mmarshall

Sure, light weight played a big role...I fully agree. But remember what I said in the opening post...though the auto companies usually didn't publish torque figures back then, big American V8s in that size/displacement range, particularly with single/dual quads or a tri-carb setup, would produce from 450 to 500 ft-lbs. of torque. The famous Chrysler dual-quad 425 HP Hemi, for instance, produced an (official) 490 ft-lbs. And Chrysler, back then, even with the relatively light Barracuda/Challenger and Duster/Dart/Demon, didn't have anything near as light as a Shelby AC.

Toys4RJill

Makes no difference if they did not publish torque ratings. A 425hp engine will have a good torque output.

You seem to have the idea that a low HP/high torque engine will out perform a HP/medium torque engine. The high HP engine will eventually win. The Shebly was a high HP, high torque engine, best of both worlds.

Here is a perfect example:

Land Cruiser 4.5 diesel make a lot more torque than the 5.7 iforce. The 5.7 gives up almost 80 lb feet of torque to the diesel but the 5.7 makes 100 more horses. Both are identical transmissions, chassis and rears. The 5.7 will destroy the 4.5 in every statisical performance test. This happens because the 5.7 makes more power than the 4.5, all things are equal in my comparison expect the different engines.

gengar

A lot of companies with a lot lower budgets have "solved" this "problem".

(It says a lot about the ridiculousness of this "debate" that this is referred to as a "problem".)

lobuxracer

iTrader: (2)

No, it's not because of the loading, it's because they only turn 3000 rpm before they run out of breath. Sure, loads of torque, but not a lot of horsepower. The engines turn slowly so they will last 250k miles (or more) between rebuilds and so they are more thermally efficient because nobody wants to spend a lot of money to ship something (maybe that's what is limiting commercial space flight....) So the loading has nothing to do with the number of gears. It has everything to do with available torque at the wheel sufficient to accelerate the load and limited rpm where sufficient engine torque is available to be multiplied.

BTW, I know that hill quite well. I passed cars going down it on my bicycle in 1977. The speed limit was 55 mph...it was a brutal climb.

FrankReynoldsCPA

Every car with an automatic transmission has a torque multiplication device

Infra

iTrader: (1)

Dynos measure torque, not HP, therefore they want the gearing to be 1:1 to make wheel torque = engine torque. You are wrong that gearing changes power at the wheels, it only changes torque.

SexyElaine

Not for nothing but feeling 383 lbs of torque underneath my newly pedicured right foot would feel soooo good driving a RC F next , next summer

Joe Z's post about the RC F Specs below !

yowps3

If you guys want efficient engines than look at GM's LS V8. They're light, extremely compact and fuel efficient for their size.

HP per litre is a joke used by governments for tax purposes.. Why not HP per Kilo?
In the aviation industry HP/weight, HP/size & power per unit of fuel are king.

The ISF engine along with all DOHC V8s are huge, very heavy and they drink too much.
And they lack a torquey feel that you expect from V8. Even the much older 5.7L LS Commodore with a power sapping 4-speed auto gives you a greater shove into seat feeling than the ISF. All while achieving better real world MPG.
Let alone the LS2, LS3 6.0L, 6.2L !! Which are newer and better.

The ISF just doesn't have that V8 surge that I expected and it drinks too much fuel for a car with a long 8-speed overdrive transmission.
The ISF feels like a V8 S2000 lol

Infra

iTrader: (1)

The IS-F has a flatter torque curve. The LS gets good highway mileage from its cylinder deactivation. Wait till you see the Atkinson cycle on the new UR, which is something GM's push-rod V8 cannot do because it has no variable valve duration, only timing.

FrankReynoldsCPA

I did enjoy the GM 5.3 in the Suburban I drove last summer. Very good power. I imagine the 6.0 or 6.2 would have been even more awesome.

