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Old 19 Sep 2007, 16:06 (Ref:2018062)   #30
knighty
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Join Date: Nov 2005
England
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knighty should be qualifying in the top 5 on the gridknighty should be qualifying in the top 5 on the grid
Hi bob, dosent surprise me they spent a fortune on the heads, the corvette has a compact cross-over induction system which must fit under the vehicle hood / bonnet, which creates a very big and nasty angle between the runner and intake valve axis…….which kills port flow and velocity………an LMP 1 car doesn't have this restriction, and near vertical inlet ports and intake runners could be pursued in order to achieve the straight inlet tract run aimed at the back of the intake valve, as pioneered on the old Gurney-Weslake 305" V8 engines used in the GT40's and Gurneys eagle indy cars in the 60's. Yes the LMP cars have rear engine covers, but having a thin section air box protruding through is no big problem, as it could be packaged to be very aero friendly

Difference of opinion here……..sorry, long stroke doesn’t mean more friction, more piston side loads induced by a poor crank to rod ratio equals more piston friction, I'm quite sure about this………the trick here is to use long cylinder liners and create a cyl head spacer plate which will give a more sensible crank to rod ratio, and therefore keep the piston friction to sensible / minimum levels

Heres some pics to illustrate my theory on the different intake systems





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