WeatherGuy

I frequently get asked what our cars 0-60 times are (the non-drag racing crowd). Last night, I did a few of the equations and posted (on the other site) what I thought the 60-ft MPH would be based on the times. Does this look right? Did I miss anything?

BTW - this is the kind of stuff you do when you are out of commission (from recent surgery), and everyone else is out racing <img src="gr_sad.gif" border="0">

***************

0-60 is a function of traction, engine power, rear end gearing, (if M6) shifting ability, and (if A4) torque converter choice.

You can kind of back out a 0-60 from a 60 ft time. For example, if you assume a constant acceleration over the 60 ft time (which is not always a good assumption), then you can assume that your time to distance function is given by the double integral of a constant acceleration:

0.5 * acceleration*(60ft time)^2 = 60 ft

Solving this gives acceleration in ft / sec^2 of

a = 120 ft / (60ft time)^2

Since 1 MPH is about 1.47 ft/sec, assuming the constant acceleration, noting velocity is acceleration times time, and solving for the math,

Velocity at end of 60 ft is approximately 81.82 / 60ft-time (units ignored for simplicity).

In other words, take your 60 ft time, divide it into 81.82, and that will give you an approximate MPH at the end of the 60 ft.

Here are a few values

2.0 60 ft - end velocity is 40.9 MPH
1.8 60 ft - end velocity is 45.5 MPH
1.6 60 ft - end velocity is 51.1 MPH
1.5 60 ft - end velocity is 54.5 MPH
1.4 60 ft - end velocity is 58.4 MPH (very quick 0-60 <img src="gr_eek2.gif" border="0"> )
1.3 60 ft - end velocity is 62.9 MPH
1.2 60 ft - end velocity is 68.2 MPH

The above values are not going to be right due to the approximations used, but are close. And this is why drag racing is frequently won/lost in the 60 ft time. Incidentally, 1 g of (average) acceleration is somewhere around the 1.9 sec 60 ft time. 1 g of average acceleration over a whole 1/4 mile gives you a 9.08 ET. Cars do not have a constant acceleration over a 1/4, however, which is why that is way off.

DriveATransAm

so if my 60' is 1.55, i can say my 0-53mph is ~1.55 seconds <img src="gr_eek2.gif" border="0">

making my 0-60 around 2 seconds <img src="gr_eek2.gif" border="0">

if so, thats freaking incredible!

Red02LS1

well according to Al Corda's car page, his car has a 1.28 60' time which says 0-60 in 1.9 seconds.

Raughammer

[quote]Originally posted by Red02LS1:
<strong>well according to Al Corda's car page, his car has a 1.28 60' </strong><hr></blockquote>


Oh man... 1.2!!! KILLER!

1.2, 1.2, 1.2.... I feel like "jim Cary" in "Dumb and Dumber" when I say, "So, it CAN be done...."

I can only dream.

WeatherGuy

[quote]Originally posted by Bad Habit Bird:
<strong>Im not sure those numbers are totally correct. The colonel posted a link to a site that had a calculator that would do this conversion, maybe he will post the link again.</strong><hr></blockquote>

They may not be right - see the other post at https://ls1tech.com/ubb/cgi-bin/ulti...c&f=5&t=000676

I was stabbing in the dark at this. The big problem is what does the acceleration curve look like for that first 2 seconds. Changes a lot of things.

Vortech396

I think this is the one Colonel posted a while back.

http://www.smokemup.com/utilities/calc/60_foot.cfm

have fun <img src="gr_grin.gif" border="0">
John

WeatherGuy

Much of how you calculate this depends upon your assumption of what the acceleration curve looks like during that 60 foot. Thinking about this a little more, I suspect that the above calculations are probably going to be a bit more accurate for a 6-speed than a high-stall auto because of the shape of the torque converter spike.

In actuality, there is no one formula that is going to be exactly right because every car's power curve and effective gearing are going to be different. Moreover, you cannot always even get very good 1/4 MPH or ET estimates from a car's peak power. For example, the calculations available at
http://www.prestage.com/carmath/calc_ETMPH.asp
seem to be way off (much too slow) for LS1-powered applications. I am sure that this has to do with the width and placement of the power curve, which does not always compare well across vehicle types.

I *think* that what I have above is probably going to get realistically close to backing out this number (unless someone has really done their homework on this for LS1s and F/Y bodies and has a better solution). It also helps to keep in mind that this a tool to let the non-gearhead crowd have some idea on how fast our cars are. No one in drag racing cares that much about 0-60.

WeatherGuy

[quote]Originally posted by Vortech396:
<strong>I think this is the one Colonel posted a while back.

http://www.smokemup.com/utilities/calc/60_foot.cfm

have fun <img src="gr_grin.gif" border="0">
John</strong><hr></blockquote>

Wow - it's giving the same answers that I posted above. Interesting.

Bad Habit Bird

iTrader: (12)

Im not sure those numbers are totally correct. The colonel posted a link to a site that had a calculator that would do this conversion, maybe he will post the link again.