My buddy has the 5.7 LT1 in his 95 Firebird Formula...that thing can haul the mail.

nipponbird

Once flew over the handlebar of a 500cc four stroke single cylinder Husqvarna enduro when shifting down at the top-end of the torque curve. Next guy in the competition was an Australian on a Honda who stopped and handed me a hot beer from his tank/tool box, while I was tending to bruises and a very sore ego. He left with the following advice ringing in my ears: "Be careful when dropping a cog on that dog, mate. A single cylinder makes much more torque than a two cylinder of same capacity."
The guy had a point, but it's not that simple. Cam timing, profile and valve lift, can make a huge difference, not
only in the amount of torque, but how and when it is delivered. The Italians realised in the late twenties that induction tract and combustion chamber shape can be crucial for a desired torque graph. Of course cylinder lay-out also comes into the equation. The firing sequence overlap on a V8 engine, giving a much more even spread of torque than on a straight eight. Although I remember my dad's straight eight Buick could really dish out some torque.
Nowadays variable valve timing and better control over ignition timing came into the game, as well as hybrid technology. We can almost say, you can have torque whenever you wish, while driving.
Torque is however fascinating, ever saw how a steam locomotive start moving from stationary, without a clutch, almost zero revs, while pulling a thousand tons?
Sometime I must tell you about the 500cc two cylinder Laverda Montjuic on the other end of the scale, which didn't want to idle under 2000 revs, but once you've wind it up it screamed a 1000cc Kawazaki right off a mountain pass (certainly the Italian handling played a big part in this). But torque? Had a torque curve as narrow as a Moulin Rouge dancer's waist, horses yes many and revs many and we're still talking four stroke engines ............boy, I get the itch to go and swing a leg over a bike the more I think about the pleasure I had on that little rocket!!!
Then there was the 1200cc three cylinder Laverda Mirage I had the privilege to own for a couple of blissful months. The one with the 180 degree crank, which caused it to have the firing sequence of a four cylinder which had lost its no. 2 cylinder. Again the opposite of the Montjuic almost, it could pick up speed uphill like a 1960's VW Bus on a downhill, which caused the m/cycle scribes to dub it the bike who makes molehills out of mountains. But let me stop, I get carried away here, luckily I still have an old BSA Gold Flash which I can take out to feel the torque and listen to the haunted sound of the parallel twin engine.

peteharvey

The fundamental factors are: time, space, and mass.

Time is measured in seconds.
Space is measured in meters.
Mass is measured in kilograms.

Speed [meters/second] = distance [meters] / time [seconds]

Force [Newtons] = mass [kg] x acceleration [m/s sq]

Power [Watts] = Force [Newtons] x Speed [meters/second]

Note also that:
Torque = Force [Newtons] x distance [meters] = Energy [Joules]
Torque is the force multiplied by the stroke of the piston engine.

And that:
Power [Watts] = Energy [Joules] / time [seconds]
Power [Watts] = Torque [Nm] / time [seconds]

Thus, Force and Torque has a mass and acceleration component, but NO speed component.
Power, on the otherhand, has all three mass, acceleration, and speed components.
Power takes into account the speed as well.

In the end, Force and Torque measurements affect acceleration, especially with suburban and highway speed limits of 40 mph or 60 mph in the USA.
However, on the race track, where there are no speed limits, power is more important, because a production engine can be modified with more ignition advance, and more valve advance timing, to be able to attain higher RPM.
In this common situation, the Force or Torque is similar, however because the torque is maintained at higher RPM's, the redline is higher - thus there is more speed, hence there is more power.

Formula 1 racing cars in atmospheric versions restricted to only 2.4 liters, previously did not have much capacity for force/torque.
Thus, Formula 1 racing cars often are designed to red line at close to 20,000 RPM to maximize their speed, hence "power".
However, by revving to near 20,000 rpm, it is extremely loud, and the engine doesn't last very long.
Turbos work by compressing larger volumes of air, such that larger volumes of fuel can also be injected; this gives more energy, hence more torque and force - albeit down at low rpm's too.
However, the higher the turbo compression, the greater the stresses on the engine.
In the 1980's Formula 1 era, the engines would race at 2.5 bar. During qualifying, they would use 4/5 bar or so, but they could only be left on 4/5 bar for 5 minutes; any longer, and the engine would overheat and blow.


Gearbox?
Another point that everyone should understand is that:
Power Input = Power Output!
Power can neither be created nor destroyed; power can be lost through frictional losses etc.

The gearbox changes the ratio between the Force and the Speed.
In other words, it changes the ratio between the Torque and the Time.
First gear has maximum Force [Torque], but minimum Speed.
Top gear has minimum Force [Torque], but maximum Speed [RPM].


