To dyno or not to dyno?
yes, that makes a lot of sense, it was a learning experience. i guess i choose the wrong tool or had the wrong expectations. They were all happy to take the booking
Dave, Sorry to read you had bad experiences at all three.
It can be a useful tool but it does take a reasonably good operator, and certainly not one that thinks its a cash machine.
The first time I took a car it was reasonably good experience. The owner had done a little talk at our SCCA region's meeting. Not that means a lot. He had his 'kid' run it and he had two rate structures. One was three pulls, the other by time. The first is for the guys just looking for a bragging number, the latter is for guys looking to tune. You bring the parts - you make the changes. He provided a floppy disk with the runs on them.
I used him again again with a different engine. By that time he had added a tailpipe WBO2.
When running on an inertia dyno my undertanding is the most consistant and reliable data is going to be when its full load. In practice this means mid rpm to max with an automatic that can downshift (don't want it downshift). With a stick or a fully manual automatic you can get it to full throttle a little lower in the rpm range.
Because that first session was run by the kid, we captured the data before the shift up, which I think is kind of cool but not really useful.
Eddy current Dynos.
All of the other shops I've used had eddy current dynos or an eddy current add-on. The Bimmer place insisted they could run my '67 but they couldn't. The Mustang dyno attaches to the wheels and the fenders on our older cars are too far out compared to the new cars.
Another shop that was a little further was a similar experience to yours. The son of the owner was the dyno guy and didn't know how to use it properly. He couldn't even figure out how to give me the data files. From what I could figure he ran it with a load 'to be more realistic'. He turned the distributor the wrong way to 'add' timing advance. It was obvious as soon as I was driving it home. :(
The place I used the most let me do what I wanted. They just set it up for me.