The fuel is so slow to fully combust versus gasoline that it not only drives the piston further downward, the tuning takes 65 degrees of ignition timing (BTDC) at redline.
The mixture in the combustion chamber runs so rich because there's oxygen in the chemical makeup of nitromethane already (CH3NO2 for you uber nerds). In fact, where it takes around 14.7:1 air-to-fuel ratio to burn regular gasoline, it only takes 1.7:1 to burn Nitromethane. That said, I think this shoots down the hey-watch-me-drop-a-match-in-this-tank-full-of-fuel trick. Maybe this is something for Mythbusters.
FACT #7: Although TNT has a higher velocity of detonation, giving it more shattering power, it's a less energetic high explosive than Nitromethane.
FACT #8: If you've ever witnessed Nitro cars warming-up in Nitro alley, you may have noticed the initial start-up sounding like a loud street-tuned V8 engine before getting into the freaky, raw-fuel spittin' pops. That's because they're first turned over with pump fuel manually squirted into the intake manifold. Why do this, you ask? For safety. If a start-up pop happened on nitromethane, the explosion would be catastrophic enough to hurt someone.
While some of the idiots–excuse me, NHRA die-hards–show their toughness by standing around and breathing this volatile cloud of death, this is what people who actually care about their lungs look like around an idling Nitro car.
Fact #9: A sprinting Top fuel car is so loud that its decibels can severely and permanently damage your hearing, it also vibrates your vision and can make it temporarily difficult to swallow if standing too close. Along with things such as a shuttle launch or volcanic eruption, a Nitro drag race is among the loudest events recorded on this earth.
The 150-160 sound decibels equal that of a .44 Magnum. But before you tell yourself, “I could handle that without going deaf!”, don't forget that it's more equivalent to:
1) Having the barrel's blast pointing at you (firing a blank, of course), instead of the other way around.
2) Firing at the rate of 4200 rounds per minute (thanks to the 8400 RPM engine speed).
With my photographer pass I got to stand about 15 feet away at the first 150 feet of track (they passed me at probably around 150 mph). It was beyond a thrill ride. From the stands it's hysterically loud, sure, and you feel the shockwaves vibrate your chest. However, up close the sound waves were so great I couldn't keep my eyes open even once as they passed. I was wearing sunglasses and earplugs inside earmuffs, and during the first several passes I found myself holding onto my earmuffs to prevent them from being blown off!
The photographer next to me, who was only wearing plugs, said a few years back he did have a plug fall out at the wrong time, and didn't notice any problem. It wasn't until someone came running up to him, and pointed to the blood oozing from his ear, that he realized he had ruptured his ear drum and needed medical assistance.