Transaxle difference?
#1
Transaxle difference?
Looking at the recent 2008 Numbers I couldn't resist looking up my codes to see if my options were rare or popular. (wow, only 22.6% SS's had LSD)
One of the items confused me though.
LS/LT
Transaxle 4.17 (FR8)
Transaxle 3.91 (FX2)
0.26 difference
SS
Transaxle 4.5 (FQ7) <- Mine
Transaxle 3.29 (FR9)
1.21 difference
On the LS/LT the ratio is pretty close between auto and stick, but on the SS they are extremely different. Anybody know why?
One of the items confused me though.
LS/LT
Transaxle 4.17 (FR8)
Transaxle 3.91 (FX2)
0.26 difference
SS
Transaxle 4.5 (FQ7) <- Mine
Transaxle 3.29 (FR9)
1.21 difference
On the LS/LT the ratio is pretty close between auto and stick, but on the SS they are extremely different. Anybody know why?
#2
The SS has a boatload more torque that either the 2.2 or the 2.4 so it can pull the taller gear.Additionally,the automatic transmission's torque converter multiplies the engine's torque whereas the manual trans relies solely on the gear ratios for the torque multiplication.
#3
Gear ratio's today are a fine balance of performance and fuel milage.
More power uses more fuel even in a Eco.
With many low power applications like a 2.2 they can work with the gear ratio to improve accelerations with out hurting fuel mileage.
Now on the turbo they have to look at more power but can adjust the ratio to give a mile or two more.
Also the Turbo automatic 4 speed is only in because the new 6 speed won't fit. This was per a GM engineer who answered off the record in a story on the SS at MaxChevy.com
3:20's is a common ratio for most performance Auto applications. The manual trannys get a little better mileage so they can use more gear. My GTP Comp G has a 3:26 Vs the standard GTP 2:96 if I recall correctly.
In the old days it was nice you could pick what you wanted to run.
GM has always played the ratio game on FEW transaxles. In my Fiero club many swap out for the 1984 4 speed that had a better ratio with a 4 cylinder and put it in with a V6 or V8 application. It really improves acceleration.
The W body transaxles are good to just over 300 HP and the best GM has is the one in the Caddy DTS that will take just over 400 HP.
The diffs in the transaxle usally give way. FWD has always been a weak link but the ones we have today are much improved but they get help from torque managment programs from the car. They ease off at the shift points.
More power uses more fuel even in a Eco.
With many low power applications like a 2.2 they can work with the gear ratio to improve accelerations with out hurting fuel mileage.
Now on the turbo they have to look at more power but can adjust the ratio to give a mile or two more.
Also the Turbo automatic 4 speed is only in because the new 6 speed won't fit. This was per a GM engineer who answered off the record in a story on the SS at MaxChevy.com
3:20's is a common ratio for most performance Auto applications. The manual trannys get a little better mileage so they can use more gear. My GTP Comp G has a 3:26 Vs the standard GTP 2:96 if I recall correctly.
In the old days it was nice you could pick what you wanted to run.
GM has always played the ratio game on FEW transaxles. In my Fiero club many swap out for the 1984 4 speed that had a better ratio with a 4 cylinder and put it in with a V6 or V8 application. It really improves acceleration.
The W body transaxles are good to just over 300 HP and the best GM has is the one in the Caddy DTS that will take just over 400 HP.
The diffs in the transaxle usally give way. FWD has always been a weak link but the ones we have today are much improved but they get help from torque managment programs from the car. They ease off at the shift points.
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