Volumetric efficiency

[TwoSeven]

You have to break things down to simple components and understand them first, before trying to understand the more complex interactions of the complete systems. This is basic human logic.

Also, i've never believed in deliberatly making something more confusing than it has to be. The trick of measuring things in the real world first before working out the math was one that was shown to me many years ago and as worked quite well over the years.

[F5 Dave]

Yeah sure it will.

Treating the items separately is a good idea & much more simple than having to consider that the engine rotates or interacts in any way.

I expect you will find the answer is 41.9 reoccurring & we’ll all slap our heads & wonder why we didn’t think of that before.

When I said that in my head it sounded so much more sarcastic.
If the effect was missed I’m sorry.

The problem with isolation is that you convince yourself that you have found the perfect way to measure something & believe it. People created the flow bench & then ported & polish heads up to big numbers & then found that the answers all change when you replicate a bore edge next to the valve or add a carburettor. Previously they had a simple measurement.

Then there are the stories of (think is was Austin car) factory team who would flow test heads & sell off the bad ones only to be beaten by privateers using ‘dud’ heads.

In simple isolation it was obvious they were flowing better. Just as simple human logic ascertained the world was flat. It was obvious in isolation. Just not correct.

My background is more 2 strokes, but as an example I was stuck for many months changing an engine one step at a time. I’d just put on a new expansion chamber & no amount of jetting would stop it plateauing. The problem was the extra suction was causing the intake reeds to flutter.

I did have some more reeds to try all those months but I didn’t want to change 2 things at once until it dawned on me the external effect the exhaust was having on the intake. When I changed them the power curve virtually doubled.

Total package.

[Sniper]

haha.. I do, well up and down the street at the moment.

Yesterday I had a go at polishing and lapping valves on the spare cylinderhead.. Tomorrow I start making the moulds for the fairing.

http://203.79.122.87/motorcycle/Asse...ikeA_thumb.jpg

Hmmmm, yummy

[TwoSeven]

he he .. kiwi sarcasm is lost on me as being one of those wierd native things where you just nod your head and smile to keep em happy

Just let me know when its time to get out the shiny beads - I sometimes forget.

[FlyingDutchMan]

Where does 'overfilling' figure in all this VE mumbo jumbo? Or doesn't it?

Thats what a turbo does! More air means you can have more petrol means more power!

[F5 Dave]

As does pressurised airboxes, airbox resonance & on 2 strokes, expansion chambers.

[Motu]

And the superdupercharger,not often seen on bikes,but are making a comeback on cars - such a linier (sp) boost,it's like a capacity increase.Saw a really nice supercharger on a HD at Paeroa last year,a vertical roots off the timing cover,a real factory looking conversion.

[vifferman]

And the superdupercharger,not often seen on bikes,but are making a comeback on cars - such a linear boost,it's like a capacity increase.Saw a really nice supercharger on a HD at Paeroa last year,a vertical roots off the timing cover,a real factory looking conversion.

I saw a BMW 5(?) or 7 series a few weeks ago with a blower stack sticking out of the bonnet.