Would you rather have hp or torque?

f you had engines with the same cubic inch, same bore and stroke but one made more hp but less torque which one one be faster?

Ex:

598 ci, 4.6 bore X 4.5 stroke

Engine A: 1130 peak hp, 870 torque peak
Engine B: 1100 peak hp, 920 torque peak

30 hp more on A, but also 50 ft/bs less torque.

To keep it simple, lets say the hp and torque curves stayed pretty much the same at 30 hp and 50 ft/lb apart all the way from 5000 to 7500 rpm. (I figure this is the usable rpm range of most bracket/index cars)

Which one would ET quicker in an the same car?
Which one would have more mph?

Would it matter if the car was a:
1900 lb dragster
or
2900 lb door car

What rpm would these engines produce peak tq and hp?

David Cole wrote:f you had engines with the same cubic inch, same bore and stroke but one made more hp but less torque which one one be faster?

Ex:

598 ci, 4.6 bore X 4.5 stroke

Engine A: 1130 peak hp, 870 torque peak
Engine B: 1100 peak hp, 920 torque peak

30 hp more on A, but also 50 ft/bs less torque.

To keep it simple, lets say the hp and torque curves stayed pretty much the same at 30 hp and 50 ft/lb apart all the way from 5000 to 7500 rpm. (I figure this is the usable rpm range of most bracket/index cars)

Which one would ET quicker in an the same car?
Which one would have more mph?

Would it matter if the car was a:
1900 lb dragster
or
2900 lb door car

I guess we should all assume that drag racing is the "be all, end all", right...?
There really are other usages on this planet for the internal combustion engine.

In drag racing it will mostly depend upon power to weight and how many gears are in your transmission.

Depends in the use, the car it's in, balance of the combo, the tracks you want to run etc.

If its a heavy car get it out of the hole fast with tq. if its a light car it won't need as much tq to get it moving. Gearing will play a big roll in it also not just the rear gear but the tranny gear also changes a lot when it comes to combos this close.

If you're willing to go through a pile of converters and a few different gear ratios,trans and rear end, you can probably end up with the same results. It's been my experience that torque becomes hard to "apply" when you get an extra large dose. like everyone has said it would be application specific.

cool40 wrote:If you're willing to go through a pile of converters and a few different gear ratios,trans and rear end, you can probably end up with the same results. It's been my experience that torque becomes hard to "apply" when you get an extra large dose. like everyone has said it would be application specific.

I'd want find out the 920 tq deal Is quiting so early.

x

I'd rather have the higher Hp. In my opinion you only need so much torque to get the car moving and as mentioned too much torque will cause you headaches applying traction.

Back when I was racing my 5,000lb 1979 F150 it had a butt load of torque and would leave the line like a pro-mod. After the first 15 feet all the action was over, even though it had 400hp it wouldn't pull hard down the track. Where I believe if I could swap a 1/4 of my torque for 1/8 more of HP it would have ran much faster times. Therefore on this new engine I want to concentrate on hp as I feel it's more useable.

Please feel free to correct me if I'm wrong, this is just my thoughts on the subject.

Just my 2 cents...

Higher hp basically boils down to carrying tq higher in the rpm range, so, the higher hp unit can utilize a higher numerical gear set to achieve the same mph.  The only difference is, the higher hp rig w/ higher numerical gear set has more mechanical advantage over the track and puts more power to the ground.  This = faster!

It is my understanding, that Horsepower is a number assigned to the relationship of Torque and Speed, of a engine, measured on a Dyno. How it is calculated, and how to explain it is not something I would not even attempt to do. It seems like a which came first, the chicken or the egg type deal, of a discussion.
I ran a sim on the Wallace ET calulator at 3000lbs 3.5 gear 2speed trans. Example A. came to 8.07ET/166MPH Example B. 8.14ET/165MPH. This program, of course does not allow for a Torque input value. What I found interesting was the 60 Ft times. A. 1.12 seconds B. 1.13 seconds. So to answer your question, if I was going to bet money on the race, I would go with example A. Would not bet much money though, as it is very close to a tie race.

supervel45 wrote:It is my understanding, that Horsepower is a number assigned to the relationship of Torque and Speed, of a engine, measured on a Dyno. How it is calculated, and how to explain it is not something I would not even attempt to do. It seems like a which came first, the chicken or the egg type deal, of a discussion.
I ran a sim on the Wallace ET calulator at 3000lbs 3.5 gear 2speed trans. Example A. came to 8.07ET/166MPH Example B. 8.14ET/165MPH. This program, of course does not allow for a Torque input value. What I found interesting was the 60 Ft times. A. 1.12 seconds B. 1.13 seconds. So to answer your question, if I was going to bet money on the race, I would go with example A. Would not bet much money though, as it is very close to a tie race.

This is the exact same thing I have found so far during my life time and basically what I was trying to explain. I think of HP as an Acceleration rate; you can have a crap load of torque but if it takes 12min to rpm out then it does you no good. Yet you could probably move a train up to speed in that 12min and never notice the load.

It is finding the right amount of torque for the mass you have to put in motion and Hp determines how fast it will accelerate the mass. I believe there is a magic torque number required for a given mass and any torque above what is needed to move that mass is wasted energy that could go toward increasing you acceleration rate.

