how does....

[Anonymous]

54 Ford-

The problem with language is that I know what I mean and you have to assume what I mean by what I say.

I did not mean to imply i think bore/stroke ration is irrelevent in the production of power, what I thought I was saying is that in the example if I fix bore/stroke ratio between all configurations (responding to Super Mags 11:19 post about using similiar bore/stroke ratio between configurations) it will not affect the outcome, since it doesn't matter what the ratio is, the greater the number of cylinders still yields the greater horsepower.

I do recognize there are certain features that racing engines seem to share, including large bore/stroke ratios (1.5-1.8), large rod/stroke ratios (>2:1).

Lazy JW-

Don't know that the Deere wouls plow better than the Honda. Just put a sand tire on the back and pop the clutch at 12,000 rpm- plow a field 1 furrow at a time

Points well taken. And I need to read more carefully...

 

[rbohm]

8) one thing every seems to keep dancing around is, if both 300 ci engines a six and a 12 for comparison, have the same bore/stroke ratio, then the 12 will make more hp at most rpm's because it simply has more piston area. this was solidly confirmed during the 60's when the offenhauser 4 cylinder engine was ruling usac indycar competition, and drake came along with their V8 using the same displacement and started winning on a regular basis, then ford and cosworth came along and cemented the V8 engine as the one to have in usac competition. the same thing happened in F1 in the eaarly 80's when the V8's and V12's started beating up on the 4 cylinder hondas.

 

[Lazy JW]

Actually, when I want to plow one furrow at a time, I hitch up my team of Norwegian Fjord horses and away we go. It's really fun
Lazy JW

 

[Thad]

OK, one last question how are we measuring power as HP or torque.
I was always told torque equated to the amount of work that could be done and HP was how fast would be done.

So which is it?
pull hard or go fast

 

[BIGREDRASA]

That's the point of the "area under the curve" phrase. An engine with a peak torque at low RPM, which decreases slowly with RPMs, will have a "flatter" power curve. It will have have "large area under the curve." This engine would do well at a track like Martinsville, where there are huge RPM swings. It is a compromise, so it will get stomped at a track like Talladega, where you run flat out all the way.
Torque and engine speed combine to give you horspower or kilowatts. An engine with tiny cylinders will have high torque and horsepower curves. An engine with tiny cylinders has a peaky curve, mening that HP and torque come on at high RPMs. It can make lots of peak HP, but needs lots of gear to get off the line. An engine with huge cylinders will have a flat curve, mening that HP and torque come on at low RPMs. The old 4 cyl. Offys used to run only a two speed rear axle; no transmission. They were described as having "stump pulling torque." They were great on banked ovals. As previously stated, 4cyls. were inherently not as well balanced, and couldn't keep revving higher and higher. They therefore were limited in peak horsepower, and were unable to compete with engines that used many tiny cylinders with multi-speed transmissions.

 

[SuperMag]

OK, one last question how are we measuring power as HP or torque.
I was always told torque equated to the amount of work that could be done and HP was how fast would be done.

Strictly speaking, torque is a force measurement. It is an instantaneous measurement.

Horsepower is a measurement of power; it has a time component. It is the measurement of work done over time. 1 HP=746 watts. Or put in terms of torque, 1 HP = the amount of power necessary to maintain 550 ft/lbs of torque for 1 second (or 275 ft/lbs for 2 seconds, etc.)

8) one thing every seems to keep dancing around is, if both 300 ci engines a six and a 12 for comparison, have the same bore/stroke ratio, then the 12 will make more hp at most rpm's because it simply has more piston area.

This is what 20over was trying to say. But my position was that while this is certainly true, the amount of horsepower gained from this phenomenon is not nearly as great as the the horsepower that is gained because of the higher RPM that can be attained from the fact a that a multi cylinder engine has a shorter total stroke (per cylinder).

 

[Lazy JW]

Think about an old fashined steam piston engine. It is capable of exerting 100% tourque at zero rpm. Yet no work gets done, therefore no horsepower is generated. By definition, HP is work accomplished in a given time frame. Any practical gasoline engine will be a compromise between the extremes of horsepower vs. torque. But then any engineering endeavor is a compromise
Lazy JW