are dynos? I know they are just a tuning tool. I ask because if you do hp, weight & quarter mile times there is a HUGE difference.
How Accurate...
- Thread starter TNRGreene
- Start date
There is no magic, so it in fact does take "X" amount of power to accelerate "X" amount of mass.
A dragstrip calculator should match your dyno sheets after allowing for a reasonable percentage of drivetrain loss.
Our heavy Allisons, 4x4 transfer case, and big 11.50 axles suck down almost 25% of the power before it gets to the tires.
The highest reading dynos are Load Cells that use STD correction.
The lowest reading dynos are Inertial dynos that use no correction at high altitude/temp.
I get 50rwhp difference in Casper between a load cell and inertial, with no other changes. See, you can go inertial on a Superflow, or load the truck, your choice, and I've done it both ways.
Problem is, the boost curve don't match my track/street testing, which affects the tuning alot.
A dragstrip calculator should match your dyno sheets after allowing for a reasonable percentage of drivetrain loss.
Our heavy Allisons, 4x4 transfer case, and big 11.50 axles suck down almost 25% of the power before it gets to the tires.
The highest reading dynos are Load Cells that use STD correction.
The lowest reading dynos are Inertial dynos that use no correction at high altitude/temp.
I get 50rwhp difference in Casper between a load cell and inertial, with no other changes. See, you can go inertial on a Superflow, or load the truck, your choice, and I've done it both ways.
Problem is, the boost curve don't match my track/street testing, which affects the tuning alot.
We dyno'd Casper on fuel on PPE's Mustang (load cell) dyno right before going to Texas for the finals.
It said 758rwhp.
At Houston Racepark, they have a scale at the strip. It said 6280 for Casper on the return road. The timeslip said 10.83 @ 126 with the exact same setup as the PPE dyno.
If you do the math, you will see it's probably a bit pessimistic. Especially since dyno loss is not truly a straight percent. It might be 25% at 250rwhp, but it is not 25% at 500rwhp, probably about 20% instead from experience.
It said 758rwhp.
At Houston Racepark, they have a scale at the strip. It said 6280 for Casper on the return road. The timeslip said 10.83 @ 126 with the exact same setup as the PPE dyno.
If you do the math, you will see it's probably a bit pessimistic. Especially since dyno loss is not truly a straight percent. It might be 25% at 250rwhp, but it is not 25% at 500rwhp, probably about 20% instead from experience.