Part: 4 10,000 Rpm On The Engine Dyno And We Get...We last left this project with a three-part interview by our engine builder Larry Widmer, the man up to the challenge of building an engine capable of 150 hp per liter on pump gas. Larry is the owner of Energy Dynamics (Endyn) in Fort Worth, Texas.
In the last 40 years Larry has worked for Ford, Toyota, Penske, General Dynamics, MSD and Lockheed Martin. His engines have won an Indy 500, numerous NASCAR races and multiple Pro Stock titles. For about the last 10 years, he's been a big Honda guy and was ready and waiting for our challenge.
After the last three installments, we now know how the entire long block went together and it's time to put Endyn's engine to the test on the engine dyno. Endyn is one of the few engine builders with an engine dyno in-house. A Superflow SF-902 is something of an industry standard and can withstand up to 1000 lb-ft of torque, if you can deliver it.
Endyn's dyno room is something any engine builder would kill to have. Built entirely of thick block, it's solid. There's also dedicated ventilation with climate controlled air for the room and the engine-it also has the most massive exhaust muffler we've ever seen. This lets Larry do dyno sessions late into the night without a complaint from anyone.
The important distinction between an engine dyno and a chassis dyno, like the Dynapack we'll use later, is that an engine dyno measures the power right at the flywheel. This is exactly how the car builders do it. When Honda says a K20 makes 200 hp, it has tested it at the flywheel, there's no transmission or other driveline connected to it. The company has to run all the power accessories like A/C and power steering plus the complete factory exhaust when doing its power ratings though.
The factory engine dynos have a shaft attached to the engine. A water brake is typically attached to the shaft to apply a load to it. Without it, the engine would just rev up until it over-revved. The running engine produces a twisting force measured in pound-feet. That force, times the rpm of the engine, divided by 5,252 is what gives us horsepower. So in reality a dyno doesn't measure horsepower, it measures torque and calculates horsepower.
Endyn's Superflow engine dyno works precisely the same as a factory dyno and has the same computer controls to regulate everything from temperature to throttle angle. Although at Endyn its test engine will only have an alternator and a basically open exhaust. This is a bit of a cheat, but for the power steering pump to have pressure it would need the entire steering rack and Endyn hadn't finalized a complete exhaust, nor was there room for it.
Connected to the engine dyno with our Endyn-built Dart block, BBK 70mm throttle body and HyTech header, controlled by Hondata's best S300 tuning hardware and software, Larry used a preprogrammed routine to quickly break the engine in. A few hours later, with everything double-checked, it was time to do some tuning. Once Larry was happy with what he was seeing, the engine was run WFO to 7,000 rpm, then 8,000, then 9,000 and finally, a stratospheric 10,000 rpm-all the Superflow could take.
As the engine wound its way down, the results came up on the screen. The Endyn engine had hit a staggering 318.6 hp at 9,300 rpm on its best run, and it had routinely stuck 310, one horsepower above our goal. All this on pump gas and what Larry considered a "live-a-long-time" tune.