13.6 @ 110 mph!

Matt Keene · Post by **Matt Keene** » Thu Jun 21, 2001 12:03 pm

Raced at North Weald on Sunday and suffered severe traction problems due to damp track conditions...
Best time was the above, however I have a question for all you mathematicians and physics type dudes...
When comparing my times/speed to the times/speed of cars running low elevens and high twelves I am surprised to find that in most cases my speed is greater than that of cars running faster et's. My best et to date is 13.1 @ 107 mph yet and my fastest speed is 110 mph @ 13.6. Can anyone explain the physics behind times and speeds? Mark Herbert's car, for example, runs mid elevens @ 107 mph on average, yet is nearly two seconds quicker! Stratching my head in anticipation...

Steve Arndt · Post by **Steve Arndt** » Thu Jun 21, 2001 12:20 pm

It is called fast vs. quick. SSB is quick, you are fast. HP=miles/hour. Chassi setup=ET. ET is what wins a sprint to the finish.
There are lots of people on the CLF that can help you with chassis setup if better drag times are what you want. As you noticed, you have the power to get into the low 12s.

Magoo · Post by **Magoo** » Fri Jun 22, 2001 12:01 am

As Steve touched on the ET requirements, traction chassis setup,weight transfer,gearing ,both in the final drive as well as the ratios in the transmission along with such arcane matters as wheel alignment,wheelweight,wheel travel,unsprung weight and a multitude of other variables all contribute to a low et whereas mph is almost strictly a matter of lbs per HP. Just take a look at the latest Motor Trend or similar rag and check out the list of recent road test summeries.You will note that the ET on the typical vehicle tested no matter the make model etc,with very few exceptions,tend to have an elapsed time for the 1/4 mile several tenths slower in relation to the average Cal look. An example to illustrate : An old Chevy wagon that I ran a few years ago was a pure stock 3
05 v8 with a 350 Turbo Hydro w/ lock up clutch and a 2.41 rear axle ratio,hardly a strip stormer but a totally consistant machine .Et would seldom vary by more than a few hundreds and has run 3 rounds in 45 minutes with a 17.168 17.172 and 17.174 mile per hour was an average 79.148 with a best of 79.334 .Using factors computed by Chrysler engineers back in the golden years of factory involment in performance we come up with roughly 144.5 hp based on 3700 lbs ,or 25.60 lbs per HP .My olde '72 sedan with amild 1776 ran a best of 16.61 @ 79.114 mph ,a virtual tie in mph so hp per lb or pounds per hp should be the same ,but the lower gearing,4.12 3.78 2.06 1.26 .89 coupled with the 60 /40 weight distrbution inherent in the standard Type 1 makes all the difference in the world! Another interesting point is at the 1/8 mile the chevy was taking about 11 seconds to make it to the 660 foot mark,while the bug was a half second or so quicker! Anytime you can beat your oppenent by half a second,you have trounced him....BAD! say by about 4-5 car lenths .Figure it out, 60 mph is 88 feet per second and your mph at the end of the eighth mile should be about 63-65 mph given the above examples so a half of 88 feet? 44 feet,or in drag racing,A LIFETIME! Hpoe that explains how important a good seup is....Dan

magoo · Post by **magoo** » Fri Jun 22, 2001 11:07 pm

After that long winded post still left out...Think Herbert runs about 111-112 thru the eyes on a typical pass. And yourc car with speeds of 107 mph should be making around 180 or so hp if it weighs around 1900 lbs that is about 860 kilos for you euro folk.... Matt ,check your time slip on that 110 mph run,what what the mph at half track,or in other words , have you been able to back up that mph on a subsequent run? As many racers know it is possible to get a"popcorn" time as a friend who has a car that runs super consistent back to back 14.20 ets suddenly and with no changes runs a 13.08 that is a popcorn time ,even on the fuelers they still suffer this occasional glitch,so it's not a knock or doubting your mph,just that if you have been unable to back the mph within a very small window,it most likely is a fluke .Still 107 is a good run ,with a bit of traction and practice should net a low 12.Keep us informed.....

magoo · Post by **magoo** » Fri Jun 22, 2001 11:13 pm

One thing ...the 13.6 110 is highly possible the new Corvette can turn in numbers such as those..... PS a friend with a 2165 Holley/to4 settup runs 11.80-11.90 @ 112,114.Now that he has the turbo 4ebuilt and all the blades are in their correct location and plane it should prove out some 11.50 next time out.

Chuck Schneider · Post by **Chuck Schneider** » Sun Jun 24, 2001 3:26 pm

A high mile per hour with a slower time is an idication of a traction problem. The reason for the high mile per hour is because you are getting the car in high gear sooner giving you a higher mph. With good traction that number will surely come down. A high mph is also an indication of h.p. because it take alot of hp to accelerate the car to 107 in high gear.

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12.70 @ 104

Matt Keene · Post by **Matt Keene** » Fri Jun 29, 2001 2:37 am

Good info guys! I consistantly run at approx 106-107 mph and have about twenty or so slips from two different tracks. 1/8th mile speeds are normally 84-85 mph so I'm pretty sure the 109 mph wasn't a fluke. I am dialling in the car more and more for weight transfer and seem to be on the right track. The front really lifts now like it never did before (thanks to drilled shocks) and I'll be running slicks for the first time at Bug Jam in mid July. I think it has been a question of traction as the car puts out 203 flywheel hp and 217 ft/lb of torque. I havn't weighed it, but it's certainly lighter than stock. If you guys have any more info/advice I'd be most grateful if you could post it. Thanks.

JohnConnolly · Post by **JohnConnolly** » Fri Jun 29, 2001 12:08 pm

Matt, you should be running around 12 flat once you get some grip, rougly.

John
Aircooled.Net Inc.

Tomj · Post by **Tomj** » Sun Jul 01, 2001 6:47 am

Excellent to see you are getting that car dialled in Matt. Hopefully see ya at Bug Jam.

Matt Keene · Post by **Matt Keene** » Sat Jul 14, 2001 3:18 am

Guys, I've finally parted with hard earned for a spare set of 6" Ercos and some Pheonix drag race slicks...Hopefully this will aid in my quest to break into the elusive twelves at Bug Jam RWYB next weekend- providing I don't lunch my transmission in the process...
Thanks again for the advice on setups etc and I'll let ya know how it went...