1. Trap speed is a good indicator of a car's acceleration over the course of a longer distance.
2. Power to weight ratio plays more of a role from a dig then from a roll. Gearing, power band, and aerodynamics are more of a factor then a power to weight ratio.
3. Your buddy can't drive. A 335 traps higher in the 1/4 then a GTI, makes more power, has a faster time to any speed from any starting speed and has a better power to weight ratio. Even if your power to weight ratio argument was valid, it's invalidated by your own example.
I don't know what else to tell you. A member on here (TSiUG) runs 12.38@112mph, I ran a 12.32@115. Almost identical times, but a 3mph difference in trap speed. If we were to go from a roll, who do you think would win?
1: Valid as it is natural physics, of course you can gauge a vehicle's acceleration rate from a quarter-mile trap, but I don't think this is accurate over a one mile course or even longer. P/W ratio and other variables stated in your second point prove this true.
2: Power to weight ratio plays the most crucial role regardless of the circumstances of a race. It's one of the benchmark comparison measurement, as is quarter mile testing. I'd think gearing has much more of an effect on 1/4 mile runs than a highway race as in the video. Power-curve and aerodynamics definitely have a significant impact here, definitely not saying you are wrong with that statement.
3: Actually, my buddy can drive, we've ran multiple times and it's always an extremely close race. Roll racing is so much more simplified than a proper launch/dig race. My argument is this exactly; the 335i traps higher and runs faster numbers from the factory than a stage 1 GTI, yet when compared in a roll race it's very neutral and comes down to shift timing, take-off speed, etc...
I'm definitely not saying your statements are invalid, but, I think you have to look at the grand scheme of things and keep an open mind.
In simplest terms trap speed=horsepower.
More horsepower = pulling away at speed.
Anybody that thinks there car is so much faster from a roll than x car try this:
Let the other car have the move.
Just let them go first, then you hit it.
I assure you, you will be in for a rude awakening.
As far as the trap speed fluctuating from traction, that is correct large amounts of wheel spin creates artificially high mph. All that would really mean is that the car doing that is even slower from a roll in an actual race.
Watch the videos a few more times. My opinion is that what you see in the first few runs is the gti driver reacting quicker to the honks with the throttle. Towards the end the zl1 driver has caught on and you don't see as much disparity. Either way I still contend both cars trap in the 115mph range in the quarter.
I understand trap speed directly correlates to horsepower as well as P/W ratio :w00t:. We've run from where each takes the hit and it's exactly as you say, whomever takes the hit wins the run essentially.
Theoretical P/W Ratios
Stock 335i: 0.0862214708 (306 CrankHp, 3549lbs.)
Stage 1 GTI: 0.0886618326 (269 CrankHp, 3034lbs.)
Couldn't the video just indicate that the GTI is experience cooling and power efficiency issues?
