HP vs Torque Discussion (No Jokes, No bantering. Just facts and reality)
02-10-2009, 01:52 PM
#181
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Thread Starter
Bingo! Great answer and exactly right. sure, it hurts this poor schmoe in the 928 with this downright ugly HP curve, but in the end, the HP and torque will be equal when the engine is allowed to breath right. sure,the HP and torque both go up, but its bettter than averaging down/up due to HP. A little off topic, but a great assement if you are part of the rules makers for GTS. in the end, thats why I let that part go, due to the main fight was averaging the HP down due to lack of torque of a cup car for example. now, that would be clearly unfair, and the GTS commitee EVENTUALLY felt the same way.
contrary to VR's perception of "engine" torque, a cup car for example, if its HP was averaged down, it would clearly be unfair to another car with equal HP and torque numerical values. (e.g 330rwhp 330rwt), as the cup car at 330rwhp and 200rwt would have just as much area under the curve due to close ratio gears, and quite possibly the same shaped HP curve, giving it the exact same rear wheel forces at ANY vehicle speed on ANY track. PLUS, traditionally, most higher reving cars are a little lighter anyway, so any advantge it would have would be counteracted by a lighter car, which can brake and handle better, even though it has the same HP to weight ratio.
That was the logic in the rule adjustment with GTS a few years back.
mk
contrary to VR's perception of "engine" torque, a cup car for example, if its HP was averaged down, it would clearly be unfair to another car with equal HP and torque numerical values. (e.g 330rwhp 330rwt), as the cup car at 330rwhp and 200rwt would have just as much area under the curve due to close ratio gears, and quite possibly the same shaped HP curve, giving it the exact same rear wheel forces at ANY vehicle speed on ANY track. PLUS, traditionally, most higher reving cars are a little lighter anyway, so any advantge it would have would be counteracted by a lighter car, which can brake and handle better, even though it has the same HP to weight ratio.
That was the logic in the rule adjustment with GTS a few years back.
mk
Mark with respect too the 200 hp 911 vs 200 hp 928.
It is a tough issue. The reason being that most motors used in race cars keep making hp to redline. Some wil drop off a bit, but very few drop off as much as the 928 motor. Even so the 928 has some clear advantages at certain speeds. Exiting some slow corners if both chassis have the same weight it will kill the 911. However once down the straight the 911 will start to catch up. So it is really a tough problem to balance these cars. The real issue with the 928 for GTS IMHO is to figure how to improve the breathing to reduce the loss of torque at engine RPM's increase. The inablity for the motor to develop torque at high RPM really hurts it. In fact GTS is right in appling a penaly to the 928 motor over the 911 motor. The reason is that since the rules are so loose a good engine builder will work to improve high RPM breathing of the 928 motor to add more torque up high. If done well he should be able to increase high RPM hp thus minimizing the drop off. Now since the rules are only a peak hp and peak torque he can increase power at 6000 RPM and still be below peak. Thus earning a "free" power gain. The 911 motor builder can try to boost low end power, but simple laws of engine build mean that 3.2L of displacement will never produce as much torque as 5.0L if you can optimize both. So the most valueable gains in the 911 motor will occur such that its peak hp number will change and as such it will take a hit in power/weight.
It is a tough issue. The reason being that most motors used in race cars keep making hp to redline. Some wil drop off a bit, but very few drop off as much as the 928 motor. Even so the 928 has some clear advantages at certain speeds. Exiting some slow corners if both chassis have the same weight it will kill the 911. However once down the straight the 911 will start to catch up. So it is really a tough problem to balance these cars. The real issue with the 928 for GTS IMHO is to figure how to improve the breathing to reduce the loss of torque at engine RPM's increase. The inablity for the motor to develop torque at high RPM really hurts it. In fact GTS is right in appling a penaly to the 928 motor over the 911 motor. The reason is that since the rules are so loose a good engine builder will work to improve high RPM breathing of the 928 motor to add more torque up high. If done well he should be able to increase high RPM hp thus minimizing the drop off. Now since the rules are only a peak hp and peak torque he can increase power at 6000 RPM and still be below peak. Thus earning a "free" power gain. The 911 motor builder can try to boost low end power, but simple laws of engine build mean that 3.2L of displacement will never produce as much torque as 5.0L if you can optimize both. So the most valueable gains in the 911 motor will occur such that its peak hp number will change and as such it will take a hit in power/weight.
