I don't know if piston type compressors are still common, but it is for old school cars. Ngayon kasi, scroll type na ang mga naka-kabit kasi mas efficient daw by 15%, and mas tahimik ang operation.

I have an old school car na bumigay ang piston compressor (beyond economic repair). So my dilemma is do I buy a new piston compressor (9k), or upgrade to the modern scroll but double the price (18k).

Syempre it is a given that the scroll is better. Pero worth it kaya yung extra 9k na investment? Double the price, but only 15% more efficient.