Split from CFDS Thread: HP vs Torque

[540Malibu]

Originally posted by Devin Mac
yeah, but what your "engine" puts out means precisely dick if you can't get any of it to the ground.

furthermore, it means even less than dick if your 300 horse are planted in a car that weighs a bazillion pounds. wheelhorse/ton is all that really matters.

you are more dead wrong than ever, explain to me how a 10k lb 350hp diesel truck can run low 14's.

[540Malibu]

Originally posted by Devin Mac
actually... torque isn't power... refer to my other post... torque is power, torque moves the car, with no torque the car will not move.

[H3llphyre]

Originally posted by 540Malibu
torque is power, torque moves the car, with no torque the car will not move.

torque is force... horsepower is power. Without torque, there is no power, without power there is no movement... this is the path to the dark side.

[H3llphyre]

Originally posted by 540Malibu
you are more dead wrong than ever, explain to me how a 10k lb 350hp diesel truck can run low 14's.

Because unlike import engines, a diesel engine makes a lot of total power... Not just peak power. As what was stated before by our resident midget.

[Feral]

That 350 HP diesel makes like 500 ft-lbs and has gearing that keeps it within it's powerband ... same reason why those torqueless wonder hondas can run 14 second 1/4's ... because they have a decent powerband up top and gearing that will keep them in it.

Torque is no less important than HP in the 1/4 but what really matters is powerband and the ability of the vehicle to stay in it. Why do you think those pro-engine builder competitions all state whoever can make the most average power between the torque peak and the HP peak ... whoever can have the broadest powerband (not necessarily the highest) is considered the winner ... because that engine will do better. May not have the best peak or the lowest end torque ... but has the best average powerband.

[Devin Mac]

Originally posted by H3llphyre
Because unlike import engines, a diesel engine makes a lot of total power... Not just peak power. As what was stated before by our resident midget.

and don't you forget it...

http://www.lvcandymania.com/images/funny%20clip%20art/hitoompa.jpeg

[540Malibu]

Originally posted by H3llphyre
Because unlike import engines, a diesel engine makes a lot of total power... Not just peak power. As what was stated before by our resident midget.

wrong, a diesel engien makes torque, it has 350 peak hp around 3000rpm, the torque gets the job done, not hp.

[540Malibu]

Originally posted by Feral
That 350 HP diesel makes like 500 ft-lbs and has gearing that keeps it within it's powerband ... same reason why those torqueless wonder hondas can run 14 second 1/4's ... because they have a decent powerband up top and gearing that will keep them in it.

Torque is no less important than HP in the 1/4 but what really matters is powerband and the ability of the vehicle to stay in it. Why do you think those pro-engine builder competitions all state whoever can make the most average power between the torque peak and the HP peak ... whoever can have the broadest powerband (not necessarily the highest) is considered the winner ... because that engine will do better. May not have the best peak or the lowest end torque ... but has the best average powerband.

most diesel truck engine produce over 1200 ft lbs of torque. and the 350hp is not going to move 10k pounds to run 14's regardless if you have it from idle to 3k rpm.

the only reason honda's can run 14's is because they weigh nothing, not because they can rev to 10 million rpm. there is very little oposing the rotation of the motor (ie- wheels on pavement) becasue it doesnt have to move mass. which is exactly why, regardless of hp an indy car engine would never get out of 1st gear in a truck even if the truck was geared to let it rev.

[Feral]

Originally posted by 540Malibu
most diesel truck engine produce over 1200 ft lbs of torque. and the 350hp is not going to move 10k pounds to run 14's regardless if you have it from idle to 3k rpm.

the only reason honda's can run 14's is because they weigh nothing, not because they can rev to 10 million rpm. there is very little oposing the rotation of the motor (ie- wheels on pavement) becasue it doesnt have to move mass. which is exactly why, regardless of hp an indy car engine would never get out of 1st gear in a truck even if the truck was geared to let it rev.


