[Land-speed] Chassis Dyno Operations

[drmayf]

Kirkwood wrote:

>The only chassis dyno pull I have witnessed in the last 10 years was a
>roadster with a C-10 automatic. That run was done in 2nd gear not high gear.
>When I asked why 2nd gear the operator said the same as you, it didn't make
>any difference but it kept all the rolling speeds lower and he preferred to
>test that way. Even at that I thought the building was going to collapse.
>The only justification I could see for a high gear pull is to quantify
>actual RWHP. If high gear is 1:1 and is a few percent more efficient than
>lower gears then you are quantifying the actual HP producing terminal
>velocity. Any gear less efficient would be an inaccurate result. Maybe I
>should rephrase that. Even if overdrive is less efficient you would want to
>test in the gear that is providing terminal velocity. Isn't that the RWHP
>that counts?
>-----Original Message-----
>From: drmayf [mailto:drmayf at mayfco.com]  
>Well, this wasn't an exercise to try and find out why a dyno I have 
>didn't work (I don't have one).  I was asking why we do testing the way 
>it is done. What is the rationale for doing it that way?