Has anybody done this?
I was quite surprised the first time I cleaned the (K&N stock replacement) air filter. It’s about the same size as on my B&S lawnmower!
So I bought 5 m of transparent hose and rigged up a quick test. I first tried methanol (to get a better reading) and whacked the throttle wide open in neutral. No good. The methanol got sucked into the air box. Then I tried water. It too got sucked in.
I need to tinker some more to make this work. But then I got to thinking: somebody must have thought about this before, and done it? After all, it’s not rocket science.
cornishflat wrote:What scale are you measuring against? What are the parameters? Meters cubed per minute / hour perhaps?
As the title said airbox pressure I assumed this is where the manometer came in. If a test of filter effect is the objective maybe pressure drop is useful to know? In which case a reading before and after the filter are needed.
But I take your point that, ultimately, flow rate is what counts.
cornishflat wrote:What scale are you measuring against? What are the parameters? Meters cubed per minute / hour perhaps?
I’m measuring the pressure drop across the intake system. Nothing else.
It’s given by: P=q*g*h Where:
P=pressure drop
q=density of the fluid in the hose
g=gravity (9.81 m/s2)
h=height of the used fluid pillar
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cornishflat wrote:What scale are you measuring against? What are the parameters? Meters cubed per minute / hour perhaps?
I’m measuring the pressure drop across the intake system. Nothing else.
It’s given by: P=q*g*h Where:
P=pressure drop
q=density of the fluid in the hose
g=gravity (9.81 m/s2)
h=height of the used fluid pillar
//T
Aren't you just describing a manometer? With only one manometer won't you only measure the pressure (or vacuum) at one place? What will this prove?
By pressure drop I meant the difference in pressure before and after the filter.
Given that the mechanics of the engine are drawing the air in to the engine. Any pressure drop from atmospheric in the airbox will in effect be a restriction that has to be overcome.
A truer test would be a reading taken on a stock system and then compared to one with an upgraded induct.
Or am i missing something?
I think that’s a really good mod to do, regardless of what performance increase it may give.
Since the stock filter is so small, it clogges up real quick.
And speaking of that: I just got back from the Tapio European tour 2013 (Poland-> Slovakia->Hungary->Romania-> back). In Torun, Poland there was a construction site and there was a lot of sand on the road. I passed it twice.
When I got back, I cleaned the filter right away. There were 2-3 tablespoonfuls of that sand in the filter!
So, as daft as it seems, it looks like the No 1 aftermarket performance part you should buy for your bike is a front fender extender!
Merecat wrote:Given that the mechanics of the engine are drawing the air in to the engine. Any pressure drop from atmospheric in the airbox will in effect be a restriction that has to be overcome.
A truer test would be a reading taken on a stock system and then compared to one with an upgraded induct.
Or am i missing something?
No, you’re not. Without comparisons this test is totally useless. I’m planning on testing the:
K&N stock replacement
BMW paper filter
Without filter
I read a thread somewhere about a home made manometer to balance the throttle bodies.
This was made from 10m of plastic tube and used 2stroke oil as the fluid medium.
Im sure this could be adapted to calculate the airbox vacuum.
Merecat wrote:I read a thread somewhere about a home made manometer to balance the throttle bodies.
This was made from 10m of plastic tube and used 2stroke oil as the fluid medium.
Im sure this could be adapted to calculate the airbox vacuum.
Surely he's not going to connect each end to each of the throttle bodies?
He will need a manometer for each side Shirley?
Also, is the reading, in inches or cm or whatever, to be taken from the starting level? In other words half the total difference in height between the two sides' fluid level?
What about damping? I realise the guy on the video used oil partly to see it, partly because it is viscous. I assume he was looking for viscosity as a means of damping? But is that the best way?
When balancing the TB you do indeed connect one to each side to detect the inbalance.Then adjust the TBs so that the fluid is the same level in both legs.
In Tapio's usage one leg goes to the airbox and the other left vented to atmosphere. Then pressure differential can be calculated in your preferred units using the SG of the fluid and the displacement of the levels.
