curb weight of truck????
#16
02-12-2017, 05:50 PM
FTE Chapter Leader
So I ran across this thread while looking around for something I saw a while back and wanted to re-read.
It's a torque converter, not a torque reducer. Two jobs that it does: 1 allows the vehicle to come to a complete stop with the engine running while allowing very little torque to the drive wheels, hence why you can hold the vehicle with the brake. 2. When Engine RPM increases it converts the revolutions into torque. (hence the name). HOW STUFF WORKS LINK
A transmission pump is NOT the same as an AC compressor, An AC compressor does rob a slight amount of power to compress a gas (freon), a transmission pump is spun by the TC to create pressure to run the other parts of the transmission.
I shall leave alone the piece about the drag racing setups. However when it comes to performance street cars, putting out high horsepower and torque, the reasons to run a manual are to allow the driver to have more control of the vehicle, and they are historically stronger.
They will not tell you that you are right, they will tell you that you were dropped on your head as a baby. A tractor trailer has a lower power to weight ratio than a car or pickup, and to compensate for that they use a manual transmission with 10 or 13 gears, which up until recently, was beyond the capability to have a reliable, inexpensive automatic with that amount of gears.
In the end a TC will help get a heavy load moving and keep it moving over a straight drive any day. Yes I know I'm opening up a can of worms, but I just couldn't leave a thread with incorrect information alone.
... Now, as I was reading through this there was somebody that said that an automatic would out pull a manual, and to that I have to ask "Were you dropped on your head as a baby?!", because, simply put, an automatic transmission sends less horsepower and less torque to the tires than a manual. The reason: an automatic first of all runs off of a torque converter, which does exactly what it says, it converts the engine torque down to the torque that an automatic transmission can handle.
... Then, the next stage is a fluid pump that is run by the engine. An example: an engine w/ an ac compressor has less hp than the same engine w/o an ac compressor because the ac compressor is a pump that requires a small percentage of your hp to be able to work. Well, a transmission fluid pump does the same thing. So, you lose torque mainly with the converter, you lose hp in the fluid pump, and the gearing of the tranny doesn't make up for it.
...Another example: performance street cars designed for real speed (example: Ford Mustang GT) almost always have a manual tranny. They don't put manual tranny's in sports cars because they output less power, they put them in there because they output more power. The only time an automatic puts out more power than your average manual is if you're talking about an automatic tranny that's specifically designed for drag race cars running insane hp and torque and those trannys use specially designed torque converters for drag racing that don't even pull until you hit excessively high rpm's, hence the stall converter, but, these setups are race only and you couldn't even drive them down the road right because they wouldn't even move at normal rpm's or shift.
... Think about it, with a tractor trailer, the tractor uses in almost all cases a manual tranny, and yes, part of the reason is that manuals if in a vehicle w/ proper gearing for that particular tranny get better fuel mileage, but the main reason is simply that in a manual tranny when that clutch is fully attached to the pressure plate (the pedal totally released) the transmission is being turned at the same rpm's as the engine is turning, in an automatic you lose somewhere around 10%- 20% of your torque, hp, and engine rpm's in the distance between the flywheel and the driveshaft. My percentages might not be exact, but ask anybody else if you think I'm wrong, I bet they'll tell you that I'm right.
In the end a TC will help get a heavy load moving and keep it moving over a straight drive any day. Yes I know I'm opening up a can of worms, but I just couldn't leave a thread with incorrect information alone.
Last edited by Benztechnc; 02-12-2017 at 05:53 PM. Reason: lubrication
#17
02-12-2017, 06:25 PM
Dan.. I didn't read your whole post but it would seem you missed the memo on this one. It's not whether an auto will out tow a manual or not it's about what the official tow ratings were from Ford. In almost all cases trucks with a manual were rated lower than automatics simply because the auto torque converter can suffer more abuse than a manual clutch.
#18
02-13-2017, 01:53 AM
Apparently Ford believes in this too, because the auto trans trucks are rated for higher towing & CGVW. That's straight out of my Ford owners manual.
Probably has something to do with that silly torque multiplication thing in the torque converter.
And by the way, nice necropost, Dan.
#19
02-13-2017, 05:05 AM
You call a manual transmission faster, however 99% of drag cars are automatic. Hell for the simple fact no matter how good you are, you will eventually miss a shift, a automatic doesn't miss.
Now for real world experience, a buddy of mine I race with, and I for have 7.3 diesels almost identical except his is 5 speed and mine is Auto. He also has more engine upgrades than I do, aswell as about 150k less miles. We both full almost identical race trucks and trailers. From a dead stop I can and will walk away from him, every time he touches that clutch pedal and comes off the gas guess what happens to his Boost? It goes bye bye.
Now for real world experience, a buddy of mine I race with, and I for have 7.3 diesels almost identical except his is 5 speed and mine is Auto. He also has more engine upgrades than I do, aswell as about 150k less miles. We both full almost identical race trucks and trailers. From a dead stop I can and will walk away from him, every time he touches that clutch pedal and comes off the gas guess what happens to his Boost? It goes bye bye.
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