UK Karting - Notice Board (4-Stroke Karting) : Re: dyno figures, drew

Notice Board (4-Stroke Karting)

Re: dyno figures, drew
Posted by 'itpro' on 09 Mar 2015 @ 16:47

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itproJoined: August 2001
Total Posts: 6
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If you thought I'd said that you could not get an 'exact' or 'accurate' bhp rating, I must have expressed myself badly.... or you misunderstood what I wrote!

I agree, there ARE ways to get an 'accurate' bhp from some dynos...... However, my point is that dynos should be set to an 'exact' figure but we have no proof that they are and we have damned good reasons to think they are not.

They get standardised 1ft rules because there are practical ways to compare one rule with another. For the degree of accuracy required from a ruler, you don't set significant changes in measurements if it rains or the barometric pressure drops. You DO get significant changes to the dyno's readings if those things change! Secondly, if Fred's dyno is in Leeds and Sid's dyno is in Kent, how are you going to compare the reading. Thirdly, if you did find a transportable 'standard', how are you going to know that the weather conditions remained identical at both locations? Yes, there are tables that allow rough adjustments for such things but that's all they are 'rough adjustments'.

Fourthly, who do you know who is doing these comparison's between dynos to check their accuracy? Even if Sid and Fred were trying to be scrupulously accurate, how would THEY know what the 'correct' calibration, especially if you were considering an 'oil pump/resistence' dyno against a flywheel/inertia dyno?

Finally, the performance of an inertia dyno is NOT the same as for the Oil Pump dyno and the method of calibrating each would therefore not be the identical, either. For those who don't already know, the oil-pump dynos apply increasing resistance until the engine sits, at 'ideal' throttle at a specific revs. The inertia dynos see how quickly the engine can change the revs of a heavy flywheel. Thus, the first sort may hold the engine at exactly 10,000 for 20 seconds or so, whereas the inertia dyno will only show the engine's performance at 10,000 rpm for a few milliseconds!

Ian

Message Thread:

dyno figures by 'ndiracing' (06 Mar 2015 @ 6:11)

Re: dyno figures by 'itpro' (06 Mar 2015 @ 17:42)

Re: dyno figures by 'DrewHoward' (07 Mar 2015 @ 13:20)

Re: dyno figures by 'GregLGracingmanager' (07 Mar 2015 @ 18:33)

Re: dyno figures by 'benbab' (10 Mar 2015 @ 12:21)

Re: dyno figures by 'matt535' (07 Mar 2015 @ 19:10)

Re: dyno figures, drew by 'itpro' (08 Mar 2015 @ 15:37)

Re: dyno figures, drew by 'PaulMRotax' (08 Mar 2015 @ 16:04)

Re: dyno figures, drew by 'orton1966' (08 Mar 2015 @ 19:29)

Re: dyno figures, drew by 'PaulMRotax' (08 Mar 2015 @ 22:12)

Re: dyno figures, drew by 'itpro' (09 Mar 2015 @ 0:22)

Re: dyno figures, drew by 'd-i-y71' (09 Mar 2015 @ 9:29)

Re: dyno figures, drew by 'itpro' (09 Mar 2015 @ 10:16)

Re: dyno figures, drew by 'd-i-y71' (09 Mar 2015 @ 10:34)

Re: dyno figures, drew by 'itpro' (09 Mar 2015 @ 10:43)

Re: dyno figures, drew by 'PaulMRotax' (09 Mar 2015 @ 13:20)

Re: dyno figures, drew by 'd-i-y71' (09 Mar 2015 @ 11:21)

Re: dyno figures, drew by 'PaulMRotax' (09 Mar 2015 @ 13:34)

Re: dyno figures, drew by 'itpro' (09 Mar 2015 @ 15:01)

Re: dyno figures, drew by 'd-i-y71' (09 Mar 2015 @ 15:36)

Re: dyno figures, drew by 'PaulMRotax' (09 Mar 2015 @ 16:13)

Re: dyno figures, drew by 'd-i-y71' (09 Mar 2015 @ 16:44)

Re: dyno figures, drew by 'itpro' << You are here!

Re: dyno figures, drew by 'PaulMRotax' (09 Mar 2015 @ 19:25)

Re: dyno figures, drew by 'PaulMRotax' (09 Mar 2015 @ 16:05)

Re: dyno figures by 'EtheT' (09 Mar 2015 @ 16:44)

Re: dyno figures by 'itpro' (09 Mar 2015 @ 16:50)

Re: dyno figures by 'PaulMRotax' (09 Mar 2015 @ 19:16)

Re: dyno figures by 'orton1966' (09 Mar 2015 @ 19:39)

Re: dyno figures by 'EtheT' (10 Mar 2015 @ 11:17)

Re: dyno figures by 'orton1966' (10 Mar 2015 @ 20:03)

Re: dyno figures by 'essexelite' (11 Mar 2015 @ 13:20)

Re: dyno figures by 'bodinski' (30 Mar 2015 @ 9:34)

Re: dyno figures by 'Knighty' (30 Mar 2015 @ 9:54)

Re: dyno figures by 'bodinski' (30 Mar 2015 @ 22:21)

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