I took my challange car to local tue night drags it was 55 out and the best I could manage was a 13.3 at 108 mph where as at the challange I clicked off a 12.8 @ 110. I guss my car likes it warmer then.
Any ideas why? Same tires, fuel level and driver.
Tighten the nut at the steering wheel.
Sea level versus Indiana.
John Brown wrote: Sea level versus Indiana.
YMMV
Indiana has a mean elevation of 700 feet above sea level. Is that enough to make a difference?
Colder air is denser air....which one makes a bigger difference? The pressure or the temp?
How about increased drag from rotating components due to the grease/oil being thicker at the lower temperature...wheel bearings, rear end, etc.?
Different surface - seems like that could make a difference.
I'm not a drag racer so I have no idea if a half second change is a lot for a different track, different location, different temperature or not.
Similar reaction times?
Post up time slips from Challenge and from this last outing.
I suspect we'll see lower 60fts and possibly other things. Or you wore the motor out down there.
Typically the cooler weather will always make for a faster car. Especially if its a turbo car.
@TJ: The reaction times will not change anything other than who is off the line first. Doesn't change 1/4 mile times at all.
His speed is within 2 mph, that is elevation, I suspect the car or driver are getting worn.
splitime wrote: @TJ: The reaction times will not change anything other than who is off the line first. Doesn't change 1/4 mile times at all.
Got it. Like I said I'm not a drag racer. So you can lose a drag race with a faster time than your opponent if your reaction time sucks? Seems like the time should be the time to me, but it is what it is.
How repeatable are times/speeds for a given car/driver combo?
EDIT: Sorry for the thread hijack.
There are calculations to find "effective altitude" which is based of relative humidity, temperature, and actual altitude. This is the end-all number which tells you which air is better than which.
If you didn't spin the tires at all in either case, the surface is irrelevant.
I would check the car - 0.5 seconds is pretty big. Shift points, and stuff should be looked at too if the mph is that close. What was the coolant temp at either run? How many runs at each place? How much VHT did they use at either place? Launch RPM?
with a dialed in bracket car your numbers shouldn't change with the same altitude more than a few thousandths, but these are not dialed in bracket cars.
Reaction time can win or lose a race. If it's a heads up race, the RT is basically added to the ET. Smaller number wins. Bracket racing is harder. Your "package" is (ET - dial in) + RT, smallest number wins unless there is a breakout (faster than your dial in) and if that happens, the worst breakout loses.
Could be several other factors: - Humidity - The track temp surface (the starting area in particular) - Starting line prep-traction - Quality of the fuel, as well as how many gallons are in the tank, the brand of the fuel, or possibly a variation with Indiana having winter fuel already? Also, the amount of ethanol in the gas. - Wind direction and speed - Barometric pressure - Air pressure in all four tires - Battery fully charged the last time out? - One track could be more be more "level" than the other - Check to be sure all of the plug wires are tight - Check the air filter (dirty?) - Brakes dragging more? - Did you eat more cheeseburgers since Florida? ( just kidding)
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