02-10-2009, 01:58 PM
#182
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Thread Starter
Good conseise reply.
However, with regards to the Honda getting out of a corner having "decent " power to get out of that corner, in the torque relm, you would have equal torque at those rear wheels if you could make the same HP as your competitor out of that turn. you mention, a broader HP curve traditional of high torque engines, however, this is true probably more often than not, but with it is certainly not the rule as several of my examples have shown. In fact, I selected the cars graphs above to show that sometimes, those higher torque engines can actually be worse in All AREAS OF A TRACK due to a poor shaped HP curve. meaning LESS torque at the rear wheels excep at the point where it makes the same hp as the other car.
This is simple Math at that point.
Mark
However, with regards to the Honda getting out of a corner having "decent " power to get out of that corner, in the torque relm, you would have equal torque at those rear wheels if you could make the same HP as your competitor out of that turn. you mention, a broader HP curve traditional of high torque engines, however, this is true probably more often than not, but with it is certainly not the rule as several of my examples have shown. In fact, I selected the cars graphs above to show that sometimes, those higher torque engines can actually be worse in All AREAS OF A TRACK due to a poor shaped HP curve. meaning LESS torque at the rear wheels excep at the point where it makes the same hp as the other car.
This is simple Math at that point.
Mark
VR to a certain extent we are arguing semantics. However the thing I have learned is that HP is really the best way to settle these arguments.
One thing that gets me is when Honda guys complain about their little 1.6, 1.8 or 2.0L motors making no torque. Well sure they don't, but unlike most street car based motors you can spin them to 9k. So your real operating band is 6k to 9k as compared to most cars 4k to 6k. So despite having 135 ft-lbs of torque you can make that level with the engine spinning so fast that you still have decient power. As for getting out of a corner withone the issue is simple. Never let the rev's drop.
So while we are talking semantics to an extent the more racers understand what really drives them the better they can set about optimizing their race car and also optimizing their use of their car's existing power band on the race track.
One thing that gets me is when Honda guys complain about their little 1.6, 1.8 or 2.0L motors making no torque. Well sure they don't, but unlike most street car based motors you can spin them to 9k. So your real operating band is 6k to 9k as compared to most cars 4k to 6k. So despite having 135 ft-lbs of torque you can make that level with the engine spinning so fast that you still have decient power. As for getting out of a corner withone the issue is simple. Never let the rev's drop.
So while we are talking semantics to an extent the more racers understand what really drives them the better they can set about optimizing their race car and also optimizing their use of their car's existing power band on the race track.
02-10-2009, 02:06 PM
#183
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Not true. Not in this case. if these two engines were in two exact same cars, is the comparison.
Those HP curves point to clear winners in all conditions. AGAIN for the 100th time, the torque value, as a value, is meaningless. an indication yes, but you need MORE information. I just gave you two HP torque curves of two cars that have same HP but vastly different torque numbers. In no way is the higher torque car in any sort of advantage at ANY point on any track. However, when you start looking at the BMW vs caddy example, same HP curve, you get the same result at any point on any track. Now factor in the variables, like the cars themselves, and you get an entirely differnet argument. also, give me a big viper engine with that high torque number and often times it will yield a very broad HP curve, trouncing on most other same HP cars for the reasons you are stuck on.
Focus on the question. Des' question. two equal hp cars, one greater one less torque, which is better on the race track? the Peak numbers provided at isolated rpm points on their respective curves.
do you have an answer yet?
mk
Those HP curves point to clear winners in all conditions. AGAIN for the 100th time, the torque value, as a value, is meaningless. an indication yes, but you need MORE information. I just gave you two HP torque curves of two cars that have same HP but vastly different torque numbers. In no way is the higher torque car in any sort of advantage at ANY point on any track. However, when you start looking at the BMW vs caddy example, same HP curve, you get the same result at any point on any track. Now factor in the variables, like the cars themselves, and you get an entirely differnet argument. also, give me a big viper engine with that high torque number and often times it will yield a very broad HP curve, trouncing on most other same HP cars for the reasons you are stuck on.
Focus on the question. Des' question. two equal hp cars, one greater one less torque, which is better on the race track? the Peak numbers provided at isolated rpm points on their respective curves.
do you have an answer yet?
mk
Correct. Plus, in his apples/oranges "examples", the cars are vastly different in weight & handling characteristics. Whereas De's original question was (IIRC) the same car, same 400hp, different torque.
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Quote:
Originally Posted by jgrant
Depends on the track, the conditions, and the driver.
I could easily pick a combination of those elements that would favour either car.
That's why all the big F1 teams do the simulation work that they do, to find a best COMPROMISE in their setup (gearing, suspension, etc) that will hopefully win the race.
And for ****s and giggles we could also talk about how various differential setups are affected (both good and bad) by torque and their effect on drivability. Same HP/TQ, same gearing, but different results.
TornadoBoy continues to flop frantically on the floor like a fish that got out of the bucket.
Join Date: Aug 2006
Location: Carjackistan
Posts: 12,193
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Quote:
Originally Posted by jgrant
Depends on the track, the conditions, and the driver.
I could easily pick a combination of those elements that would favour either car.
That's why all the big F1 teams do the simulation work that they do, to find a best COMPROMISE in their setup (gearing, suspension, etc) that will hopefully win the race.
And for ****s and giggles we could also talk about how various differential setups are affected (both good and bad) by torque and their effect on drivability. Same HP/TQ, same gearing, but different results.
TornadoBoy continues to flop frantically on the floor like a fish that got out of the bucket.
Last edited by mark kibort; 02-10-2009 at 02:29 PM.
02-10-2009, 02:32 PM
#184
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Thread Starter
Do you need help with the answer yet?? After all, these two curves have just what Des' was asking for. same HP, yet vastly different torque values.
Which is better?
If you are choosing one vs the other, which is going to perform better on the Road course?
Well, lets dig in.
When you look at these dyno runs, you have to look closely as to what is going on.
Here are some data points for both the operational ranges of 4600 to 6400rpm:
V8 vs 911 average for both is about 185rwhp (near the same, but both have trade offs)
4600rpm 190hp vs 160hp
5000rpm 200hp vs 175hp
5500rpm 195hp vs 190hp
6000rpm 185hp vs 200hp
6400rpm 170hp vs 200hp
if you average them out (crude area under the curve), they are about equal. the high torque engine is better out of turns, and the 911 would be better at the end of all gears. If you look at telemetry and time spent at rpms, the 911 might have the edge, due to more power at the upper RPM ranges due to more time in those area, generally.
It was kind of a loaded question and VR wasnt going to respond, so here it is.
I figure it had all elements of everyone's case for HP and torque values.
now, if you look at the BMW vs V8 curves, the story is a little more clear.
QUOTE]
Which is better?
If you are choosing one vs the other, which is going to perform better on the Road course?
Well, lets dig in.
When you look at these dyno runs, you have to look closely as to what is going on.
Here are some data points for both the operational ranges of 4600 to 6400rpm:
V8 vs 911 average for both is about 185rwhp (near the same, but both have trade offs)
4600rpm 190hp vs 160hp
5000rpm 200hp vs 175hp
5500rpm 195hp vs 190hp
6000rpm 185hp vs 200hp
6400rpm 170hp vs 200hp
if you average them out (crude area under the curve), they are about equal. the high torque engine is better out of turns, and the 911 would be better at the end of all gears. If you look at telemetry and time spent at rpms, the 911 might have the edge, due to more power at the upper RPM ranges due to more time in those area, generally.
It was kind of a loaded question and VR wasnt going to respond, so here it is.
I figure it had all elements of everyone's case for HP and torque values.
now, if you look at the BMW vs V8 curves, the story is a little more clear.
QUOTE]
Last edited by mark kibort; 02-10-2009 at 03:18 PM.
02-10-2009, 02:48 PM
#185
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Thread Starter
Bob, this is what you said. Heck, I've been well known for fat finger'ed responses, but it was a logical question.
By the way, you or VR still have not answered the question, yet there have been some inciteful posts regarding the topic as it relates to rule making as well.
Anyway, here was your post to me originally. I know its a bash, but read the underlined sentence. what in the heck is this?
See Mark, you can only answer one question...over, and over, and over, and over again! If a person's question doesn't fit your rote, pat answer, you must rephrase it to fit your simplistic, standard answer. I'm taking a further discount you you personally Mark, as you continue to show that unless you can use the terms "if" and "magically", you are lost
By the way, you or VR still have not answered the question, yet there have been some inciteful posts regarding the topic as it relates to rule making as well.
Anyway, here was your post to me originally. I know its a bash, but read the underlined sentence. what in the heck is this?
See Mark, you can only answer one question...over, and over, and over, and over again! If a person's question doesn't fit your rote, pat answer, you must rephrase it to fit your simplistic, standard answer. I'm taking a further discount you you personally Mark, as you continue to show that unless you can use the terms "if" and "magically", you are lost
You just either can't get it, or refuse to get it! Run Forrest Run!
02-10-2009, 03:19 PM
#186
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The Lecture Hall is empty as the las tof the few attendees filed out a while ago, but the Professor continues to drone on. Meanwhile the cleaning crew stands by with a look of disbelief as they wonder when he will finally wind down and leave too.
02-10-2009, 03:28 PM
#187
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Thread Starter
I had to respond to the 11 posts I woke up to. yours were a few of them. I see, its only fun if YOU are doing the bashing. you are a piece of work as well!
you might want to remove the duplicate post.
by the way, what is your background besides having a quick wit and a white porsche?
Mk
you might want to remove the duplicate post.
by the way, what is your background besides having a quick wit and a white porsche?
Mk
The Lecture Hall is empty as the las tof the few attendees filed out a while ago, but the Professor continues to drone on.
and my favorite:
I'm taking a further discount you you personally Mark, as you continue to show that unless you can use the terms "if" and "magically", you are lost
[IMG][/IMG]
and my favorite:
I'm taking a further discount you you personally Mark, as you continue to show that unless you can use the terms "if" and "magically", you are lost
[IMG][/IMG]
02-10-2009, 04:24 PM
#188
Rennlist Member
You just cannot buy this level of entertainment, eh, Bob? Truly epic.
02-10-2009, 05:18 PM
#189
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Oh, wait... it's not.
I guess the thing that I'm seeing here is that you're arguing theoretical applications of physics when those physics are a subset of the real-world model.
In THEORY, the majority of your statements are correct, and would be perfectly at home on the chalk board of a high-school physics class. In reality, they represent simply a base line of understanding that may or may not work out as you'd expect.
Before you ask my background, I'm a computer engineer, and I worked for years doing dynamic process simulation. This involved mathematically modelling the real world, and coming from university physics class into the real world where it didn't really work as expected, I struggled with this myself.
It's not that the theoretical model is wrong, it's simply incomplete, and doesn't take all of the required elements into account to provide a result that was close enough to the "real world" observations to take the theory as a certainty.
That is why racecar engineering is as much an art as it is a science.
Why is it that some cars/teams "get it", and others don't, when the science is all the same?
It's because they can fill in the blanks of that model with more information, and adjust their setup/process/build to account for it.
A whole slew of obscure things like individual driving styles, car dynamics (front vs rear engine, wheel base, diff setup, gearing, etc), track layouts, engine life requirements, etc., all have an impact on how successful a car will be on the track. That information is also used to help design an engine's output to best match the specific situation that they are expected to face in the race.
That's why teams do the amount of testing that they do... because there's more to racing than a few high-school formulas.
There's also a reason why the big teams have racks upon racks of computers that do nothing but run simulations 24x7 to try and find the best overall design/setup. And the algorithms they're using aren't exactly the simplistic formula you're posting about.
A friend of mine just set up a new simulation cluster for Toyota's F1 team last year. NASA doesn't have that kind of power for the space program.
Just sayin.
02-10-2009, 05:30 PM
#192
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Thread Starter
You are right. The theory and hard facts, give the basic foundation for where you start. Everything you say is true, but we were talking about a car that was the SAME car , meaning all those tunable differences were negated. EXCEPT for the HP being the same, but torque different.
I race. I know of many of the trade offs between tracks, cars , set, ups, etc etc, to infinity! yes it is an artform, but like an artist, you better know that if you mix yellow and blue you get green, not red. Just real basic physics 101 stuff here.
So, in the end, the real answer is, (to Des' question), it depends. Sometimes a higher torque engine with the same hp will be better on an road course, and sometimes it wont. The answer lies first in the HP curve shape, and the rest is found in the countless other areas that are infinitely variable. There are times when a high torque version of the same HP will make more torque at the rear wheels coming off turn compared to another and there are engine profiles that will not. Torque at the engine is just a factor of HP. Without RPM, it is realitively meaningless. Looking at power curves and completely ignoring torque is a good way for those interesting in maximizing performance, to start. A lot of the manual calculations are already done for you. With engine torque, you need a few more elements to make performance baseline decisions. That's another key point here
mk
I guess the thing that I'm seeing here is that you're arguing theoretical applications of physics when those physics are a subset of the real-world model.
In THEORY, the majority of your statements are correct, and would be perfectly at home on the chalk board of a high-school physics class. In reality, they represent simply a base line of understanding that may or may not work out as you'd expect..
I race. I know of many of the trade offs between tracks, cars , set, ups, etc etc, to infinity! yes it is an artform, but like an artist, you better know that if you mix yellow and blue you get green, not red. Just real basic physics 101 stuff here.
So, in the end, the real answer is, (to Des' question), it depends. Sometimes a higher torque engine with the same hp will be better on an road course, and sometimes it wont. The answer lies first in the HP curve shape, and the rest is found in the countless other areas that are infinitely variable. There are times when a high torque version of the same HP will make more torque at the rear wheels coming off turn compared to another and there are engine profiles that will not. Torque at the engine is just a factor of HP. Without RPM, it is realitively meaningless. Looking at power curves and completely ignoring torque is a good way for those interesting in maximizing performance, to start. A lot of the manual calculations are already done for you. With engine torque, you need a few more elements to make performance baseline decisions. That's another key point here
mk
I guess the thing that I'm seeing here is that you're arguing theoretical applications of physics when those physics are a subset of the real-world model.
In THEORY, the majority of your statements are correct, and would be perfectly at home on the chalk board of a high-school physics class. In reality, they represent simply a base line of understanding that may or may not work out as you'd expect..
02-10-2009, 05:48 PM
#193
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You are right. The theory and hard facts, give the basic foundation for where you start. Everything you say is true, but we were talking about a car that was the SAME car , meaning all those tunable differences were negated. EXCEPT for the HP being the same, but torque different.
Depends on the track, the conditions, and the driver.
I could easily pick a combination of those elements that would favour either car.
That's why all the big F1 teams do the simulation work that they do, to find a best COMPROMISE in their setup (gearing, suspension, etc) that will hopefully win the race.
And for ****s and giggles we could also talk about how various differential setups are affected (both good and bad) by torque and their effect on drivability. Same HP/TQ, same gearing, but different results.
I could easily pick a combination of those elements that would favour either car.
That's why all the big F1 teams do the simulation work that they do, to find a best COMPROMISE in their setup (gearing, suspension, etc) that will hopefully win the race.
And for ****s and giggles we could also talk about how various differential setups are affected (both good and bad) by torque and their effect on drivability. Same HP/TQ, same gearing, but different results.
Wasn't addressing the original point of the original question...
But even then, I'll say "it depends" and leave it at that.
"The more you learn, the less you know". -- one of my old profs, on modelling real-world scenarios
02-10-2009, 05:56 PM
#194
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LOL my name appears in this thread about 20 times and not spelled right once. Maybe that will provide more constructive conversation as opposed to half trying to solve the question through physics and the others giving personal driving impressions and some saying nothing at all but continuing to post.
I guess that's why we are posting on the internet and not leading engineers for F1 or ALMS or paid professional racing drovers.
FWIW I have learned something in this thread in spite of and the fact still remains that both type's of approaches to power application have won in various series. Seems like for every championship team that has high revs there is one with lots of torque. So both have proven their merit in racing.
I drive a car with lots of torque, but being FI the power application is not smooth and I still prefer NA and high revs.
As for the V vs the M5 if you plug their gearing into a calculator the M5 is much more efficient at using more of the powerband before needing to shift. 1rst and 2nd have optimal shifts right at redline while the V gets up to 1400 rpm below redline for the optimal shift points at times. I'll take the M5 with an equal weight/power ratio over the V all day. Except I hate the SMG's shifting while on the track and BMW added the manual as an afterthought and begrudgingly so I'm still fairly torn.
Anyways, back off topic.
I guess that's why we are posting on the internet and not leading engineers for F1 or ALMS or paid professional racing drovers.
FWIW I have learned something in this thread in spite of and the fact still remains that both type's of approaches to power application have won in various series. Seems like for every championship team that has high revs there is one with lots of torque. So both have proven their merit in racing.
I drive a car with lots of torque, but being FI the power application is not smooth and I still prefer NA and high revs.
As for the V vs the M5 if you plug their gearing into a calculator the M5 is much more efficient at using more of the powerband before needing to shift. 1rst and 2nd have optimal shifts right at redline while the V gets up to 1400 rpm below redline for the optimal shift points at times. I'll take the M5 with an equal weight/power ratio over the V all day. Except I hate the SMG's shifting while on the track and BMW added the manual as an afterthought and begrudgingly so I'm still fairly torn.
Anyways, back off topic.
02-10-2009, 06:13 PM
#195
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Thread Starter
That was exactly the point of all that discussion. For some reason, and that could be another discussion on its own, VR had seen the CTSV outpeform the BMW. However, i doubt that the BMW and CTSV curves were the same as we saw here on this discussion. equal hp of 438rwhp and disparate torque values.
I would say the curves and the torque levels are a little unusual, but it makes the point of , "it depends".
mk
I would say the curves and the torque levels are a little unusual, but it makes the point of , "it depends".
mk
LOL my name appears in this thread about 20 times and not spelled right once. Maybe that will provide more constructive conversation as opposed to half trying to solve the question through physics and the others giving personal driving impressions and some saying nothing at all but continuing to post.
I guess that's why we are posting on the internet and not leading engineers for F1 or ALMS or paid professional racing drovers.
FWIW I have learned something in this thread in spite of and the fact still remains that both type's of approaches to power application have won in various series. Seems like for every championship team that has high revs there is one with lots of torque. So both have proven their merit in racing.
I drive a car with lots of torque, but being FI the power application is not smooth and I still prefer NA and high revs.
As for the V vs the M5 if you plug their gearing into a calculator the M5 is much more efficient at using more of the powerband before needing to shift. 1rst and 2nd have optimal shifts right at redline while the V gets up to 1400 rpm below redline for the optimal shift points at times. I'll take the M5 with an equal weight/power ratio over the V all day. Except I hate the SMG's shifting while on the track and BMW added the manual as an afterthought and begrudgingly so I'm still fairly torn.
Anyways, back off topic.
I guess that's why we are posting on the internet and not leading engineers for F1 or ALMS or paid professional racing drovers.
FWIW I have learned something in this thread in spite of and the fact still remains that both type's of approaches to power application have won in various series. Seems like for every championship team that has high revs there is one with lots of torque. So both have proven their merit in racing.
I drive a car with lots of torque, but being FI the power application is not smooth and I still prefer NA and high revs.
As for the V vs the M5 if you plug their gearing into a calculator the M5 is much more efficient at using more of the powerband before needing to shift. 1rst and 2nd have optimal shifts right at redline while the V gets up to 1400 rpm below redline for the optimal shift points at times. I'll take the M5 with an equal weight/power ratio over the V all day. Except I hate the SMG's shifting while on the track and BMW added the manual as an afterthought and begrudgingly so I'm still fairly torn.
Anyways, back off topic.