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Flat slide carbs on an old 2-stroke

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8 hours ago, jaguar57 said:

man, you had me worried for a moment there. you're good. 

the formula from the site is horsepower per cylinder = Coefficient of power x Test Flow in  cfm

So if the CFM increases 1.7% then the hp increases 1.7%

So for a 25hp engine a 1.7% difference is .425 hp

Do you think you would even feel that small a change? (hint - the answer is NO)

The story line is shifting to some degree here.

At a 25 hp level, I would not be able to feel a 1.7% increase in output, but I would tell a friend, competitor or customer that it can be measured in reduced average lap times, reduced successful pass attempts by your competitors and increased opportunities to pass. HP is a unit that measures work performed over time. Races take time. No way would I suggest that anyone leave that .425 HP on the table, particularly when the cost to have it is so low.

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anyway the carb is not the biggest restrictor in the intake system, it is the reed valve.

that can be proved by the pressure difference across it. You won't find a pressure difference across the carb at WOT.

The flow test of those two carbs was without a reed valve. fatal flaw. so there is not even a 1.7% advantage.

if the design of the flat slide carb offers any advantage then it is probably a more linear/consistent fuel/air regulation across the full throttle range. I don't doubt that is possible but I have no evidence either way to state an opinion.

Edited by jaguar57

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