I’ve said many times that power comes from the engine, but you need a well-suited transmission to make effective use of it. In my limited experience with tractor-trailers, I’ve observed that truck tractors built for residential moving and the like (bulk that requires a lot of space, but not real heavy) have different transmissions than truck tractors built with flat bedding steel and heavy equipment in mind. I’ve driven 9-speeds that were hard to get started in 2nd gear, and I’ve driven 10-13 speeds that I was hitting the splitter and shifting to 6th gear at 15 MPH.
@doubleclutch–You make a good point. I once owned a 1954 Buick Special with a manual transmission. The engine was a 264 cubic inch V-8 and rated at 143 horsepower. I also owned a 1955 Pontiac V-8 with a manual transmission. The engine was a 287 cubic inch rated at 180 horsepower. The Buick could run circles around the Pontiac. The Buick could pull away from a stop on level ground in second gear. I didn’t have to downshift from high to second going around a corner. I had to downshift the Pontiac under the same situation and it couldn’t pull away from a stop sign in second gear. Now I know that engine torque also makes a difference, but there was too big a gap between first and second on the Pontiac.
a lot of transmission dissatisfaction,rests under the hood,a gutless engine will wear your right arm out ,a truck with a high torque rise engine will go ,while a barely adequate engine will keep you plenty busy.I remember those old V-8 cats in Louisville trucks,even with a 5x4 tranny wouldnt hold a candle to maxidyne of comparable displacement with a 6 speed transmission-Kevin
@doubleclutch–You make a good point. I once owned a 1954 Buick Special with a manual transmission. The engine was a 264 cubic inch V-8 and rated at 143 horsepower. I also owned a 1955 Pontiac V-8 with a manual transmission. The engine was a 287 cubic inch rated at 180 horsepower. The Buick could run circles around the Pontiac. The Buick could pull away from a stop on level ground in second gear. I didn’t have to downshift from high to second going around a corner. I had to downshift the Pontiac under the same situation and it couldn’t pull away from a stop sign in second gear. Now I know that engine torque also makes a difference, but there was too big a gap between first and second on the Pontiac.
Are you sure the 1954 Buick didn’t just have a lower axle gear ratio than the Pontiac?
A lot of the '60’s muscle cars came with awfully low gearing in the rear end resulting in a car that would win drag races but had engines that would roar at some ridiculous rpm when going down the highway getting maybe six mpg or so, but you could climb any hill without downshifting, the car was permanently downshifted.
The whole reason for modern cars having 5, 6, or even 7 and 8 gears in some automatics is so you have enough range of gearing to give both lively acceleration in the low gears and economical cruising in the upper overdrive gears, without having enormous gaps between the gear ratios.
Try driving a modern 5 speed manual car as a three speed, using only 1st, 3rd, and 5th gears and you’ll see that the range of gearing is too much for three speeds, Sure, it “works” but you’ll find yourself wishing for ratios between those three gears.
@B.L.E–Actually the Buick would go almost 80 mph in second gear. It would accelerate faster than the Pontiac, it had a higher top speed and got better gas mileage. I think that the torque peak may have occurred at a lower rpm than the Pontiac.
The Pontiac never did have the power I thought it should have. The crossover pipe for the exhaust system looked as though it was made in a blacksmith shop. My Pontiac was a 1955. By 1957, the displacement was upped to 347 cubic inches and the 1957 was a very good performer. 1955 was the first year for the Pontiac V-8 and there may have been some kinks to straighten out. The Buick V-8 came out in 1953 as a 322 cubic inch engine. The displacement was reduced for the Special in 1954 to 264 cubic inches. The 1953 Buick Special used the overhead valve inline 8 cylinder engine.
The never-ending equation and constant battle.
Engine dispalcement
Cylinder size
Combustion chamber shape.
bore
stroke
numbers of cylinders
rpm
final drive ratio
transmission ratios
transmission type
fwd
rwd
gas
diesel
ethenol
etc
Since the dawn of the internal combustion engine, everyone has been constantly attempting to inprove on or top one another in one aspect or another
cost to produce, own and repair.
mpg
power
?
?
Ken Green’s comment made me think about my experience with the 1954 Buick vs the 1955 Pontiac when both cars were equipped with a manual transmission. By the mid 1950s, most Buicks and Pontiacs were equipped with automatic transmissions. However, the Buick depended on the torque converter for torque multiplication in its Dynaflow automatic, while the Pontiac had the 4 speed Hydramatic with a fluid coupling that did not multiply torque. Therefore the Buick may have depended more on the torque of the engine coming on at a lower rpm. My suspicion is that neither the Pontiac nor the Buick were really designed for manual transmissions at that time.
There is an analogous situation with steam locomotives, @doubleclutch. Passenger trains were light and easy to accelerate, but were also operated at higher speeds. That’s why passenger locomotives had much larger drive wheels (and usually fewer of them) than freight locomotives. They didn’t need massive traction to get under way quickly and the big drivers let them operate at higher speeds (per rotation.)
For heavier freight trains the challenge was to get them moving at all without the wheels slipping. That ability is measured as tractive effort and was often more important than hp for a freight locomotive, especially the really big ones that pulled the heaviest trains at moderate speeds (like the coal trains over the Appalachians). Once underway, many large freight locomotives produced plenty of horsepower to move the trains at decent speeds.
The diesel-electric locomotive was adopted first for switchers and passenger use because they were clean, modern, and didn’t produce enough power for heavy freight use. The more powerful second generation diesels could be combined into enough units to pull anything, and all those electric motors driving bunches of wheels gave massive torque to get moving. Which is why we’re still using diesel-electric drivetrains all these decades later. Driving an electric motor is a great transmission choice for heavy equipment that needs low speed torque.
None of this directly applies to cars, but it shows how different industries have tackled seemingly similar problems that are actually quite different.