Snorkel flow rates

[sambo]

slight mistake there, you have 40mm of h20, Hg is mercury and I am pretty sure that looks like water in the tube.

1mm of water is worth less than 0.1mm of mercury.

I am very impressed that someone else has actually taken a measurement, I hadn't gotten around to doing the same thing.

[Struth]

I'll get the ball rolling.
Measure the vacuum before the filter, IE in the cavity in the airbox on the snorkel side of the filter.(so we're measuring airbox vacuum, before the filter, not having our results affected by clena/dirty/different brand filters)




^The setup



^omm hg at rest





notice the water in the tube has lifted 20mm on one side and lowered 20mm on the other side. this means we have a total of 40mm hg.

^40mm hg at 4200rmp WOT, full load, using brakes to load engine.



GQ 4.2 carby, on gas, no snorkel.

start measuring your airbox vacuums and post up to make this thread useful.

Wouldn't the size and vertical length of the tube and therefore the volume of water in it make a difference to peoples results, coupled with the size of the orifice in the fitting you have placed in the airbox and the size of the inlet to the airbox?

Cheers

[85lux]

Sambo, good spot, my bad. mm H2O is correct.

Hey Struth, size, diameter, length, cross sectional area of fittings do not make a difference(when measuring fairly constant pressures). the size of the fitting would affect the rate which the manometer responds to rapidly changing pressures as air must pass through the fitting to affect the water. This however is not of concern to us. What you suggest struth seems logical on the surface, but is unfortunately not true. You better get onto merls and screw that bugger on to his airbox. You could also take a measurement with and without the snorkel connected to see if it is helping or hindering your situation.

Righto, whos got test data....

[Struth]

Cool, next question, you stated a parameter was to have WOT and use the brakes to hold the car back, does it matter when and at what revs the WOT is applied, ie: from standing start from 1800 rpm, etc ie: why load the engine up and how critical is that loading.

No doubt any vehicle will have better performance if 2 things are pressent IMO, good air (outside atmospheric, not engine heated) and shortest distance/length of snorkel if fitted. Would you agree with that?

[85lux]

The amount of air flowing through your intake will affect the restriction the intake is providing(thats what we're measuring). Hence WOT and a fixed RPM at full load to stabilise and fix the airflow through the intake. Then give the manometer a second or two to stabilise and take your reading.

[mattsluxtruck]

Im building my 4" snorkel at the moment and where do you get the 4" snorkel heads from?