21/11/05 Chargecooler layout considerations

Finally managed to get some cash together to carry on with the chargecoolers. Ordered 3off 100mm x 255mm 4 row water cores from Pace Products.

Ive decided to put the chargecooler in the engine bay rather than the inner wing,Mainly because I didn't like the look of all the charge piping going everywhere. As ever, first task was to take some digital photo's and sketch out some ideas.

Option 1: Three cores out front:

Option 2 and 3: One core either side or front and back:

Now children, when your'e in skool wondering what's the point of trigonometry and that will never be any use to you...think again; This little creation took me ages to make because I couldn't work out how draw the angled bit on a flat piece of paper which would fold into the correct shape without any gaps.

Chargecooler fabrication

The final design choice is the three in a row design, as its the most effective. First step is to fabricate the end tanks. These are made from a single piece and then divided up to form the compartments later.(Which doesn't seal very well, don’t copy this idea - keep reading..)

Original plan was to butt-weld the tanks to the flanges, but I found that one of the supplied cores was slightly different from the other two (both in height and length) which would of made butt-welding very difficult, So I overlapped the tanks. From my (bitter) experience avoid doing this as it brings your weld bead too close to the inner edge which is very dirty (and cant be cleaned).

Despite cleaning the ally flanges up, I still suffered from dirty welds - which caused leaks where the two units are welded together. You only find this out after fitting the tanks, so you either scrap the whole thing or cut a big hole in the tank to get in there and fix it. First photo clearly shows the effect of dirty flanges - the weld pool just separates and never bridges the gap.

Once all the holes were patched, you cut a slot down the tank and weld in a divider to form the water compartments. Tried it out on the bench with a 3KW fan and my pump unit.

30/12/05 Charge tank fabrication


Cut the hole out with a Jig saw, was only supposed to tack weld it inside - but had a nice bead so carried on. Carb hat was made by myself on the lathe with my dad directing. (Last thing my dad ever helped me with sadly)

Tricky bit of welding the 3mm plate to the 6mm top-hat went surprisingly well. Attaching the top and bottom plates to the cooler was ok once I cranked the current up high enough.

Scored a cheap motorbike radiator to use as a pre-rad, quite handy as it comes with a filler cap and should avoid the need for a seperate water tank.

Yes, the bonnet does close!


Another weekend of welding gets most of the cooler completed. Can now start on the connecting pipes.


Charge pipes done. Although not seen in this photo, the other side is very short which made getting the tig welder in very difficult.

When I originally fitted the dowel rods that prevent the charge tank from ballooning, I didn't clamp the assembly together - which resulting in the top and bottom plates warping outwards. I ground the welds down and clamped it properly this time and re-welded.

Drill press used with a centre to ensure the tap goes in straight. I used a 3/8 BSP which is fairly close to the 3/8 NPTF for the air temp sensor.

All welding completed. Pressure tested the charge side, no leaks at-all first time!