Recently I acquired a slightly used (170 hours) SR20 and of course as luck would have it, I experienced a primary vacuum pump failure. Luckily the secondary pump flipped on as advertised and the whole event was no cause for alarm. However I had a friend on board, and told him of the planes history devouring vacuum pumps and he suggested that I add a shroud over the pump to increase the cooling efficiency. I wanted to know if anyone has attempted to modify the primary vacuum pump in this way. Or has substituted brands, with some measure of success. If so, what other brand of pump did you use?