General

Breaking the beams, cockpit canopies, fuel tanks and top-end Top Fuel smoke

NHRA

At every NHRA national event, NHRA announcer Alan Reinhart offers fans the chance to email him with technical questions about the race cars, tracks and procedures. As part of a semi-regular feature, we will be sharing those questions and answers on NHRA.com.

Fan can write Reinhart at: [email protected]

Here we go!

When a Funny Car leaves the starting line, the front tires break the beam, but is it the front of the body or the tire that breaks the beam at the finish? — Barbara Ling

The body.

The start line bars are 1-9/16 in. high and will cushion the tire. The finish line is 6 inches and captures the leading edge of the car or wing in Top Fuel.

Fun fact: Ever wondered why body handles are so big? There is an overhang rule and the front of the body slopes back so that the handles of the body are large enough to accommodate the beams.

I have long noticed that the reaction time rates of older breeds differ significantly from those of current breeds. For example, a good response time in Top Fuel is slightly better than a .075 (depending on the depth of the stage). But in older races, a good rt seems to be something around a .450. What’s up with that? †– Clay Schaeffer

Back then, the response timer was based on the yellow lights, since you’re reacting to the yellow flash, not the green one. On a Pro Tree there is 0.4 seconds between yellow and green, so a perfect reaction time was 0.400 with 0.399 or faster being red.

On a Sportsman Tree there is 0.5 between orbs, so a perfect one for a countdown Tree was 0.500, and a 0.499 or faster would be red.

It was suggested that could be confusing especially for a new fan why not make it universal so we changed it to .000 perfect for both, anything that would be red would be a negative number. So the old .452 is now .052.

What is the significance of the few red colored awning attachments? It seems they are in the same location on all cars. –Bill Mitchell

You have a sharp eye. The red ones fix the hood to the car, the others hold the windshield. In an emergency , Simpson ‘s Safety Safari knows exactly which bolts to remove to remove the cover and wastes no time on the others .

Why does a Top Fuel car smoke at the end of the lane? †– Arnie Meece

Assuming nothing happened to damage the engine, the smoke you see is blower oil. There are fuel nozzles in the injector hat above the blower, and that fuel serves to lubricate and cool the Teflon or Nylatron blower strips.

When you shut down a nitro car, you do it by turning off the fuel so the blower spins without lubrication while the engine stalls. There’s a can of oil on the blower that lubricates it when it shuts down, and that’s the smoke you see at the top.

They are set on a timer, and sometimes if a car smokes the tires, the oiler will go off and the smoke will come out as the cart is idling down the track.

When they lift the body after the burnout, I see two tanks at the front of the chassis. What are they for? — David Ziny

The big one is the fuel tank; the small one is the oil tank. All Funny Cars have a dry sump oil system. A Funny Car engine sits so low in the frame that there is no room for a pan big enough to run a wet sump.

Most Top Fuel dragsters have a wet crankcase because they are less complicated, and they boast the engine high enough that there is room for the larger oil sump.

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