Weight comes somewhat into play for those cars' times ... but if you took a honda and redlined it at 6k rpms it would lose 2 second in the 1/4. They did a test like this with an S2000. Short-shifting at 7,000 rpms the thing ran a low 16.

You cannot simply distregard HP ... but I agree it is very overhyped, most of all by the car companies trying to sell their products and VTEC-junkies wanting to have a three digit number to talk about. :thumbsup:

Torque goes a long ways but it isn't everything. Look at TPI Camaros. 240HP, 335ft-lbs ... has trouble breaking into the 14's and it's one of the lighter camaros made. Then again that's probably mostly because of the slushbox ... lol ... put a T56 on those things and you would probably be mid 14's ... but another good example is an LT1 vs an LS1. They LS1 makes 350/350 ... the LT1 275/350. The LT1 can barely sneak into the 13's @ 100-101... the LS1 can consistently hit low 13's @105-106 and has hit 12's bone stock. Of the two cars the LS1 F-bodies were about 50-100lbs heavier as well.

A better example. My car and Jesse's car weight the same amount but he makes at least 100-150 more ft-lbs than I do off the juice (my car is good for about 425/425 at street level boost). Let's disregard ET (since AWD owns). At that level I hit 110-114mph traps pretty consistently as does he but he's got a shitload more torque than I do. It must be my HP that keeps me running with him??

[grygst76]

Originally posted by Feral
This is true ... in an oval track application a heavy drivetrain is important while acceleration doesn't really matter. You are correct. In a road-race applicaton it only matters if fuel economy will matter (this only applies in certain endurance racing situations). For general road-racing where fuel economy isn't a big deal then the lighter flywheel is superior for quicker double-clutching.


I shift pretty fast even without powershifting ... I don't know if my RPMS drop 100-200 even with my lightened flywheel.

However when changing gears in the 1/4 a lighter flywheel is better since when you disengage the clutch after the gearshift there is a moment where the engine has to rapidly decelerate from a higher RPM to a lower RPM ... at this point you want the flywheel and crankshaft to be as light as possible so that less energy is lost decelerating (less time spent getting the engine down in RPMS). Still in a heavy AWD car I think a moderately heavy flywheel is important for launching purposes.

As for the driveshaft indeed it can preserve some rotating momentum for you when out of gear (again I contest this is a tiny amount of time) ... but I seriously doubt this little momentum lost isn't adequately made up for by the HP gained to the wheels. Going from the stock metal driveshaft to a carbon-fiber one in VR4's reduces the total drivetrain loss by about 5% ... it adds a solid 20-25 AWHP to a near-stock car ... more like 35-45 in a heavily modified one. That' a non-trivial amount of ponies hitting the ground.

So for oval track racing and some enduro racing I'm all for a heavy drivetrain!!! For drag racing a lightened transaxle-back (tires, shafts) is superior and an appropriately sized flywheel (to facilitate a good launch and as you stated to store some energy when the clutch is engaged).

You brought up some good points I hadn't thought of though ... awesome.
thought I would add-----Heavier flywheel means it stays in the revzone longer not shorter......lighter flywheel drops revs quicker because of less reciprocating mass LT1's vs LS1's no comparison due to different engines, powerband, gearing, aerodynamicy, e.t.c In a street vehicle it is completely IMO a waste of money for aluminum flywheels and carbon D/S's only because by the time you hit your powerband at 7-8000RPM's, you are at a stoplight or redlight. If you only drag/autox/rally/cross, then it's well worth it. Horsepower is a measure of torque, cars with 1000 horses will NEVER autox or rally check the stats of those cars you will see that they are torque monsters not horses The F1 corvette uses a Billett steel flywheel and aluminum driveshaft and wins consistently all the time with more torque then horses. Horsepower is how FAST you hit the wall, torque is how HARD..

[540Malibu]

Originally posted by Feral
Weight comes somewhat into play for those cars' times ... but if you took a honda and redlined it at 6k rpms it would lose 2 second in the 1/4. They did a test like this with an S2000. Short-shifting at 7,000 rpms the thing ran a low 16.

