What is a Nitro Harley?

A highly modified Harley-Davidson based motorcycle that burns Nitromethane for fuel and engages in an acceleration contest over a 1/4 mile.

        Purvis Motorsports  Nitro Harley

What is Nitromethane?

Niotromethane is an organic compound CH2NO2. It is more energetic high explosive than TNT and is produced by treating propane with nitric acid. Nitromethane has a high oxygen coefficient. Therefore, it does not need as much air to burn as gasoline does. Gasoline burns with an air fuel ratio of 14.7 to 1 (14.7 pounds air to 1 pound of fuel).  Nitromethane burns with an air fuel ratio of 1.6 to 1 (1.6 pounds of air to 1 pound of fuel). As you can see, Nitromethane burns approximately 9 times as much fuel as gasoline. Because there is such a rich mixture you will see flames coming out of the exhaust of a Nitro Harley. Not much for economy, but great for power which is about three times as much as gasoline.

Is a nitro engine the same as a gasoline engine?

No, a Nitro Harley motor shares the same basic design as a Harley motor... a pushrod 45 degree V-twin. However, due to the explosive nature of nitromethane the engine is built much stronger to withstand the increased combustion pressure and abuse.

      121 cubic inch Derringer Nitro Pro Drag Motor

Is there more than one kind of Nitro Harley?

Yes, the major racing association that sanctions Harley Drag Racing is the AHDRA (All Harley Drag Racing Association). Here is a brief description of the three classes of Nitro Harleys.

  200 cubic inch displacement maximum any transmission, fuel injection   
  and supercharger allowed
     Current Records    ET  6.21   MPH 233.68

  151 cubic inch displacement maximum without transmission or 122
  cubic inch displacement with transmission, fuel injection or carburetor
  maximum rear tire width is 13 inches
      Current Records  ET 6.502  MPH 220.08

  122 cubic inch displacement maximum, carburetor only, no transmission
  high gear only, maximum rear tire width is 11 inches
      Current Records  ET 7.128  MPH 191.21
       (E.T. record was set by Johnny Vickers on  one of the Hawaya Racing          School bikes at the 2011 Manufactures Cup)  

Here is a Youtube link to a Nitro Harley video by the NBRA

Here is a  Youtube link to a Nitro Harley video by Joey Sternotti

Here is a Youtube link to some Nitro Harley Helmet cam footage with Tommy Grimes