Underdrive Pulleys

[strike1980]

i have a 2004 automatic and i want to know if
it is worth it to get Underdrive Pulleys?
and how hard are they to intalle????2:

[lowflyn]

If you are expecting great gains from it....then no. Look to get 3-5 hp as with any bolt on mod. As far as install...I have no personal experience with them, but..wouldn't think they are that bad.

[Kiljosh]

There was a change in underdrive pulley design for 99-04. Not sure exactly what it is, only that it deals with the harmonic balancer design. Someone else will probly know more.

As for the install? Well on mine it was pretty straight forward. I think you'll need a balancer puller if you replace yours. An impact wrench would help to break the crank bolt on the pulley, that or stop the engine from turning somehow. I removed my starter and just wedged a prybar into the flexplate(?) so it wouldnt spin.

It's not hard but if you get a water pump pulley you need a puller for that too. So look to buy some tools ar rent them atleast.

[I_luv_HP&trq]

It's a pain and a half to install the dampner without the right tools and no I don't think it was worth it for me.

[Scoot99V6Stang]

Back when I was running 15.0s I ran my friend kyle with a 04' Auto w/ The Pony Package. He had only a SCT Tune, CAI, and the UDP and our races were. NECK AND NECK. Above 120 he would pull me in my 99" 5 speed. Then I installed my 25% udp, a short throw shifter, and a suspension kit. And now I"m runing 14.8s. They are a VERY VERY well worth while mod. I wish I would have done it earlier. As for the install, get a harmonic balancer puller from autozone and it's super easy with just a little mechanical experience. I say go for it, You'll love it.

[ricklmesa]

I know the one of the new underdrive pully's for the 05,06 v6 claims 12 HP but only puts out like 4 HP. I 'll just haft to wait for a good pully

[SpectorV]

they help, they help more than exhaut or cai, but they dont help much. You will see 7rwhp/7rwtq~ doubtful you can even feel the difference~

they do help gas milage, you only get the crank pulley anyay, and they are easy to install.

[Herbstang]

UDP is a good bang for the money .If you have access to air tool install is easy

[DarkShadow]

They are pretty good, but don't expect too much as with any bolt on. You can rent a puller and installer from Advance, Autozone, etc, use it, and then return and get your deposit back 100%. Install isn't too bad if you have the right tools, but if it's an auto, you'll definately need an impact wrench.

Also the difference was with the harmonic balancer, I THINK before `02 the pulley and balancer were separate items, and then after `02 they were one piece. Again I think that was the years, not positive.

[BirminghamStang]

yeah you need a puller....air tools would be GREAT.....however.....i did do mine with just a ratchet set..not really any noticable gains.....but...if you are just trying to squeeze all you can off of bolt ons....then i say go for it

[justin00stang]

It takes me about 45min to install one, most will take 1-2hrs. There is a noticeable difference in feel IMO, I put one on my car years ago when it was stock. I also did back to back testing at the track with D99Stang's car and saw a .2 drop in ET.

[CHiPSV6]

I agree that the under drive pulleys are well worth the effort, regardless of whether you have a 94-98 or 99-04. You might want to look at my article about under drive pulleys on my web site. See my e-mail address for website name.

[232stang01]

I put one on my 01, and I'd say it was worth the effort. Just don't expect it to give up HP like a dozen or so NAWSSSS stickers.

[SpectorV]

the KEY to the installation is a pulley puller and to MAKE SURE YOU TQ THE CENTER BOLT TO 125ftlbs. They just impacted mine on, then ... the CEL came on with multiple missfires. I tq'ed it down and its fixed.

[Nite-Mare]

I think it was worth it. It's a 5hp increase for the entire rpm range. It feels like the car has got avlot more torque. Install was $20 from a guy down the road... The U/D pulleys with the harmonic balancers are cool because it smooths things out a little. If you live in the city, you will NOT be impressed. If you live out in the sticks where it's hilly then you will think they are the best invention since the styrofoam cooler.

[Kiljosh]

Originally Posted by SpectorV

the KEY to the installation is a pulley puller and to MAKE SURE YOU TQ THE CENTER BOLT TO 125ftlbs. They just impacted mine on, then ... the CEL came on with multiple missfires. I tq'ed it down and its fixed.

Yea DO NOT slack on the torque, It's hard to make on something that spins, but do it with the belt on and stop the engine from turning.

[PCD]

Strike, I've got 25% UD crank pulley and an OD pulley on my alternator. I got 2 MPG more in the city. I have a bad torque converter right now, so my highway mileage is not reliable until I get that fixed.

I noticed more snap off the line and my car DOES run cooler.I have no charging problems with my car, and I do make short, in town trips with it.

[1997grnstang]

i didnt have the tools to install mine, so i took it to a shop and they did it for $15

[DarkShadow]

Originally Posted by PCD

Strike, I've got 25% UD crank pulley and an OD pulley on my alternator. I got 2 MPG more in the city. I have a bad torque converter right now, so my highway mileage is not reliable until I get that fixed.

I noticed more snap off the line and my car DOES run cooler.I have no charging problems with my car, and I do make short, in town trips with it.

How does it do that? The UD slows down your water pump. Stock temp gauges suck anyway.

[PCD]

In this set up, the belt speed is the same because the OD Alternator pulley compensates for the UD Crank pulley. Oh, the belt I'm using is shorter than stock.

Since I haven't changed the temperature sender or gauge, but the readings are much lower. I have to go that I'm running colder.

I do plan to put in an A Pillar triple gauge pod with water temp, tranny temp, and volts.

[SpectorV]

I have an aftermarket autometer temp gauge the temps are exactly the same as stock, my stock POS battery took a dump though, and may or may not have been pulley related.

My new battery has been 100% fine though.