[Jeff Higgins]

Yeah, that is the Ron Capps incident to which I referred. Like I said, his outcome was "better", if you can call it that.

Pretty amazing how high the 'chutes lifted the rear of his car. Even more amazing was how he held onto it. Remember - in both cases, we are looking at somewhere around 300 mph when this happened.

Capp's explosion was a real head scratcher. It just happened with no warning. In Wilkerson's, we see the more typical chain of events. You can see where it loses traction, then drops cylinders, then goes "boom".

The rear end hops as it loses traction through tire shake, the motor over-revs, spark plugs fail under the increased fuel load and boost, cylinders quit firing, and all that unburnt fuel has to go somewhere - right past the rings into the crankcase.

These are cave man crude machines. Fuel is delivered through two mechanical pumps with no regulation beyond engine RPM. Boost is delivered via a mechanical supercharger, again with no regulation beyond engine RPM. Fuel delivery and boost are both entirely dependent upon RPM. When it suddenly over-revs, both arrive in excess, and spark plugs get welded shut. Now you have no spark coupled with excessive fuel delivery and boost, driving it all past the rings. With even one cylinder still lighting, its blowby lights the charge in the crankcase, and the rest is history.

Watch right before Wilkerson's explosion, and you will see the fire going out on multiple cylinders. Their exhaust pipes look like garden sprinklers. That white/gray mist is the fuel being pumped out the exhaust port, signifying a "dropped" cylinder. Remember, these things run a roughly 2:1 A/F ratio, with the stoichiometric ratio of pure nitromethan at 1.7:1. They can do that because nitromethane releases an oxygen molecule when it burns, so it doesn't need nearly the A/F ratio of gasoline. They run 90% nitro, 10% methanol, thereby the 2:1 ratio. So, yeah, some of the fuel is going out the pipes. The rest goes into the crankcase. Once you see that, the result is inevitable.