta for the GT-3. I am certain I am not the only one thinking this way.
For us cheap guys, Ring and Pinion is about $2,500...about $1,000 in labor to install it.
To do a tranny right with LSD and 993 RS gears and steel synchros + steel shifter forks, steel synchros...about $10,000.
It's all about what one is willing to "invest". With the value of the 993 between $25,00 and $30,000 it doesn't make a lot of sense to me to invest 1/3 of the value of the car into the tranny.
With 04 - 06 GT3 prices down around $50,000....do I put more money into the 993, or sell it for $25,000 or so and cough up the delta for the GT-3. I am certain I am not the only one thinking this way.
10-05-2009, 08:46 AM
#55
a cwp cwp change isn't all that bad, here's a comparison of a race /30 a stock /20 and a /20 w/ 8:32 cwp
you'll notice that the drops or splits don't change w/ a cwp change, top end is still a reasonable 160ish which means a reasoanble cruise rpm too.
you'll notice that the drops or splits don't change w/ a cwp change, top end is still a reasonable 160ish which means a reasoanble cruise rpm too.
10-05-2009, 12:04 PM
#56
Rennlist Member
"You might be able to save some money by not doing 2nd, but you would need to determine if it was going to save all that much given the cost for the labor. And why would you want a poor 2nd to 3rd transition?"
10-05-2009, 12:05 PM
#57
Bill,
Do you have a speed/gear/rpm graph for the G50/20US with the 8:32? Seemed to me basic calculation shows a 16% increase in RPM in all gears for any given speed. Is that right?
Do you have a speed/gear/rpm graph for the G50/20US with the 8:32? Seemed to me basic calculation shows a 16% increase in RPM in all gears for any given speed. Is that right?
10-05-2009, 12:08 PM
#58
Rennlist Member
"...and a used $5K g50/20 gearbox to sell when you're done. Note that the extra wide ratios of the g50/20 are much more suitable for the big V8s the Factory Five guys use in their cars - which is why they are sought after."
Best,
Matt
10-05-2009, 03:00 PM
#59
Rennlist Member
Lurking on this thread...I believe 16% is the magic number. The more I think about the R&P change, the better it sounds. I know it's not ideal...but I'll just drive through any shortcomings. All I lnow is where I was lugging at 4000 RPM in the past...I'll have the 16% factor going for me.
10-05-2009, 03:55 PM
#60
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Wouldn't an 8:31 cause a lot of shifting on the race track? I notice that the ring and pinion is allowed for 'improved' stock for PCA (class H for 993). What are your thoughts for this application vs. a stock R&P?
Bob