The Test
Good dyno testing requires making as many pulls as possible while theatmospheric conditions are the same. NTI's engine building classes wereinstrumental in helping make the many pan changes quickly throughout ourtests.
NTI instructors Luke Woroniecki and Rick Touchette led our dynosessions. After a 30-minute break-in session to allow the hydraulicflat-tappet lifters to mate to the cam, we made a few runs to establishour baseline setup. Timing was set at 38 degrees, the Holley carb wasoutfitted with No. 70 jets, and a 1-inch open spacer was used betweenthe carb and intake. Once we settled on these parameters, they were notchanged for the duration of the test. We also determined that holdingthe water temperature around 180 degrees F and the oil temperaturearound 195 degrees F would keep the pulls as consistent as possible.This provided us with 267.8 peak horsepower at 4,300 rpm and 349.7 lb-ftof torque at 3,600 rpm with the stock pan and 5 quarts of oil. Valvecontrol faded well before 5,000 rpm, so all pulls were run between 2,500and 4,500 rpm. The dyno cell used Nextel Cup-legal race gas. It wasn'tthe best choice for our heads, which don't feature a super-efficientcombustion chamber (like full-race heads) and only allow 8.5:1compression, but we saw little reason to change it. There is certainlymore power to be found in this Chevy engine by tweaking the tuning, butthis is the combination we felt would provide us the most repeatability.
Notice the kickout on the right side of this Champ pan (left in thisphoto) that extends all the way up to the block. To install this pan,the bolts have to be inserted through plugs in the bottom of the pan andinstalled blind. It makes for a difficult install, but the windagesavings can be worth it.
One of the difficulties with this test is that the stock heads andlightweight springs we used significantly limited the rpm. Windagebecomes a much more pronounced problem the faster you spin the engine,and we were looking at horsepower changes that were quite small (as youcan see from the accompanying charts). Still, in racing, an extrahorsepower or two can make all the difference in the world, andimprovements of single horsepower that you see in the charts at 3,000rpm likely will translate to three or four at 7,000 in a full-blown racemotor. This is by no means an exhaustive test that answers everyquestion when it comes to oil control, but it does reveal a lot aboutwhat is going on inside an engine.
This chart shows how oil levels can affect power. Using the stock pandesigned to hold 4 quarts (so the system total is 5 quarts when thefilter is included), we varied the oil levels to see how power wasaffected. As you can see, more oil created more windage problems.Unfortunately, 5 quarts is often too little oil to properly protect theengine under racing conditions. The oil is too easily overheated, andthe potential for the oil pump to completely drain the pan is too high.Racing pans are normally designed to hold more oil so that this doesn'thappen. Both the Champ pans we used are designed to hold at least 7quarts of oil. (For the sake of consistency, we used 5 quarts of oil asour baseline in all our tests no matter what pan we used.) | 
This chart compares the stock pan to Champ's dual kickout pan with awindage tray. Notice how the differences become greater as rpm levelsincrease. Runs were made with both pans using 5 and 6 quarts of oil.With a quality racing oil pan, you can use more oil for betterprotection while still getting better performance from your engine. | 
Varying oil levels in the racing pans didn't provide as much change asit did with the stock pan. That's probably because the design featuresare capable of properly protecting the crank from the oil at much higherlevels. At 4 quarts, however, we noticed that the oil pressure wasunstable--dropping as low as 58 psi at 4,400 rpm when we were normallyseeing over 75 psi at that level--so we determined this was our minimum. |
The Dyno Mule
Our baseline comparison of all three pans. The Champ pans had theirwindage trays installed. As you can see, this just isn't a fair fightfor the stock pan even at just 5 quarts.
Our Chevrolet test engine was assembled with repeatability in mind. Wewere looking for changes in the range of 1-2 hp, and the dyno mule hadto be able to make pull after pull consistently. For that reason, wewere careful with the components we chose that would represent thepieces a racer may use but that would also work well through the stressof repeated dyno pulls.
Engine
Chevrolet supplied a stock long-block 350 with cast-iron 23-degree heads(non-Vortec), 8.5:1 compression, flat-tappet hydraulic lifters, andfour-bolt main caps for stability. The valves were 1.94 intake and 1.50exhaust. Properly tuned for power, the engine is rated at 290 hp with326 lb-ft of torque.
Intake
This chart was our big surprise over the two days we spent testing. Weran Champ's high-end single kick-out pan with and without the windagetray and were surprised to see the results were better without the tray.This, however, turned out to be a flawed test. With just 5 quarts of oilin the system, the pan could adequately protect the crankshaft from theoil with or without the pan. But use 7 quarts in the system, as weshould have done, and put the engine in a car that's on a racetrackwhere the oil will slosh around, and the results will be much different.
Since we were using a low-rpm engine package, a good dual-plane intakemanifold was a must to properly match the powerband. Weiand's new ActionPlus intake fit the bill perfectly.
Carburetor
The vast majority of all stock car racers out there use Holley-basedproducts, so that's what we wanted. We went with a 650-cfm four-barreland only had to make one jet adjustment to the jets.
Belt/Pulleys/Water Pump
A dyno mule needs to be as simple as possible. They aren't going to beused, so there is no need for brackets for an alternator orpower-steering pump. CV Products produces a pulley set for racers thatuses a square-tooth belt that is very adaptable. We ran just the crankand water pump pulley, and the toothed belt meant we didn't need anadjuster. This is perfect for racers who don't want to run an alternatorduring short events.
Ignition
A Mallory HEI is the ultimate in simplicity and ease of use. The HEIdesign is upgraded with a hot coil that provides plenty of power wellbeyond 8,000 rpm.
Accessories
NTI had never run anything on its dyno except Nextel Cup engines, sohooking up our wet-sump motor provided a few challenges. Another problemwe encountered at the last minute was that the stock valve coverswouldn't allow installation of a racing-style breather or relievecrankcase pressure. Bradley Auto Parts is a speed shop specializing inassisting stock car racers that we turned to for everything from aproper set of valve covers, to a multitude of brackets, plugs, andadapters, to a reusable oil-pan gasket to facilitate our multiple panchanges. Because the company specializes in racing, everything was instock when we arrived to look for a new set of plug wires at the lastminute.