UK Karting - Notice Board (2-Stroke Karting) : Re: Max revs

Notice Board (2-Stroke Karting)

Re: Max revs - Gearing?
Posted by 'SimonS' on 19 Nov 2009 @ 12:32

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SimonSJoined: December 2004
Total Posts: 4
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"Hi all, Does what gearing you run impact on the max revs you get?"

Er, yes and no.

The Maximum revs you will get depends on all sorts of factors, including the temperature and pressure on the day, the state of the engine (internal friction etc) and the drag of the kart.

It will also depend on the accuracy of your instruments.

Also it isn't unknown for the ignition system to fail to get every spark to where it's needed and that can result in a loss of revs.

So, while the engine manufacturer may say that 17500 is possible, it may not be gearing that is preventing you from getting there but the toe out on your front wheels.

There's a very quick check you can do as to whether you are hitting the limit of gearing or whether it is other factors. If you are changing a the rear sprocket by one tooth then calculate the increase in maximum engine revs you should see.

For example, if you change from an 88 to an 87 tooth and you have been seeing 16100 revs, then you should see a drop to 87/88*16100=15917 revs. If you go up from 88 to 89 then you should see an increase to 89/88*16100 =16282 revs.

If you see exactly those calculated revs then you are reaching the same top speed, but check your lap times as teh different acceleration patterns may speed you up or slow you down.

On any normal track you never want to see the theoretical maximum anyway. What you gain gearing for the fraction of a second at 'top speed' is lost by being overgeared for accelerating out of the slowest corner.

Message Thread:

Max revs - Gearing? by 'Attack2001' (18 Nov 2009 @ 23:45)

Re: Max revs - Gearing? by 'winger93' (18 Nov 2009 @ 23:56)

Re: Max revs - Gearing? by 'Attack2001' (19 Nov 2009 @ 0:03)

Re: Max revs - Gearing? by 'winger93' (19 Nov 2009 @ 0:56)

Doh! by 'Attack2001' (19 Nov 2009 @ 1:21)

Re: Doh! by 'chriskasch' (19 Nov 2009 @ 10:16)

Re: Max revs - Gearing? by 'SimonS' << You are here!

Re: Max revs - Gearing? by 'Geoffy' (19 Nov 2009 @ 12:52)

Re: Max revs - Gearing? by 'Attack2001' (19 Nov 2009 @ 13:30)

Re: Max revs - Gearing? by 'chriskasch' (19 Nov 2009 @ 14:37)

Re: Max revs - Gearing? by 'Attack2001' (19 Nov 2009 @ 18:34)

Re: Max revs - Gearing? by 'winger93' (19 Nov 2009 @ 19:45)

Re: Max revs - Gearing? by 'Attack2001' (19 Nov 2009 @ 20:22)

Re: Max revs - Gearing? by '100ccnational' (19 Nov 2009 @ 21:56)

Re: Max revs - Gearing? by 'Attack2001' (19 Nov 2009 @ 22:15)

Re: Max revs - Gearing? by 'rogergreen' (22 Nov 2009 @ 23:03)

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