What’s Everyone’s Opinion On Underdrive Pulleys?

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by BlakeusMaximus, Nov 12, 2017 at 8:02 PM.

  1. I had under drive pulleys on one of my past mustangs. I did have charging issues and the lights would flicker at idle, driving me nuts. I fixed it with smaller pulley off of a mid 90s Ford Escort. Pullet fit with no issues. After the pulley swap I felt more power pulling off. Before it felt like the car stumbled for a spit second from a light.

    To my understanding....the crank pulley has to be changed with the alt and wp. If using just the crank one issues can result.
  2. My current car had an under drive crank pulley, I chased a mild cooling problem for a long time before I figured it out. Simple swap and it’s fixed. If it was a car I was building for speed I’d do it, but not on a driver.
  3. Stock mechanical cool fan on that car I would assume?
  4. When I originally got it yes. It now has the dual contour setup. 90% of the time it was fine, but on a hot day, ac on, and not moving the temp would rise.

    Can’t say for sure if the stock fan would of dealt with it or not, the ac didn’t work when it had the stock fan.
  5. Lots of people use them. My pulleys are such a mismatch now, I don't even remember what was part of the under drive kit. I think I have an under drive crank pulley, and standard everything else. Bottom line is, it never frees up enough power to be worth the hassle.

    88LXSleeper likes this.
  6. I had them on my SN95 back in the day. Started getting cooling and charging issues once I put them on. I also didnt feel any noticeable difference in power.
  7. I pulled them off my '95 Cobra about a year ago. I had been running them since I bought the car and noticed no difference in performance after they were removed. I did, however, sell them for $35 a few weeks ago.
    90sickfox, revhead347 and karthief like this.
  8. Ill probably end up throwing the stock pulleys back on. My aftermarket pulleys are anodized blueish color, so they look cool but I like the idea of the car running, charging and cooling the best it can. Like one of you guys said, these cars stock really don't cool and charge that well anyways.
    karthief likes this.
  9. When my car was 100% stock, I added u/d pullies. Never had cooling or charging issues and the car was a daily driver back in those days.
    Now, the car is essentially a no options car too, so, that may help.
    I still run the same u/d pullies now... but have Ron Davis rad, E-brock water pump, Lincoln MK8 fan with variable speed controller and 3G alt.
    Still no issues, but running around in Phoenix when it's 119*F should expose any cooling issues... then again, rad/fan/controller are pretty good pieces and no a/c car... guess it doesn't hurt that the car idles at 1200rpm...
    So, it all comes down to application... with a/c, aftermarket stereo and stock cooling system/alt. I'm sure it would be a different story