You cannot simply distregard HP ... but I agree it is very overhyped, most of all by the car companies trying to sell their products and VTEC-junkies wanting to have a three digit number to talk about. :thumbsup:

Torque goes a long ways but it isn't everything. Look at TPI Camaros. 240HP, 335ft-lbs ... has trouble breaking into the 14's and it's one of the lighter camaros made. Then again that's probably mostly because of the slushbox ... lol ... put a T56 on those things and you would probably be mid 14's ... but another good example is an LT1 vs an LS1. They LS1 makes 350/350 ... the LT1 275/350. The LT1 can barely sneak into the 13's @ 100-101... the LS1 can consistently hit low 13's @105-106 and has hit 12's bone stock. Of the two cars the LS1 F-bodies were about 50-100lbs heavier as well.

A better example. My car and Jesse's car weight the same amount but he makes at least 100-150 more ft-lbs than I do off the juice (my car is good for about 425/425 at street level boost). Let's disregard ET (since AWD owns). At that level I hit 110-114mph traps pretty consistently as does he but he's got a shitload more torque than I do. It must be my HP that keeps me running with him??

yes, a certain amount of hp can make the car as fast as x amount of torque, BUT your car will be affected more, by added weight/ uphill/wind, than jesse's; you must also notice that in comparison to yours, jesse's car is a brick, and with the same hp can run the same MPH by using its torque.

lets also say for example, that the LT-1 has 425 ft lbs of torque with teh proper gearing it most likely could run faster.

the gen III small blocks also have ALOT more average torque than the Gen II

[H3llphyre]

Originally posted by 540Malibu
most diesel truck engine produce over 1200 ft lbs of torque. and the 350hp is not going to move 10k pounds to run 14's regardless if you have it from idle to 3k rpm.

the only reason honda's can run 14's is because they weigh nothing, not because they can rev to 10 million rpm. there is very little oposing the rotation of the motor (ie- wheels on pavement) becasue it doesnt have to move mass. which is exactly why, regardless of hp an indy car engine would never get out of 1st gear in a truck even if the truck was geared to let it rev.

You still don't get the point. This isn't an arguement about HP vs TQ.... This is an arguement about where the power band of an engine is.

[540Malibu]

Originally posted by H3llphyre
You still don't get the point. This isn't an arguement about HP vs TQ.... This is an arguement about where the power band of an engine is.

no it isnt, i started the debate and it was about the way hp an torque affect the engine and drivetrain.

[540Malibu]

Originally posted by H3llphyre
You still don't get the point. This isn't an arguement about HP vs TQ.... This is an arguement about where the power band of an engine is.

i never said honda's dont make more power in the higher rpms, but if you stick the same honda motor, into something else that weighs considerably more and use the engines powerband by selecting apropriate gear ratios its still going to have a hard time to get moving because the motor does not have the torque to spin the axles due to the added imposed weight.

now if the high revving motor had a way to get the torque curve of the engine into the upper rpms and it was used in the apropriate manner as compared to the same hp/tq smallblock which spins less rpm then it would perform the same in the exact same vehicle, with exact same weights.

[540Malibu]

Originally posted by tims



And finally since torque obviously equals power, I can take a 55HP geo metro motor, put a 100 to one gearbox on it, then attach the flywheel to the output shaft of the 100-1 gearbox, and it will have 5000+ft-lbs of torque at the flywheel. That will make your car pretty fast huh? I wonder why people use huge ass engines when they could just stick a gearbox on a 1 liter, and make more torque.... I guess the engineers are just confused.

no, but it will have more torque to the wheels becasue gear reduction adds torque, which is why you dyno it the gear closest to 1:1 and above t/c lockup to minimize any effects of gear reduction.

and engineers do put a gearboxes on 1 liters and add crazy gear ratios in order to put more torque to the wheels, and when you get on it in 1:1 or o/d the car either barely pulls or slows down.

[Feral]

Originally posted by 540Malibu
and engineers do put a gearboxes on 1 liters and add crazy gear ratios in order to put more torque to the wheels, and when you get on it in 1:1 or o/d the car either barely pulls or slows down.

