You guys crack me up sometimes.
Dean, the advantage of the dyno is repeatability. You put he exact same lod on the car every run, so you get exact quantified data of what the last set of changes you made did. With a dyno and a couple hours, you can do every sort of load testing there s- steady-state cruise, tuning thottle tip-in, WOT runs, everything you and Austin has mentioned, for far less than the cost of one speeding ticket (or reckless driving, even). I plan to run a Hydra from Element in the car once it has a turbo, and it's going to get road tuned to make it drivable, then it's going to Nate. Then, everytime I go someplace with a change in altitude (Thunder Hill, Reno-Fernley, Stead, Infineon, wherever I'm racing) I'll do as much datalogging as possible to see if it actually NEEDS adjustment. I'm betting the tweaks will be minor with my car, because it's a speed/density setup. Tweaking all it will need to scrape that last 5-10 hp up. It's not as if the car will suddenly run poorly at high altitude on a good valley-tuned map. There may or may not be a few extra horepower left is all. Point is, you're spending a lot more on your equipment and assuming a lot more risk by attempting to tune your car yourself than you'd spend by letting Nate apply his experience (and training, and factory information sources) on his dyno, for the sake of small gains. Then there's the consideration of the hardware- there's a guy in Sac whose AP can't even report a CEL code properly (reported as "06B7" and believed to be "P0607"- Performance Control Module failure.
) and plenty of issues reported with adding and divorcing APs to cars.