Hey guys, anybody have any experience with buying a smaller size belt that would enable me to bypass the smog pump pulley altogether? It's an '88GT. Thanks in advance.
If it has a/c and p/s, it will likely take something in the 84" range; but all of these are a bit different. I bought 3 belts - 84.5, 84, and 83.5 and put on the one that fit the best; returned the other two. Parts place had no problems with that approach.
Look closely at the front of the tensioner and you'll see a small arrow with a "range" bar -- the correct length belt will put the arrow in the middle of the range. Put it on the loose end and a slipping belt can be the result; put it on the tight end, and you'll see lots of fine black powder all over the pulley areas -- and likely will break a belt shortly thereafter due to wear.
I doubt you'll notice a performance gain; marginal if any. If you have to pass emissions tests, it could be a problem with no pump. The pumps themselves usually lock up if not used regularly - so you likely will have to replace it if you put it back on. Lastly, the cats require the excess O2 provided by the air pump to do what they do -- the lack of excess air will make them run hotter, and some people complain of clogged cats sooner with no air pump since they're not working as designed.