Recent Content by ptraufler

Yes this is an average HP, we have no other information to make any other calculations on. This is a simple only good for comparing one run to another NOT engine tuning. The dyno's I have seen had a large steel "drum" that the wheels rolled on and the machine knew the rotating mass of the...

I still would think the dyno would be the most repeatable measurement. The only thing would be the poeple running the test and any changes to the machine due to wear/use. The local conditions for the atmosphere will change what the engine produces but I do not see the dyno being affected by...

Man I never knew so many people would be so interested in this! Math was never so popular! I guess if you tie in some diesel trucks into math things will be better. :)

The avg speed is used as we know the conditions at the start and end only, we have no other data to use! Given all the assumptions and data this is as close as we can get. The gTech thing will do more as it does something like this calculation over very small time samples and then adds them up...

Yes we did not talk about rolling resistance, static friction, aerodynamic drag, gravity, solar/lunar affects, and other less know issues! OK the physics class is dismissed for the day! Just drive the truck and enjoy it! (BTW a dyno is only a know mass accelerated by the vehicle over a time...

Here is the trouble, the wheel slip is important as at the start it is the big power waster, as the speed increases drag takes over and saps power. The formulas do not account for this at all. I guess you COULD do a "decceleration" test, going from a steady 60 MPH to say 50 MPH with NO brakes or...

If we looked at time errors: Assumes 7500lbs weight Sec to 60 MPH, HP 6. 0 272 6. 1 268 6. 2 264 6. 3 259 6. 4 255 6. 5 251 6. 6 248 6. 7 244 6. 8 240 6. 9 237 7. 0 233 7. 1 230 7. 2 227 7. 3 224 7. 4 221 7. 5 218 7. 6 215...

Opps I did make a math error, pushed buttons on the calculator and did not look at it! 233 HP is what I came up with now. This is at the wheels more or less. No drag or wheel slip or measurement errors. It would be a good guess that at least 20% loss for the drive line would be in order so maybe...

Yes! I figure the weight and the times are not spot on, also if the speed is based on the speedometer and watching it you will be off for sure. I would say use a GPS to get the speed and log the data so you could get a better time. If the wheels slip a bit the speed would read higher than...

The math is not flawed it is correct, the trouble is you have to account for drag, rolling and wind and several other things to get the correct values. It is ONLY as good as the data input! If F = MA is not right then we are in a world of trouble! Mr. Newton you were wrong?:confused:

Given: W = 7500 lbs 0 to 60 MPH = 7 Sec ? Hp We also know this: Gravatational constant (g) = 32. 2 ft/s/s OR we will use 21. 95 mph/s (32. 2 ft/s/s) * (1 Mile/5280 ft) * (3600 Sec/1 Hour) = 21. 95 mph/s One HP = 550 ft-lb/s OR we will use 375 lb-mph (550 ft-lb/s * (1 Mile/5280...

I little math here first, (Force)(Distance)/Time = Power Horsepower = 550(ft)(lb)/s The crankshaft converts the linear form of power to a rotational form of power. (Torque)(RPM)=Power Horsepower = (Torque)(RPM)/5252 Force = M*A (Mass times acceleration) Here is the...