UK Karting - Notice Board (4-Stroke Karting) : Re: Rpm dyno reading?

Notice Board (4-Stroke Karting)

Re: Rpm dyno reading?
Posted by 'RoadRat' on 09 Aug 2009 @ 16:19

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RoadRatJoined: July 2007
Total Posts: 1
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You shouldn't buy an engine on the basis of only a peak power figure, whatever name it has on it. When you consider Honda used to claim 5.5 hp for a governed engine, a figure like that is only useful for direct comparison with another engine run on the same day on the same dyno. Otherwise you have to make a lot of assumptions to read anything useful from a single Dyno graph. Even assuming their correction factors are appropriate(standard correction factors supplied with most Dyno software does not tend to suit the GX engines)and you can compare max HP from another engine run on the same Dyno, then you still need to know much more. Because this is only one point in the power curve.

With an inertia dyno, proper tuners will often compare accelaration time between 2 points for their own use. On an absorber type, you can calculate an average between two points in the usable rev range. While the peak figure might give an indication to the operator is should otherwise be considered only good for selling and or bar room chat.

On my dyno a good GX160 reads between 6.7 and 7 hp, even my best GX120's put out peak power of between 5.2 and 5.5hp. But these figures in themselves are meaningless. Only way to know for sure is to run it back to back with a known engine.

Message Thread:

Rpm dyno reading? by 'Cannar' (09 Aug 2009 @ 11:54)

Re: Rpm dyno reading? by 'daveleeroth' (09 Aug 2009 @ 11:59)

Re: Rpm dyno reading? by 'RoadRat' << You are here!

Re: Rpm dyno reading? by 'lard ass bob' (09 Aug 2009 @ 19:02)

Re: Rpm dyno reading? by 'Trev' (09 Aug 2009 @ 19:07)

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