Which Calc Is More Accurate?
#1
09-09-2008, 02:15 PM
Which Calc Is More Accurate?
Ok so I was using the Hp calculator on the site and The trap speed and 1/4 time both gave me very different answers.
Here is my truck: 2002 QC LB HO 6 speed 2500 W/ 4.10 gears. It weighs aprox. 7300 lbs. My mods when I raced it: Edge EZ, AFE stage 1 intake, Afe 4" exhaust, Edge Jammer stage 3 and 285/75 tires.
My 1/4 time and trap speeds were : 16.167 and 88.38 MPH. This was in Kearny Nebraska and it was about 100 degrees out.
So the 1/4 time calc gave me 287 HP at the wheels and the trap speed calc gave me 341 Hp at the wheels. Naturally I would like to believe the trap speed is more accurate.
Also I might note that this pass is the second pass I have made down a drag strip ever! I'm hoping the slow time is due to my inexperience. Time was done by using 3rd gear and 4wd. TIA
Here is my truck: 2002 QC LB HO 6 speed 2500 W/ 4.10 gears. It weighs aprox. 7300 lbs. My mods when I raced it: Edge EZ, AFE stage 1 intake, Afe 4" exhaust, Edge Jammer stage 3 and 285/75 tires.
My 1/4 time and trap speeds were : 16.167 and 88.38 MPH. This was in Kearny Nebraska and it was about 100 degrees out.
So the 1/4 time calc gave me 287 HP at the wheels and the trap speed calc gave me 341 Hp at the wheels. Naturally I would like to believe the trap speed is more accurate.
Also I might note that this pass is the second pass I have made down a drag strip ever! I'm hoping the slow time is due to my inexperience. Time was done by using 3rd gear and 4wd. TIA
#2
09-09-2008, 02:38 PM
Keep in mind that these calculators are to give you a basic idea based upon known variables. Your friction factors will always change depending on track conditions and the driver so the numbers will be off. After looking at your numbers I'm willing to bet the trap speed time is too high.
Here's an example: Back in '99 I had a Corvette that would consistently turn a 12 - 12.15. My trap speeds would normally be between 117-120. With those numbers calculated I'm showing 50 more hp on the top end. What was actually happening is that I would spin off the line and and get a semi-slow start but by the 60ft mark the car would be hooked up and I could drive it wide open. My actual hp numbers in that case will be closer to the numbers calculated on the trap speed. With a slow heavy diesel truck your numbers are going to be more consistent with the ET calculations.
Here's an example: Back in '99 I had a Corvette that would consistently turn a 12 - 12.15. My trap speeds would normally be between 117-120. With those numbers calculated I'm showing 50 more hp on the top end. What was actually happening is that I would spin off the line and and get a semi-slow start but by the 60ft mark the car would be hooked up and I could drive it wide open. My actual hp numbers in that case will be closer to the numbers calculated on the trap speed. With a slow heavy diesel truck your numbers are going to be more consistent with the ET calculations.