Aka Electricity
Likewise, in electricity:
Voltage [Volts] is the intensity of the current, or the potential difference to be exact.
Amperage is the speed of the current, actually measured in Coulombs of Particles per Second.

Power [Watts] = Voltage [Volts] x Amperage [Amps]

Electrical power can neither be created nor destroyed.
So a "transformer" is the equivalent of a gearbox.
The electrical transformer changes the ratio between voltage to amperage.
The step-up transformer will increase the voltage, and decreasing the amperage.
The step-down transformer will decrease the voltage, and increase the amperage.
In both cases, the total electrical power always remains the same; albeit less frictional/resistance losses.


Aka Light
The Power of Light [Lumens] = Intensity of Light [Lux] x Lateral Surface Area of Illumination [sq m]
The total volume of light can neither be created, nor destroyed; it can only be lost through reflector/lens inefficiencies etc.

A reflector is the equivalent of a car's gearbox, or an electrical transformer.
A large diameter reflector focuses the light beam so that the surface area of illumination is reduced, but the intensity of the light is increased!
The larger the diameter of the reflector, the smaller, yet more intense the hot spot.
However, the total power of light in Lumens always remains the same; albeit less reflector efficiency and atmospheric losses etc.

The intensity of light in Lux, determines how far it will throw longitudinally.
Remember that to double the longitudinal throw of light, we must increase the intensity in Lux four times!
Likewise, to double sound volume, we must increase the power eight times!

When a flashlight beam hits the wall, the "hot spot" is light that is reflected indirectly from the reflector [equivalent to a car's gearbox].
The "spill" of light on the wall, is light that comes directly from the emitter/bulb itself!

The deeper the reflector, the narrower will be the lateral direct spill.
However, as a reflector gets deeper, there will be a circular secondary ring of light encircling the hot spot, known as a "corona", such that the deeper the reflector, the narrower the spill, but the more prominent the secondary circular ring of light around the hot spot.

Instead of having a reflector as a gearbox for a flashlight/headlamp, we can also use the "lens".
However, lenses tend to have a very poor lateral spill of light for practicality, but they have a very intense hot spot to maximize the longitudinal throw!
Surefire flashlights use hybrid type reflectors, which is a combination of both the reflector, and the lens - to deliver characteristics that are intermediate between lateral spill reflectors and longitudinal throw lenses.


This should help one understand the relationship between mechanical power, electrical power, and even the power of light.
And how the mechanical gearbox, electrical transformer, and light reflector/lens - can modify the components within, by increasing one factor, at the expense of decreasing the other factor.
The gearbox can change the torque to speed ratio, but the gear box cannot change the power, outside from some frictional losses...

nipponbird

Geesss peteharvey, am I glad you weren't behind me that day when the Husqvarna let me ate some dirt.
Only joking. I've read what you've said a couple of times. It does put a lot of things into perspective.
You have a link? I love stuff like this.

mmarshall

Those diesels also last several hundred K between rebuilds because of their greatly strengthened blocks and internal components required by the 20: 1 compression ratios.


Nevertheless, a 75-80K trailer-load is not going to get rolling easily without a lot of torque-multiplication in low, short gears. Otherwise, diesel torque or not, the engine would simply lug too badly, and maybe have its crankshaft damaged.

Pretty impressive descent, isn't it? And a nice view west from the lookout point. That hill is famous among truckers....and there are a lot of trucks in that part of Pennsylvania running coking coal from the mines to power plants and what few steel mills are left around Pittsburgh.

I did a lot of driving in the Central Appalachians. Nowhere else, however, even descending from Virginia's much higher Skyline Drive, was I as apprehensive or nervous as coming down that hill into Uniontown, even in a relatively modern car with good brakes, cooling system, and up-to-date transmissions. Many decades ago, when traffic was much lighter, a number of American automakers used that particular hill to test the durability of their latest components under load.

Och

iTrader: (3)

I've been on that hill, and the trucks there really struggle, even with all their torque. However, I think the drivers are far more concerned with their brakes when it comes to steep grades like that - if the compressor is not keeping up and air brakes lose pressure, it can be a disaster.