The Truth about HP and TQ (proven w/ physics)
Banned
Joined: Oct 2002
Posts: 6,518
Re: The Truth about HP and TQ (proven w/ physics)
Guys go look up the Advanced Tech thread that OldSStroker and Racer got into this a LONG time ago.... Otherwise you guys are missing out on something that beat a hole heard of horses to death.
In reality it's the TQ at the tires that counts the most.
I like to look at TQ at HP peak per cube (or L) that tells you a lot more about a motor.
Bret
In reality it's the TQ at the tires that counts the most.
I like to look at TQ at HP peak per cube (or L) that tells you a lot more about a motor.
Bret
Thread Starter
Registered User
Joined: Apr 2004
Posts: 1,347
From: Austin/Houston, TX
Re: The Truth about HP and TQ (proven w/ physics)
Im pretty sure its nailed down in my head. If it didnt come across, then maybe I needed to elaborate more. I am a Jr in Aerospace Engineering at the University of Texas, so Ive been around the block when it comes to physics and statics/dynamics and all the calculus.
I realize that it is a dynamic condition where there are multiple variables to determine acceleration (i was ignoring traction, rolling resistance, wind resistance, and moment of inertia of the rolling masses). I beleive that the (HP/Speed) x Constant = Acceleration is an accurate formula and can be even used with HP as an appriximated function of RPM.
I realize that it is a dynamic condition where there are multiple variables to determine acceleration (i was ignoring traction, rolling resistance, wind resistance, and moment of inertia of the rolling masses). I beleive that the (HP/Speed) x Constant = Acceleration is an accurate formula and can be even used with HP as an appriximated function of RPM.
Originally Posted by OldSStroker
Here we go agian. 
It's about time for this again, isn't it? Yes, it's a good topic to discuss. You may get a few (?) differing opinions. disco192, you are on the right track, but that you "fully understand it" might be an very slight exaggeration.
FWIW: Yes, F=ma applies. That's going to be the difficult part to remember as this thread goes where most have gone in the past. The "F" is the (thrust) force applied to the chassis by the drive tires. This is an opposite reaction to the force at the tire/road contact patch, which depends on the axle torque and rolling radius of the drive tires, as well as load and tire fricton coefficient, sometimes referred to as "bite" or simply "traction".
This much is intuitive to many, but not all, folks. However, this is just an instantaneous or "static" look at it. As soon as the vehicle moves, we have a "dynamic" condition, so we need to look at the rate at which the torque is applied. Here is where "power" comes into play, and where this type of thread usually diverges.
My $.02.
Let the games begin...
It's about time for this again, isn't it? Yes, it's a good topic to discuss. You may get a few (?) differing opinions. disco192, you are on the right track, but that you "fully understand it" might be an very slight exaggeration.
FWIW: Yes, F=ma applies. That's going to be the difficult part to remember as this thread goes where most have gone in the past. The "F" is the (thrust) force applied to the chassis by the drive tires. This is an opposite reaction to the force at the tire/road contact patch, which depends on the axle torque and rolling radius of the drive tires, as well as load and tire fricton coefficient, sometimes referred to as "bite" or simply "traction".
This much is intuitive to many, but not all, folks. However, this is just an instantaneous or "static" look at it. As soon as the vehicle moves, we have a "dynamic" condition, so we need to look at the rate at which the torque is applied. Here is where "power" comes into play, and where this type of thread usually diverges.
My $.02.
Let the games begin...
Registered User
Joined: Dec 1969
Posts: 482
From: Mukilteo, WA
Re: The Truth about HP and TQ (proven w/ physics)
Originally Posted by disco192
I beleive that the (HP/Speed) x Constant = Acceleration is an accurate formula and can be even used with HP as an appriximated function of RPM.
Definately check out the thread Bret mentioned.
Registered User
Joined: Dec 2004
Posts: 927
From: Queens, New York City
Re: The Truth about HP and TQ (proven w/ physics)
torque is multiplied through the gear ratios and final drive of all cars
the dyno measures the torque at the wheels which may be around 1250 or so
but the tire is not moving 5000 rpms
so the equation still applies
hp = tq*rpm/5252
u get a huge amount of torque but the same horsepower
the way i see it, the dyno reads the torque at the wheels
then reads the wheels speed to determine horsepower
which then uses engine rpm to find gross engine hp
the dyno measures the torque at the wheels which may be around 1250 or so
but the tire is not moving 5000 rpms
so the equation still applies
hp = tq*rpm/5252
u get a huge amount of torque but the same horsepower
the way i see it, the dyno reads the torque at the wheels
then reads the wheels speed to determine horsepower
which then uses engine rpm to find gross engine hp
Thread
Thread Starter
Forum
Replies
Last Post
PFYC
Supporting Vendor Group Purchases and Sales
0
Aug 17, 2015 09:50 AM
redzed
Automotive News / Industry / Future Vehicle Discussion
20
Nov 5, 2002 06:24 PM