Vintage Air RPM Cutout

[jdorrough]

I thought I'd pass along how I wired up my Vintage Air WOT sensor in case others may find it useful. To set the stage, I'm running an LS3 engine, vintage air A/C and Dakota Digital gauges.

I didn't like the idea of my compressor engaged when I get a wild hair and flog it up to redline of +6K rpm for two reasons. First, the stress on the compressor and secondly the drag on HP. The easy way around this is to simply reach up and turn the A/C off before stomping on it but I've found myself forgetting to do that and I'm all about adding automation. After reading forums until I went crossed eyed on how to send WOT signals from the ECM, I decided to go a different route. I instead used the switched ground "warn" output of the Dakota Digital gauges to trigger a simple relay to power the orange WOT input on the VA system.

This method is nice because I can easily set the triggered RPM setting through the gauges. I tested the VA system before wiring it all up and found that whenever it receives power on the orange wire, it will disengage the AC clutch until it no longer has power on the orange wire +5 seconds. I set my cutout at 4800rpm as don't typically shift above that range unless I'm really getting into it. Hopefully this helps others looking for a WOT AC solution.

[AcampoDave]

I lack any high tech things except the Vintage Air and have wondered if it's bad for it when i see the tach needle aproaching 5k. I guess i should do the ol' "reach up and shut it off" thing then. Is 5000 rpm too much for an A/C on a short wide open blast thru the gears?

[theastronaut]

Sanden compressors are rated for 6000 rpm continuous, you'll need to calculate the compressor rpm vs engine rpm due to the difference in pulley sizes.

https://www.vintageair.com/basic-aut...pressor-facts/

[AcampoDave]

That link was a good read, thanks.