Horsepower/ torque
Team Owner
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From: Athens AL
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Originally Posted by Nathan Plemons
That's why I said "loosely" Torque is a calculated value which depends on force applied and lever arm distance.
Sometime's it's better to stick to the quick and dirty answers.
Safety Car
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From: Hinckley Ohio
[QUOTE=vader86]Now to answer the original question, as has been said its just a mathematical relationship between the two. I try to think of torque as what gets me going and that HP just gets me that top-end speed, but that is not exactly right, I just dont care to write a full essay. QUOTE]
What?????? Acceleration is what gets you going and continued acceleration is what continues to push you to the top speed.... 
acceleration comes from a force at the rear wheels "loosely" decribed as torque.......so you need torque anytime you want to accelerate.....at the starting line or the finish line.....
difference is at the line you do have more rear wheel torque since you are in a lower gear than you are at the finish line and thus more multiplication of motor torque.....
So you need horsepower, torque, and gears........oh and traction especially at the start.....forgive me for my opinon but I very humbly think your statement is not really all that accurate......but I can see why people say that...
Give me horsepower, the right gears, and traction and you will have a winner...btw horsepower and gears will maximize rear wheel torque..
This is really a tough subject......
What?????? Acceleration is what gets you going and continued acceleration is what continues to push you to the top speed.... acceleration comes from a force at the rear wheels "loosely" decribed as torque.......so you need torque anytime you want to accelerate.....at the starting line or the finish line.....
difference is at the line you do have more rear wheel torque since you are in a lower gear than you are at the finish line and thus more multiplication of motor torque.....
So you need horsepower, torque, and gears........oh and traction especially at the start.....forgive me for my opinon but I very humbly think your statement is not really all that accurate......but I can see why people say that...
Give me horsepower, the right gears, and traction and you will have a winner...btw horsepower and gears will maximize rear wheel torque..
This is really a tough subject......
Race Director
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Originally Posted by NitrousSam
John Lingenfelter has written tremendous articles and he even wrote a book on this exact subject and torque generally is the winner for the street.
Hell a damn Honda makes "more torque" than my engine does at 8000 RPM's because my engine doesn't even rev to 8000 RPM's, that doesn't mean that it'll win squat.
All John Lingenfelter was doing in those books was finding ways to sell his products which were specifically designed to increase the low end torque, ultimately increasing horsepower in that operating range. Honestly you could throw torque out the window entirely and just look at horsepower over and RPM range. What you cannot do is simply look at peak numbers.
It really make me laugh my *** off that people argue till they're blue in the face about which is "better" when in reality if you increase one you're increasing the other, which means that they're the same damn thing!
Last edited by Nathan Plemons; Jan 5, 2006 at 11:25 PM.
Safety Car
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From: Hinckley Ohio
Originally Posted by NitrousSam
Interesting discussion going on here.
If I have a heavy street car like a C4 or heavier I will focus more on building torque than horsepower every time. ......................... John Lingenfelter has written tremendous articles and he even wrote a book on this exact subject and torque generally is the winner for the street.
If I have a heavy street car like a C4 or heavier I will focus more on building torque than horsepower every time. ......................... John Lingenfelter has written tremendous articles and he even wrote a book on this exact subject and torque generally is the winner for the street.
but ultimately you want to maximize rear wheel torque at all times.....horsepower, gears, wide flat torque curves all help acheive that goal...
Team Owner
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From: Athens AL
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Originally Posted by LT4BUD
What?????? Acceleration is what gets you going and continued acceleration is what continues to push you to the top speed.... acceleration comes from a force at the rear wheels "loosely" decribed as torque.......so you need torque anytime you want to accelerate.....at the starting line or the finish line.....
You missed what I was saying altogether. I was giving him the KISS answer. (keep it simple stupid) Your right to post intelligently on the subject is revoked!
Race Director
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Originally Posted by NitrousSam
Sure, put that Honda engine in your Corvette and see how it runs. It won't get out of it's own way because it can't get your heavy car moving.
If you have an engine that makes 300 HP it can be geared to put the same torque to the ground as another 300 HP engine no matter what RPM they operate at respectively.
Drifting
Joined: May 2003
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From: Charlotte NC
St. Jude Donor '05
Horsepower is ultimately what you want in a race application
Torque is like saying.. I can take this heavy car and push it down the road.. HP is saying I can take this heavy car push it down the road in 4 seconds.
See the difference?
Torque is like saying.. I can take this heavy car and push it down the road.. HP is saying I can take this heavy car push it down the road in 4 seconds.
See the difference?
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Melting Slicks
Joined: Oct 2003
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From: Mount Vernon OH
Originally Posted by Nathan Plemons
That is complete bull**** provided that you are allowed to gear the Honda engine appropriately.
If you have an engine that makes 300 HP it can be geared to put the same torque to the ground as another 300 HP engine no matter what RPM they operate at respectively.
