mpg plummets w ac on

[///M42 sport]

I did a road trip and noticed 5mpg decrease with the ac on. Is it normal to decrease so much?

[gearheadE30]

yeah, unfortunately. New cars won't do this because they don't have the same on-off compressor setup. On e30s, the compressor is either pumping full pressure or not pumping at all, so the parasitic drag is quite a bit. I think I noticed a 6 mpg drop under similar circumstances.

[E30SPDFRK]

M42's dont have much hp to start with, so add a large draw on it and the big mpg loss starts to make sence.

[///M42 sport]

crazy, I guess more of a reason to get a newer car for daily driving

[Holland]

Well don't use it then.

[Kershaw]

on my rx8 its a difference of about 2mpg.

so instead of 18mpg on the highway, i see 16mpg.

i think you're still coming out ahead of me.