Horsepower
06-03-2012, 08:02 AM
#26
Senior Member
It takes 314.6 Hp to acceleate a 3200 lb mass from 0 to a velocity of 108 mph in the distance of 1320 feet.
The above numbers were used from this website
Horsepower from 1/4 Mile Time & Speed (ET/MPH) Calculator
The top number would probably make a good Average HP for the entire race. When your raceing your HP output isnt constant, as your RPMs are constantly changeing, if youve ever seen a Dyno printout you know what i'm typeing about.
Its probably safe to take the second number as your maximum or peak Hp for the race, as you launch your RPMs are going to be starting out lower, thus youR HP and Acceleration are slower then it speeds up some and then tapers off.
I THINK I understand that correctly....
As for your torque
Im too zombiefied tired to figure it out so here is a link
RevSearch Engine Dyno; Torque vs Horsepower
06-03-2012, 02:45 PM
#27
no. physics horsepower calculations just don't work in drag racing trying to figure out times. because it doesn't factor in air density, altitude, drag, shifting(car ain't makin power/stop accelerating), tire spin, getting out of the groove or having to steer the car, etc.. just too many factors involved. you can't just plug et and weight into a formula.
it just, doesn't work like that. his car does not have 281, and especially not 314. guaranteed.
it just, doesn't work like that. his car does not have 281, and especially not 314. guaranteed.
06-03-2012, 07:15 PM
#29
physics is easy when you don't have gravity.
you can only estimate with these "horsepower calculators". and i'd say they're anywhere from 25% under to 25% over. and all of them are meant for rwd. OP said he went 13.1@108, my buddy i race with in his cuda goes 13.60s@97. rwd vs fwd. calculations will ALWAYS be off.
you can only estimate with these "horsepower calculators". and i'd say they're anywhere from 25% under to 25% over. and all of them are meant for rwd. OP said he went 13.1@108, my buddy i race with in his cuda goes 13.60s@97. rwd vs fwd. calculations will ALWAYS be off.
06-03-2012, 07:25 PM
#30
Senior Member
But still, you have a known mass, known distance, known time, known starting velocity known finish velocity.
While you may not be able to compute exact horsepower, you should be able to compute
how much HP a car would have to put down to make it in a certin time or speed.
RWD FWD shoudlnt matter, If we eliminate any friction calculations, then the HP requirement would be smaller, since you arnt calculating the horsepower to overcome aerodynamic drag, wich at higher elevations would be less.
While you may not be able to compute exact horsepower, you should be able to compute
how much HP a car would have to put down to make it in a certin time or speed.
RWD FWD shoudlnt matter, If we eliminate any friction calculations, then the HP requirement would be smaller, since you arnt calculating the horsepower to overcome aerodynamic drag, wich at higher elevations would be less.
06-03-2012, 07:42 PM
#33
But still, you have a known mass, known distance, known time, known starting velocity known finish velocity.
While you may not be able to compute exact horsepower, you should be able to compute
how much HP a car would have to put down to make it in a certin time or speed.
RWD FWD shoudlnt matter, If we eliminate any friction calculations, then the HP requirement would be smaller, since you arnt calculating the horsepower to overcome aerodynamic drag, wich at higher elevations would be less.
While you may not be able to compute exact horsepower, you should be able to compute
how much HP a car would have to put down to make it in a certin time or speed.
RWD FWD shoudlnt matter, If we eliminate any friction calculations, then the HP requirement would be smaller, since you arnt calculating the horsepower to overcome aerodynamic drag, wich at higher elevations would be less.
you're just not getting it lol. and idk how else to explain it. other than these formulas and equations you're trying to use here, just don't apply. like i said, you can use them to guesstimate a +/-25% window, but getting anything closer than that just isn't going to happen.
06-04-2012, 12:56 AM
#34
You're never gonna know what your HP is. You can find out what the HP is on a particular dyno on a particular day.... but that same dyno can give you different numbers on a different day. Go to a different dyno and the numbers could be totally different.
