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maxbow said:One may assume that 3mm is nothing, but if you consider that this is a measurement in diameter, then the increase in volume is considerable.
Surface of a circle ie: area of the pipe/throttle body can be seen as this:
65mm= 331.83mm.(approx)
68mm= 363.16mm.(approx)
This is using the formula Pi(3.14159) x r (radius of circle) squared.
This means that a 68mm TB has 8.63% more area than a 65mm TB, therefore it flows 8.63% more air than the 65mm TB.
I have a 69mm in mine and: 1) It's more responsive
2) It uses more fuel. 3) Shifts are smoother(Don't ask me but they are)
$100 is dirt cheap for a good one and I would *grab it *put it in and *experience the difference. If you don't like it, change it back and sell it to someone else.
Hope this helps, cheers Max.:bang: