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[Nick]

Lydd, Senior Max, driver and kart just 172Kg so 8.5 or 12.5 with a K27 or K98 and why?

It is my understanding that a fast track like Lydd favours the 12.5 and K27 and a slower track like (say) Bayford favours the 8.5 with possibly the K98 in it for the slightly heavier driver, can anyone back that theory up, or of course, demolish it.
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Nick

[M.Smith]

Your Understanding is Correct.

12.5 For Lydd, with a K27 P2.

Basically what happens is that the 12.5 has a bigger venturi, and therefore allows a higher airflow, which results in more top end...suposedly. whereas a 8.5 carb has a smaller venturi, allowing a smaller airflow, which helps the engine pick the revss up more easily off the slow corners. But of course jetting and kart set-up all contribute to this, but ultimately between the two carbs there is at the most 0.5 secs difference (12.5 for faster flowing track - 8.5 fo short twisty track)

Hope this helps
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...:::PAULMART RACING:::...

[Nick]

Excellent, thanks Martin

[Wack Montero]

Do different size venturis require specific needles. Like does the 12.5 venturi run better with the K27 or is it a matter of testing to see what the conditions prefer?

[M.Smith]

Its a matter of going out and testing.
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...:::PAULMART RACING:::...