Yeah I've had this problem with one of my saturns before ... fast as all hell to 60 (you go through 3 gears nearly redlining to hit 60) and then it falls on its face. hehe.

[tims]

Originally posted by 540Malibu
no, but it will have more torque to the wheels becasue gear reduction adds torque, which is why you dyno it the gear closest to 1:1 and above t/c lockup to minimize any effects of gear reduction.

and engineers do put a gearboxes on 1 liters and add crazy gear ratios in order to put more torque to the wheels, and when you get on it in 1:1 or o/d the car either barely pulls or slows down.

Yup, thats my point, gear reduction adds torque, so torque in itself does not necessarily increase, or decrease 1/4 time, or acceleration. Average power affects how quickly the car accelerates, Average torque affects how the car should be geared, nothing more.

[540Malibu]

Originally posted by tims
Yup, thats my point, gear reduction adds torque, so torque in itself does not necessarily increase, or decrease 1/4 time, or acceleration. Average power affects how quickly the car accelerates, Average torque affects how the car should be geared, nothing more.

wrong, you spend most of the 1/4 mile in high gear, were the torque works because the engine is stressing, torque in itself makes a huge difference. example, jesse's car.

[tims]

Nope, torque really doesn't matter in the high end. You will simply be in a lower gear with a high revving, low torque motor. The torque at the wheels will still be the same assuming you have the same HP.

[TunedPort 335]

Originally posted by 540Malibu
wrong, you spend most of the 1/4 mile in high gear, were the torque works because the engine is stressing, torque in itself makes a huge difference. example, jesse's car.

I agree. Someone then explain how TPI cars that dyno near my numbers run mid-high 13's, where as LT1's with 265rwhp and 310rwtq run high 13's?

Torque does infact decrease 1/4 time. But I also agree with the average power statement. I dunno this shit is confusing! :hmm: :eh:

[92vr4ny]

If you are talking about tq being the one and only variable changing on a car, then at some point the tq is going to do you no good becuase you not going to be able to get all that to the ground sucessfully. Torque is good up to a point, but depending on your application I think there is point where it does more harm then good. If you have the traction for all the torque (within reason) then I think it is is fine. Lets say you look to race at the stop light on the street up to 100 for example. If you have so much damn hp and torque you can not hook up till 80.... then it is kind of pointless IMO! Doing burn outs is fun and all, but if you racing and you cant hook up... a smoke show will not win you anything! Unless you want to run around on drags (which some do) which is a different story.

Ex. I watched a HUGE single turbo supra pull a 14sec flat 1/4 @ like 118 or some sick speed like that. He was on street tires I must say and was spinning them violently in 3rd and had to let up I believe. He is now on drags and in the low 12's or better. Lets say he did not want to put drags on his car, cause he wanted it to be his daily driver, then it is really on for bragging rights to have that much pointless power... unless you look to start your races at 80+ and end whever! I am too afraid of dear and other animals to cars about racing that fast all the time.

[Feral]

Originally posted by 92vr4ny
If you are talking about tq being the one and only variable changing on a car, then at some point the tq is going to do you no good becuase you not going to be able to get all that to the ground sucessfully. Torque is good up to a point, but depending on your application I think there is point where it does more harm then good. If you have the traction for all the torque (within reason) then I think it is is fine. Lets say you look to race at the stop light on the street up to 100 for example. If you have so much damn hp and torque you can not hook up till 80.... then it is kind of pointless IMO! Doing burn outs is fun and all, but if you racing and you cant hook up... a smoke show will not win you anything! Unless you want to run around on drags (which some do) which is a different story.

Ex. I watched a HUGE single turbo supra pull a 14sec flat 1/4 @ like 118 or some sick speed like that. He was on street tires I must say and was spinning them violently in 3rd and had to let up I believe. He is now on drags and in the low 12's or better. Lets say he did not want to put drags on his car, cause he wanted it to be his daily driver, then it is really on for bragging rights to have that much pointless power... unless you look to start your races at 80+ and end whever! I am too afraid of dear and other animals to cars about racing that fast all the time.

