Shortened gearset for 993 gearbox
10-22-2009, 05:21 PM
#1
Shortened gearset for 993 gearbox
Hey there everyone,
In a unrelated post I have here the subject came up with regard to regearing options for the 993 gearbox.
I have taken a good look at the gear ratios that are currently in this gearbox and have come up with a recommendation that I think everyone will like.
Leaving the 1st and 2nd gear alone to keep costs reasonable, and pushing the 5th gear set into the 6th gear position, you can achieve a very tight and quick gearbox simply by changing out 3rd, 4th, and putting in a new 5th.
Here is what I have come up with:
replace 3rd with 1.6 or 20:32 tooth count
replace 4th with 1.3077 or 26:34 tooth count
replace 5th with 1.0833 or 24:26 tooth count
move stock 5th into 6th gear position.
Here are what the speeds look like taking the following into account.
Redline 7000
Tire Diam 24.732
1st gear at redline 39.178 MPH
2nd gear 73.055 MPH
3rd gear 93.493 MPH
4th gear 114.391 MPH
5th gear 138.082 MPH
6th gear 162.411 MPH
Here is what the cost would look like, keep in mind that this does not take into account the R&R for the gearbox.
New 3rd gear set $895.00
New 4th gear set $895.00
New 5th gear set $895.00
Steel synchros 3-6 $189.95 each, 759.80 total
New Seals and Gaskets $89.95
New Synchos 1st and 2nd $640 complete
New Differential side bearings $150 for both
Labor 10 hours @ $90 $900.00
Shipping est $400.00
Total for this upgrade and freshen up $5624.75
So what does everyone think of this option? I look forward to getting some feedback from everyone here.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
In a unrelated post I have here the subject came up with regard to regearing options for the 993 gearbox.
I have taken a good look at the gear ratios that are currently in this gearbox and have come up with a recommendation that I think everyone will like.
Leaving the 1st and 2nd gear alone to keep costs reasonable, and pushing the 5th gear set into the 6th gear position, you can achieve a very tight and quick gearbox simply by changing out 3rd, 4th, and putting in a new 5th.
Here is what I have come up with:
replace 3rd with 1.6 or 20:32 tooth count
replace 4th with 1.3077 or 26:34 tooth count
replace 5th with 1.0833 or 24:26 tooth count
move stock 5th into 6th gear position.
Here are what the speeds look like taking the following into account.
Redline 7000
Tire Diam 24.732
1st gear at redline 39.178 MPH
2nd gear 73.055 MPH
3rd gear 93.493 MPH
4th gear 114.391 MPH
5th gear 138.082 MPH
6th gear 162.411 MPH
Here is what the cost would look like, keep in mind that this does not take into account the R&R for the gearbox.
New 3rd gear set $895.00
New 4th gear set $895.00
New 5th gear set $895.00
Steel synchros 3-6 $189.95 each, 759.80 total
New Seals and Gaskets $89.95
New Synchos 1st and 2nd $640 complete
New Differential side bearings $150 for both
Labor 10 hours @ $90 $900.00
Shipping est $400.00
Total for this upgrade and freshen up $5624.75
So what does everyone think of this option? I look forward to getting some feedback from everyone here.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
10-22-2009, 06:01 PM
#2
For me and my daily driver/commuter, this does not really address the biggest issue for me. The rpm drop from 1st to 2nd is too much. That would be my primary goal, either a shorter second or taller first. I shorter second will require a shorter third, fourth, and maybe fifth. I'd leave 6th on a streetcar.
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
10-22-2009, 06:43 PM
#3
Race Car
For me and my daily driver/commuter, this does not really address the biggest issue for me. The rpm drop from 1st to 2nd is too much. That would be my primary goal, either a shorter second or taller first. I shorter second will require a shorter third, fourth, and maybe fifth. I'd leave 6th on a streetcar.
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
10-22-2009, 07:19 PM
#4
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I like it.. As a street set up. I hardly ever scream out of 1st anyway, If I nail it It's always from 2nd on.. nice alternative. If my clutch was shot and needed a tranny freshen up, I'd do it!
10-22-2009, 08:42 PM
#6
Rennlist Member
Good price here...
Steel synchros 3-6 $189.95 each, 759.80 total
I have paid a lot more for them...try about $300 a pop, wow did I take a reaming...ouch, but maybe they were the "high quality" steel synchros.
BTW, I have heard that a ring and pinion will do wonders...you'll be in 3rd gear before you know it.
I have paid a lot more for them...try about $300 a pop, wow did I take a reaming...ouch, but maybe they were the "high quality" steel synchros.
BTW, I have heard that a ring and pinion will do wonders...you'll be in 3rd gear before you know it.
10-23-2009, 02:51 AM
#7
For me and my daily driver/commuter, this does not really address the biggest issue for me. The rpm drop from 1st to 2nd is too much. That would be my primary goal, either a shorter second or taller first. I shorter second will require a shorter third, fourth, and maybe fifth. I'd leave 6th on a streetcar.
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
I think your suggestion would appeal to those looking for a gain in the 50-120mph range who track their cars.
The street cars would really only benefit from a tight 1st - 3rd gearset, although additional changes would be required to avoid a jekyl and hyde gearbox at low vs. high speed.
The hot ticket for a streetcar might be the taller 1st and a subtly revised 3rd (and also take into consideration the cars without a removable 2nd gear). Also, are the better steel synchros an advantage on a street car?
Anyway, that's my opinion - worth exactly what you paid for it!
