Have you ever wondered how we take jet engines out of planes and put them into our jet dragsters? To take these engines from an airplane and make them fit into a racing application, we “put the engines on a diet.” A handful of changes are made to the engine to lighten up the weight and make it more efficient for drag racing.
J-85 engines weigh just a little under 400 pounds when they are taken straight off of the plane. We place our own custom afterburner on the jet engine. Starting from the exhaust flange back, we remove the original exhaust in order to apply our custom racing afterburner. The new afterburner adds about 60% more power to the engine itself.
Some other parts that we remove from the engines when they come off of the plane are the engine anti-ice system, bleed air plumbing components, factory engine mounts, the exhaust gas temperature probes and harness, and any rear components that must be removed to place our custom afterburner on.
With the plane to race car transformation also comes maintenance differences. The biggest difference between the two applications is how the engine is cooled after being shut off. Airplanes equipped with jet engines can fly for almost 1,000 hours before having to stop for major maintenance routines. This involves an inspection of the hot section of the engine. This time frame is not the same for our racing application. We inspect the hot section of our engines for every 90 seconds of full power. A race run takes about 6 seconds, so it takes about 15 runs down the track until the dragster reaches 90 seconds of full power. For a hot section inspection, the combustion section goes through a disassembly in order to look for cracks inside from shock cooling.
So let’s talk about engine reliability, because you obviously cannot make these changes to a jet engine without making sure that it is still going to be reliable. To answer this question in short, yes, the reliability of the engine is affected. Take a plane with a jet engine, for example. When a plane lands its engine is still running, but it is running at a lower power setting while taxiing into the gate, all while cooling the engine. Once our jet dragsters reach the end of the drag strip, the engine is fully shut off. Cold air goes down the inlet which shock cools certain parts of the engine. These parts require additional maintenance attention.
Taking engines from planes and putting them into jet cars is not necessarily hard, but it is important to keep safety, efficiency, and reliability in mind. Here at Larsen Motorsports, we do a very good job at keeping our engines in top shape so we can continue racing as often and as successfully as we do!