Lucky Breathes Easy

I use a pair of Ryco A1705 filters - Ryco Air Filter A1705 -168mm long, same ID and OD. Something similar used in some UK vehicles. Need longer screws (1/4-20 thread). Still looking for an SD1 air cleaner casing. Also 2.5" OD flexible tubing from air inlet to nearside headlight area to avoid hot engine bay air.
 
Re negative comments about oiled K&N filters - I have seen some comments that a tendency to over oil these (more is better, right?) can be detrimental to cars with hot wire MAFS, as the oil tends to stick to the wire and degrade it, despite Bosch systems doing a high current feed at switch off to try to burn off debris. I have lately fitted a length of 2.5" flex hose to the air cleaner inlet, running it into the RHS corner behind the lights, and my seat-of-the-pants impression is quite positive.
 
Found a spare P6B air cleaner to play with locally. More thoughts on the shape of the inlet 'cone' - Bernoulli's work says that when a fluid emerges from a pipe into a large space volume and its speed drops, the pressure goes up - makes me wonder about changing the shape of our inlet. Will the effect be significant? Only at high power output? The Penguin tests using an air cleaner with an enlarged inlet showed a useful increase in peak power, but I didnt register what happened lower down the curve.
The Hawker sea fury, with a large radial of some 3000hp, has a very large spinner, leaving what appears to be an annular gap of only a few inches to the cowling. This fits with Bernoulli, as there is a large space around the front casing of the engine in which the air slows and pressure increases before hitting the cylinders.
 
There is a fair amount written about intake air flow. K&N actually made some induction systems where the power increased when the filter is on...Seems the filter dropped the pressure which cooled the charge and made the gas more dense, hence extra power. The Norton rotaries used a similar arrangement of passing the inlet air into a large box (the bikes sealed frame) to cool it.
The best book on the subject I've found is by Professor Gordon P. Blair - Design and simulation of Four Stroke engines published by SAE in the US. You can buy it online for about $150 (from memory) catalogue no. R-186 via SAE's website. being in Melbourne you might find a library with it.
 
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jp928 said:
More thoughts on the shape of the inlet 'cone' - Bernoulli's work says that when a fluid emerges from a pipe into a large space volume and its speed drops, the pressure goes up - makes me wonder about changing the shape of our inlet.
Click to expand...
So, in theory, the shape and size of the inlet helps pressurise the filter canister? In that case perhaps, as you say, it's more beneficial at lower revs and might only be a restriction at the top end.
 
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