Obviously, we all know the answers - yes dyno numbers aren't unfailable. And yes, of course you can make 500 cam only - we've seen plenty of examples here over the years.
So, it's not the point, but I did make 497whp here, "cam only". M6 car, and it's the GPI SS3, and all the supporting mods that go along with that for breathing and the valve-train. The curve is incredible, the car makes STRONG power from 5000rpm right on through 7200rpm. They let me operate my own car on the dyno too, which was awesome. I've never seen that happen anywhere, and it was a truly unique experience I couldn't pass up. If that's all you wanted to know, you can move on. If you wanna here about why I don't trust dyno numbers, continue reading below.
The point is about dyno results, and why they always need to be taken with a grain of salt (or maybe a whole jar of salt!). The package in my car was installed and tuned this spring at New Age Hotrods. Josh has a Dyno-mite dyno which operates with a load cell. We did a baseline pull on the car before the under-drive, intake, and cam which was 402rwhp. The car had previously been dyno'd a few years before at a competitors shop when the first round of mods went on, and did 412rwhp, on a dynojet. So, about a 2.5% difference there. After the mods the car put down 473rwhp, corrected with whatever Dyno-mite's software uses for a correction factor, probably SAE J1394. Knowing Josh's dyno has a reputation for being a heart-breaker I was plenty satisfied with that, the car had a savage curve that we know is gonna haul at the track.
Last night a local shop hosted a dyno-day with a Dynojet. I watched several other cars go, and the results were pretty much exactly what I expected, certainly nothing bogus or abnormally high. Knowing that a Dynojet usually beats Josh's dyno by at least 10whp I figured I'd see what I could lay out.
I made my pulls and made 485whp and 483whp, uncorrected. When you apply the STD (SAE J607) correction (which is the Dynojet STD correction factor) for temp, humidity and baro the corrected HP is 497whp.
Also, for what it's worth, my buddies ZL1 made 543whp on the New Age dyno, and laid out 570whp last night.
So, that's almost 5% variance between those two dynos. The variance was dead consistent between both cars - so I think it's safe to say it's the dyno's differences. Zero changes on either car between runs on each dyno. Not surprised, but more just interesting.
I figured I'd share my experience here, because it's all first hand, same cars, same geography, no trickery or weird stuff going on. If there is a point, it's that dyno numbers don't mean all that much, they are ok for general comparison. But don't get lost in a 5% difference, because it just doesn't translate 1:1 between each dyno, even with correction factors.
Oh, and video, because the sweet sweet sound of an LS3 running to 7200rpm should be enjoyed by all.