Shorter Final Drive?
09-27-2010, 05:28 PM
#47
Drifting
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Yes dump the main shaft, that's a problem for me (grinding in first), 3rd gear synchro for me (grinding getting into 3rd) so since I have to do the whole damn box I might as well re-gear. I fell like 2nd is too low for my home track, i keep running out of revs. With the 4:1 I can start in second with no ill effects. too low. I'm definitely doing the guard parts they're like 900 per vs 2000 per from Porsche.
yes, do 3-5 and put 5 on 6.
but do both RP and regear, you will end up with cup car box.
you need to dump main shaft, get new 1-5, at the point, might as well get new 6 since you already emptied the bank. just put it on credit now.
GT now has some options that provide more ratio vs oem.
i know dell knows it, but for the slightly less crazy GT3 drivers, no matter which gear set you choose, unless you only do one track, they are somewhat a compromise. so do something reasonable, dont go empty your bank. (ok,i am trying to convince myself...)
if i were to do it. i probably just do 3-5 and put 5 to 6. most nor cal track wont need 6th gear anyways. 140-150mph if you are realy really good.
but do both RP and regear, you will end up with cup car box.
you need to dump main shaft, get new 1-5, at the point, might as well get new 6 since you already emptied the bank. just put it on credit now.
GT now has some options that provide more ratio vs oem.
i know dell knows it, but for the slightly less crazy GT3 drivers, no matter which gear set you choose, unless you only do one track, they are somewhat a compromise. so do something reasonable, dont go empty your bank. (ok,i am trying to convince myself...)
if i were to do it. i probably just do 3-5 and put 5 to 6. most nor cal track wont need 6th gear anyways. 140-150mph if you are realy really good.
09-27-2010, 05:35 PM
#48
Burning Brakes
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I am in the process of getting a cup car (the H-pattern kind) transmission installed in my car. There are some (...ahem...) teething issues that may or may not be due to the unit itself or my clutch or that I need a ceramic clutch or something else. Car was driveable on the street but not able to be pushed. I loved the top speed in 5th (220 km/h). That mean even at Tremblant I would need 6th. All gears are very tightly spaced.
I got mine used but it was just refreshed so in theory I am good to go.
Cup car setup uses both 4.00 rear end and closer spaced gears. 1st is taller than stock because of the shorter rear ratio. After that they are very close together. Will keep me very busy on the track.
I will report my findings once I can actually drive it properly.
P.S. I determined the top speed in 5th by getting the car to 4000 rpm and looking at the speedometer. Multiplied that number by 2. There is no need to actually get to 8000 rpm in a gear to see how fast it will go.
I got mine used but it was just refreshed so in theory I am good to go.
Cup car setup uses both 4.00 rear end and closer spaced gears. 1st is taller than stock because of the shorter rear ratio. After that they are very close together. Will keep me very busy on the track.
I will report my findings once I can actually drive it properly.
P.S. I determined the top speed in 5th by getting the car to 4000 rpm and looking at the speedometer. Multiplied that number by 2. There is no need to actually get to 8000 rpm in a gear to see how fast it will go.
07-18-2012, 03:02 AM
#49
Rennlist Member
Sorry for reviving such an old thread but I'm trying to better understand all of the many mods done to a new to me 6gt3.....built by PJS. The car has a 4.0 and while I understand the limited use of first, high cruising RPM etc, I do not understand the higher wear the 4.0 causes over the stocker mentioned by a couple of people. Is it just due to higher RPMs.....or ? What am I missing?
Thanks!
Thanks!
07-18-2012, 06:47 PM
#50
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4.0 is 8/42 evenly divisible. u always on the same tooth
the other ratio (OEM) is not evenly divisible, so ring and pinion not alway on same tooth,slightly less wear. not sure I'm explaining it well enough so it's understandable. sorry
the other ratio (OEM) is not evenly divisible, so ring and pinion not alway on same tooth,slightly less wear. not sure I'm explaining it well enough so it's understandable. sorry
07-18-2012, 10:21 PM
#52
Rennlist Member
Isn't regear has the same durability of the existing stock gear sets? From what I heard r/p accelerates wear vs regear which is probably true esp in racing conditions.
