To those who say underdrive pulleys don't work

[jhonda]

Your wrong. I have a 91 mustang with offroad x pipe, c&l 76mm maf and tube, magnaflow catback, ford udp (except for alternator), and rebuilt rear end with stock 3.08 gears. Before I did the pulley swap I could only spin second gear about 20ft, after I installed them I can spin them for 125ft and that was down a slight hill. I will post pictures when I get them. Also when in first gear I can stab the throttle at anything above 2500rpms and lay rubber. Its great and I recommend underdrive pulleys. I bought them at a car show for $40 brand new, I thing orginally they are over a hundred for the ford pulleys. Only bad thing about them is I need to adjust the idle up alittle for when I have my lights and air on at night. If I don't have the air on there is no noticable differance in charging. Does any one know how to adjust the idle on these cars (i know someone does)

Thanks
Jason

 

[Mustang5L5]

Does any one know how to adjust the idle on these cars (i know someone does)

Thanks
Jason

It's technically not user adjustable. The computer controls the idle. There is a minimun idle set screw under the TB.

More than likely it's just not enough output voltage from the alt at idle.

Buy an ASP 1 7/8" overdrive alt pulley to bump up Alt RPM's a tad and see if that helps.

 

[Fett]

I don't think anybody says that pulleys don't work, it's just a matter of how well they work compared to the negative driveability aspects that come along with them.

I don't have them and I never will, because I have seen too many people with idle issues and charging issues related to their UDPs. To me personally, the slight re-gain of power isn't worth the issues associated.

 

[iwashmycar]

ya they worked just fine, but my alternator couldnt keep up and god forbid i get stuck in summer traffic!

 

[2000xp8]

Your wrong. I have a 91 mustang with offroad x pipe, c&l 76mm maf and tube, magnaflow catback, ford udp (except for alternator), and rebuilt rear end with stock 3.08 gears. Before I did the pulley swap I could only spin second gear about 20ft, after I installed them I can spin them for 125ft and that was down a slight hill.

Thanks
Jason

Never heard anyone say that pullies don't work, but if you think underdrive pullies added 105ft to your burnout facing downhill, you are god damn nuts.
If 8rwhp gets you 105ft, how far you think you can do a burnout with an extra 75rwhp? Till the tires fall off?

They are worth a tenth in the quarter, hardly enough to celebrate.

 

[302RollinHard]

XP8 all up in your grill.......
I agree. they work, but prolly not that well. Something else must have changed (cooler weather etc)

 

[Mustang5L5]

They do work. I did my pullies at the same time along with a 3G alt, electric fan, smog and A/C elimination. I noticed a big increase in SOTP feel, but it only ended up being worth about .1 at the track

 

[Mr. Rustypwnz]

yeah i have way more mods than you and i cannot spin them 125ft, If i have my good tires on I can spin them maybe 3ft in 1st, and chirp 2nd. I say you spun them maybe 20ft.........

 

[foxmustangman]

I put on pullies and left the alternater pulley off and kept the stock one. Then i got a shorter belt. It works fine!

 

[lang williams]

i changed the water pump an crank pullies an left the alt pulley in my aod car an never had a prob with overheating an i drove it as a dd in the summer with a/c. but i didnt have power windows or seats or a big amp stereo. the stock temp guage did read a little higher but not enough to worry about.

 

[25thmustang]

yeah i have way more mods than you and i cannot spin them 125ft, If i have my good tires on I can spin them maybe 3ft in 1st, and chirp 2nd. I say you spun them maybe 20ft.........

I had 26x11 slicks on my car and pedalling it through 1st and second have a good 300+ foot marks. Spinning tires doesn't mean much as there are 15000 variables that go into it. There have been days I have spun into 4th, others where I barely spin into 2nd.

 

[Fett]

To add to all of this, a longer burnout is hardly a way to tell power. I don't remember any local dyno shops taking customers cars out to the alley and seeing how far they can burn out.

If you want to see what new mods can do to your car, dyno it before and after, or take it to the track before and after. Burnouts are for showing off, but back in the early 90s I used to get nasty burnouts in my 83 Celica, which had roughly 95 HP.

 

[Mustang5L5]

I think the original posters point was UDP are a good mod

/thread

 

[Foxfan88]

UD pullies seemed to help my car, noticed the engine revved smoother but it didnt give me a SOTP gain. i wouldnt pay for a name brand set, my old ones were a cheap ebay brand i got for 40 bucks, alot better deal. worked great! they dont do much. i dont use them now with my supercharger, i need the stock pulley so the SC pulley will fit in it and with the stock crank pulley on, i couldnt used the bigger WP pulley, i never used the alt pulley it made my car charge low.

 

[Daggar]

after I installed them I can spin them for 125ft and that was down a slight hill. I will post pictures when I get them. Also when in first gear I can stab the throttle at anything above 2500rpms and lay rubber.

Great! You now have power equivalent to a stock Fox in good condition.

Never heard anyone say that pullies don't work, but if you think underdrive pullies added 105ft to your burnout facing downhill, you are god damn nuts.
If 8rwhp gets you 105ft, how far you think you can do a burnout with an extra 75rwhp? Till the tires fall off?

They are worth a tenth in the quarter, hardly enough to celebrate.

As much as it pains me to say... 2000xp8 is right on the money.

 

[85_SS_302_Coupe]

ya they worked just fine, but my alternator couldnt keep up and god forbid i get stuck in summer traffic!

Exactly. Two things that i would never consider slowing down at the pulley. Sure, they work, and they're great for a racecar, but i'd never run them on a street car. There's plenty of other ways to free up power.



Oh, and i will add, if you really want to get the absolute best you can get out of a 1/4 mile pass, forget UD pulleys....just pull off your serpentine belt RIGHT before you make the pass...like as you're sitting in the staging lanes and you're next up, hop out and pull off the belt. Your car won't over heat in that short amount of time, and you really don't need charging or power steering for one pass. Stop at the end of your run, put the belt back on and drive back to the pits. You'll free up more power than under drive pulleys ever could, and you'll get whatever gains you'd see with them and probably a tad more. Then you can drive back home knowing that your car is getting plenty of cooling and charging with stock sized pulleys.

 

[LaserSVT]

I noticed a SOTP increase when I put them in my 92, but had the standard electrical problems. 3G alt on eBay for $85 shipped and all was good. A must for underdriven Foxes. That being said there is no way I am putting them on my Cobra.

 

[5spd GT]

Did you do a before or after test? As stated, there is so many variables: Same highway? Fresh, chip-seal, uphill, downhill, etc.

I know in the summer time I wouldn't even in spin in 1st gear from a roll. When winter comes along (harder tires/cooler intake), I can spin 1st easy, second nicely and chirp 3rd.

I'm glad I didn't add a K&N filter and tested the before as summer, and then the K&N in the winter, or the claims that they say would be true

 

[1991vert]

underdrive pulleys dont work

 

[jhonda]

I think the original posters point was UDP are a good mod

/thread

I should have just put it your way....I didn't mean to start a debate.

They conditions were pretty much the same all but the hill with the underdrive pulleys, temp same, tires same, gas tank was more full with the longer burn out.