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Old 06-11-2010, 09:24 PM   #32 (permalink)
steffen707
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Quote:
Originally Posted by jdgFirefly View Post
I don't think its this is something you can do an apples to apples comparison on.

As for the dyno test showing hp gains. It should show hp gain's when doing a dyno pull because the engine is quickly accelerating to the redline, the heavier flywheel takes more energy to accelerate and hp is the rate of energy output. so the faster you rev up the engine, the more hp is required. If you could test hp at a constant rpm you would see no significant difference.
I think maybe you're confused about my apples to apples definition. The perfect scenario would be to take a car and use scangauge to calculate what mpg you get an a specific X mile stretch, drive home, change flywheels with the same car, same tires, same exact speed, same weight (because you would top off the gastank) go to that same X mile stretch and have scangauge calculate mpg. In doing this you would eliminate as many variables to isolate the results to just the flywheel and weather (unfortunately I don't have an enclosed course to test on). this would be an apples to apples scenario where the only thing you changed as far as variables was just the flywheel.

Horsepower actually is "One horsepower is defined as the energy needed to lift 550 pounds one foot in one second, and an engine's horsepower rating is simply it's torque multiplied by rpm, divided by 5,252 to convert to revolution per minute (rpm)."

And dynos can test the torque and thus horsepower because horsepower comes from torque, at specific rpms, That's what the dyno plot is, its showing at all those rpms what the torque of the engine is. They do have dyno brakes that can allow you to tune hp for specific rpms. So there are actually VERY SIGNIFICANT gains made from this one particular car on importtuner.com with a lighter flywheel with nothing else changed at not just the top rpm but along every rpm of the usable rev range.

True most people wouldn't do my apples to apples "test", but i'm hoping somebody on ecomodder has tried it. Its valuable info for people that are going to extents of taking mirrors off cars and making underbody pans to know if it helps or hurts or doesn't help much at all, and therefor is more of a pain in the butt to drive and not worth it in their opinion.

metrompg showed 10% gain in mpg from alternator delete on his car, does everybody on this site now do that? No way, but for some that's their cup of tea.
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