Hey. Lets see if I can address all these to the best of my knowledge...
mrabusa_h: The Dynojet dyno drum can be considered a flywheel of sorts. Bascially, it's an drum that requires HP to turn it from speed a to speed b in a measured amount of time. Basically, the change in velocity over time is acceleration. With acceleration, and a known mass (the drum's inertia), HP can be mathematically calculated. Add RPM to the equation, then you also have torque.
The EC997a and other load style dyno's measure either current or pressure to get a torque figure. There are several problems with this method.
Even though controls have gotten much better over the years, heat influences measurements. The inertial design does NOT need to measure anything by way of friction, therefore it's more consistent and repeatable.
The horsepower model used by dyno's may be different. This can account for differences between different manufacturers of dynos. Typically, as tested by multiple magazines, the Dynojet dyno's vary less than 1/2% on a consistent test subject from dyno to dyno.
I don't know where you came up with that 1.18 correction factor from Dynojet...was that something that the Factory dyno operator told you to use? If that was a correction factor as shown on one of the dyno runs made on a Dynojet, that means that for the conditions of that day, for each 100 rear wheel horsepower, the SAE correction factor was adding 18% to account for atmospheric condition. That is feasable for their location in Montana. You should see much less than that in California, Florida, etc. (sea level states), more like 1.00 or there abouts.
The real problem with trying to correlate a Dynojet number with the EC997a number is the testing method used. A load style dyno measures the amount of resistance needed at given RPM intervals in order to give a torque reading. The inertia dyno's give a reading of the acceleration. Now, when you ride your bike, do you accelerate, or sit at a given RPM?
Bob: That tire speed measurement device that the SF dyno's have is difficult for me to fathom. My understanding is that they are measuring to see if the speed of the tire is different than the speed of the drum. Okay, so if they are different, slippage is occuring. How could that add that back in to figure horsepower? If horsepower can be calculated by accelerating a known mass, yet slippage means the tire is accelerating, but NOT the known mass, how can they calculate anything?
Also, if a dyno run starts at 3k or 4k RPM, why should tirespin be a problem? Typical runs are made in 4th gear. Traction shouldn't be a problem without the extra torque multiplication of a lower gear.
The load devices are extremely useful for tuning the FI bikes. They are mandatory for producing load at given RPM's. If you've used a Power Commander, then you know what I mean. Dynojet has this, as well as the others. Dynojet doesn't offer CO%, but rather air/fuel ratio, which can be displayed after the run on the same dyno graph. This will give excellent data on whether the bike is rich or lean and at what RPM.
Regarding the big fans on the SF...how does that work? I was thinking about those and how do they account for the losses of spinning the fans? I'd imaging that the losses would be different with different conditions as well (ie, higher altitude means less dense air, so easier to spin the fans, etc.).
JimP: The 'Busa is an FI bike with an AP sensor. This means that as air box pressure builds, it automatically corrects with fuel. Sure, peak power output may be slightly higher at speed (I seem to remember one mag doing a test on the ZX-9 a few years ago and figured it gained 6hp at 160mph), but if everyone is tested on even ground, the amount of difference due to airspeed is negated. If you make X on the dyno, then you make X + ram air. If your buddy makes X+5 + ram air, then he has 5 more with the ram air as well, at the same speed.