Like Soccer said, there are too many variables to calculate HP on the track using distance, weight and time. Maybe you could but you would have to determine what track path you took down the track and then measure the amount of friction/traction. Since it won't be consistent, you're gonna need samples at intervals down the path each tire took. The closer your samples, the more accurate your data will me. You're also going to need to measure air density at the time. You're going to need to know what direction the wind was blowing and how hard at different intervals down the track. Again, the closer these intervals are, the more accurate the data. Then you're going to need to calculate the amount of resistance there was from the wind using the aerodynamics of your car. Since the wind didn't blow directly over the front of your car, you're going to need wind tunnel data at all angles. I'm pretty sure GM did mostly tests with the wind coming from the front. The temperatures along the track may vary. Get some measurements as close as possible (similar to the wind and traction measurements). Which brings up another thought. Since you're going to need numerous measuring instruments, you're going to need to make sure they are all calibrated exactly the same. That's gonna be tough. You could use averages but then that just ***** up the whole thing. Also be sure to calculate how much surface area on your intercooler was blocked or affected by bent fins or bugs and other debris. Near the start of the track where the burnout area is, there are usually some rocks. You're gonna need to know if you picked any of these up and took them with you down the track. Even one small BB-sized rock could affect your traction calculations, especially if you're working with 1"x1" patches (which is the minimum I suggest). The easiest way to do this is to scan the burnout area before and after you go through it. After the run, make note of each missing particle. You're then going to need to locate each partical along the track. Each located particle is going to need to have it's estimated trajectory calculated so that it can be determined exactly where and when it was flung from the tire. Of course, all of the same variables need to be accounted for when calculating how far the rock flew, where it came from, what angle it left the tire, how fast the tire was spinning etc. Wind resistance is really gonna really be a bitch with this one because the rock has different wind resistant characteristics depending on its position. Since the rock is rotating during its flight, there is going to be some serious number crunching going on here. While you're at it, you're probably going to want to analize the staging lane you used before and after you drive through using the same methods used on the burnout/staging area. Get a sample of the water sprayed onto the track and send it to your local university for analysis. PH balance plays a large part in water's lubricating properties. Ideally, you want a less acidic composition. You're going to need to conduct extensive testing on yourself in an effort to get a true grasp on your reaction times. Even then you're still working with averages. The only way to get a true reaction time is to have an atomic clock (receiving the radio frequency from the atomic clock in Ft. Collins, CO). This clock will have to be attached to the optic region of your brain and to the various muscles needed to let off the clutch, push the gas, etc. This clock will also need to be attached to the tree. This way you can know exactly when the light goes off, when your optic nerves are stimulated, how long it takes for your brain to process the image, send the signals to the various muscles required to launch and then the time it takes the muscles to respond. You're going to need to have all wires from each sensor to the time clock the exact same length and made from the exact same material. Even though electricity travels at nearly the speed of light in a vacuum it actually travels 50-96% the speed of light depending on what material it is travelling through and the conductivity of those materials. Then, of course, there are engine components, the amount of oil on each part, the temperature at each location, the viscosity of the oil, etc.
So that takes care of some of the small things. I'm sure others will chime in with more factors that you're going to need to consider.
