Having a clear goal in mind in the first step in building a great engine, according to Comp Cams’ Billy Godbold, who led off the afternoon session on the first day of the Advanced Engine Technology Conference (AETC).
Godbold’s discussion focused on the new line of 4-pattern camshafts that apply NASCAR technology to street hydraulic-roller cams. EngineLabs covered this award-winning product in an exclusive story earlier, but Godbold expanded on the benefits of the cams to bracket and index racers at the dragstrip.
“They’re less sensitive to weather changes and easier to tune because the air-fuel ratio stays more consistent,” says Godbold.
The 4-Pattern cam is designed for single 4-barrel engines where the intake manifold has longer runners to the outboard cylinders than the inboard cylinders. The difference in length is about 10 percent, which disrupts fuel distribution to the engine. The 4-Pattern cam helps compensate for the airflow dissimilarities with different cam profiles for the inboard and outboard cylinders.
“If you get the cylinders working the same,” adds Godbold, “then there are fewer tuning problems when the weather changes.”
In a wide-ranging talk, Godbold noted that good engines have great parts, but great engines always start with good plans.
“You get a guy to who buys the best heads, best cam and best manifold but the parts don’t match,” says Godbold. “Then the other guy doesn’t have as much money in his parts but he has a better engine because had a plan from the beginning.”
Godbold also stressed the importance of establishing relationships with key suppliers.
“It’s hard to know everything about every component in an engine,” says Godbold.
The move to crank-driven oil pumps in late-model engines like the LS platform at General Motors and Ford’s modular line has changed the lubrication dynamics of the engine, according to Osterhaus. Traditional cam-driven pumps are more efficient but today’s crank-driven pumps turn twice as fast, therefore, supply more oil to accommodate new features like cylinder deactivation and variable valve timing.
Osterhaus showed a comparison between a Melling Gen 1 small-block oil pump that flows .0006 gal per single turn or rev of the pump, while a Gen III pump is rated at .0004 gal per rev. But consider that the Gen III pump turns at engine speed and the Gen 1 turns at half engine speed, so the Gen III pump delivers more oil at the same engine speed.
The problem with late-model pumps, according to Osterhaus, has been cost compromises in materials and design that may not keep up with performance modifications to that engine. For example, automakers have been moving away from cast-iron to reduce weight.
“We like cast iron,” notes Osterhaus. “It’s a good wear surface and has pores that help with lubrication.”
Crank-driven pumps also change the way engines are primed before initial startup. The old drill-and-oil-shaft routine no longer applies, so engine builders must invest in a pressure tank system.
“But it’s a necessary step,” stresses Osterhaus.
Cummins’ presentation focused mostly on the benefits of data acquisition but separated the end user between open- and close-course disciplines. The open-course user is in drag racing, truck pulling and other racing outlets where engine performance is more of a factor than the driver. The closed-course viewpoint is that data acquisition needs to help the driver and the engine is secondary. Either way, data acquisition is only a tool for improvement in engine or vehicle performance.
“The improvement is proportional to the effort in learning how to use the data,” confirms Cummins, who races a 300-mph nitro-fueled roadster at Bonneville.
By monitoring the acceleration with G meters, engine rpm and driveshaft rpm, drag racers can determine unwanted wheelspin or missed shift points that otherwise could have been mistaken for being down on horsepower. For circle-track and road-course racers, monitoring lateral G forces — along with steering, brake and throttle inputs — can help drivers execute turns and set up the chassis.
“For drivers, data acquisition is like being a tattle tale,” adds Cummins. “But everyone stops playing the guessing game.”
For the future, Cummins announced that Racepak is working with AEM on integrating a torque sensor off the tailshaft housing to give racers additional information to monitor performance and set up their vehicles. A system should be introduced sometime in 2013.