Josh

iTrader: (9)

I must admit, I'm a bit embarassed to not know the answer to this question, but say you're cruising along at 4,000 RPM in second and punch it--is it HP or TQ that throws your back into the seat?

I'm sure both play a role, but which has the greatest effect?

Josh

AggieTA

Torque

shadow

Yepper

DONAIMIAN

iTrader: (18)

I throws you back in your seat, breaks the tires loose, twist the car to the passenger side, and breaks motor mounts in some cases

Lason

iTrader: (1)

Yup tourqe throws you back and horsepower is what keeps you from grabbing that $100 bill on the dash

parish8

iTrader: (6)

i have something to throw into the conversation, not sure how it aplies to the question though.

6000lb truck, 500hp, 1000tq, = 13's(diesel)
5000lb truck, 500hp, 500tq, = 12's

both 4wd so traction is not an issue.

if you just look at the hp the numbers make complete sence, if you look at the tq then there is something way out of wack. seems to me that there is alot of rave about how TQ is what moves you but from what little i have seen it is the hp that gives you the most predictable numbers and the TQ doesn't seem to matter.

like i said, "what little i have seen" so no flaming please. is it just me or is it HP that wins the race?

XLR8NSS

iTrader: (4)

One thing about your example. The diesel has less rpm before redline. Imagine the area under the curve for the diesel as a tall narrow box and the gas motor as a short wide box. They both might end up with the same area under the curve but, the diesel has to make ALOT more torque due to the short rpm range.

HP is not measured directly but, is calculated from torque and rpm. So if you talk about a certain rpm then either hp or torque could be the answer.

This debate will never die.

soundengineer

iTrader: (16)

HP = (Torque x RPM) / 5252

ever notice all Dyno Sheets cross at 5252???

and the answer to your question is torque...
in simple terms...
torque is the measurement of force to move an object...
HP is just how fast the torque moves the object.

and cruising at 4000 rpm???
man..you should shift to a higher gear for cruising....and just downshift to punch it....

Colonel

I promised myself that I wouldn't get into another HP v/s TQ thread this year. So, ya'll have fun!

soundengineer

iTrader: (16)

you dont have to get into it...Hp IS Torque...according to the formula I mentioned above....HP is torque at a given rpm divided by 5252...Its MATH

Smoke_Ford

XLR8NSS said it the best. Horsepower is made up. It cannot be measured, but it is calculated from torque.

If I am not mistaken, the equation is horsepower is (torque*RPM)/5252
Correct me if I am wrong, but I dont think so.

Torque is what makes your quarter mile time faster, and torque is what slams your passanger into the seat.

bryan c

Acceleration is caused by your engine doing work that is ultimately transferred to the pavement via your tires. Like Soundengineer said, torque is a measure of an engines ability to do work. Torque = force (lbs.) x distance (ft.). Power is the rate at which an engine performs work. Power = work (ft. lbs.) divided by time. In the case of horsepower, Smoke Ford is correct, HP = RPM x Torque divided by 5252.

Ackattack1

iTrader: (7)

In the example with the pickkups. I think the discrepency is that those are peak numbers. If you look at the HP and TQ curves over the RPM range in which they are driven, you may see other trends.

HOGGER

Exactly

beat me to it.

Smoke_Ford

Now that that has been solved, do you guys know why cars burn out to the right?

Bearcat Steve

Torque is a force. Power is an amount of work performed over a period of time.

Jordan_J

Well I might not be right but I think it is because they have a drive tire which gets most of the power that the rear differential transfers to the tires. On my brothers truck it was the right tire so it might be that way on every car and truck thus meaning that wheel pulls a little more than the other and so you goto the right.

Smoke_Ford

It is due to the gravitational pull due to us being on the northern hemisphere. Can you believe that?

Fulton 1

iTrader: (9)

Its caused by a phenomenon called angular momentum. To illustrate you can use what they teach you in Physics class as the "right hand rule". Take your right hand and curl your fingers like you're making a fist then stick your thumb straight out. The direction that your thumb points is the direction an object will want to travel if a force is applied around an axis in the direction that your fingers curl. Here's a pic that may help describe:



In the case of a burnout, your tires rotate forward so you would think that the rear should drift to the left, but in fact its the reaction to that forward rotation (Newton's third law - "for every action there is an equal and opposite reaction") that causes the drift to the right. Imagine the traction that you get as the ground pushing back against the tire rotating forward and therefore the thumb in your right hand rule example illustration would point to your right.

The same principle makes a gyroscope stand and a motorcycle want to stay upright at speed. It would also dictate that if you were doing a burnout in reverse that the rear would drift to the left. Never tried that myself though...

bryan c

I thought we learned the right hand rule in dynamics.