Looking forward to the discussion on this thread...
What you've described and what Bill has illustrated with his chart is gearing similar to the g50/3x gearboxes. In my experience, this is the gearing that really fixes the problem. And having a reasonably short 6th (still good for 170mph - top speed for an NA car) makes it a useful gear.
Cheers,
Joe
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10-23-2009, 02:54 AM
#8
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I would like the gears to be close, keep 1st the way it is, and just stack them closer. I would prefer not to have a tall 1st gear, in the city its just harder on the clutch. Also, 5th can definitely become 6th, I would not mind that my highest top speed is cut down a bit...where do I get a chance or dare to go that fast, even on the track (at least around here)?
BTW, why are these gear sets so bloody expensive? You figure we should be able to put together a group buy, say 10 full sets of gears, and get a good gear-cutting shop to make up sets. I do not think the alloys are that exotic, are they? I would prefer not to contribute to VW's bottom line.
Cheers,
Mike
BTW, why are these gear sets so bloody expensive? You figure we should be able to put together a group buy, say 10 full sets of gears, and get a good gear-cutting shop to make up sets. I do not think the alloys are that exotic, are they? I would prefer not to contribute to VW's bottom line.
Cheers,
Mike
10-23-2009, 03:17 AM
#9
Rennlist Member
I would like the gears to be close, keep 1st the way it is, and just stack them closer. I would prefer not to have a tall 1st gear, in the city its just harder on the clutch. Also, 5th can definitely become 6th, I would not mind that my highest top speed is cut down a bit...where do I get a chance or dare to go that fast, even on the track (at least around here)?
Cheers,
Mike
Cheers,
Mike
IIRC Guard makes a mainshaft with removable 1/2 gears.
Last edited by MarinS4; 10-23-2009 at 11:59 AM.
10-23-2009, 05:10 AM
#10
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The first to second RPM drop is too much for me also. Even if I red line, I have to let the clutch slip a bit going into second for a smooth transition. I feel the 6th gear is very nice on the freeway at about 80 mph. 5th gear at that speed is too high for me. I have experimented with this many times on the way to the Monterey Historics driving up the 5. I think I would rather put up with a big RPM drop between 5th and 6th and have a nice tight equal spacing from 1st all the way to 5th. This means 4 gears need replacement and hopefully no mainshaft, as my car is very early 95. I estimate the cost at 6k if I am lucky. And then, can I put up with possible gear noise from all these new gears.
Just some of my thoughts on regearing.
Michel
Just some of my thoughts on regearing.
Michel
10-23-2009, 01:30 PM
#13
I can see that this is going to be an interesting thread. I realize that different driving styles and requirements are going to be the issue here. Some people want a taller 1st and 2nd some want a tight 1-5 and tall 6th. This is always the issue that transaxle builders run into, it is tough to try to find a solution to fit everyone's needs. What I was trying for here was a night tight gearbox without having to change out the 1st and 2nd gear. Now of coarse we can always find another option here for those who really do not like their 1st and 2nd, but count on that option being a bit more expensive.
I will try to put something together however for comparison sake and see what I can come up with that might still be cost effective. As to the gearing cost, you are all preaching to the choir here, I would love to be able to offer less expensive gear choices, but at what cost here guys? If I did develop a gearing option that cost less, and it broke as a result inside someone's gearbox, do you all think that I would be forgiven here? I doubt it. It cost quite a bit of money to develop a new gear, ensure that it is hardened and toleranced correctly etc. It has taken companies a ton of money and time to get this right. So for my piece of mind I would rather use something that is proven then take a chance with something that is not with relationship to the gearing. Just my .02 cents.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
PS you think my pricing here on the gears is high? Call Porsche Motorsport sometime and check what the cost of those gears would be. It will shock you.
I will try to put something together however for comparison sake and see what I can come up with that might still be cost effective. As to the gearing cost, you are all preaching to the choir here, I would love to be able to offer less expensive gear choices, but at what cost here guys? If I did develop a gearing option that cost less, and it broke as a result inside someone's gearbox, do you all think that I would be forgiven here? I doubt it. It cost quite a bit of money to develop a new gear, ensure that it is hardened and toleranced correctly etc. It has taken companies a ton of money and time to get this right. So for my piece of mind I would rather use something that is proven then take a chance with something that is not with relationship to the gearing. Just my .02 cents.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
PS you think my pricing here on the gears is high? Call Porsche Motorsport sometime and check what the cost of those gears would be. It will shock you.
10-23-2009, 01:45 PM
#14
Rennlist Member
I often drive 80mph+ and doing this "5th" gear swap to 6th gear would not be acceptable. When I re-geared my box, I did 2nd through 6th and put in an Euro 6th gear (0.821) gear! Perfect cruising gear which I use almost every time I'm on the freeway!
10-23-2009, 02:58 PM
#15
Nordschleife Master
I will try to put something together however for comparison sake and see what I can come up with that might still be cost effective. As to the gearing cost, you are all preaching to the choir here, I would love to be able to offer less expensive gear choices, but at what cost here guys? If I did develop a gearing option that cost less, and it broke as a result inside someone's gearbox, do you all think that I would be forgiven here? I doubt it. It cost quite a bit of money to develop a new gear, ensure that it is hardened and toleranced correctly etc. It has taken companies a ton of money and time to get this right. So for my piece of mind I would rather use something that is proven then take a chance with something that is not with relationship to the gearing. Just my .02 cents.