Torque?

[udumkid]

torque: is what moves the car from a stand still.

Horsepower: is what keeps the car in motion at speed.

good reading material:
http://dmiessler.com/study/horsepower/

[KingMarineM16a4]

Originally Posted by udumkid

torque: is what moves the car from a stand still.

Horsepower: is what keeps the car in motion at speed.

good reading material:
http://dmiessler.com/study/horsepower/

Wrong.

Tq is the measurement of rotating power in the engine. Horsepower is the measurement at the rate which tq is being produced.

[asndragonboii]

Originally Posted by KingMarineM16a4

Tq is the rotating power of the engine and horsepower is the rate a at which tq does work. Basically.

HEY! You cant post that kindergarden stuff after BlaineStang just wrote a novel!!

[KingMarineM16a4]

Originally Posted by asndragonboii

HEY! You cant post that kindergarden stuff after BlaineStang just wrote a novel!!

Umm... Who is going to school to be an automotive technician? Oh... That's me. What are you one of his followers?

[SternoBoy]

Originally Posted by KingMarineM16a4

Umm... Who is going to school to be an automotive technician? Oh... That's me. What are you one of his followers?

Please don't take offense but you might want to study a little harder. Torque is not power. it is not a mesurement of "engine power". Torque is force. Force and power are different.

A dictionary definition:

something that produces or tends to produce torsion or rotation; the moment of a force or system of forces tending to cause rotation.

- Mike

[asndragonboii]

Originally Posted by KingMarineM16a4

Umm... Who is going to school to be an automotive technician? Oh... That's me. What are you one of his followers?

I was just playing dood. Kinda hard to detect sarcasm on the internet

And you had me read your post like 5 times because i thought you were talking about me. I was thinking, "how does this guy know im going to school?"

I'm also going to school to be a technician.

[udumkid]

Originally Posted by KingMarineM16a4

Wrong.

Tq is the measurement of rotating power in the engine. Horsepower is the measurement at the rate which tq is being produced.

Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000pounds one foot over a period of one minute, you would have been working at the rate of one horsepower.

[sgtpruitt]

I think the question has been answered. Lets not beat a dead horse. Put the google down and step away.

[mO 64 StAnG 06]

This must be a part of Google's conspiracy plan..... It's turning all of us against each other.

[Johnold]

I think the reason why HONDA's last as long as they do is because of the lack of tq. Most of these GM cars that have TONS of tq are completely rattled and shaken to DEATH by all the tq they have. Thats why (IMO) GM/domestic cars don't last. Imports just last longer cause they're made safely and in a way that they won't be too overpowering for their own good I.E Domestic.

[drfters13]

delete

[drfters13]

good info in here

[sheek360]

Originally Posted by TJ213

IMO the reason that the Si, and many other Hondas, don't have torque is that tq usually requires more displacement, which usually means lower fuel economy, and a lower redline.

wtf? more tq downlow = better fuel economy! just look at any hybrid man.

[Blainestang]

Originally Posted by KingMarineM16a4

Umm... Who is going to school to be an automotive technician? Oh... That's me. What are you one of his followers?

Well, it's not like I'm TOTALLY unqualified... I do have a degree in Mechanical Engineering

Originally Posted by SternoBoy

Please don't take offense but you might want to study a little harder. Torque is not power. it is not a mesurement of "engine power". Torque is force. Force and power are different.

A dictionary definition:

something that produces or tends to produce torsion or rotation; the moment of a force or system of forces tending to cause rotation.

- Mike

BTW, SternoBoy... I think we are MUCH closer to being on the same page than we might think. I think when VetteNet guy says that acceleration is maximized at peak Torque... I think he really means "peak APPLIED Torque", but it can EASILY be misunderstood to mean "peak ENGINE torque".

To connect that with my explanations, Max ENGINE Horsepower is the point at which the engine has maximized the POTENTIAL for APPLIED Torque.

Because of this, we can say that, "Given equal gearing (as well as weight, aero, etc), the car with the greater HORSEPOWER at any given moment will be the faster of the two cars." Just because a car has 400 ft*lb of torque doesn't necessarily mean it has a greater POTENTIAL for APPLIED Torque than a car with, say 200 ft*lb of torque, as long as the second car is running at sufficiently high RPM (and therefore, making more horsepower), it can be geared to take advantage of that Horsepower, which can be also known as "the POTENTIAL to produce APPLIED Torque".


I'm kinda thinking out loud here, Sterno... working through it in my head. Any comments?

[Shark Tek]

Originally Posted by Blainestang

Well, it's not like I'm TOTALLY unqualified... I do have a degree in Mechanical Engineering

Partner remember most FG2/FA5 are just kids, so don't lose your time like I did many times.

I'm not a "Mech Engi" but I also have a degree on engineering too and cars are just a hobby.

[Blainestang]

Originally Posted by Shark Tek

Partner remember most FG2/FA5 are just kids, so don't lose your time like I did many times.

I'm not a "Mech Engi" but I also have a degree on engineering too and cars are just a hobby.

Yeah, I definitely a lot of young people on here... but I'm only 22 myself, so I don't mind TRYING to help other people out with their understanding sometimes ... and I often learn a lot in discussions as well, so it's a win-win.

