Ceci n’est pas un pipe and some more corner cutting

A few thoughts on measurement and flowbenches in general.

The trouble with measuring things in general is that you tend to forget what the heck you are really doing. As an example : Ferraris  are red and fast therefore red cars are fast. SO if you measure the redness of an object you can see how fast it is..enter the very expensive spectroreflectometer. Now of course the thing can measure the colour of an an object with very high preciscion,but not really tells you how fast the cars will be.. it is not the fault of the device. The device is fine , but if you use a device on the basis of a wrong idea you get send up the creek without a paddle . This seems like a very stupid comparison but I have noticed that when you start to do weirder measurements people start to make these kinds of mistakes, it is  just less obvious.

You have to keep in mind that a flow-bench is a device that measures the flow at a constant depression at more or less room temperature. By improving the flow you have in all probablility improved the flow on the head when you have put it on a running engine but it does not take into account the vagueries of thermodynamics, wave mechanics, flow quality, fuel dropout etc etc..  For the exhaust side it is useful up to a point but IMHO CFD is the way to go there ( well CFD is the way to go .. but not at my budget)

This indeed not a pipe.. and a flowbench is not an engine

I am reasonably shure that no flowbenches where used by BMW when they designed the truely awesome engine for the S1000RR (999cc and 193 bhp.. pretty stout specific output). When the OEM’s get a bit motivated they mass produce things to this level. Up to a few years ago BMW produced a 130 bhp cruiser as the max bhp option, they just could not be arsed building something like the RR. Das braucht ja keiner !

However the A-series engine is comparatively stone age and thus you can a get some very serious percent gains  by doing some basic mods. Although the siamese ports do seem to be truely british oddities obeying they own odd rules (like cricket I guess)

speaking of  basic mods..

todays test..

Old vs new model valve  now both back cut. Remember that the old valve was surpassed quite a bit  in flow by the new model with a back cut. Could the old model be even better when  treated to a wider back cut instead of the small break ??

Surprisingly the modification absolutely duplicates the flow of  both valves (I have done the tests within 30 minutes of each other corrected for todays less hot weather and high humidity and new barometric pressures).

Thus the aperture ( as theory would suggest), is very important but the regions a bit further away do not do all that much.

Now finding a way to break through to 8mm lift CFM barrier without mucking things up .

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