So I’ll promise to stop spamming the air compressor threads soon! 😬😂
I recently upgraded my onboard air, and as part of that, installed the ARB Pressure Control and an air tank.
The air tank does not make anything appreciably faster. But there is a logic which I’ll explain…
ARB Brushless Compressor, pressure controller, manifold and valves (going up to a reel air hose mounted on the roll cage). This setup will be made tidier once the line adaptive arrives and I can remove the manifold and connect the line directly to the solenoid valve block.
Air tank mounted to the underside of the car, roughly placed under the driver’s side passenger footwell.
The ARB pressure control is a nice-to-have in that you can hook up a four-hose line, preset the desired pressure and leave it running automatically while you go and do other stuff (…take down flag, pack gear away, swat flies, send the other half increasingly fictitious reasons as to why you’re running late to the afternoon event that you totally forgot about).
However the controlling algorithm is really dumb!
Most auto inflation systems would do something like this:
1.) Measure the pressure
2.) Apply pressure for a short period of time (say 10 seconds)
3.) Measure the pressure again and guesstimate the time required to reach the target pressure (based on measured pressure now, target pressure, and pressure gained during the short fill)
4.) Do a long fill for half the time you expect to need
5.) Stop, measure (should be roughly halfway to target pressure), recalculate, go again.
6.) Stop, measure, fine tune to target pressure - done
The ARB controller instead stops every 15-20 seconds and measures the pressure. This stop-start is short, but if you have the compressor directly connected to the line, you’re cycling the pump on and off repeatedly (solenoid valve closes, pump runs until it quickly hits the 150 PSI cut-off, turns off until solenoid valve opens again).
If however you have an air tank in the mix, when the ARB controller closes the valve to measure the pressure, the pump can keep going and top up the air tank. When the valve opens you get a quick extra burst of pressure, and the pump runs continuously.
Testing on a like-for-like basis, the time to inflate my 4 x KN02’s from 7.5 PSI to 35 PSI did not change without (manual method, by hand) and with an air tank (with ARB controller); however with an air tank, the pump ran continuously and did not pressure cycle repeatedly.
There are some secondary benefits - using air tools and having a quick burst of pressure for a stubborn pop-out…but this would be a rare use case I expect.