boxerscott wrote:So the lennies air supply pipe uses the same orifice as the bmw stock one? How can that be an improvement using the same mouth? perhaps someone will come along and enlighten us just how it digests the oxygen supply better? I was curious about this mod 12 years ago and am still not understanding why it is perceived to be better than the stock one?
Chris
I am aware of Ronnies inlet duct but haven't looked at it closely.
i strongly suspect that it is related to the dark art of fluid dynamics (yes, air is a fluid)
if the inlet mouth is the same size, but the internal volume of the inlet duct is larger then the pressure inside the duct will reduce and temperature will drop. My thinking is that as the valves open and the piston is on the intake stroke, because the pressure is lower, and volume larger, the airwill flow in to the cyclinder quicker and more freely. The temperature drop is an advantage but by how much i dont know. I think it might be more of an advantage on a hot day because the differental is greater.
Boyles gas laws will feature in the above as well. As presure increases, so does temperature. If the pressure reduces (due to larger volume of the inlet duct) then the temperature will drop as well. Therefore cooler air going into the cylinder. This is why there are intercoolers between the turbo and inlet manifold on most diesel engines these days (that have a turbo).
What advantages these would be for the average joe on the public road, I dont know, but combined with other mods in the induction system (more free flow air filter) these little amounts all add up.
I fitted the sprockets too my 1150GS just over 1 year ago and it completly transformed the bike, more torque, get up and go, lower rpm and improved fuel range. fitting the inlet duct isn't in my program however, and I dont need any more speed - i need to slow down
The above are my thought from my knowledge and being involved with aircraft and looking at / studying the inlet systems for various aircraft and helicopter engines.
