No More Underdrives!
 

Once and for all I got rid of my "March" underdrive pullies on my '89 Mustang LX! They're cool and add a little power but I got real tired of having to avoid stop and go traffic or letting the car idle for a few minutes.

The first thing I noticed is the A/C will now blow 38 degrees at the vents at idle on a 90 degree day. With the underdrives, it would cool to 38 while driving, but as soon as I came to a stop light, the vent temp would start to creep up to 50 degrees or higher!

Second, the temperature gauge runs a little cooler at idle. With the underdrives, (again at idle) the gauge would always creep up a little bit.

Last, (and I don't know why) the idle smoothed out! Maybe I wasn't getting the proper voltage for the computer.... With the underdrives, if I used the blower Fan at idle the meter would read discharge until I started moving again. Now I't always charging even with the fan on high and the headlights on!

IMO, underdrive pullies or good for strip cars but not street driven cars.
Glad I finally dumped 'em!
Phil

phil,

i know underdrives can be a pain, but look at the big picture, you are right with a stock set up, they suck for a everyday driver. but with a few modifications, they can be great. to be able to keep my pulleys i added the following things

1. A 130 amp altenator, because the stock altenator sucked anyway and i wanted to add a electric fan, and there was no way with a stock altenator (130.00 from oreilly's)

2. A black magic electric fan, because my car only overheated at a stop so with an electric fan, it is putting out alot more air than a stock fan at idle with pulleys. so that cured that cured the overheating at idle.

so to sum it up, with adding an electric fan ($200) and a sn-95 alternator, i picked up nearly 15-20 hp at the rear wheels and get better mileage. some people are lucky to get that to the rear wheels after head work.

so pulleys can be bad, or not to bad if a few modifications are made.

good luck
brian

huh??
 

How on earth do you think putting an electric fan on gave you 15-20hp at the wheels? Did you have it dynoed? Do you realize that is like 30hp at the flywheel?! There's no way. Otherwise I must have gained that much or more from removing my smog pump and A/C?! I don't hink so. More like 5hp at the flywheel if I'm lucky.

i meant to say 15-20, with the underdrives and fan.

Underdrives and an electric fan can add quite a bit, especially on the top end. On www.fordmuscle.com they show E/Ts where they run with stock configuration, then underdrives, short belts, no belt. It's pretty amazing the differences they got between the setups. On my 84 I'm going to run a 3 inch, yes 3 inch, crank pulley and the water pump pulley that comes with it, and a stock alternator pulley, electric fan, and no power steering, a/c, or smog pump. I just hope with my single core radiator that I don't overheat. Hopefully the fan and a lower temp thermostat will help with that....

Plus, I plan on getting one of those finned aluminum oil filter covers, that will add like 40 horsepower don't you think? Plus, my valve covers are finned aluminum so that should help cool it down like 50 degrees or so. Hehehehe.