[sportrider - tech] - Dragstrip Time and Fuel Tanks | Ask the Geek

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Fudging numbers at the strip
When I lived in Hickory, NC, I owned a 2007 Kawasaki ZX-6R with a Dynojet PCIII, K&N high-flow air filter and a Two Brothers exhaust (slip-on). We would go to two of the closest dragstrips, which were eighth-mile. My fastest time was 7.21 sec. at 101 mph. First off, is that good for a 600? Second, could you help me understand how corrected time works, and what my time corrected might have been? Mike Hildebrandt
South Bay, FL

A low seven-second time in the eighth-mile is quite respectable for a 600, although we have seen times in the high six-second range. We have always used NHRA correction factors when running bikes at altitude; these convert quarter-mile time and speed to reflect what the pass would have been at sea level. For example, the Honda Proving Center of California, where we used to run our test bikes, is at an altitude of 2000 feet. The NHRA correction factors were (at the time) .9770 for ET and 1.0241 for speed, so an actual pass of 10.50 seconds at 130.0 mph would convert to 10.26 sec. at 133.1 mph. The NHRA has since adjusted the factors slightly, and HPCC is now closed. Lately we’ve been testing at either Auto Club Speedway in Fontana or at Buttonwillow Raceway, and haven’t been using any correction factors in our dragstrip number because the NHRA does not correct for tracks below 1300 feet. Fontana is at 1200 feet of elevation and Buttonwillow is almost at sea level (even though it’s in the middle of the desert). Unfortunately, you will have to improve your 7.21-second time the old-fashioned way. I’m not sure you can accurately apply the NHRA numbers to an eighth-mile track, and in any event Hickory, NC is at 910 feet of elevation — too low for NHRA correction.

Tuono Troubles
I have an Aprilia Tuono with a plastic tank that is expanding. Luckily this bike is still under warranty but is there anything I can do to prevent it from happening in the future? I didn’t think it would be a problem for me because the bike is ridden regularly.
Jim Turino
Los Angeles, CA

You are definitely not alone with this problem, and Aprilia is not the only manufacturer affected. We have heard of many instances of plastic tanks expanding, and have even seen it in our shop here. The problem led to a class-action lawsuit against Ducati North America, which was settled earlier this year with an extended warranty on certain Ducati models with plastic tanks. The expansion seems to be a result of ethanol used in the fuel; ethanol can absorb water, which is then absorbed by certain types of plastic used in making fuel tanks, resulting in expansion. The ideal solution once you get a new tank is to avoid ethanol-enhanced fuels, which you will not be able to do easily — all commercially available gasoline in California contains between 5.7 and 10 percent ethanol, and there are no labeling requirements for pumps so it will be difficult to know just how much ethanol you are putting in your tank. Ethanol is also causing trouble in the marine and small-engine industries, so there is ethanol-free available fuel if you hunt around. One option is to use an additive such as Sta-Bil Ethanol Treatment, which is said to help remove water from fuel. Another is to seal the tank with an ethanol-resistant epoxy, such as Caswell Gas Tank Sealer. If you store your bike for any period of time (doubtful if you live in California), leave the tank empty or fill it with ethanol-free fuel.


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