How to Start an A/Fuel Dragster

Lighting the Wick
How to Start an A/Fuel Dragster

Written by Randy Fish

Unlike their blown alcohol cousins that share the Top Alcohol Dragster category, the often unpredictable A/Fuel (unblown, injected-nitro) Dragster can turn into a bomb upon initial start-up, if the right procedures aren't followed very carefully. Though nitro is hard to light with a match, it can self-detonate when compressed by less than 200 pounds (of pressure), resulting in a dynamite-like explosion.

Over the last decade or so, numerous teams have experienced devastating accidents while attempting to fire their potent A/Fuel powerplants. In some instances, cylinder heads have literally been blown apart when things have gone terribly wrong. Problems set in when fuel residue finds its way into a cylinder. As soon as you try to spin the engine over, that piston cannot compress the liquid and you have a hydraulic situation. During one of these episodes back East, a crew member was seriously injured during a normal warm-up in the pits. A similar incident occurred at Indy a few years ago when a respected team lit their car to warm it up. Needless to say, these race cars can be like wild animals - turn away for one minute and they'll put you in a world of hurt.

Researching this phenomenon was very interesting, to say the least. While it's common for crew members to rotate the motor in order to adjust the valve lash, cylinder number two is normally the last valve adjustment made, which causes the number eight intake valve to open slightly. Any fuel present in the system that can trickle into the nozzles will end up in cylinder number eight. If that fuel is not evacuated, it will cause the aforementioned catastrophic explosion (a.k.a. kaboom) upon attempting to start the engine. Trust us, it ain't pretty; it's pretty ugly.

To set things straight, we contacted veteran drag racer, Jerry Darien. Teamed with his long-time partner, Ken Meadows, Darien has been a fixture in the Southern California Pro Comp and Blown Alcohol Dragster wars, driving his string of successful "Green Gang" cars. More recently, the team has fielded competitive A/Fuel Dragsters from coast to coast, while training drivers like Melanie Troxel, Brandon Bernstein and Ashley Force, as well as his 2007 candidate, Lindsey Wood.

Jerry Darien told us, "Back at Sonoma in 1998, we exploded the engine while attempting to start it before making a run." Continuing, Darien said, "It took us a while to analyze what exactly went wrong there. We concluded that towing out of our pit uphill towards the staging lanes is what caused an unusual chain of events. At the time, we had no idea that fuel was hydraulically locked between the barrel valve and the nozzles. Gravity overcame the lock and it trickled into the number eight cylinder. I just touched the starter and the thing exploded."

To further emphasize the point, Jerry mentioned, "It only takes about a shot-glass of nitro to blow one of these things up. You can even spill some nitro on the floor and hit it with a hammer and it'll explode." And while the average fan sees pair after pair of cars fired during qualifying, little do they know how critical it is to have everything go right during a normal start-up procedure. That's what prompted us to ask, "How do you start one of these things?" Although it seems like a simple question, this has proven to be a very interesting story, and we hope you all have a new-found respect for A/Fuel Dragsters. Oh, and as they say on TV, don't try this at home. DR

Lindsey fills a small auxiliary tank with alcohol, which is used for initial start-up so as to build enough heat in the engine to accept the nitromethane.

Jerry unplugs the air bleeds on the injector (shown just above each individual hat nozzle) before starting. This makes the motor lean, which also builds heat. These bleeds can also be used to adjust the idle speed.	The electric starter is attached to the crank and the auxiliary start-up tank is put in place.	Jerry turns a valve on the start-up tank to start the flow of methanol, which feeds into individual nozzles over each manifold runner that supply the motor at idle.
The starter comes to life and spins the motor over. Jerry is shown holding the butterflies open to let more air into the motor. Then, a crew member pulls the kill wires off the coils, which allows the motor to start.	Jerry checks for possible fuel leaks or anything abnormal. Then, he signals Lindsey to turn the fuel pump on and the car begins running on nitromethane, evident by the all-important cackle and pop. Additional air bleeds on the injector are plugged as necessary to adjust the idle, which Darien likes to be in the neighborhood of 2,800 RPM. Jerry disconnects the start-up tank and it's time for the burnout.	Jerry gives Lindsey the signal to pull it to the starting line.
During the burnout, Darien watches the pipes for excess fuel and listens to the motor.	During launch, the crew looks at the flame pattern from the pipes, hoping there are no dropped cylinders. These photos demonstrate a clean run, where all cylinders are firing and the car moves hard through the 1320. Once the chutes are out, a kill switch cuts all electrical power to the ignition, the fuel shutoff starves the engine, and the pipes go silent.