Quote:
Originally Posted by Domman56
wouldn't it make LESS of a difference on the dyno because the truck is just rolling on the rollers and not really working to pull the truck along?
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Quote:
Originally Posted by Domman56
you strap your car to the dyno and do pulls to see how much power your car makes to the Drive wheels because there is a significant loss from the crankshaft to the actual rear wheels. Variables on a dyno would usually be whether you had a fan infront of the intake or not as well as tempurature Air fuel ratio ect.
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You can't determine HP ratings or Torque output without loading sufficient to create that output. Therefore, the truck (vehicle) is absolutely not just rolling on the rollers, as you put it. The engine is stressing just as hard, if not harder, on a dyno environment, than it would be in the real world on a normal street.
The Dyno is considered controlled conditions, and thus, is able to be used for scientific testing moreso than driving the vehicle in the open. More variables can be controlled using the dyno, and in some cases, fuel input can be logged directly and compared to HP output to determine things like peak efficiency, BSFC maps, BMEP maps, peak torque output, and more.
I'm not sure where you got the idea that it's just "rolling on the rollers", and I don't want to know... but it's just not the way it works.
I've made runs on a dyno in several types of vehicles. Particularly of note, and something I didnt' know until recently, is that turbo cars require a different type of run to get an accurate reading, because the dyno doesn't load the engine properly to spool the turbo. You rev the engine up to enough speed to get into 3rd/4th gear (doesn't actually matter what gear you're in, but you want to load the engine for an accurate reading, and not take all day doing it), then the dyno loads the engine up enough to surpass it's power output and drag it back down to a decent engine speed, then lets it rev up under load. The cycling is to keep the turbo spooled for max output, and an accurate reading.