Actually this is an entirely different issue than we are discussing. The reason why supras suck is because they have IRS. '03 Cobras have the same issue as do Vette's and ZO6's. There are ways to get rear wheel traction well into the 1000 ft-lb area.

[Feral]

Also ... for the record ... above when I was comparing my car to jesse's and I said mine was 425/425 ... that's at the wheels ... she probably makes about 550/550 at the flywheel. I figure Jesse's big block makes about 475/550 at the flywheel and puts about 400/475 to the wheels so my 425/425 = 400/475 in cars that weigh pretty much the same. Yeah mine does have better aerodynamics but his has a shitload more torque. Regardless its all just speculation as I don't truly know what mine puts to the wheels (425/425 is a bit high ... 400/400 is probably more fair) and I have no clue what a 468 BBC puts to the wheels through a T56.

[Shawn96VR-4]

Originally posted by 92vr4ny
Ex. I watched a HUGE single turbo supra pull a 14sec flat 1/4 @ like 118 or some sick speed like that.

Jon Williams? The guy that WAS going to race Feral?

Yea.. He ran a 11.1 @ 130MPH w/ a shitty 1.9 60' :eek:

[540Malibu]

Originally posted by Feral
Also ... for the record ... above when I was comparing my car to jesse's and I said mine was 425/425 ... that's at the wheels ... she probably makes about 550/550 at the flywheel. I figure Jesse's big block makes about 475/550 at the flywheel and puts about 400/475 to the wheels so my 425/425 = 400/475 in cars that weigh pretty much the same. Yeah mine does have better aerodynamics but his has a shitload more torque. Regardless its all just speculation as I don't truly know what mine puts to the wheels (425/425 is a bit high ... 400/400 is probably more fair) and I have no clue what a 468 BBC puts to the wheels through a T56.

jesse's motor is more liek 425 at the flywheel with 600ft lbs

[540Malibu]

Originally posted by 92vr4ny
If you are talking about tq being the one and only variable changing on a car, then at some point the tq is going to do you no good becuase you not going to be able to get all that to the ground sucessfully. Torque is good up to a point, but depending on your application I think there is point where it does more harm then good. If you have the traction for all the torque (within reason) then I think it is is fine. Lets say you look to race at the stop light on the street up to 100 for example. If you have so much damn hp and torque you can not hook up till 80.... then it is kind of pointless IMO! Doing burn outs is fun and all, but if you racing and you cant hook up... a smoke show will not win you anything! Unless you want to run around on drags (which some do) which is a different story.

Ex. I watched a HUGE single turbo supra pull a 14sec flat 1/4 @ like 118 or some sick speed like that. He was on street tires I must say and was spinning them violently in 3rd and had to let up I believe. He is now on drags and in the low 12's or better. Lets say he did not want to put drags on his car, cause he wanted it to be his daily driver, then it is really on for bragging rights to have that much pointless power... unless you look to start your races at 80+ and end whever! I am too afraid of dear and other animals to cars about racing that fast all the time.

my mid 11 second smallblock had no problem hooking on the street, with NO burnout, and a 5k rpm launch, malibu81's car hooks even better, as does pauls and hey are all on 8.5" tires.

[Don's Bolt]

HP is great but torque is what shoves your Ass back into the seat.

[FATBLOCKMARO]

Originally posted by 540Malibu
jesse's motor is more liek 425 at the flywheel with 600ft lbs


:no:

[Paulie C.]

hey spence how much torque did Toretto's Charger have?:lol:

[Devin Mac]

Originally posted by Don's Bolt
HP is great but torque is what shoves your Ass back into the seat.

and where do you hit your torque peak, don? where do you shift? because by what you just said (along with all the other nitwit sheep who ramble on about "horsepower sells cars, torque wins races" etc...) you damnw ell better be shifting right at your torque peak, or you're not gonna go as fast... right?