BTW, I'm with you on the hobby part. I WISH I could research, test, and modify cars for a living, but that's not in the cards just yet. We'll see in the future though.

[SternoBoy]

Originally Posted by Blainestang

I think the real answer here is a mix of both your explanation and mine. In the end, yes, maximum acceleration IS at Max Torque, BUT, not necessarily Max ENGINE torque... Max acceleration is at Max APPLIED torque, which, if geared properly, is at Max Engine HORSEPOWER, not max Engine Torque.

I thought some more about what you wrote and modified my thought experiment to this: Imagine you have one bitchin' CVT. Would it be better to hold the engine at a constant 100ft/lbs of torque at 8000rpm or a contant 95ft/lbs at 9000rpm? And the answer of course is 95ft/lbs at 9000 rpm because for any given final drive speed, while losing 5% torque at the engine, one would gain 12% through gear reduction ( 95ftlb * 9 / 8 = 106 ft/lbs).

So I take it back. You're right. Sorry I doubted you.

[Blainestang]

Originally Posted by SternoBoy

I thought some more about what you wrote and modified my thought experiment to this: Imagine you have one bitchin' CVT. Would it be better to hold the engine at a constant 100ft/lbs of torque at 8000rpm or a contant 95ft/lbs at 9000rpm? And the answer of course is 95ft/lbs at 9000 rpm because for any given final drive speed, while losing 5% torque at the engine, one would gain 12% through gear reduction ( 95ftlb * 9 / 8 = 106 ft/lbs).

So I take it back. You're right. Sorry I doubted you.

After reading what your post USED to say before you edited it (which is below), I performed the very same 'thought experiment' as you did

Excellent post, btw... it definitely helped me finalize my understanding of the relationship of Horsepower and Torque. So, for learning/understanding purposes, here's your pre-edited post and how I think both of us came to the same conclusion:

Originally Posted by SternoBoy

Follow the math with me:
In my earlier examples of peak horsepower of at 163 @ 9000rpm (and 95 ft/lbs tq), a 9:1 total drive ratio resulted in a thrust of 789lbs and an acceleration of 0.39G, but with the same 9:1 total drive ratio and the peak torque of 100 ft/lbs at 8000rpm, the resulting thrust would be 830lbs accelerating at 0.44G (albeit at a lower final drive speed of 889 rpm). Thus, peak torque is where maximum acceleration occurs. (Again, in this thought experiment the thrust and acceleration figures are based on a 26" diameter tire and a total vehicle weight of 2000 lbs.)
Or more fundamentally, since a = f / m and torque is force, then maximum acceleration is going to happen at maximum force (torque) for any given gear ratio.

- Mike

As it turns out, your above calculation proves that you are correct that:

Maximum Acceleration occurs at Maximum ENGINE Torque... IF GEARING IS HELD CONSTANT.

However, this results in the two numbers being compared AT DIFFERENT SPEEDS because, with gearing held constant, the car running at a greater RPM will be going at a proportionally higher speed.

So, I solved for the gear ratio that would make the car @ 9000rpm run at the same speed as the car @ 8000rpm (which had a final drive speed of 889rpm).


9000 rpm / 889 rpm = 10.1237:1 ratio


So, solving for the thrust, I used the thrust calculated by the old final drive ratio (9:1), divided by the old final drive ratio (9:1), and multiplied by the new final drive ratio (10.1237:1).

789 lbs thrust (@ 9:1) / 9 (old FD ratio) * 10.123 (new FD ratio) = 887.514 lbs thrust

SO, given a CONSTANT SPEED (and OPTIMIZED GEARING), the car with more HORSEPOWER, not Torque, produces the most Thrust (Applied Torque), becasue it can multiply the torque by a greater gear ratio.

So, just for fun, I decided to compare the Thrust and Horsepower ratios for the car @ 9000rpm and the car @ 8000rpm:

887.5 lb thrust (@ 9000 rpm) / 830 lb thrust (@ 8000 rpm) = 1.069


HP @ 100tq/8000rpm = 152.3


162.75 hp (@ 9000 rpm) / 152.3 hp (@ 8000 rpm) = 1.069


Therefore, because the ratios of thrust and hp between the two cars are the same, we can conclude that:

HORSEPOWER is directly proportional to an engine's POTENTIAL to produce THRUST.

Therefore, it follows that,

At any given SPEED, assuming OPTIMIZED GEARING, the car producing more HORSEPOWER will produce more THRUST proportional to it's horsepower advantage.


_________________


Well, I think we are finally in agreement here, SternoBoy... And I think real answer was somewhere between what each of us originally thought.

I've still got a lot fine-tuning to do with my thoughts, and I've got to correct any previous statements to align with my new understanding... and hopefully eventually be able to provide a simple explanation, because I KNOW that the above is not going to cut it

[ibanez37]

MUSTANGS RULE!! ***waits patiently for Blaine's Engineering degree to prove this one to the masses***

[TJ213]

Originally Posted by sheek360

wtf? more tq downlow = better fuel economy! just look at any hybrid man.

NA torque is made through displacement, that requires more fuel, the hybrid gets its down low torque from an electric motor