If you have an engine that makes 300 HP it can be geared to put the same torque to the ground as another 300 HP engine no matter what RPM they operate at respectively.
"Big horsepower typically requires a loose converter and a lower gear ratio to allow you to take advantage of the operating range otherwise it is tough to get the car moving" Your Honda bolted into a heavier C4 with the same horsepower but down on torque won't get moving as fast unless you take advantage of the gear and converter/launch rpm.
Race Director
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Agreed, forgot about your previous post.
Better wording might would be that Honda engine operating in the Vette engine RPM range won't move the heavy Vette worth a ****. Of course for that matter the Vette engine probably wouldn't do much good operating at the Honda's RPM range either!
Better wording might would be that Honda engine operating in the Vette engine RPM range won't move the heavy Vette worth a ****. Of course for that matter the Vette engine probably wouldn't do much good operating at the Honda's RPM range either!
Melting Slicks
Joined: Oct 2003
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From: Mount Vernon OH
Originally Posted by Nathan Plemons
Agreed, forgot about your previous post.
Better wording might would be that Honda engine operating in the Vette engine RPM range won't move the heavy Vette worth a ****. Of course for that matter the Vette engine probably wouldn't do much good operating at the Honda's RPM range either!
Better wording might would be that Honda engine operating in the Vette engine RPM range won't move the heavy Vette worth a ****. Of course for that matter the Vette engine probably wouldn't do much good operating at the Honda's RPM range either!
Melting Slicks
Joined: Oct 2003
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From: Mount Vernon OH
Originally Posted by Alvin
Horsepower is ultimately what you want in a race application
Torque is like saying.. I can take this heavy car and push it down the road.. HP is saying I can take this heavy car push it down the road in 4 seconds.
See the difference?
Torque is like saying.. I can take this heavy car and push it down the road.. HP is saying I can take this heavy car push it down the road in 4 seconds.
See the difference?
I hear what you are saying and I think I understand your point. My position is that it's a lot harder to take a heavy car and make it fast with horsepower unless you raise your converter/launch rpm and you change the gear because it is harder to get the engine into it's operating range fast. Your 4 second comment is ok but doen't apply unless you can get the engine into it's ideal operating range. Kinda like the discussion you and I participated in last night about your MPH being down due to a skipped gear (for a lack of a better description) which I totally agree with because I have done it also.
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by Nathan Plemons
Hey I'll work with any units you want, but when you give me a problem in one set of units and want an answer in a similar set of units and I can do it directly without having to convert to something completely different, that's certainly the route I'm gonna take.
When I pull 2-ply TP off my TP roll at a constant rate of 4 sheets per second, what is the angular acceleration of the TP roll, if any? Assume 500 sheets on a 6" roll on a 2" cardboard tube.
Drifting
Joined: May 2003
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From: Charlotte NC
St. Jude Donor '05
Originally Posted by NitrousSam
Alvin,
I hear what you are saying and I think I understand your point. My position is that it's a lot harder to take a heavy car and make it fast with horsepower unless you raise your converter/launch rpm and you change the gear because it is harder to get the engine into it's operating range fast. Your 4 second comment is ok but doen't apply unless you can get the engine into it's ideal operating range. Kinda like the discussion you and I participated in last night about your MPH being down due to a skipped gear (for a lack of a better description) which I totally agree with because I have done it also.
I hear what you are saying and I think I understand your point. My position is that it's a lot harder to take a heavy car and make it fast with horsepower unless you raise your converter/launch rpm and you change the gear because it is harder to get the engine into it's operating range fast. Your 4 second comment is ok but doen't apply unless you can get the engine into it's ideal operating range. Kinda like the discussion you and I participated in last night about your MPH being down due to a skipped gear (for a lack of a better description) which I totally agree with because I have done it also.
I was just pointing out the defintion of power and torque as there always seems to be alot of confusion there. vehicle dynamics is a different subject all together.
Melting Slicks
Joined: Oct 2003
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From: Mount Vernon OH
Originally Posted by Alvin
I was just pointing out the defintion of power and torque as there always seems to be alot of confusion there. vehicle dynamics is a different subject all together.
Safety Car
Joined: Sep 2000
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From: Hinckley Ohio
Originally Posted by vader86
. I try to think of torque as what gets me going and that HP just gets me that top-end speed, but that is not exactly right, .
1) REAR WHEEL TORQUE is what accelerates the car....
2) So to have constant acceleration you need constant torque......actually more torque at higher speeds to overcome windage etc...
3) Since REAR WHEEL HORSEPOWER is a direct function of rear wheel rpm you DO need more horsepower at higher speeds than at lower speeds.
4) Neglecting drive line losses rear wheel horsepower equals motor horsepower!!!! but motor torque and rear wheel torque are related by the gear ratio....also rear wheel rpm and motor rpm are related by the gear ratio...
