3/12/06 Calculating the head pressure of the water pump
Using an unfeasible long piece of hose I made a DIY manometer to measure my head pressure. All I can tell you is that the pressure is between 4m/H20 and 6mH20 - this is because i didn't have a big step ladder to measure exactly where it got to. Which equates to about 5.5 to 8.5 psi. Neighbors took a dim view of 6 meters of steel waggling around over his car.
18/12/06 Calculating the head pressure the proper way
Obtained a 1 bar pressure gauge from ebay - brand new only cost £5.0 delivered. I made a little spigot so i can measure the water pressure easily, although i managed to knacker the gauge by grinding the brass fitting and now it reads out by 1psi.
The pump has a back pressure of about 6.5psi - and a stall pressure of 12 psi - Here's a short video showing how noisy the pump is: Click here
Sooo, if I fitted the Jabsco 50830 Pump - we can see that it should pump 38LPM at 6psi - which is 630cc of water per second, which means it would take only 6 seconds to pump 10 Litres of water into the cooler - which means it should drastically reduce the time to cool the Inlet after a hot restart.
24/12/06 Auxiliary Chargecooler Water tank Fabrication
So from my testing, adding 10L of water into the cooler provides a good stabilisation of inlet temperatures. The Dakar has two battery boxes, one of which is empty - so this was chosen to be the location of an auxiliary water tank, which is conveniently comes out at 10 Litres. The following sequence of photo's will show how I made a simple tank from aluminium without using shears or a folding machine. Examining my professionally made fuel tank I noticed two design features:After making a cardboard mockup, I started with some 16 Gauge aluminium - I think the grade is NS4. I used a jigsaw with a very course blade to cut out all the panels. By clamping the metal between a think piece of metal, it was quite easy to bend the metal by hand - on the first bend I used a hammer to get a tighter fold, but this is unnecessary and results in dented metal. On the final fold, it aligned up perfectly with the start - all done by hand.
Next the end tanks were cut out and folded up. This time I had to use a hammer, but these folds are internal and therefore not seen.
Here you can see the resulting box prior to welding.
Then tacking and final TIG welding - welds not up to professional standards, but overall i'm pleased with it - how many professional welders are also IT consultants "as a hobby" ?. I really should get round to buying the proper 5% magnesium rods, as i've only got 5% silicon rods. You may be interested to know that the welder used 33Kw of electricity - which at todays rates equates to about £6.00 worth of electricity.
7/1/07 - filter and deck plate
Ive added a 4 inch deck plate to the tank - this allows access to the water filter and also i can play around with adding Ice to the water tank in the summer - to see how much it lowers my inlet charge.
After spending several weeks looking for the tool holder, i finally had a go at screw cutting on the lathe - made loads of test cuts, which all kept tearing the ally up - in the end I done the one in the top of the photo by making multiple passes and turning the chuck by hand.
8/5/07: New Bosch cooler pump, tank fitted and bigger pipes
Fitted the tank and changed all my hoses for 19mm ID - which involved cutting, making and rewelding the fittings on the cooler and both rads - Another lesson learnt is to fit 19mm (3/4") water fittings in the first place.
And I have FINALLY made a decision on which waterpump to use. My original plan was to purchase the Jabsco Cyclone pump which I knew was over the top, but I wanted to research the effect of varying the speed of the flow (using a motor speed controller) - but in the end I decided to use the Bosch PCA12 pump instead. Which was cheaper and also Automotive spec (although not waterproof ironically).
Here's a comparison against my existing bosch pump - it dwarfs it! - the pump is magneticly driven and pumps around 20LPM. To put that into context, my garden hose at full shifts 25LPM - so its not hanging around. Its almost totally silent also which is good.
Couple of shots of it installed - you have to make your own mounting bracket. Ive since tidied the plumbing and made a splash-proof rubber cover for it.
Here's a short clip of it running to give you an idea of the flow rate. Its normally silent - but I left the hose off so you can see the flow.
Datalogging shows it performs the same as when I ran the noisy vane pump with the big beer barrel during testing- so main gain is the silence!. Ive tested the backpressure and its now down to about 3.5PSI (It was 5.5psi with the vane pump and small hoses). Overall it seems like a decent pump, I would reccomend it.