Like Soccer said, there are too many variables to calculate HP on the track using distance, weight and time. Maybe you could but you would have to determine what track path you took down the track and then measure the amount of friction/traction. Since it won't be consistent, you're gonna need samples at intervals down the path each tire took. The closer your samples, the more accurate your data will me. You're also going to need to measure air density at the time. You're going to need to know what direction the wind was blowing and how hard at different intervals down the track. Again, the closer these intervals are, the more accurate the data. Then you're going to need to calculate the amount of resistance there was from the wind using the aerodynamics of your car. Since the wind didn't blow directly over the front of your car, you're going to need wind tunnel data at all angles. I'm pretty sure GM did mostly tests with the wind coming from the front. The temperatures along the track may vary. Get some measurements as close as possible (similar to the wind and traction measurements). Which brings up another thought. Since you're going to need numerous measuring instruments, you're going to need to make sure they are all calibrated exactly the same. That's gonna be tough. You could use averages but then that just ***** up the whole thing. Also be sure to calculate how much surface area on your intercooler was blocked or affected by bent fins or bugs and other debris. Near the start of the track where the burnout area is, there are usually some rocks. You're gonna need to know if you picked any of these up and took them with you down the track. Even one small BB-sized rock could affect your traction calculations, especially if you're working with 1"x1" patches (which is the minimum I suggest). The easiest way to do this is to scan the burnout area before and after you go through it. After the run, make note of each missing particle. You're then going to need to locate each partical along the track. Each located particle is going to need to have it's estimated trajectory calculated so that it can be determined exactly where and when it was flung from the tire. Of course, all of the same variables need to be accounted for when calculating how far the rock flew, where it came from, what angle it left the tire, how fast the tire was spinning etc. Wind resistance is really gonna really be a bitch with this one because the rock has different wind resistant characteristics depending on its position. Since the rock is rotating during its flight, there is going to be some serious number crunching going on here. While you're at it, you're probably going to want to analize the staging lane you used before and after you drive through using the same methods used on the burnout/staging area. Get a sample of the water sprayed onto the track and send it to your local university for analysis. PH balance plays a large part in water's lubricating properties. Ideally, you want a less acidic composition. You're going to need to conduct extensive testing on yourself in an effort to get a true grasp on your reaction times. Even then you're still working with averages. The only way to get a true reaction time is to have an atomic clock (receiving the radio frequency from the atomic clock in Ft. Collins, CO). This clock will have to be attached to the optic region of your brain and to the various muscles needed to let off the clutch, push the gas, etc. This clock will also need to be attached to the tree. This way you can know exactly when the light goes off, when your optic nerves are stimulated, how long it takes for your brain to process the image, send the signals to the various muscles required to launch and then the time it takes the muscles to respond. You're going to need to have all wires from each sensor to the time clock the exact same length and made from the exact same material. Even though electricity travels at nearly the speed of light in a vacuum it actually travels 50-96% the speed of light depending on what material it is travelling through and the conductivity of those materials. Then, of course, there are engine components, the amount of oil on each part, the temperature at each location, the viscosity of the oil, etc.
So that takes care of some of the small things. I'm sure others will chime in with more factors that you're going to need to consider.
06-05-2012, 12:13 PM
#36
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I tried to read what casionerd wrote, but it kept going blurry....last thing I knew I was waking up on the floor with foam on my mouth and a sore noggin....
(lol)
Dyno your car Mike S and save me from these seizures.........I will pitch in $10 bucks for ya :>
(lol)
Dyno your car Mike S and save me from these seizures.........I will pitch in $10 bucks for ya :>
06-05-2012, 02:17 PM
#43
Senior Member
I still dont get why FWD and RWD matters when calculatiing horse power, or if you have a jet engine in your trunk, or if you have a cable pulling the car from the finish line with a motor. Its going to take a spific amount of power, to move a set weight a set distance at a set time/speed. True you wouldn't be able to calcualte the HP of the engine in the car, but you would be calcualteing more or less an average of the HP that the car put down on the pavement during the coruse of the race.
06-05-2012, 02:23 PM
#44
right like i said, you can use those calculators to get within, what i'd put it at, +/-25%.
fwd/rwd matters because this. rwd car @ 3000lbs vs fwd car @ 3000lbs. both run 13.00. the rwd car is going to have less horsepower, and a lower trap speed than the fwd car. if you just plug in et, trap, and weight into some calculator(99.9% of which are for rwd) you will have results that aren't even close to realistic.
fwd/rwd matters because this. rwd car @ 3000lbs vs fwd car @ 3000lbs. both run 13.00. the rwd car is going to have less horsepower, and a lower trap speed than the fwd car. if you just plug in et, trap, and weight into some calculator(99.9% of which are for rwd) you will have results that aren't even close to realistic.
Last edited by EXsoccer1921; 06-05-2012 at 02:30 PM.
06-05-2012, 02:24 PM
#45
Senior Member
Speekign of Elevation and races....
Is there an elevation in which our cars do the BEST?
I mean a few things to consider, is we are forced induction, that can have the side effect of compensating for higher elevations to a point. (I would say when your boost limiter stops limiting your boost)
But here is what I mean
As you increase in elevation, air pressure goes down, theres less atmoshphere, this effects our cars in TWO ways..
