Contour Enthusiasts Group Archives Forums General Dyno and Drag Trap speed and hp relation question

So I went back and took a look at my old dyno sheet from Feb. and looked at my track times and got to thinking....

The trap speeds for a stock SVT should be 90-91mph correct? With the mods I have done, I would guess I should be at about 92-93, if not at least 91mph. But my trap speeds vary in between 86-88....which is rather embarassing on the boards. I thought I just maybe had an upper hp deficit, but JoseSVT has the 3L from LowBudgetRacing and is only trapping at 89, at the same track. I know the track conditions play a nice role in things, inluding temp, but is it rational to blame the 88mph trap speeds on the temp, despite night/day runs? Granted it never got 60 degrees at night, but it still came down from ~90 to the mid-high 70s. I am just trying to figure out why my trap speeds are so embarassingly low. My best was a 15.3 @ 88mph for god's sake. I'll try to find out the altitude at that specific track, but I don't think it's anything abnormally high....


Edit: Ok, I found out that it is ~1000-1200ft. above sea level. I think this may be at least half the problem...am I correct or is this not that big of a factor?

1000 feet isn't that bad at all, the local track here is 500 feet. Trapping that low is strange. Have you had your car dyno'd? Have you let you car cool down between runs? Is there a possiblity the track is actually going up hill? Could it be the wonderful 91 octane? Heck could it be all of them?

Try a different track...

i ran a 15.02 and trapped at 91 mph, on a 90+ degree day right after it rained (rained in between passes)

trap speed is related to alot of things, hp/tq curve or certain engine and then gear ratios. For example, my lightning only traps at 103mph (so far with me driving) and Greg (Demon) traps at 101. Both on the opposite sides of 13s...

it's all in the launch...well...not all...but a good launch really helps. a strong pull out of the hole will give you more time building speed on the rest of the track. you'd be surprised what 2 tenths in the 60 ft equates to in e/t and speed.
i'm sure that lightning gets out of the hole really quickly wich results in the low 13 quarter. where as greg's car makes up its deficit at the starting line with all muscle down the track, resulting in a similar mph with slightly longer e.t.

bump...

Elevation decreases trap speed.

So does temp, humidity, BP, tire pressure, weight, etc.