UD pullies bad idea?

ItaliStang · November 30th, 2008, 01:56 PM

was told this by someone on a local forum...

(he quoted someone from a mach1 site) but just wondering... full of BS? cause it seems to be a popular mod for 6ers, and lots of people run it without problems...

Under Drive Pulleys (or commonly referred to as UDP's) are used to slow down the engines accessories. by doing so, you free up HP and TQ that would normally been lost.
The problem in doing so is...when you decrease the size of the harmonic balancer, you decrease the amount of vibrations that can be absorbed and canceled out.
This is a MAJOR problem when running the factory oil pump, the gears in these pumps are very weak. and any increases in vibrations reaching the teeth GREATLY increase the chance of failure.
This failure will most likely occur at very high RPM's, when vibrations are at the highest frequency and intensity. if oil pump failure occurs at 7,000 RPM's...your engine is TOAST.
My Recommendation: ALL people who own a Mach 1 is to STAY AWAY from them.
15hp is NOT worth the chance of jepordizing your engine.

riddlee josh · November 30th, 2008, 02:51 PM

the pulleys i have didn't replace the harmonic balance. i got mine from jegs. they are bbk. i have the crank pulley and the alt. pulley. i could feel a slight improvement in them. i would say that they are a good mod.

scubasteve041186 · November 30th, 2008, 03:01 PM

yeah i dunno..
the idea of making them smaller / lighter
we decrease the interia of the pullies and the forces of the vibrations but we doo increase the harshness if their were vibrations because they are alot closer to the shaft.
but on the other hand with bigger heavier pullies, the forces are greater and can have a lot more force due to the idea of leverage and torque. greater forces and even greater distance from the shaft. which in my head equals worse things to happen but if designed properly should be fine.
makes sense what he's saying that if shit does fail you will kill your engine but i'm not sure if his idea of worse vibrations is known? like yeah you can have human errors in the machining of the pullies or just installation that will screw things up or even just wrong materials ( moto blue are ones to stay away from I heard they warp)
but I have yet to see anyone complaining about UDP's wrecking thier cars just yet.. other then AB and his moto blue disaster

engineering stand point I don't see them causing a problem, just get a better belt and make sure stuff stays tight and you should never have a vibration problem if the bearings are good

408gt91 · November 30th, 2008, 04:50 PM

Call march and get the power and amp series. That way there your alt wont drag ass and your car wont heat up.

gooberhead320 · November 30th, 2008, 04:54 PM

lol just install them already tony

97mustanggt · November 30th, 2008, 04:58 PM

so should cobra owners stay away from underdrive pulleys also?

riddlee josh · November 30th, 2008, 10:14 PM

i have a 1000 watt amp and two 10 inch subs and my alt. doesn't drag any.

ItaliStang · December 1st, 2008, 02:02 AM

Originally Posted by gooberhead320

lol just install them already tony

oh, I will be... as soon as I find room in my garage to fit the car (as you could tell from that pic of the ugly ass couch... it's messy in there)
hell, even if someone proved to me that it would fuck up the car, I'd put them on... perfect excuse to get rid of it and get a V8

I just felt like proving someone wrong out of boredom... needed other people's opinions

gooberhead320 · December 1st, 2008, 11:20 PM

Originally Posted by ItaliStang

oh, I will be... as soon as I find room in my garage to fit the car (as you could tell from that pic of the ugly ass couch... it's messy in there)
hell, even if someone proved to me that it would fuck up the car, I'd put them on... perfect excuse to get rid of it and get a V8

I just felt like proving someone wrong out of boredom... needed other people's opinions

you don't need a garage to install them.. hell if you really need a garage come and use mine... we can push my mustang out, or just move the nissan

ItaliStang · December 2nd, 2008, 11:13 AM

it's 20 degrees out... I'm not freezing my ass off for it...

finding time to do it is also a problem... working both jobs leaves basically no days off...

stangcharger · December 2nd, 2008, 11:25 AM

UDP was one of the best bolt-on mods i did. and many people comment on having great gains from them for what they are. they work.

03_StangGuy · December 2nd, 2008, 11:49 AM

I had under drive pulley on my car and they worked fine. The vibration dampener is necessarily moved just the surface the belt it on. If designed properly the new dampener would work just as good as the old one.

gooberhead320 · December 2nd, 2008, 01:08 PM

Originally Posted by ItaliStang

it's 20 degrees out... I'm not freezing my ass off for it...

finding time to do it is also a problem... working both jobs leaves basically no days off...

i have a heated garage, thats one of the reason our nicest cars are parked in the garage.. while the expedition and ranger are parked outside

November 30th, 2008, 02:51 PM	#2
riddlee josh Enthusiast 1998 mustang 3.8l v6 Join Date: Nov 2007 Location: portsmouth ohio Posts: 811 iTrader: 0 reviews	the pulleys i have didn't replace the harmonic balance. i got mine from jegs. they are bbk. i have the crank pulley and the alt. pulley. i could feel a slight improvement in them. i would say that they are a good mod. __________________ RACING because baseball,basketball, bowling,football, and golf only require one ball

November 30th, 2008, 04:50 PM	#4
408gt91 Regular Join Date: Aug 2007 Location: ya mudda's house Posts: 204 iTrader: 0 reviews	Call march and get the power and amp series. That way there your alt wont drag ass and your car wont heat up. __________________ 408stroker/tf track heats/scat crank/h beams/srs fordged/351sportsman block/trick flow rrkrs/msd dist/edelbrock victor5.8intake/aeromotive fuel system/accufab 80mmtb/pro-m80mm,maf etc.

November 30th, 2008, 04:58 PM	#6
97mustanggt Hardcore Enthusiast 97GT & 97Snake & 00L T.B.A Join Date: Aug 2008 Location: Richgrove, Ca Posts: 2,183 iTrader: 0 reviews	so should cobra owners stay away from underdrive pulleys also? __________________ 97 Cobra & 00 Lightning Beauty & The Beast I rev next to hybrids so they can hear me kill the environment MM Cobra Club Member #77 MM Lightning Club Founder

November 30th, 2008, 10:14 PM	#7
riddlee josh Enthusiast 1998 mustang 3.8l v6 Join Date: Nov 2007 Location: portsmouth ohio Posts: 811 iTrader: 0 reviews	i have a 1000 watt amp and two 10 inch subs and my alt. doesn't drag any. __________________ RACING because baseball,basketball, bowling,football, and golf only require one ball

December 2nd, 2008, 11:25 AM	#11
stangcharger Enthusiast Join Date: Sep 2008 Location: OKC, OK Posts: 806 iTrader: 0 reviews	UDP was one of the best bolt-on mods i did. and many people comment on having great gains from them for what they are. they work. __________________ 436rwhp/378rwtq tuned by HPP www.hppmotorsports.com - www.stangcharger.com - www.rpm-mustangs.com

November 30th, 2008, 03:01 PM	#3
scubasteve041186 Hardcore Enthusiast 2004 mustang 40th annv. Join Date: Sep 2006 Location: kelowna,BC, Canada Posts: 1,382 iTrader: 0 reviews	yeah i dunno.. the idea of making them smaller / lighter we decrease the interia of the pullies and the forces of the vibrations but we doo increase the harshness if their were vibrations because they are alot closer to the shaft. but on the other hand with bigger heavier pullies, the forces are greater and can have a lot more force due to the idea of leverage and torque. greater forces and even greater distance from the shaft. which in my head equals worse things to happen but if designed properly should be fine. makes sense what he's saying that if shit does fail you will kill your engine but i'm not sure if his idea of worse vibrations is known? like yeah you can have human errors in the machining of the pullies or just installation that will screw things up or even just wrong materials ( moto blue are ones to stay away from I heard they warp) but I have yet to see anyone complaining about UDP's wrecking thier cars just yet.. other then AB and his moto blue disaster engineering stand point I don't see them causing a problem, just get a better belt and make sure stuff stays tight and you should never have a vibration problem if the bearings are good

December 2nd, 2008, 11:49 AM	#12
03_StangGuy I Poop Entirely Way Too Much Blown 03 GT Join Date: Jun 2007 Location: Long Island NY Posts: 6,918 iTrader: 0 reviews	I had under drive pulley on my car and they worked fine. The vibration dampener is necessarily moved just the surface the belt it on. If designed properly the new dampener would work just as good as the old one. __________________

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