I wonder how much wear on r/p for de's. I've had mine(Copans r/p) for well over 6 years wo issue. I do change gear oil more then often though. Matt of Guard Transmission- where are u? I know u posted pros/cons but lazy to search. Mike
I wonder how much wear on r/p for de's. I've had mine(Copans r/p) for well over 6 years wo issue. I do change gear oil more then often though. Matt of Guard Transmission- where are u? I know u posted pros/cons but lazy to search. Mike
07-19-2012, 06:54 PM
#53
I think you mean an 8:32, which is 4.0 to 1. I have done this too -- I changed to a 4.0. Though I never really drove the car with a stock R&P, I can say that I'm very pleased with the outcome of this mod. I couldn't care less about first gear being shorter -- it still seems quite usable to me for what little street driving i do. But the increased snap from 2nd through 5th, which is where I am on the track, has been very nice.
07-22-2012, 12:52 AM
#54
Three Wheelin'
I think you mean an 8:32, which is 4.0 to 1. I have done this too -- I changed to a 4.0. Though I never really drove the car with a stock R&P, I can say that I'm very pleased with the outcome of this mod. I couldn't care less about first gear being shorter -- it still seems quite usable to me for what little street driving i do. But the increased snap from 2nd through 5th, which is where I am on the track, has been very nice.
07-22-2012, 01:26 AM
#55
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I think you mean an 8:32, which is 4.0 to 1. I have done this too -- I changed to a 4.0. Though I never really drove the car with a stock R&P, I can say that I'm very pleased with the outcome of this mod. I couldn't care less about first gear being shorter -- it still seems quite usable to me for what little street driving i do. But the increased snap from 2nd through 5th, which is where I am on the track, has been very nice.
be careful with the 4.0 and what it will do to your gear usage on your favorite tracks...... 4.0 is great where you can use 2nd gear to come out of hairpins as it puts the rpm on the cam and is also shorter... at most tracks a 4.0 will work... at some tracks it's ineffective... I've heard of one 6GT3 that ran tremblant in 2nd, 3rd and 4th and after a 4.0 he had to run in 3rd 4th and 5th !!! what a waste... even though 3rd 4th and 5th are shorter than original gears this gear usage was slower than the original 2nd 3rd and 4th!!!
8:32 not 8:42, idiot me.
on some track, the 4.0 is perfect. but most track i go, instead of 2-4, it's not 3-5. i have the same issues, (rpm dropping) but just one gear higher up. if i do again, i would regear to fit your home tracks. every gear box is a compromise. that's why pro's change stacks. but for us, we just pick the best compromise.
07-22-2012, 01:27 AM
#56
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Isn't regear has the same durability of the existing stock gear sets? From what I heard r/p accelerates wear vs regear which is probably true esp in racing conditions.
I wonder how much wear on r/p for de's. I've had mine(Copans r/p) for well over 6 years wo issue. I do change gear oil more then often though. Matt of Guard Transmission- where are u? I know u posted pros/cons but lazy to search. Mike
I wonder how much wear on r/p for de's. I've had mine(Copans r/p) for well over 6 years wo issue. I do change gear oil more then often though. Matt of Guard Transmission- where are u? I know u posted pros/cons but lazy to search. Mike
07-22-2012, 08:47 AM
#59
Three Wheelin'
U r both right.
8:32 not 8:42, idiot me.
on some track, the 4.0 is perfect. but most track i go, instead of 2-4, it's not 3-5. i have the same issues, (rpm dropping) but just one gear higher up. if i do again, i would regear to fit your home tracks. every gear box is a compromise. that's why pro's change stacks. but for us, we just pick the best compromise.
8:32 not 8:42, idiot me.
on some track, the 4.0 is perfect. but most track i go, instead of 2-4, it's not 3-5. i have the same issues, (rpm dropping) but just one gear higher up. if i do again, i would regear to fit your home tracks. every gear box is a compromise. that's why pro's change stacks. but for us, we just pick the best compromise.
regearing 3-5 would and leaving 2nd gear stock would be best on longer tracks but dropping in a 4.0 will shorten your 2nd gear which is helpful on smaller tracks with hairpins.... stock 2nd gear is too tall for these situations...
I'm wondering if a 3.73 instead of 4.0 would do the trick.. only 6% taller than the 4.0 and may let you stay in a 2-3-4 sequence vs 3-4-5
07-22-2012, 08:58 AM
#60
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I think Mooty's point was since its an evenly divided ratio that the same tooth on ring always meshes with the same tooth on the pinion gear and that this can create accelerated wear.