HP vs Torque Discussion (No Jokes, No bantering. Just facts and reality)
02-13-2009, 09:45 PM
#271
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02-13-2009, 09:58 PM
#273
Burning Brakes
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02-13-2009, 09:58 PM
#274
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Mark has to be involved getting it there, A Whyne. It's can't just be tweedle dumb and tweedle dumber. 
02-13-2009, 10:02 PM
#275
Burning Brakes
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Mark-
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
02-13-2009, 10:05 PM
#276
Rennlist Member
Mark-
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
DUDE..........clicky here
02-13-2009, 10:42 PM
#277
Rennlist Member
Thread Starter
Glad you asked. One of my favorite comparisons. Ever see the porsche turbo vs F16 jet? ever wonder why the race ends up the way it does?
They barely tie at about 1/4 mile, and the jet continues to accelerate as it goes sceaming by, taking flight about 150mph. The jet starts with very little hp and with a constant force (call it constant like a rocket) acceleration is constant. HP goes up with velocity, as noted in the formula:
power= Force x velocity. so , a jet starts out with very little HP and ends up with somewhere over 50,000hp by the time it is at speed. Interestingly, the "HP-seconds of both, adjusted for weight, are equal at 1/4mile.
Again, acceleration= power/(mass x velocity) this is true, even with jets , but since you are dealing with lbs of thrust, its easy to just use that to figure out and compare acceleration vs the 1600ft-lbs of torque or force at the rear wheels on the car after multiplication of the gear box, determined by the HP level at any speed. Its constantly changing lower with speed, even if the HP was constant. The jet, the opposite is true. acceleration is constant, because force is near constant, and HP is going up with speed. 50,000lbs of thrust at 150mph speed is a huge HP number! HUGE!
So, to answer your question directly. The toruqe at the rear wheels is thrust force, just like the jet. With 24" wheels, its going to equal ft-ls of torque (radius 12" or 1 foot) (thats a hint for the previous 928 vs M3 comparison by the way
mk
PS You said, "it's all in the TQ" line of thinking? Did you mean HP way of thinking? anyway, you can look at the hp curve to see what every 1lb of thrust will buy you in terms of HP. but, you better have your gear ratios handy
again, each lb of thrust is like a ft-lb of torque. (e.g. If you are going 5250rpm in 3rd gear at 5:1, each lb of thrust would be worth 5HP.)
Did that answer your question. I like the turojet roof mount idea . For the rain too!
They barely tie at about 1/4 mile, and the jet continues to accelerate as it goes sceaming by, taking flight about 150mph. The jet starts with very little hp and with a constant force (call it constant like a rocket) acceleration is constant. HP goes up with velocity, as noted in the formula:
power= Force x velocity. so , a jet starts out with very little HP and ends up with somewhere over 50,000hp by the time it is at speed. Interestingly, the "HP-seconds of both, adjusted for weight, are equal at 1/4mile.
Again, acceleration= power/(mass x velocity) this is true, even with jets , but since you are dealing with lbs of thrust, its easy to just use that to figure out and compare acceleration vs the 1600ft-lbs of torque or force at the rear wheels on the car after multiplication of the gear box, determined by the HP level at any speed. Its constantly changing lower with speed, even if the HP was constant. The jet, the opposite is true. acceleration is constant, because force is near constant, and HP is going up with speed. 50,000lbs of thrust at 150mph speed is a huge HP number! HUGE!
So, to answer your question directly. The toruqe at the rear wheels is thrust force, just like the jet. With 24" wheels, its going to equal ft-ls of torque (radius 12" or 1 foot) (thats a hint for the previous 928 vs M3 comparison by the way
mk
PS You said, "it's all in the TQ" line of thinking? Did you mean HP way of thinking? anyway, you can look at the hp curve to see what every 1lb of thrust will buy you in terms of HP. but, you better have your gear ratios handy
again, each lb of thrust is like a ft-lb of torque. (e.g. If you are going 5250rpm in 3rd gear at 5:1, each lb of thrust would be worth 5HP.)Did that answer your question. I like the turojet roof mount idea . For the rain too!
Mark-
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
Question for you.
I've had a bit of a problem with my new race car, in that every track day I've been to in the last year, it's PISSED down rain. So much so that it's a running joke with my local friends.
They've offered to put together a bit of a "mod" for my car, in order to assist with the wet-track conditions.
The problem I have is that it totally messes with my power-to-weight ratios, and I'm having a hard time figuring it out.
So, question for you...
What do you suppose the HP/TQ graphs would look like for the proposed setup, as depicted in the super-secret testing photos taken at PIR a few months ago?
Lots of HP there, but I'm thinking not so much TQ. But then there's tons of thrust... so would thrust == torque in this application?
Does that lend credence to your "it's all in the TQ" line of thinking?
Just curious as to your thoughts on the subject.
...jeff
02-13-2009, 10:55 PM
#278
Burning Brakes
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Yeah, but F-16's are old and slow, just like the 928... what if JATO rockets were used instead? Or RAM jets? In the case of the latter, acceleration is NOT constant. Better yet, if you used both, it'd be like a 2-stage turbo setup... where you get the best of both worlds. Immediate and absolute thrust from a solid fuel rocket, and then the ever-increasing thrust from a RAM jet.
And what if it was done in a lower gravity field?
Just throwing some hypotheticals out there.
And what if it was done in a lower gravity field?
Just throwing some hypotheticals out there.