So the statement of torque being more important at low speeds is kinda true.....but not really.....you need at least as much or more rear wheel torque at higher speeds....difference is torque at higher speeds means mathematically more horsepower..
Can't really make this a KISS topic.....but once you understand it, it really is a pretty staight forward concept....
So ultimately you need horsepower!!!! Plus appropriate gearing...to create a matched system.....and get torque to the rear wheels at all speeds.....it really isn't an choice between torque and horsepower at all.....it must all come together as a system to accomplish your desired performance
Last edited by LT4BUD; Jan 6, 2006 at 08:30 AM.
Race Director
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Originally Posted by LT4BUD
4) Neglecting drive line losses rear wheel horsepower equals motor horsepower!!!! but motor torque and rear wheel torque are related by the gear ratio....also rear wheel rpm and motor rpm are related by the gear ratio...
In our design class we had to design a manual transmission and select the shaft sizes appropriately, etc. We were given both the torque peak of the engine as well as the horsepower peak. One might think that you would want to focus your analysis on the speed at which the torque peak occurs because it has the most "raw force" if you will and thus the most stress. Unfortunately this is completely untrue. You need to focus on the HP peak. I actually made a spreadsheet and worked it out for both cases. I was initially shocked with my results but then I had one of those "duh, you knew that" moments.
Le Mans Master
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From: South-central Missouri
Originally Posted by GeosFun
Our L-98's are a good example of high torque/moderate HP. The cars have very fast low end acceleration, but fizzle out at about 4600rpms due primarily to limited airflow through the long tube runners and manifold. I think I read where the TPI was originally designed for a 305 to move a station wagon. High rpms was not an issue.
The trick is trying to maintain a good low end torque signature but increasing the higher rpm curve. This gets done by shifting the torque curve "to the right." As a practical matter we do this with cams, heads, better induction etc. Result is the engine's ability to process more air/fuel mixture at higher rpms. The formula's above demonstrate the mathematical relationships of torque at higher rpms makes more HP.
But with enough of that "shifting to the right" we can destroy an engines street manners by not leaving enough torque to move the car at low rpm's.
We end up with a race car that must be launched at high rpms where it is back in its torque curve or risk falling on its face while trying to move from a stand still. The myriad of good alternatives available within the SBC framework, for example, from 265 cu inches to 434 and beyond, reflect the bewildering array of alternatives of shifting the torque signatue all over the boards. 
So "which is better" depends upon what you want to accomplish.
The trick is trying to maintain a good low end torque signature but increasing the higher rpm curve. This gets done by shifting the torque curve "to the right." As a practical matter we do this with cams, heads, better induction etc. Result is the engine's ability to process more air/fuel mixture at higher rpms.
The formula's above demonstrate the mathematical relationships of torque at higher rpms makes more HP. But with enough of that "shifting to the right" we can destroy an engines street manners by not leaving enough torque to move the car at low rpm's.
We end up with a race car that must be launched at high rpms where it is back in its torque curve or risk falling on its face while trying to move from a stand still. The myriad of good alternatives available within the SBC framework, for example, from 265 cu inches to 434 and beyond, reflect the bewildering array of alternatives of shifting the torque signatue all over the boards. So "which is better" depends upon what you want to accomplish.
Nothing is as misleading as a stated (peek) HP rating. A narrow torque or HP peak sells a lot of stuff, but is meaningless if the driver can't keep the engine in the desired range. Ideally an engine would have a flat torque curve from off idle to red line, IMO. I guess that is why I love the LT1 so... 95% of max torque just off idle and flat as a board to redline. No surprises or modulating the throttle in the twisties or when coming out of a corner - the torque is a known quantity up and down the tac. And for 1/4 mile stuff, just shift at the rpm limit and don't give it another thought!
P.
Last edited by Paul Workman; Jan 6, 2006 at 09:38 AM. Reason: spelling error
Race Director
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Originally Posted by Paul Workman
And for 1/4 mile stuff, just shift at the rpm limit and don't give it another thought!
P.
P.
The TPI cars are a different story. Sure they'll turn 6000 RPM's but it'll only slow you down to do so because there comes a point where you're actually putting less power to the ground by holding out in the lower gear. On the LT1 this never happens so the optimum shift point is about 1 RPM off the rev limiter!
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Your rate of acceleration is determined by engine torque, gear ratio, tire diameter, and vehicle weight.
A car with 500tq will accelerate the same as a car with 250tq and 2x the gear ratio.
The high revving motor will have to shift more though for the same size powerband.
high HP motors just means the torque peak happens in higher rpms, high TQ motors, the torque peak happens at lower rpms.
A car with 500tq will accelerate the same as a car with 250tq and 2x the gear ratio.
The high revving motor will have to shift more though for the same size powerband.
high HP motors just means the torque peak happens in higher rpms, high TQ motors, the torque peak happens at lower rpms.