[540Malibu]

Originally posted by Devin Mac
and where do you hit your torque peak, don? where do you shift? because by what you just said (along with all the other nitwit sheep who ramble on about "horsepower sells cars, torque wins races" etc...) you damnw ell better be shifting right at your torque peak, or you're not gonna go as fast... right?

according to what you say, if i rev my big block to 8000 rpm (which it will do) i will go faster then if i only rev it to 6k if i optimize the gear ratio for the 8k.

[Feral]

Originally posted by 540Malibu
according to what you say, if i rev my big block to 8000 rpm (which it will do) i will go faster then if i only rev it to 6k if i optimize the gear ratio for the 8k.
It really depends on your torque curve past 6,000rpms. If you can hold a pretty decent torque curve up there then hell yeah it will help you ... if not ... then nope.

[540Malibu]

Originally posted by Feral
It really depends on your torque curve past 6,000rpms. If you can hold a pretty decent torque curve up there then hell yeah it will help you ... if not ... then nope.

but it keeps building HP after 6k, at 8k ill have 1050 instead of 950 at 6500, so it must go faster by neon boys reasoning.

[Feral]

Originally posted by 540Malibu
but it keeps building HP after 6k, at 8k ill have 1050 instead of 950 at 6500, so it must go faster by neon boys reasoning. If it really does keep building HP then sure as hell do it. Only if your HP is dropping off should you short-shift. HP is really nothing more than torque X RPMS and it exists to show how much power you really are making. For instance 350 ft-lbs at 5250 RPMS is the same amount of power as 175 ft-lbs at 10500rpms and will accelerate the car just as fast. By the same token 1200 ft-lbs (your truck example) at 2625RPMS is the same as 600ft-lbs at 5250RPMs or 300 ft-lbs at 10500rpms and will accelerate the truck just as fast in all 3 cases regardless of RPMS. So say you have your big evil-deisel engine making 1200 ft-lbs at 2625rpms and you have your wankel making 300 ft-lbs at 10500RPMS ... assuming the two engines weigh the same you can put them in the same car and will have the exact same amount of acceleration out of them ...

So as long as your HP isn't dropping (which means your torque is falling off faster than your RPMS are rising) ... then you should keep on pushing it until you either reach the limits of your valvetrain or your HP curve does fall off ... and that's where you set your redline.

[540Malibu]

Originally posted by Feral
If it really does keep building HP then sure as hell do it. Only if your HP is dropping off should you short-shift. HP is really nothing more than torque X RPMS and it exists to show how much power you really are making. For instance 350 ft-lbs at 5250 RPMS is the same amount of power as 175 ft-lbs at 10500rpms and will accelerate the car just as fast. By the same token 1200 ft-lbs (your truck example) at 2625RPMS is the same as 600ft-lbs at 5250RPMs or 300 ft-lbs at 10500rpms and will accelerate the truck just as fast in all 3 cases regardless of RPMS. So say you have your big evil-deisel engine making 1200 ft-lbs at 2625rpms and you have your wankel making 300 ft-lbs at 10500RPMS ... assuming the two engines weigh the same you can put them in the same car and will have the exact same amount of acceleration out of them ...

So as long as your HP isn't dropping (which means your torque is falling off faster than your RPMS are rising) ... then you should keep on pushing it until you either reach the limits of your valvetrain or your HP curve does fall off ... and that's where you set your redline.

yes, but the amount of hp needed at 10k rpm for 175ft lbs to do the same is exponentially greater, say a nextel cup motor 700hp/350ft lbs at 9krpm, in an optimized combo this only runsmid high 11 seconds in the 1/4 mile, however, big block chevy in the same chassis (optimized for the motor again) with 600hp and 500 ft lbs at 5800rpm runs teh same distance in low 10 seconds.

i always set redline at the point where the recovery from an upshift will put you at the broadest area of the torque curve,

[TunedPort 335]

You guys should pick up the Jan 2004 of Hot Rod magazine. It has a whole article on "HP vs. Torque" Maybe it will end alot of the BS arguements going on in here :thumbsup: