underdrive pulley how to: ?

04sxt2.0 · Post by **04sxt2.0** » Sat Jul 28, 2007 1:19 pm

does any one have a how to , on installing a underdrive pulley almost the same thing as an unothidox racing pulley...

j0n · Post by **j0n** » Sat Jul 28, 2007 1:44 pm

I don't have a how-to but it was very easy and took me about an hour. Make sure you rent a 3-jaw puller from autozone. You want to pull both belts off and remove the plastic shroud under the serpentine assembly. Then pull the crank bolt out and put a smaller diameter bolt in its place for the puller to push off of. Use the puller to pull the pulley off and then toss your new pulley in the oven on 475* for 10 minutes(works better if you preheat the oven first). Then take a leather work glove and run the pulley from your oven to the car and slide it onto the crank. Thread the crank pulley back in and torque it down. Put the belts back on and the shroud and you're good to go.

kc2005ptgt · Post by **kc2005ptgt** » Sat Jul 28, 2007 2:58 pm

there is a lot of stuff on this topic, just doa search... here is what I turned up:

http://forum.2gn.org/viewtopic.php?t=22 ... dp+install
http://forum.2gn.org/viewtopic.php?t=21 ... dp+install
http://forum.2gn.org/viewtopic.php?t=18 ... dp+install

edit: funny, the first one is you asking similar question

04sxt2.0 · Post by **04sxt2.0** » Sat Jul 28, 2007 6:20 pm

i draw blanks some times, i am sorry.

lilolneon · Post by **lilolneon** » Tue Jul 31, 2007 8:31 am

better than shootin blanks i suppose

and this actually helped me too... i plan on doing this today

gilly02le · Post by **gilly02le** » Wed Aug 01, 2007 2:07 am

Make sure it's VERY HOT, and i mean VERY, otherwise, it will not fit on, and it will get stuck half way, and you don't want to be banging the hell out of it trying to get it on there! just my .02 cents

lilolneon · Post by **lilolneon** » Wed Aug 01, 2007 11:53 am

30 mins at 400*F and it slid right on... well 1/2 way, screwed the rest of it on... still slid on easy tho

04sxt2.0 · Post by **04sxt2.0** » Wed Aug 01, 2007 5:32 pm

i plan on doing it when i get the belts in a couple of weeks, and when i get a saturday to my self.. i have to put on alt over drive one also..

lilolneon · Post by **lilolneon** » Thu Aug 02, 2007 9:02 am

yea, i still want the alt ODP for now i will settle with the udp

but word of advice if you have a local autozone, go rent the Chrysler Harmonic Puller. it will help you out more than you can believe. I found it much easier to use than the universal puller, much smaller compact size made it easier to fit on the pulley and unlike the universal one, it comes with the metal rod thingies to stick in the lil hole to help. and i love how ur car looks 04sxt2.0

dblsg · Post by **dblsg** » Thu Aug 02, 2007 11:55 am

gilly02le wrote:Make sure it's VERY HOT, and i mean VERY, otherwise, it will not fit on, and it will get stuck half way, and you don't want to be banging the hell out of it trying to get it on there! just my .02 cents

you can bang on it, but just make sure to use a block of wood over the pulley and then bang the hell out of the wood block with a BFH (Big F-en Hammer)

Adionik · Post by **Adionik** » Thu Aug 02, 2007 1:05 pm

Just a quick q while were on this topic.

But for those who DO have a UDP installed, how many of you all have ran into problems? Alternator/etc ya know...the usual you hear about with udp's.

Cuz I'm thinking about getting an obx one.

kc2005ptgt · Post by **kc2005ptgt** » Thu Aug 02, 2007 3:23 pm

nothing, 2 years running strong, after the new battery (optima red top)

04sxt2.0 · Post by **04sxt2.0** » Thu Aug 02, 2007 5:11 pm

i've heard some times along the lines that they cause the alt to over charge battery, but haven't heard anything recently... i just took the extra step and got an adam K over drive alternator pulley which is slightly bigger than the stock pulley so it wont cause the alt to over charge its self and kill its self out. lilneon thanks, I really needed to hear something positive like that, just having some hard times right now. i haven't taken any recent pics but i have to take some soon.

Adionik · Post by **Adionik** » Thu Aug 02, 2007 6:58 pm

kc2002acr wrote:nothing, 2 years running strong, after the new battery (optima red top)

Nothing with your power steering pump or alternator?

lilolneon · Post by **lilolneon** » Thu Aug 02, 2007 10:13 pm

you know... i was driving today w/ my system on... rather loud... normally my lights would dim like a mofo, but... it didnt today... im thinkin the UDP helped, but i dunno

the car seems to idle a bit smoother too. havent really noticed any performance changes, but i also ahvent reset the pcm. ive been more affraid of the new belts snapping while im driving... but i have no worries now. i drove over 200 miles today and nothin fuked up... so... i musta done sumtin right

and the UDP that i got was an OBX off of ebay. i watched that thing spin the other day. not a single wobble, lined up perfectly w/ the belts too. (btw, if you do, do this mod, you will need new belts to match the size change)

j0n · Post by **j0n** » Fri Aug 03, 2007 1:41 am

dblsg wrote:
gilly02le wrote:Make sure it's VERY HOT, and i mean VERY, otherwise, it will not fit on, and it will get stuck half way, and you don't want to be banging the hell out of it trying to get it on there! just my .02 cents
you can bang on it, but just make sure to use a block of wood over the pulley and then bang the hell out of the wood block with a BFH (Big F-en Hammer)

no no no no no no...do you know what happens when you start banging on your crankshaft? cuz that's what you're doing...its a great way to fubar your main bearings

Adionik · Post by **Adionik** » Fri Aug 03, 2007 2:33 am

What are the belt sizes for the OBX udp?

Thanks!

04sxt2.0 · Post by **04sxt2.0** » Fri Aug 03, 2007 6:56 am

on of the other threads i asked that and they gave me the belt sizes, i think one is 49-50 i think.. not to sure..

kc2005ptgt · Post by **kc2005ptgt** » Fri Aug 03, 2007 11:39 am

Adionik wrote:
kc2002acr wrote:nothing, 2 years running strong, after the new battery (optima red top)
Nothing with your power steering pump or alternator?

Nada... all runs just fine, ac is cold as heck, power steering works fine, no problems, and altinator is still stock, no problems. I bought a VOLT guage, and I read normal volts at all times (14.1 cruising ~13.5-.7 when idle).

Adionik · Post by **Adionik** » Fri Aug 03, 2007 12:12 pm

kc2002acr wrote:
Adionik wrote:
kc2002acr wrote:nothing, 2 years running strong, after the new battery (optima red top)
Nothing with your power steering pump or alternator?
Nada... all runs just fine, ac is cold as heck, power steering works fine, no problems, and altinator is still stock, no problems. I bought a VOLT guage, and I read normal volts at all times (14.1 cruising ~13.5-.7 when idle).

Sweet, I like hearing that. Someone local is selling a new power steering pump for $40...I might pick it up.

I guess i'll get a pod and gauges before i install the udp...

lilolneon · Post by **lilolneon** » Fri Aug 03, 2007 1:13 pm

i dont have any pods or gauges, and i sent you a PM with belt sizes, but so everyone else will know, ehre they are...

Alternator - 5040320
Accessory - 5040500

Those are dayco belt numbers btw.

and thats curtiosy of BlackRose from an old topic i searched for earlier.

and my AC has always been ice cold. i have to have the temp thingy almost in the red for it to not freeze my ass while its on

Adionik · Post by **Adionik** » Fri Aug 03, 2007 1:46 pm

Thanks for the help.

I called Autozone and these are the part numbers for 'their' belts. I hope they fit my obx udp.

320k4 - 10.99

500k4 - 11.99

lilolneon · Post by **lilolneon** » Fri Aug 03, 2007 1:48 pm

they should, i was worried that they wouldnt fit mine either, but they do

Adionik · Post by **Adionik** » Fri Aug 03, 2007 11:50 pm

I bet it's going to be a bitch and take a whole day for me to install this thing...

OB · Post by OB » Fri Aug 03, 2007 11:59 pm

04sxt2.0 wrote:i've heard some times along the lines that they cause the alt to over charge battery, but haven't heard anything recently...

Since alternater output is directly controlled by the PCM, I find it hard to believe this. Maybe on certain other cars, but this shouldnt be an issue with ours. If the PCM sees the alternator putting out more power than is needed, the voltage regulator will prevent that power from charging the battery.

People say the accessories might be negatively effected by a smaller diameter crank pulley, but how can that be when the pulley is actually spinning faster than it was before? All things equal, this should increase power to all effected components, not cause it to be lowered. The only concern I would have with a UDP would be regarding its ability to create the same balance as the stock one. With its lighter wieght and lower intertia, I could see this being more a concern than anything. It might not effect anything right away, but after a few years who knows. Just a theory.

04sxt2.0 · Post by **04sxt2.0** » Sat Aug 04, 2007 7:08 am

an alternator is and will never be monitored by any controller unit, it may look at the voltage it is creating, but a voltage regulator can go bad, with a udp with is smaller and more light weight, your causing the alternator to spin faster, thus shorting some life out of it, i've heard about it on other forum boards, thats why they created the alt over drive pulley to limit the alt spinning faster than normal.. but if it doesn't happen fine, i'm just going on what i've heard, and what i know from being a mechanic

lilolneon · Post by **lilolneon** » Sat Aug 04, 2007 12:52 pm

since i installed the UDP, my lights dont dim as much as they used to when i have my system on loud... so... i take it as a benefit

pyro · Post by **pyro** » Sat Aug 04, 2007 1:12 pm

with a udp with is smaller and more light weight, your causing the alternator to spin faster, thus shorting some life out of it, i've heard about it on other forum boards, thats why they created the alt over drive pulley to limit the alt spinning faster than normal

An Under Drive Pulley spins the accessories slower. Think about it. Every revolution a smaller diameter crankshaft pulley will move the belt the amount of its circumference which is smaller than stock. With the accessory pulley size remaining constant, it(the accessory) will spin a lesser amount for the same crankshaft revolution.
Putting a larger pulley on the driven side will further slow the accessory being driven, a smaller (alt. overdrive pully) will speed it up.

How can you think you're gonna gain power by making the engine work to accellerate the accessories faster? Physics doesn't work like that, even with a lighter rotational mass to compensate. The gains to be had are mostly from the lower frictional losses & not putting as muck power into the accessories, the allternator will only take an additional amount of force to turn as the regulator lets it make more current as needed to maintain voltage. The a/c will run slower, and doesn't work as well, works good enough, but not as well-ditto the P/S pump.

and what i know from being a mechanic

O.K. whatever, tell us where so we all can avoid the place.

anomalous0 · Post by **anomalous0** » Sat Aug 04, 2007 2:37 pm

He's right, you know. Make a mockup with rubber bands and tinker toys if you have to.

OB · Post by OB » Sat Aug 04, 2007 3:49 pm

Pyro nailed it right on the head. Thanks to a discussion we had today when we met up, it makes perfect sense to me now.