What is horsepower?

[Godlaus]

horsepower doesnt move nething
torque is the force that drives the wheels which move the car, i can output any amount of torque at the wheels from any given engine using gear ratios, this is what determines acceleration, what speed im going at will depend on the horsepower of the engine true

And of course, as torque rises due to gearing, the revs go down, making the horsepower output stay the same. I believe what I said was that a high HP stat will always matter more than a high torque stat, including at the wheels. That is unarguable.

no single stat can determine top speed, or acceleration, you need ALL OF THEm, torque, horsepower, drag, tranny ratios

Yes, but you take 2 cars, both equivilant in every aspect, except that one has 150 hp and 1200 ft-lbs, and the other 650 hp, and 300ft-lbs, the latter will accelerate faster.

[KnifeEdge_2K1]

And of course, as torque rises due to gearing, the revs go down, making the horsepower output stay the same. I believe what I said was that a high HP stat will always matter more than a high torque stat, including at the wheels. That is unarguable.



Yes, but you take 2 cars, both equivilant in every aspect, except that one has 150 hp and 1200 ft-lbs, and the other 650 hp, and 300ft-lbs, the latter will accelerate faster.

yeah, so a 200 hp car geared taller then a 200hp car geared shorter will move like a snail while the 200 hp car geared shorter will take off like it sat on a wasp, pretty big diff aint it

[KnifeEdge_2K1]

150 hp and 1200 ftlbs will accelerate much higher then the 300 hp one assuming same drag coefficients size ,the stats being at same rpm, everything else equal

the 300 hp one will have a top speed about 1.4 times of the 150hp one

[KnifeEdge_2K1]

if i gave you the stat 200 hp at the wheels without the rpm its at u dont know how fast its accelerating, if i give u torque at the wheels you can figure out exactly how fast it's accelerating regardless of rpm, thats why torque is more importnat then horsepower, the shape of torque rpm graph (and area under it) will be more important then horsepower vs rpm and the area under it since the torque vs rpm graph can be used to plot displacement given original speed

[scottie300z]

horsepower doesnt move nething


why does an f1 car with over 900 hp hit speeds of only 180 mph while a maclaren f1 with like 600 hp can hit 240 mph??

no single stat can determine top speed, or acceleration, you need ALL OF THEm, torque, horsepower, drag, tranny ratios

If you had two cars same tq same gearing everything but one had more hp would they be just as quick as eachother? No, so i wouldnt say Horsepower does move stuff, or else why did you add it at the end as something you need to determine speed and acceleration.
As for the f1 car, they do go faster then 180 and they really arent geared for top speed. Has anyone topped out an f1 car?

[KnifeEdge_2K1]

Horsepower does move stuff, or else why did you add it at the end as something you need to determine speed and acceleration.

As for the f1 car, they do go faster then 180 and they really arent geared for top speed. Has anyone topped out an f1 car?

it doesnt determine it, it's a factor

[scottie300z]

i didnt say it determined it, i just dont agree w/ the opinion that it doesnt move stuff, if its a factor then yes it does help move stuff

[Rockefella]

Has anyone topped out an f1 car?

Yes, in my backyard.

[scottie300z]

Yes, in my backyard.

ha, ferrari built your lawnmower huh?

[gpatmac]

This may not be in the direction of the thread, but when putting an engine together and tuning it, how does one go about achieving a particular output?

If I built a car (let's just say RWD and same dyno/temp/baro pressure...) that was 450hp/390tq how would it feel or perform vs. the same car pushing 390hp/450tq vs. 420hp/420tq?

Now, I imagine that it would also be important to define what those numbers really mean with regards to @ rpm. Well, I would define it if I knew but my guess would be that they are where the output peaks.

So if that is true, is it worthwhile in saying that I'd need to define what type of output I'm looking for, ie. if I want to road race then I'd be shooting for area under the curve whereas if I were a drag racer, I'd be looking for the MOST power I could get and since I knew that I would generally be near the redline, I wouldn't care that my low rpm power output was relatively low.

Let's say I want a road racing setup and I've got a target output in mind. Knowing the relativity between hp and tq with regards to the magic 5200rpm, what are some things that I'd want to focus on if I wanted X hp at Y rpm and X1 tq at Y1 rpm with as wide and flat of a curve as possible?

My initial ideas would be in a enlarging and smoothing my entire exhaust tract, to include head/cam/valve work, header and wide, straight pipes. I'm thinking shorter duration cams with high lift, larger ports and valves, port-matched header with smooth, mandrel bends, and a straight, 3"-3 1/4" exhaust pipes.

[Rockefella]

ha, ferrari built your lawnmower huh?

No, Fernando Alonso let me borrow his F1 car, we're good friends. I took it up to 210 mph but then he punched me and said, that wasn't funny. So then I shot him.

[Nerys]

Hm, what is horsepower? I know cocksure that you can't have enough of it.
But I think the fine-tuning is very important, for example Alpine V6 Turbo has not really the most horsepower but the weight and the aerodynamic drag compensates that.

I guess the primary meaning of horsepower can't be applied today.

[clutch-monkey]

I guess the primary meaning of horsepower can't be applied today.

thats why we use kilowatts

[Nerys]

thats why we use kilowatts

It should be like this, but if you tell somebody how much kw your car has, he asks you "And how many hp (here: PS)??"

[targa]

torque is like god
horsepower is like jesus

which is better?

[questions religion]