PSU_Engineer

From all the posts that I have read, an automatic equipped Camaro is faster than it's manual counterpart, (all things being equal of course). The question that I have is why the GM transmission is so much better than Ford's "performance" automatic. Performance being a subjective term since both GM and Ford throw these transmissions in everything rear wheel drive. I read in a magazine article that the GM TurboHydro 350 is the most efficient transmission. Since the roots of development of the 4L60e stem back to the 700R4; and since the 700R4 is simply a TH350 with overdrive, it stands to reason that our 4L60's would as efficient, if not better than a TH350. The efficiency of the Ford, is questionable. I beleive that the 4R70W is an improved version of the AODe. Since the AOD, was a "clean sheet" design for Ford, and many internals are based on the problematic, and inefficient FMX transmission, it would seem that the Ford automatic would be an inefficient design.
In a purely hypothetical situation between the two cars, if all the variables of horsepower and traction were equal, would the victor be the Camaro? And if so, how much of difference between the two would there be?
I am asking this question to explain to all the people that look at my car, then sigh, when they see the auto shifter in the center console. I'd like to explain to them that the GM transmission is superior to many automatic transmissions, and that a sports car can have an automatic and still be a performance machine.
Thank you
Tony

JoSeY

Ever been in a H/C LS1 w/a big stall?? That'll prove the point right there....nothing...NOTHING like it!!!!! I wouldn't go back to a 6spd if you gave it to me...I'd trade for a built 4L60 with a 4000 stall anyday...and from a punch....SHOOOT....I can hang w/a similar modded 6spd anyday. But the converter is the key...if you have an inefficient converter (TCI, big yanks) you won't...my 3disc vigilante only lost 3hp locked vs unlocked on the dyno.

JoSeY

Ever been in a H/C LS1 w/a big stall?? That'll prove the point right there....nothing...NOTHING like it!!!!! I wouldn't go back to a 6spd if you gave it to me...I'd trade for a built 4L60 with a 4000 stall anyday...and from a punch....SHOOOT....I can hang w/a similar modded 6spd anyday. But the converter is the key...if you have an inefficient converter (TCI, big yanks) you won't...my 3disc vigilante only lost 3hp locked vs unlocked on the dyno.

PSU_Engineer

Josey,
Beleive me, I'd like nothing better than to have such a car as you're describing. I keep looking at the Yank SS3800 for an install over the winter. This modification alone, has my brain scrambled. A stall as high as 3800 in a STREET CAR!! I thought that stall speeds as high as those were reserved for race only, never driven on the street, vehicles. The point I was trying to make, is that I've never heard of a Mustang/ (any other vehicle) owner bragging about the fact that he had an automatic equipped car. The only way for our competition to make any speed is with a stick shift. Our cars have the luxury of being equipped with one of the best designed manual transmissions, or the option of one of the best automatics. (Both are my opinions)
Even my two buddys (with LS1 Camaros) are skeptical about the capabilities of my automatic. Both their cars are M6's.,and both of them are not LS1tech members.

Tony

joecar

Some of the reasons why an AT is better than an MT (assuming it is designed and built properly;
the 4L60-E, 4L65-E, 4L80-E, 4L85-E are designed and built quite good (Hydra-Matic did a very good job)):

a. sum of side forces on pinions/sun/ring gears adds up to zero (you're an engineer: "vector addition"); this is why white-metal bushes/bearings are sufficient (a MT requires big ball bearings; in a MT, the gear side forces try to separate the trans case);
b. TC multiplies torque during acceleration;
c. It stops you from upshifting too late;
d. It stops you from missing a downshift
(see all those M6 people who munged their pushrods due to overreving when they did a 3-2 shift instead or 3-4 shift at WOT);
e. With some tuning (power programmer) you can adjust the shift time and line pressure to chirp the tires a little or to make them really bark during a upshift; you can also adjust the shift points (rpm/mph)... see c. and d. above.
f. AT shifts way quicker than a person is able to shift on a MT.
g. You can power stall/brake.
h. You can install a trans brake.
i. You can install a stall TC for increased "slingshot" effect.
j. Because the TC has no solid connection (except when TCC is locked), AT is much easier (less abusive) on the powertrain components (engine, trans and axle).
k. AT is much easier for daily commuting in stalled fwy traffic.

Brains

iTrader: (7)

The 4R70W is a wide-ratio gearset version of the AOD-E .. 2.84 first gear vs. 2.40 .. It's actually a very good transmission for performance applications, and can be built to hold over 1000HP. It's a fully electronic unit, and there's aftermarket bellhousings to adapt it to pretty much any motor from any of the big 3 .. There's also a nice aftermarket shift controller for putting it in any application you wish.

WILWAXU

iTrader: (6)

A 3800 Yank is NOT a high stall in a LS1 car. I've daily driven a 4200+ stalled car for over 2 years. You cannot apply old school logic to LS1 converter choices. The torque, low gearing and lock features make the 4L60E behind a LS1 love larger stalls. I would not look at anything under a 3500 stall and would suggest a Yank TP-4400 for the best street/strip combo... of course I'm a little hardcore

FASST

PSU Engineer,

First off, nice choice in educational institutions...I'm an alumni myself (chemical engineer '01). NEway, I had my Camaro at school (see sig as it was identical to described minus the true dual exhaust), and had to explain to countless car "enthusiasts" that an auto was the right choice in transmission. In fact, when I purchased my SS back in '99 it was a manual. I switched it over to an auto and have never looked back.

The only bad part about a higher than stock stall, is that during civilized cruises down College ave, people think that you're reving your engine I think the Yank SS3800 would be a great choice for you. If I were to replace my converter, that's the one I would choose. Currently, sitting with a vig3200, I feel my car is a great blend of street/strip. Completely civilized on the street, but once you hit WOT, hang on.