The onboard air project

[Aidan]

what does that lot and associated gubins weigh ?

[silverbullet]

The York compressor weighs ~7kg, so a bit more than 2nd alternator; the a/c bracket weighs next to nothing, maybe 1/2 kg, the Audi air receiver only 2kg. It's all pretty light.

The great thing about the York is that it displaces 10cu.in or 160cc, so at a 1500rpm fast idle* that's 240 litres FAD. Enough to fill tyres in no time, as the fella with the Jeep discovered

I decided to run some tests to see how fast it would fill tires and if it could really run air tools. My first test was to air down a 35" BFG MT to 12 psi, then fill it back up to 33psi. The total time on the fill was about 45 seconds.

*I have a spare choke cable that will be used for a hand throttle behind the rear flap, along with the airline connection.

[Zebedee]

Onboard air sounds like a good idea to me, especially as those stupid small compressors you plug into a ciggy lighter take minutes and minutes to pump up just one tyre.

[silverbullet]

Slight whoopsie, the drive belt just fouls the header tank leg on the water pipe. I forgot to fit it when starting the mockup ...I'll have to get a stainless one and have it tweaked to suit.
I've made some legs to support the air tank on the heatshield, looks ok. Now I need to make a decision on pipe fittings as the tank has only got a tiny M8 x 1 tapping for a skinny air suspension pneumatic line, which could open up to 1/8" BSPP at a push, it's not much bigger in diameter.
It's getting close!

[Fabzzz]

Hi mate interesting that ! would you do a Air preload adjuster too if you have compressed air onboard ? you can stay in normal position on road and give it more lift offroad... and also a beer pump !

[silverbullet]

Hi Fab, not thought of that but now you mention it...

It looks like I have got to re-make the T-shaped alloy compressor mount to drop it 15-20mm and get everything to clear, bit of a shame but I had to make something to get a start point.

That's R&D for you!

[silverbullet]

Mk 2 is looking a lot better. Significantly lower than the first attempt, it's now only 45mm taller than the breather tower. I ditched the cam tensioner and shortened an E30 one, not dissimilar to VW alt.one but it was gash. A slightly longer belt has helped get the pump vertical again:







Apart from a bit of lightening (it's a hefty 10mm slab at the mo) and maybe swapping spacers about to use the rear pulley groove (to improve the clearance on the top corner head nut) it's fit to paint and whack onto the SS.

Then it's hoses and PCL time

[orcecaveman]

Hoses, you will probably need to use Braided PTFE due to the heat, and those unions will most certainly be JIC.

[silverbullet]

Thanks! I did wonder about the a/c connections, luckily we have a compressed air trade shop very close to our works so I'll see if they can supply some aluminized/fireproof sleeving too, otherwise it's off to Agriemach but they're not cheap...

[orcecaveman]

Go for convaluted s/steel braided PTFE, if you get smooth bore its cheaper but not as flexible. JIC fittings are UNF thread, so you should be able to work out hose length and ends and get a decent price online. Dont forget dash sizes are, 1 dash = 1/16" that applies for both the end fittings and hose bore, eg 1/2" hose is -8, 5/8" JIC fittings are -10. Hope this helps.
You should be able to get hoses made up while you wait from your local Pirtek depot, not the cheapest but they are most likely to have the items on the shelf.

[silverbullet]

Thanks again. I also have to make up my own manifold with a non-return valve, to carry the pressure switch and airline fittings, plus a drain-down/blow-off valve. The manifold will mount just inside the inspection flap for easy access. I have got the check valve that matches the compressor fittings but it's got 1" x 18 UNEF male on the other end. That's one tap that we don't have in stock

[Fabzzz]

Thanks again. I also have to make up my own manifold with a non-return valve, to carry the pressure switch and airline fittings, plus a drain-down/blow-off valve. The manifold will mount just inside the inspection flap for easy access. I have got the check valve that matches the compressor fittings but it's got 1" x 18 UNEF male on the other end. That's one tap that we don't have in stock

mate if you are interested i know some places where to get ANY hydraulic or pneumatic fittings ... search for Camozzi pneumatics and let me know if anything help i can have good price on them.

[silverbullet]

Good man! It's all engineer's playtime. I wish you had never mentioned air springs though...

[Fabzzz]

Good man! It's all engineer's playtime. I wish you had never mentioned air springs though...

are you stuck in a loop ? coz i cant sleep every time i look at your post ! preload.... air .... god....bed time.... i can't help you make something 3D if you need t.designed one already for a superbike scale it by 2 and you have a syncro preload adjuster.

[silverbullet]

We must talk about this some more...