Champ Car gets more durable, quieter engine
"I think the different exhaust note that you notice is from the wastegates and a slightly different tailpipe arrangement compared to the Lola's system which was a bit longer and a bit more directional. The new exhaust is shorter and dumps straight out. We've also tuned-up some of the fuel-mapping in the new ECU and because we have a split system where the gear control unit is a separate ECU altogether. And that probably has some effect on the sound as well. The end result is that the engine is a little bit more powerful with a bit more smooth of a power curve.
"A lot of people over the years mistake rev-limiter for valve popping," Deagle added. "But the valve has never been audible in any capacity except for perhaps on a very high-speed oval where if the engine speed was below the maximum rev limit and the valve dumps, you probably would hear that. But on any circuit that Champ Cars typically have run on for the last three or four years, you would never hear that."
Improved pistons and oil control system have enabled Cosworth to add 200 miles to the duty cycle of each engine.
"The engines now will run to 1,400 miles," Deagle said. "The limiting factor on running more than 1,200 miles was the piston. After 1,200 miles they were pretty much used up. The duty cycle just beat them up and certainly, if a driver was a little overzealous on downshifting, that was a negative as well. What we learned in the last two years and last year in particular with piston development with our CA Formula One engine were some slightly different approaches for piston design in materials and manufacturing that carried over to this new program. We've also improved the oil control a little. So while the horsepower output is the same, the internal components have been improved to get an extra 200 miles between rebuilds." ChampCar.ws