Under drive pulley
 

I put on a under drive pulley earlier this year and have felt the few extra horses it provides was worth it. I was a little worried about when it gets hot (110 the other day) that I would possibly have problems with the car overheating and the A/C not cutting it. So far neither has been an issue. The A/C is as good if not better then other cars I owned. Thought some of you would be interested in my observation since we have extreme heat that puts these two systems to the test.

I found that if I'm idling with a UDP and not-running the AC -- the coolant temp rises above
normal. I believe this is because without the AC the idle speed is low enough there
isn't enough WP rpms to get good coolant flow.

Put the AC on -- no issues.

YMMV,

Mike

Texan here. I had my worries too with a 4in UDP. The A/C is great, idling is not an issue.

Tried both and it seems to make no difference. Idle speed also does not seems to change.