It is easy for any relatively well-made distributor to perform well at 2,000 rpm. But where's the fun in driving around just slightly above idle?
When your engine is at higher rpm levels, that added engine speed makes it harder for any distributor to hit the timing target accurately. And its this loss of accuracy that can cost you horsepower. Whether you are racing, having a little track-day fun or just the occasional blast from stoplight to stoplight, nobody wants to give up any horsepower unnecessarily. Don't worry, we're here to help.
Engine builder Keith Dorton of Automotive Specialists employs a pretty rare piece of diagnostic equipment on his engine dyno that actually gives him the ability to accurately track ignition spark timing in all eight cylinders individually ever one hundred rpm across the span of a dyno pull. As you can guess, this produces information that can be much more useful than you can gather with a timing light, and he regularly uses it to tune his race-winning engines. Thankfully, he also allowed us to document some testing he was doing with several different distributors to determine their accuracy.
The results were pretty enlightening. Obviously, the distributors with the fewest moving parts consistently proved to be able to maintain the greatest accuracy across a wide rpm range. Check it out for yourself in the video below.
There are also several charts in the video, and it can be hard to soak it all in on the screen. If you want to take a closer look, we've included several of the charts below.
Please make sure to let us know what you think in the comments below!