06-01-2016, 11:03 AM | #1 |
Founder of Cocoa Studios™
|
Easily Determine Torque and Horsepower (w/out dynamometer)
Over the past couple of weeks, I have been working on a physics project to find the horsepower and torque of my car without the use of a dynamometer. Attached is my work and a link to my research. I encourage anybody to take a look who may be interested in finding the torque or horspower of their car in different sections of their drivetrain, or anybody who is just interested in the physics behind it. http://bit.ly/1WwQ9AM.
I would like to start off by saying there are MANY variables that go into a calculation like this such as torque lost to friction, RPM range, gear the driver is in, rear diff. ratio, etc. After researching different concepts, I discovered that someone can find the torque of their car at the rear wheels simply by using the equation (values in metric units), linear acceleration found by filming speedometer in slow motion and using A=V/T: Torque = Mass (of car) x Linear Acceleration (of car) x Radius (center hub to ground)The above equation is derived from a basic equation for finding torque: Torque = Force (perpendicular to pivot) x Distance (from pivot)By substituting force with F=MA, there is no need to directly calculate turning force. After using the above equation and converting the torque from metric units (Nm) to imperial units (ft lbs), and then figuring out the ratio of the gears the torque is emitted through, someone can also find the theoretical horsepower of their engine (actual value of engine will be more because of drivetrain loss ~%15), using the equation: Horsepower = (Torque x RPM) / 5252Thanks for reading and leave a comment if you have anything to add, this thread will be a work in progress as I simplify the calculations and make it easier to find the acceleration of a car. Also attached are a couple pictures of the setup I used to determine the acceleration for later analysis with LoggerPro. Last edited by Dooder; 06-01-2016 at 02:16 PM. |
06-01-2016, 11:45 AM | #2 |
Drives: '23 LT1 A10 Join Date: Oct 2015
Location: Austin Texas
Posts: 1,006
|
Wow, this is very interesting.
|
06-01-2016, 11:58 AM | #3 |
Long reading but interesting indeed. Will provide my feedback once I am done ))
|
|
06-01-2016, 12:13 PM | #4 |
El Duderino
|
To be safe, I would recommend wearing a helmet with a face-guard at the minimum. Even a small fender bender might find you with an iPhone embedded in your forehead.
__________________
I bowl. Drive around. The occasional acid flashback.
|
06-01-2016, 12:14 PM | #5 |
Ok..QQ: what was your top numbers for TORQUE and POWER (at redline) ?
Do you think you can do the same computation by doing data log (SCT or Diablo Sport or any similar) devices? Thanks |
|
06-01-2016, 12:21 PM | #6 |
|
|
06-01-2016, 12:22 PM | #7 |
Drives: 2014 2SS RS LS3 Join Date: Oct 2012
Location: Oshawa, Ontario. Home of the Camaro
Posts: 810
|
Really cool concept. The only problem you'll find, is that the visual measurement (slow-mo of speedometer) will not be very accurate. the Speedo lags when under quick acceleration, as does the tach.
__________________
Thank our veterans for peace today, Support our troops for peace tomorrow. RIP Dad, 1962-2012 SYOTOS |
06-01-2016, 12:28 PM | #8 |
I think similar concept is being used by some portable devices which are capable to estimate the power & torque. Keep forgetting what dev. is capable to do so.
But I agree, really cool idea! |
|
06-01-2016, 01:02 PM | #9 |
So how did you estimate the 295.19 ft lbs at the crank? Is it MAX torque or it's related with 2500rpm?
If I simply estimate: Horsepower = (295 ft lbs x 6000 RPM) / 5252 I get 337 hp at 6000 RPM which could be truth for the rwhp, but not for the crank hp, so I am a bit confused, I guess I am missing something.. |
|
06-01-2016, 02:14 PM | #10 | |
Drives: 2011 L99 SS Join Date: Oct 2014
Location: Texas
Posts: 500
|
Quote:
|
|
06-01-2016, 02:18 PM | #11 | |
Daily Driver 24/7 365
Drives: '15 CRT 2SS/RS/1LE Join Date: Jul 2015
Location: Cape Cod, MA
Posts: 827
|
Quote:
Also, L99 = 400HP, LS3 = 425HP
__________________
NPP Fuse Pull, Z28 CAI =
Previous Rides: 2005 Magnum R/T A5 CAI, Cat-Back 2014 RRM Camaro 1LT/RS A6/NPP CAI Follow Me On Instagram! |
|
06-01-2016, 02:25 PM | #12 | |
Founder of Cocoa Studios™
|
Quote:
I have not yet tested 4k-5k rpm range which should be max torque and power. I'll make sure to update thread when I do. |
|
06-01-2016, 02:41 PM | #13 | |
Founder of Cocoa Studios™
|
Quote:
Earlier in the thread I had mentioned drivetrain loss which I estimated to be around ~%15. When you estimated hp using "(295 ft lbs x 6000 RPM) / 5252 = 337 hp", you were using the torque produced at 2500 rpm. There would be significantly more torque at 6000 rpm. |
|
06-01-2016, 02:53 PM | #14 | |
Quote:
Thank you! |
||
|
|
Tags |
acceleration, horsepower, physics, torque |
|
|