1: Reduced Air to consume for engine power, thus lowering the engines power output
2: Less aerodynamic drag, this decreases the power that it takes to accelerate your car.
Obviously the reverse is also true as you decrease elevation,
1: You get more air for the engine to make more power
2: You get more aerodynamic drag, requireing more power to pull through
The two are probaly not perfectly matched up, so there has to be some point, some pressure
at whitch, if you go any lower in elevation, the drag increases more then the engine can compensate with its increased power. Granted this may be some theroetical mathmatical number that exists only on paper and maybe if you bilt a 1/4 mile long hyperbaric chamber to test it in but still.
06-05-2012, 02:29 PM
#46
Speekign of Elevation and races....
Is there an elevation in which our cars do the BEST?
I mean a few things to consider, is we are forced induction, that can have the side effect of compensating for higher elevations to a point. (I would say when your boost limiter stops limiting your boost)
But here is what I mean
As you increase in elevation, air pressure goes down, theres less atmoshphere, this effects our cars in TWO ways..
1: Reduced Air to consume for engine power, thus lowering the engines power output
2: Less aerodynamic drag, this decreases the power that it takes to accelerate your car.
Obviously the reverse is also true as you decrease elevation,
1: You get more air for the engine to make more power
2: You get more aerodynamic drag, requireing more power to pull through
The two are probaly not perfectly matched up, so there has to be some point, some pressure
at whitch, if you go any lower in elevation, the drag increases more then the engine can compensate with its increased power. Granted this may be some theroetical mathmatical number that exists only on paper and maybe if you bilt a 1/4 mile long hyperbaric chamber to test it in but still.
Is there an elevation in which our cars do the BEST?
I mean a few things to consider, is we are forced induction, that can have the side effect of compensating for higher elevations to a point. (I would say when your boost limiter stops limiting your boost)
But here is what I mean
As you increase in elevation, air pressure goes down, theres less atmoshphere, this effects our cars in TWO ways..
1: Reduced Air to consume for engine power, thus lowering the engines power output
2: Less aerodynamic drag, this decreases the power that it takes to accelerate your car.
Obviously the reverse is also true as you decrease elevation,
1: You get more air for the engine to make more power
2: You get more aerodynamic drag, requireing more power to pull through
The two are probaly not perfectly matched up, so there has to be some point, some pressure
at whitch, if you go any lower in elevation, the drag increases more then the engine can compensate with its increased power. Granted this may be some theroetical mathmatical number that exists only on paper and maybe if you bilt a 1/4 mile long hyperbaric chamber to test it in but still.
yes there is some elevation at which any lower, too much drag. and any higher, not enough power. but finding that height while at the track making a pass and having a car that is 100% consistent with no variables, is not going to happen.and you gotta remember. elevation doesn't effect the sc and turbo cars like it does the n/a cars. cause we're still able to compress the air and make good amounts of boost and only go slightly slower. n/a cars are just sol
06-05-2012, 03:08 PM
#49
another thing about these calculators, is that they're computing your et trap and weight with the assumption that the car was ran as fast as it could possible go. they don't factor in that maybe the car had a bad launch.
so for ***** and giggles i used the calculator you posted early Horsepower from 1/4 Mile Time & Speed (ET/MPH) Calculator
i put in my stock+ebay muffler time of 14.225@100.3 3100lbs. ET Method says 212.9hp. Trap Method says 244.1hp. it doesn't say wheel or crank though. but either way i did 231whp 205wtrq. so like i've been saying, you can get within a window. but you'll never be able to use these for an accurate number.
so for ***** and giggles i used the calculator you posted early Horsepower from 1/4 Mile Time & Speed (ET/MPH) Calculator
i put in my stock+ebay muffler time of 14.225@100.3 3100lbs. ET Method says 212.9hp. Trap Method says 244.1hp. it doesn't say wheel or crank though. but either way i did 231whp 205wtrq. so like i've been saying, you can get within a window. but you'll never be able to use these for an accurate number.