Champ561

This kid I know just got a sct chip and upr c.a.i put on his car and wanted to know what his 1/4 time was. So just to get an idea we went to this to this development that is being built. There is only one house starting tobe built but all the roads are paved and there is one that 3/4 of a mile. So we measured a 1/4 out and he was doing runs. He would go to one end and we were at the other with a stop watch he would honk 3 times and we would start counting on the third. The best time we got was 12.98. How close would that be for an 05 gt auto tranny with his mods. Thanks

WhiteStallion06

An auto with just a cai and tune .... might be able to hit low 13s but i am seriously doubting he will be able to get into the 12s..... but the tunes for the 05 06 07s autos really do help them out with shift points and everything ... but he can still only launch around 2000 rpms
So by just using a stop watch thats pretty good actually because its so hard to get it right down to the 1000s of a second with a stop watch ... being around organized sports i have noticed that when kids are timed running with a stop watch their time always differs .2 or .3 but when done by laser its always very consistant .... its very hard for the human hand to be right on target with the reaction time so good work ....

Depending on how good the tune is ..... hes prob running mid to low 13s but im seriously doubting he is into the 12s yet but i could be wrong

FL510

You might also note the lag in time it takes sound to travel 1/4 mile.

Might try flashing headlights next time.

swensicle

That's what I was going to say FL. Speed of sound?...(7xx mph) Speed of light?....(speed of light)

ski

Speed of sound at sea level, 70 deg. F, 50% relative humidity = 760 mph = 1115 fps
1/4 mile = 1320 ft
1320 ft/1115 fps= 1.18 seconds (This is the time delay between the horn's 3rd beep and the stopwatch being started, assuming the stopwatch is started exactly at the 3rd beep)
Hence,a 12.98 second run timed with the above methodis actually 12.98 + 1.18 = 14.16 seconds

swensicle

Well done Ski. I wasn't going to go to that much work, but nice job. Maybe you should just ride along with him from start to stop and then deduct about a tenth or two for your weight. That's probably as accurate as you'll get with a stop watch.

Champ561

Thanks guys. Yeah we were just bored so we figured we would give it a shot. The times 12.89 13.03 13.0, but I figured we had to be off and he would be runing around 13.3-5.

bascho

Man that sounds like it takes longer than it should for sound to travel 1/4 mile.

Crazy.

swensicle

Well, now you know that next time you're counting seconds between lightning and thunder it's a little under 5 seconds for each mile.

Maybe I'm the only one that does that though.

WhiteStallion06

I just finished my first semester in college ..... and i just learned more in 5 minutes reading this post than i did my whole fall semester.

Knowledge is power
Thanks!!