I actually am still learning with the dyno and it's important to understand my knowledge is largely "southern or east coast" based. :1tooth:
I have not tried to run a dyno in Denver, nor have I tried to race in Denver.
The Dyno Jet weather station reads temp, vapor pressure, and barometric pressure. With these readings it selects a correction based on the factor used. Example, SAE would have a correction formula based on those readings and the dyno would apply it.
Calculating 1/4 mile MPH based on a dyno run. In many cases they won't be exact. That can depend on a ton of stuff from wind direction, accuracy of the dyno, accuracy of the track timing lights for MPH, and accuracy of weight. They all have impact. From having to scale at every Pro Street race, scales vary largely from track to track. Wind direction can play a large role, and I would expect (don't know this) that at higher elevations where air is thinner, it's also easier to move these bricks of ours through it.
The reason I like a dyno jet for street/strip is because the dyno jet will tell you how responsive the truck is. If I can't get 10 lbs of boost on a turbo before the run, it's laggy. If it's laggy then it will be harder to launch on both street and strip. A truck that will make that 10 lbs will be responsive, and aside from much more fun on the street, it will launch harder and yeild a better ET. So in this example, a truck with a slow responding turbo may make a bigger number on a load cell than dyno jet, yet lose the race.
There is always talk about not making street boost on a dyno jet. Some trucks don't that is for sure. Some do. So I have to ask why is that? When I put tubz 7.3 on my dyno, when I got into it, it spun the boost guage hard, the truck slapped down a great number on the dyno. Many PSD's I do have a lazy boost gauge and don't make peak boost until the upper RPM's. Many duramax's I do will make a good boost number in the beginning of the run, then the boost will fade as the run progresses. Why?
I figured I would not be able to get Maddog's turbo's lit. Those are the largest chargers I have had on my dyno. His small charger was an A5000. Before the run I asked how much boost did it make. After the run it had made the same number. Even stage boost was where it should have been. This set-up was right IMO and the result was a new dyno record.
In 2002, I raced a Denver truck here in Atlanta that had dyno'd 90hp more than me. Same truck configurations, the only difference was mine was 90hp less on a Atlanta dyno. We ran identical times and speeds. So then you have to ask, where was the 90hp or was that 90hp corrected to altitude that was in fact bogus?
Bottom line is none of accepted methods of measuring HP is gospel. One track I was on showed I had gained 3 mph. Yet the dyno said I had gained no power. So what was up? A quick run through the pits and I discovered EVERYONE was 2 - 3 mph faster at this track which told me the timing lights were wrong. So in this case, without checking, I could have said the dyno was wrong. But was it?
Again, I like load dyno's. You can do some cool stuff with them. I also remain open to the day when turbo's may get to a point where I have a hard time loading them, It's just that so far, when I can dyno two trucks with the same set-up, one hits hard and runs well and the other does not, I have to point to the truck, not the dyno. But I am sure I will be proven wrong sooner than later... LOL