What makes an Auto Trans so slow?

[mistermoonpie]

What is it that makes an automatic transmission so much slower than a manual? Is it the fact that it takes longer to shift between gears in an automatic, or is it cuz the automatic doesn't pull to redline? Because I was wondering...If it were the later, is there some way you can adjust the rpm's at which the auto trans shifts? I mean, there has to be a little piece of computer or something somewhere that tells an auto trasmission "SHIFT NOW". That being the case, wouldn't one be able to "reprogram" (for lack of a better word) that computer (or whatever) to "SHIFT NOW" at redline instead of 500 or so RPM's before? I've always wondered.

[jason_bet]

it shifts probably faster them most manual drivers can.. and it doesnt ever miss gears.. it is slower cause there is not a direct conection.. like a clutch on a manual.. see when you let the clutch out your tires are going to go exactly what your motor is revving.. however in an auto you have a torque converter.. emagine if you will two fans one hooked to the motor turning and one to your tranny.. and emagine them in a little case togeather with ATF.. when the motor spins if spins the fluid making it spin the tranny.. does that make sense?? leaving it with a lot of lag..

Jason

[jason_bet]

this is a better explaination.. haha

http://auto.howstuffworks.com/torque-converter.htm

Jason

[VR43000GT]

Depends on the the setup you are running. If you are looking to have a true drag car autos are the route you want to go if all you want is the lowest ET time possible.

[youngvr4]

yea, also depends on the car and tranny

[Stealthee]

First gear is exceptionally long in 3s's. Thats the main killer in them.

[mistermoonpie]

alright guys thats all i wanted to know thanks! And Jason Bet, thanks for explaining it to me i completely (more or less) understand now. thanks again guys

[talskinyguy]

Because autos are generally designed to be smooth and ride well. They can be setup for speed, and when they are they are much faster than manuals, but also eat more power.

[mistermoonpie]

eat more power? Do you mean more gas?

[jason_bet]

both

[Hotshot8792]

auto trannies are really good if you are making a lot of torque, if your not, then it will be slower.

[jason_bet]

hot shot!! haha.. still waiting on those pictures.. hahahaha just playing its all good i figured I wasn't getting any a long time ago

Jason

[Shane361]

Stock for stock the manual will take the auto from a roll and from a dig. However..most people do mod their cars. With the proper gears, tc and even a built tranny you can walk manuals all day long. Now..auto are NOT good for the street due to the fact they do not downshift very fast. Upshifting as in the track autos shift very fast. Manuals also can not handle big HP which is why autos are a top choice at the strip. Now..autos also loose more HP in the driveline than manuals. Rule of thumb is 10%-15% for an manual and 15%-20% for an auto. It will very per make and model of course. Gears are the best bang for the buck and the difference is incredibly. Autos gearing are made incredibly safe from the factory when infact there is sooo much more there. Good luck-Shane

[Stealthee]

Very few people have gotten good performance out of the 3s ATX. I'll repeat the same story again, BrettRT on 3si put a shift kit, tranny cooler, high stall torque converter, down pipe, test pipe, and other misc bolt ons on his 92 RT. He bested a 16.08 is a DOHC. My SOHC Stealth did 16.04 100% stock. Flat out the gearing kills these cars.

[VR43000GT]

^ True, in these cars, ATX's suffer severly from a dig. The ATX DOHC does much better from a roll since it can access the higher end of the power band by downshifting. However, from a stop, they start from a near idle and are geared very tall which makes it hard from the get go.