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Old 10-30-2005, 04:25 PM   #7
Scooby Specialist
Member#: 4498
Join Date: Feb 2001
Chapter/Region: NWIC
Location: Portland, Oregon
WRX H6-3.0 Turbo


Originally Posted by RainMaker
So one gets the impression (that I have always had), that the dyno could potentially be used for 2 seperate functions:

1. Simulate operating conditions for an automobile in particular, thereby allowing tuning to be most thorough, safe, and repeatable.

2. A standard communication device. i.e. a method for communcating the potential output of a vehicle.

For each of these two purposes, a different tool would be optimal, yes?

If we are speaking of purpose #2... then it seems to me that on the surface we are merely lacking the coordination to organize and standardize the details. There are many variables at play beyond simple air density correction. My car, yesterday, was at no risk for heat soak. 55 degree air was blowing at a hell of a rate over the intercooler, the engine, etc. The same engine, in Houston, in August, would see heat soak much faster. Net out... if we are to make a dyno curve a standard cumminication mechanism... several variables need to be pegged.

If the interest in standardizing the variables in order to communicate engine output is purely scientific, it's going to be difficult to do. There is business at play here... marketing, sales, promotion, grass roots innovation, etc. Only a portion of forum members would have an interest in standardizing variables for the better of alot of us. Many would probably rather stick to a deceptive game of dyno queening and unsupportable showboating.

If we could standardize, would "we"?
On #2, that is a very tall order.. As you suggested, the best tool for #1 might not be the best for #2. If you ignore the atmoospheric variables, in a non corrected mode the dyno tells you what power you made.

I think it is a critical point that corrections are not to correct to what you really made. You made what the dyno measured uncorrected, period. The correction is intended to help you understand what you MIGHT have made in different conditions, assuming you follow logical and well established procedures, and your not an idiot.

IMHO, all results should be pubished uncorrected, with data logs. Then again I believe in the tooth fary, so better discount what I say a bit.

As for the showboating, it occurs in so many ways. Even thou 1/4 mile times are a display of power they cover VERY narrow portion of the equation. My opinion of correcting 1/4 mile times (not done here, but the car magazines do it) is the same. Flawed. Very flawed with forced induction vehicles. As well, lap times at your local track are very dependable in the driver, tires, suspension, etc.

In the end, I think it it GREAT that so many people publish the results they get. I very much welcome the information, and it is the intrepretation that needs more thought.


Jeff Sponaugle
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