In a recent Ford vs Chevy thread there was a discussion about 1/8 mile times and converting said times into 1/4 mile equivalents. I have not heard anyone mention terminal speeds and the role it plays in this conversion. Example:

Car #1 goes 9.2@74mph.
Car #2 goes 9.3@81mph.

Car #1 gets an excellent start but obviously has limited horsepower.

Car #2 gets a poor start but is coming on like gang busters by the end of the 1/8th.

According to the charts, car #1 wins in the quarter using the conversion charts I have seen. It doesn't take a genious to figure out that car #2 would be the winner in a 1/4 mile race by a wide margin. The above 1/8 mile examples were taken from actual time slips. Is anyone aware of a conversion chart that takes in to account terminal speeds when doing 1/8 to 1/4 conversions. (The import guys seem to rely heavily on the 1/8 to 1/4 conversion for comparisons. If one used the same logic, couldn't a 60' time could be used to determine the winner in the 1/8?)

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1999 Black Roush-Lowered Lightning - w/Super Chip (YEEEOW!), JBA Headers, Power Surge air kit, AAD Cobra hood, carbon fiber dash kit, CD Changer, Towing Package,Grey Rhino, clear corner lenses.
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[This message has been edited by sixpipes (edited 01-21-2000).]

 

Your right.
And college mid-terms should not count.
Everyone should have a nearby 1/4, that is my dream.

 

hehe, chud is a jerk!! His stupid 280zxt probably would break down as soon as it kit 80mph

 

Actually, I have to disagree. There is no way to determine which of those two cars would win soley based on thier 1/8 mile times. Maybe if they were two identical cars, in which you know that the 1/4 mile times are equal. But just given 1/8 mile times and mph, you cannot determine who would win. All cars run different. Some run stronger up top and can get the win on the last half of the 1/4 mile. Here is an example- Take a turbo vehicle vs a nitrous vehicle. Off the line, turbo cars tend to come out slow, while nitrous cars launch hard. Turbo cars pull like crazy on the top end. So by the 1/8 mile, if they both had the same E.T., the nitrous car could have a higher mph, but the turbo car could still win, since it makes tons of power after the 1/8. Same goes for 60-ft times. You could take an 11 second Vortech Lightning, which let's say, clicks off a 1.70 60ft on slicks, and put it agianst Jason Brown's low 9 second turbo Lightning, which turns about the same 60ft. Doesn't take a genius to figure out who will win that race , But obviuosly the 60ft times wouldn't help you determine an outcome. So you see that those E.T. calculating programs are neat, but there are too many variables to make them accurate.

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SAL
13.35@103mph
All stock with PSP 99 Lightning Chip and Filter Kit

Power Surge Performance--- Your SOURCE for SVT Lightning EFI Tuning and Performance!! http://members.aol.com/NLOCsvt/svt.html

 

Hi Sal

 

The rule of thumb for converting 1/8th mile to 1/4 mile is based solely on ET (1.55*ET in the 1/8th = ET in the 1/4th), so if the driver can't drive - which is what would seem to me to be the case with Car #2, then that goes out the window.

Remember, this is a empirically derived rule of thumb. (If you take my best 1/4 mile and divide it by my best 1/8th, - [11.92/7.67] it yields 1.554, which tells me that rule of thumb is pretty dang close, given that my truck is very soft out of the hole and doesn't 60' particularly well!) Traction and driving problems will definitely make it not work.

I believe that you could make a very fair assessment based on the above numbers that car #2 would win handily presuming it didn't run out of gearing. By the 1/8th mile any car is into its power band and has worked through at least two gears, which means that the 1/8th mile mph is a good predictor of power-to-weight and who will win in the quarter. MPH is determined by power-to-weight and ET is determined by the driver and chassis.

BTW, Sal, I don't know if you were saying "IF Jason ran a 1.7 60', he'd still win" or that he actually DOES. I have time slips with me in one lane and him in the other - he ran well into the 1.4x range with the 4 link. I bet that with the new tube chassis and the 19" wide tires he'll get into the low 1.3s. He'll need that back brace again. ::chuckle::



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Later!
Jeff S.
President, National Lightning Owners Club - http://nloc.org
SVT Lightning #74 in '95
11.92@115.2 on radials, driven daily
jeff_s@nloc.org or fmosracing@aol.com

 

testhttp://www.autometer.com/99catalog/gaugeworks/17_gw_trucks.html

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[This message has been edited by Twisted99 (edited 02-20-2000).]

[This message has been edited by Twisted99 (edited 02-20-2000).]