Drag Racing Tech - couple 1/4 mile questions
04-09-2008, 12:14 PM
hey guys, i was wondering if someone can explain a couple things. for example, what is the importance of r/t and 60 ft? all i know is that the first
60 ft almost determines the race and its pretty good to get under 2.0? also what bout ET's and MPH? what is a good MPH? all i know also is that MPH= is a good indicator of a cars power. i also dont get how lets say one guy get across the 1/4 mile quicker but the other guys MPH is higher? sorry such a noob question.
04-09-2008, 01:02 PM
In terms of ET, reaction time is of absolutely zero consequence. In test n tune, you can cut a 30 second light and run a 13 just the same as a perfect light and a 13. It's only important in heads up racing and bracket racing. For just getting your ET it doesn't matter.
Your ET is all made early in the run. Say you get a 60 ft. 2 tenths better than the guy next to you, that would take a lot of MPH to overcome that 2 tenths. It's hard to explain but ET is SOOOOO important on the early part of the run when you have no momentum. I ran 9.30's last year, I could let off at the 1/8 mile and still run a 10.60 just to show how important the first half of the run is. On the other hand, bracket racing I can kill 10 MPH at the finish line and only run around a tenth slower than usual.
Good MPH and 60 ft. just depends on what's done to your car.
04-09-2008, 01:29 PM
Yes, et shows how quickly a car gets moving from point A to B.
MPH is tied to horsepower, weight, rolling resistance, and aerodynamics.
If you run a 13.50 @ 97mph and I run a 13.6 @ 107mph and reaction times are the same you win. But I am flying up behind you catching up quickly because you got a good launch and jumped out on me but have no top end power and I left softly but am hooking up and charging hard by mid track.
Picture a rail buggy that leaves the line wheels up and runs a 12.5 et at really low mph because he's ultra light and hooks up good but has no horsepower vs. a corvette that can't launch real well but is screaming on the top end.
60ft times let you measure improvements on launch, mph tells more about horsepower improvements
Good ET? 4.40
Good MPH? 330
04-09-2008, 01:31 PM
it is all about the setup. Your 60ft time has to do with the weight of the car, how fast it will move, traction and of course power and torque, and the list goes on. My best run so far in my Z28 is an 11.45@117 a good run in itself, it won'y MPH very well because the heads suck (stock 862's with a 220 baby cam). It is a torque monster though being a 408 with truck heads on it so it will 60ft well, 1.52x's full weight.
RT is about the rollout specificially, not to mention YOUR ability to time the lights aka "trim the tree". RT is only important when racing: bracket or heads up racing, as said above. If the car has a slow rollout, you must leave sooner and vice versa if it has a fast rollout. If you get stuck in a rut on your RT's when bracket racing, and say you keep cutting 60's and 70's all day long... you can put on a shorter front tire to speed up rollout and you can cut your lights down to 30's and 40's without making any other changes. Simply put, if your car is consistent and will run its number 99% of bracket races are won on the tree.
MPH is yes, a good indicator of power...if comparing the same car mainly because gearing can change it as well as aerodynamics. If you notice et and trap speeds of fast trucks will be strange looking compared to cars. They will have a killer ET but their MPH will be slow for the ET, almost like they are on the brakes...this is because of the drag.
04-09-2008, 07:37 PM
thanks guys. now i got a little better understanding!!! thanks trooper car..
my question is what is a good MPH? is there a certain MPH we should atleast run? or is everything still based off of 60 ft. and all? so what is more important the ET or MPH?
04-09-2008, 07:45 PM
all stock, mine went 13.54@ 102mph 2.07 60ft
6 spd cars are usually a little faster stock all other things being equal
The mods in my sig put me at a best mph of 110 on a 50 degree night to 108-109 normally
mph is also affected by altitude, I'm at sea level. Cars are less powerful in higher, less dense air.