UK Karting - Notice Board (2-Stroke Karting) : Re: measured jets

Notice Board (2-Stroke Karting)

Re: measured jets
Posted by 'SimonS' on 23 Apr 2014 @ 17:24

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SimonSJoined: December 2004
Total Posts: 4
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Looking at the problem of measurement:

Things that can affect the flow rate include:

Temperature
Viscosity of the fuel
Turbulence in the flow
Pressure of the fuel
The shape of edges of the jet (at the microscopic level)
The general size and shape of the hole
Size, shape, and taper of the needle.

Even something as simple as the shape of the edges of the hole ;ie: are they sharp or rounded, was the drill sharp(fresh) or blunted (just before being changed for a new one can make a difference to the measured flow.

The manufacturers make them to a tolerance. If one gets the jet made to the maximum + tolerance and the needle made to the maximum negative tolerance, then the effect can be measurable.

You could have each needle and jet inspected and charted compared to an 'ideal shape', but typically it would cost two to three times what it costs now. Aircraft parts are ferociously expensive simply because many of them, down to the nuts and bolts and things like brake seals, are measured and certificated as being 'right'.

This is how people make better performing engines out of standard, not to be altered, parts. Buy many engines and bits, weigh and measure them to find those that can be combined to make the best performance and turn out a 'best' engine.

It (tolerances and conditions at use) explains why parts can perform differently from one's expectations, while meeting the manufacturers' labelling exactly. It isn't 'sharp' practice or bad manufacture at all, though this isn't to say that some people won't take advantage of it.

Message Thread:

measured jets by 'DaveBuky' (22 Apr 2014 @ 20:39)

Re: measured jets by 'd-i-y71' (22 Apr 2014 @ 22:30)

Re: measured jets by 'DaveBuky' (22 Apr 2014 @ 22:34)

Re: measured jets by 'd-i-y71' (22 Apr 2014 @ 22:43)

Re: measured jets by 'DaveBuky' (22 Apr 2014 @ 22:53)

Re: measured jets by 'd-i-y71' (22 Apr 2014 @ 23:12)

Re: measured jets by 'moondog78' (23 Apr 2014 @ 0:07)

Re: measured jets by 'DaveBuky' (23 Apr 2014 @ 9:19)

Re: measured jets by 'TeamPoor' (23 Apr 2014 @ 10:37)

Re: measured jets by 'alanrr' (23 Apr 2014 @ 10:53)

Re: measured jets by 'DaveBuky' (23 Apr 2014 @ 11:37)

Re: measured jets by 'SimonS' << You are here!

Re: measured jets by 'BanzaiBoy' (23 Apr 2014 @ 17:56)

Re: measured jets by 'DaveBuky' (23 Apr 2014 @ 21:00)

Re: measured jets by 'moondog78' (23 Apr 2014 @ 21:37)

Re: measured jets by 'BanzaiBoy' (23 Apr 2014 @ 23:08)

Re: measured jets by 'alanrr' (24 Apr 2014 @ 9:47)

Re: measured jets by 'moondog78' (24 Apr 2014 @ 10:58)

Re: measured jets by 'alanrr' (24 Apr 2014 @ 11:25)

Re: measured jets by 'MikeSimpsonsnr' (25 Apr 2014 @ 19:37)

Re: measured jets by 'TeamPoor' (26 Apr 2014 @ 13:02)

Re: measured jets by 'NJB' (29 Apr 2014 @ 12:20)

^^^^^lol^^^^^.NT by 'moondog78' (29 Apr 2014 @ 15:51)

NJB is right :-) joys of on track adjustment NT by 'BanzaiBoy' (29 Apr 2014 @ 17:06)

Re: measured jets by 'alanrr' (29 Apr 2014 @ 1:39)

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