Then comes transmissions and gear ratios. If you don't have enough torque to move that mass you can use torque multiplication in the transmission or gear ratio to bandaid the problem. Example would be a light car running power glide, they normally don't need as much bandaid to find the best combination. There is enough torque coming out of the engine to move the mass through two gears (less bandaid) instead of a 3-5 speed transmission. Because you want to get to 1:1 as quick as posable to let that acceleration rate pull you down the track..


Once again this is just how I view things, I'm not saying I'm right.

On the 1900lb car, same gear, trans, tire, used above where A. 6.93ET/193MPH 60ft .96sec.  B. 6.99ET/192MPH 60ft. .97sec.  It is too bad they don't carry out the 60 foot times, and the MPH out another descemal point, so we could see just how close they are. I want to know what would the times be, if you change the torque on example B. to 900ft/lbs, if Nasa could calculate it? It would seem that it should equate to dead even then? I don't know if it could be done, or Wallace, and all the other programs would probably have a SIM with a torque input available, and nobody would be asking this question so often? I am not trying to be a smartass, as I have  thought about the same question myself, and have never seen a concrete answer, backed by mathmatical formula's for ET's and MPH's.

supervel45 wrote:On the 1900lb car, same gear, trans, tire, used above where A. 6.93ET/193MPH 60ft .96sec.  B. 6.99ET/192MPH 60ft. .97sec.  It is too bad they don't carry out the 60 foot times, and the MPH out another descemal point, so we could see just how close they are. I want to know what would the times be, if you change the torque on example B. to 900ft/lbs, if Nasa could calculate it? It would seem that it should equate to dead even them? I don't know if it could be done, or Wallace, and all the other programs would probably have a SIM with a torque input available, and nobody would be asking this question so often? I am not trying to be a smartass, as I have  thought about the same question myself, and have never seen a concrete answer, backed by mathmatical formula's for ET's and MPH's.

I have done these types of calculation before, it's basically Trig and use to have a spread sheet that I used to calculate electric motors on conveyors and elevators. You tell it how much it weighs, coefficient of frictions (drivetrain, tires, atmosphere) specify your desired rpm for a given mass and like magic it pops out numbers.

Do You Have Both Engines, are or you trying to pick a combo for a build? Lem had a good point about the torque droping off on the high HP engine.

Torque is MEASURED on a dyno...Horsepower is merely a CALCULATION. The formula is as follows: HP=TQ x RPM divided by 5252....which means that on ALL engines, the HP and TQ numbers are identical at 5252 rpm and that we CANNOT produce one without the other. I think of horsepower as a way to measure how quickly torque is regenerated as it's "used up".

THAT BEING SAID.....This becomes a question of keeping both engines in their "sweet spots" in the rpm range, all the way down the track from starting line to the traps. Assuming both engines have the right combinations of converter, gearing, tire size, traction efficiency, etc., I'd pick the higher hp number in a lightweight car...and I'd choose the torque number in a porker. Finding those two perfect combinations is a question of how much time and money you're willing to spend to get an answer to your question.

My suggestion is to run 'em both in your car and pick the one that's happiest in your combo...to avoid spending thousands on a few thousandths of e.t.

Short answer: I'd sure hate to live off the difference.

maverick wrote:Torque is MEASURED on a dyno...Horsepower is merely a CALCULATION.  The formula is as follows:  HP=TQ x  RPM divided by 5252....which means that on ALL engines, the HP and TQ numbers are identical at 5252 rpm and that we CANNOT produce one without the other.  I think of horsepower as a way to measure how quickly torque is regenerated as it's "used up".

THAT BEING SAID.....This becomes a question of keeping both engines in their "sweet spots" in the rpm range, all the way down the track from starting line to the traps. Assuming both engines have the right combinations of converter, gearing, tire size, traction efficiency, etc., I'd pick the higher hp number in a lightweight car...and I'd choose the torque number in a porker.  Finding those two perfect combinations is a question of how much time and money you're willing to spend to get an answer to your question.

My suggestion is to run 'em both in your car and pick the one that's happiest in your combo...to avoid spending thousands on a few thousandths of e.t.

Short answer:  I'd sure hate to live off the difference.

^^^^^^^ this

My last big diesel had 400hp and 1200 ft/lbs of torque. It wasn't very fast.

Curt wrote:My last big diesel had 400hp and 1200 ft/lbs of torque. It wasn't very fast.

Seems it quit early.

Lem Evans wrote:

Curt wrote:My last big diesel had 400hp and 1200 ft/lbs of torque. It wasn't very fast.

Seems it quit early.

But she had a lot of stroke for the bore......

Practically extinct other than in legend and lore.....

Lem Evans wrote:What rpm would these engines produce peak tq and hp?

920 tq x 5,500 rpm / 5252 = 963 hp
870 tq x 6,000 rpm /5252 = 994 hp

It really does matter where the peak values are.

I'll take the engine that has the better performance from 6,000 to 7,000 rpm.

Torque is just a force. HP represents actual work done. If you can keep the RPM at the point of max HP and put it to the ground it will be fastest.