idle revs

[AaronATX]

any reason why shortening my exhaust would lower my revs at idle? i recently shortened it to dump right before the rear tire while i get some pipe measured and cut for a different route, and now when i'm running in my stock, 50, 75 and 100 tunes i idle about 200rpm less than normal, and in the 140+ it revs right at or just barely above 500rpm. is this normal? it gives it a chunky lugged idle which is cool but i just wanna make sure nothing's getting hurt.