: Any auto guys switched to the manual gearing?



cbloveday
03-18-11, 02:46 AM
Considering going to the 3.73 from 3.23. Any thoughts from those who have done this on their AUTO V?

Transmissions

Type:
(1.) Tremec TR6060 six-speed manual; fully synchronized with single overdrive (MG9)
(2.) Hydra-Matic 6L90 six-speed electronically controlled automatic overdrive with torque converter clutch (MYD)

Gear ratios (:1)



First:
2.66 , 4.03

Second:
1.78 , 2.36

Third:
1.30 , 1.53

Fourth:
1.00 , 1.15

Fifth:
0.80 , 0.85

Sixth:
0.63 , 0.67

Reverse:
2.90 , 3.06

Final Drive Ratio:
3.73 , 3.23

tedcmiller
03-18-11, 03:31 PM
I have an automatic 2009 CTS-V. The main reason I traded in my 2005 CTS-V was to get the automatic transmission. I am not likely to ever switch voluntarily to another manual transmission.

Luna.
03-18-11, 03:53 PM
I have an automatic 2009 CTS-V. The main reason I traded in my 2005 CTS-V was to get the automatic transmission. I am not likely to ever switch voluntarily to another manual transmission.

I think he's referring to just the gearing, not the transmission.

As a manual owner, I'm out of this equation. :)

wait4me
03-18-11, 03:58 PM
The advantage that is possible here is, shifting takes up time, and if you can launch hard off of second gear instead of first gear, what would that do for you?

gnxs
03-18-11, 04:10 PM
The advantage that is possible here is, shifting takes up time, and if you can launch hard off of second gear instead of first gear, what would that do for you?
All other things being equal, a first gear launch should always produce the best results.

PhxTriode
03-18-11, 04:37 PM
The advantage that is possible here is, shifting takes up time, and if you can launch hard off of second gear instead of first gear, what would that do for you?

Would this be for traction purposes or simple effective gear ratio?

wait4me
03-18-11, 04:43 PM
It would be for both Phx, look at the gearing. The second gear of the auto is near the first of a manual. So a launch at 3000 rpms in second gear should net a better time. Once because of being able to put the power to the ground better, and second saving .400 of a second of a shift..

PhxTriode
03-18-11, 05:02 PM
It would be for both Phx, look at the gearing. The second gear of the auto is near the first of a manual. So a launch at 3000 rpms in second gear should net a better time. Once because of being able to put the power to the ground better, and second saving .400 of a second of a shift..

Nice! thanks.

Hey since this is a tranny thread, did you get those auto clutches in yet?

elphil
03-18-11, 05:21 PM
cbloveday doesn't say what he hopes to achieve with taller gearing. Should increase gas mileage a bit, shouldn't it?
Edit: nevermind. He is going to a shorter gear.

CTSV4now
03-18-11, 05:44 PM
What would a swap like that cost?

cbloveday
03-18-11, 05:51 PM
Anyone have any idea what gear I'd be in and what rpm, as I cross the trap? I do not want to be in between gears.

CTSV4now
03-18-11, 06:11 PM
Depends on how high your limiter is set

4th gear
6200 rpm @ 115 mph
6600 rpm @ 122 mph


Good chance you will cross in 5th gear with stock diameter tire.

gnxs
03-18-11, 07:35 PM
Curtis, you need to determine what redline your new combo will be capable of, what tires you will be running and guesstimate what trap speed you think you'll be capable of (with some room to grow) before you can even ask yourself what axle ratio (3.73 or 3.23 in your example) would be the best for your needs. IMO, changing the gears should not even be on the table until you get the car back with your new combo and make some shakedown runs at the track. At the very least you need to have answers to all the questions I listed above.

My $0.02.

newcadman
03-18-11, 08:53 PM
Curtis, you need to determine what redline your new combo will be capable of, what tires you will be running and guesstimate what trap speed you think you'll be capable of (with some room to grow) before you can even ask yourself what axle ratio (3.73 or 3.23 in your example) would be the best for your needs. IMO, changing the gears should not even be on the table until you get the car back with your new combo and make some shakedown runs at the track. At the very least you need to have answers to all the questions I listed above. My $0.02.




IMO and FWIW, excellent advice.

cbloveday
03-18-11, 10:48 PM
Curtis, you need to determine what redline your new combo will be capable of, what tires you will be running and guesstimate what trap speed you think you'll be capable of (with some room to grow) before you can even ask yourself what axle ratio (3.73 or 3.23 in your example) would be the best for your needs. IMO, changing the gears should not even be on the table until you get the car back with your new combo and make some shakedown runs at the track. At the very least you need to have answers to all the questions I listed above.

My $0.02.

Larry, my only concern is if Byron gets stingy with the NHRA rules for 2011, they may kick me off before I can determine that. Jesse said he would give me a great deal or loan the 3.73 to me for the slip. I will weigh your advise and discuss it further with Jesse. The decision is tough.

gnxs
03-19-11, 09:27 AM
Larry, my only concern is if Byron gets stingy with the NHRA rules for 2011, they may kick me off before I can determine that. Jesse said he would give me a great deal or loan the 3.73 to me for the slip. I will weigh your advise and discuss it further with Jesse. The decision is tough.
Until you determine all of the things I mentioned earlier, for all you know the 3.73's might hurt your performance not help it (e.g. if it required a shift into 5th that the 3.23's did not). Just because it's more aggressive doesn't always mean it's the best choice for your combo. Like everything else, it's the complete package working well together that gets you the quick timeslips. Not saying it won't be better, just that you need to get all the other information nailed down before being able to determine which might work best.

I'm going to contact Ron today and ask him what we can expect from tech this year at Byron. There are also other tracks around here to run at, so all would not be lost.

BeagleBrains
03-19-11, 11:25 AM
3.73/1 Gearing applies higher RPM for greater torque application for fastest acceleration numbers. You will find on any Corvette Link that owners do gear swaps to a lower numerical ratio (not caring about winning a drag race) to gain milage efficiency and raise that top speed attainable.
My Jeep has a very aggressive exceedingly low 4.11 ratio to provide torque advantage for off-road or towing advantage. It also has the poorest gas milage of my cars; however, it does what it was built to do quite well.