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Old 09-29-2013, 10:25 AM   #510
Studly Adventurer
Joined: Jun 2013
Location: Alaska
Oddometer: 585
Originally Posted by roger 04 rt View Post
The dyno operator has the ability in input temperature, elevation (?) and humidity. However, many, if not most, dyno pulls only last a few seconds and the machine only gets rolling at above 2000-2500 rpms.

A more interesting test would be to put the bike in each gear at several rpms between 2000-4000 against a load controlled dyno, turn the throttle a fixed amount and see what the rate of acceleration was. This is more representative of what we want to know as riders, IMO. However, this is the type of costly testing that only a company can usually afford.

While I commend your work, you are either unaware, or choose to ignore how a skilled dyno operator produces a quality dyno tune. For starters, they don't simply stuff a sniffer up the tail pipe. If proper bungs aren't already on the headers, in the proper location, then Rivnuts are installed where they belong, to provide sample ports for wide band sensors. To produce the fuel/spark maps, the engine is run through as many throttle position, rpm, MAP as possible, under varying loads, so the correct adjustments can be made to the fuel/spark tables. The final pull that you see printed out, is done at WOT, in a single gear, in a few seconds, as you say. What you don't see are the hours of data collection done to reach that point.

Is a generic, across the board enrichening device helpful to correct an engine tuned on the lean side....absolutely! However, it cannot possibly match the performance of a QUALITY dyno tune. With it, you can run the engine rich where either low speed manners, or under heavy load/high throttle settings for power. But keep it near Stoich at steady state cruise, and preserve fuel economy, as well as keep emissions low.

Devices like the Xied are great bang for the buck, but to say they outperform a proper dyno tune, coupled with a remap of the fuel tables, is wishful thinking, IMO.

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