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