1 bar is approximately equal to atmospheric pressure.
1 bar = 100 kPa
Standard atmospheric pressure at the Earth's surface is 101.325 kPa. So for all intents and purposes 1 bar = 1 atm or 14.7 psi. I think the stock boost of a DET is 7 psi, which is 0.48 bar.
1.8 bar = 26.5 psi
I was doing some research on my ghetto fab intercooler today. Im gonna try and see if I can use an intercooler from an Audi 200 or 5000turbo. Did u know they do 1.8 bars??? Thats unreal to me now that I know what it means.