[TH]

I need the formula that allows you to compute an approximate 1/4 mile ET based on a known 1/8 mile time. It's not in the dang Auto Math Handbook!

Thanks much.

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Tom H.
Member #259 www.iquest.net/~harold2/

[Chevy454]

Here is the chart that I use, which I found in an "Car Craft":

1/8=1/4
4.6=7.08
4.7=7.24
4.8=7.39
4.9=7.55
5.0=7.70
5.1=7.85
5.2=8.00
5.3=8.16
5.4=8.32
5.5=8.47
5.6=8.62
5.7=8.78
5.8=8.93
5.9=9.09
6.0=9.24
6.1=9.39
6.2=9.55
6.3=9.70
6.4=9.86
6.5=10.01
6.6=10.16
6.7=10.32
6.8=10.47
6.9=10.63
7.0=10.78
7.1=10.93
7.2=11.09
7.3=11.24
7.4=11.40
7.5=11.55
7.6=11.70
7.8=12.01
7.9=12.17
8.0=12.32
8.1=12.47
8.2=12.63
8.3=12.78
8.4=12.94
8.5=13.09
8.6=13.24
8.7=13.40
8.8=13.55
8.9=13.71
9.0=13.86
9.1=14.01
9.2=14.17
9.3=14.32
9.4=14.48
9.5=14.63
9.6=14.78
9.7=14.84
9.8=15.09



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Rob Clary
'70 LS-6 Chevelle
Team Chevelle Gold Member #85
Interested in COPOs, Yenkos or other dealer built muscle cars then go here: www.yenko.net

[Doug Garland]

Wow, I knew my father-in law's car was fast, but I never thought about 9.40's through the 1/4! Out of the box he ran a 6.19, but hey, it is an aluminum headed 468 B/B in an Opal GT body!

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

[72chevelle350TH350]

Now Doug, you know those 1/8 guys are geared to hell and back. He would have to run through the traps at over 7000RPMS probably

That chart differs some for 60' times.

With my 3.73 posi (motor is a little weak) I got he following

1/8th = ~10.00 sec

1/4th = ~14.5 sec

I know it's at the bottom of the list, but things do very some with a 4,000 pound car and less than 4:11 gears.

my .02

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SB350 will soon be a BB396 w/nitrous
TH350 will be replaced by a TH400 (shift kit, slight stall)
shooting for low 12s in 1/4
college student budget and wisdom.

[Doug Garland]

Mike- His car weighs right at 1900lbs, and he has a 4.88 or 5.13 under it right now. It is still spinning as he goes through the traps. I haven't volunteered to drive,because, as you know, I'm a pretty good sized guy, and folding myself up to get in that sardine can isn't in my future!

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

[TH]

Chevy454,
Thanks a lot for the chart. I printed that thing out. Nice reference!


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Tom H.
Member #259 www.iquest.net/~harold2/

[Corey872]

We'll see if the image comes through...I put the numbers into an Excel spreadsheet chart. Sort of the 'po mans pocket calculator. The equations are on the chart, too. But they worked out to:

1/4 mi = (1/8 mi) x 1.54

1/8 mi = (1/4 mi) / 1.54

Or very roughly just multiply or divide by 1.5x


Also, looked like the list numbers contained a small error at 1/8mi=9.7 sec. The 1/4 mile should be 14.92 to fit on the line with all the other points...unless the laws of physics somehow break down approaching the 9.7 sec 1/8 mile barrier.

(awww---looks like I'll have to beam the image up later tonight)

[Corey872]

Give this a shot:

[crankshaftkid]

I've been using 1.575....seems to be really close in most cases.