Originally Posted by willwren
DISCLAIMER- I don't know how accurate the G-tech meter is, but it has to be better than a stopwatch in the hands of the co-pilot. Remember that these times from the G-tech DO NOT include driver reaction time. My track times wouldn't be nearly this good, especially at my age. I'll take the 7.0/15.1/93. Decent bragging rights for a 93 SSEi.
1/4 mile track times don't include reaction time, either. If you go to the track, have 2 identical runs, but for one of them you are sleeping at the light, your time slips maylook like these:
run 1 run 2
RT .550 1.023
60' 2.40 2.40
1/8 9.78 9.78
1/4 15.32 15.32
That'* a big ricer misconception at the track, to subtract your RT from your ET to see how fast your car is. I guess the ricers need that ... alot of them will actually sit there on the line after the light is green bouncing off the rev limiter, leave two seconds later, run a 16, and brag in the pits that they ran a 14! Funny bunch, those ricers
Anyway, G-techs in general are pretty good for ET as long as you're on a nice level spot of road. However, the mph of the G-tech typically reads about 2 mph high or so, and here'* why: The G-tech gives you the exact mph at 1320 feet for your 1/4 mile mph. In real life, the track actually has 2 beams, one at 1280(?) feet, and the other at 1320 feet, and measures your mph over them - essentially averaging your mph over the last part of your run. How fast you're going at the 1320 is always going to be a *little* quicker than what you average over the last 40(?) feet (because you're accelerating), hence the G-tech reads a little high. Other folks that use the G-tech (actually even at the track) in the 14-15 second region seem to report that the ETs are very close, but the mph is about 2mph higher on the G-tech than on the timeslip.
So, realistically, if you went to the track that same day, you probably would have run about 15.1-15.2 at maybe 91mph or so. Which is pretty good!
I am a little bit surprised that with the new chip your mph didn't go up. Typically the mph increase is more telling of the actual power that you are making than the ET ... the ET is typically more reflective of how well you launched, given the same mph.
The launch really does make a big difference - this little rule of thumb works pretty accurately - a 0.1 second improvement in your 60' time will yield a 0.2 second improvement in your 1/4 mile ET.
For FWD street tired cars, a 2.2 60' time is very good, a 2.1 is outstanding, and a 2.0 or 1.9 is a once in a lifetime God-must-have-lit-a-fart-behind-you-as-the-lights-dropped event. Realistically, a 2.3 or a 2.4 is probably the launch you will get without too much wheelspin and good traction, and a crappy launch will be as bad as a 2.9 or a 3.0!
But anyway, comparing a 2.7 launch to a 2.4 launch, you'll be cutting 0.6 seconds off of your ET!!! That'* why mph is generally more reliable for indicating what kind of power you have.
Sorry so long!