We all know the importance of cylinder heads, induction systems, camshaft selection, compression, and other major factors when it comes to making real horsepower out of your engine. Well, what about the silent killers that rob horsepower while simply doing their job. Things like fans, alternators, water pumps, and even your humble oil pan. These may not be the make or break between a lazy dog of an engine and a real hardcore screamer but they all have a role in making your engine work its best or leave something to be desired.
In this compilation video made with pieces of different episodes of Engine Masters you’ll see Freiburger, Brule, and Dulcich test stuff on the dyno at Westech and take a hard and fast look at how these “little” things can subtract from your stable or ponies.
Maybe this stuff is too small to matter to most hot rodders but for racers where tenths of a second count it could be the difference between winning and losing. Outside of the mechanics of the whole thing it is pretty neat to see, in real testing, what’s good and what needs to be avoided. The shocking things may not be the parts themselves but rather their potential performance cost. Watch!
Too bad they didn’t take it a step further and test a power steering pump and AC compressor. Gotta think adding these two stock OE accessories will cost about the same as the tested alternator and water pump. Looks like we are looking at about 70-80 HP loss for all accessories. Add an air filter and full exhaust and we are showing the difference between pre 1972 SAE (or gross) HP and the net HP ratings after 1972. Then take off for drivetrain loss and it’s easy to see how stock 1970 LS6 Chevelles with 450 SAE HP made less than 300 at the tires. Cool test.
Good testing. The drag losses are exactly why the NHRA MANDATES that the drive belt MUST be tight enough to run all the pulleys present on the engine.
Some people in the Jr. Stock classes figured out that a very loose belt freed up HP and got caught.