A4 Guys-Overdrive Alt. Pulley
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From: Petaluma, Ca
A4 Guys-Overdrive Alt. Pulley This is just an FYI for A4 guys who might be looking for info on 25% underdrive pulleys and overdrive alt pulleys and belt sizes. I've got a '01 Z28 that I had put an underdrive pulley on. As most of you know, sometimes you get dimming headlights, slow turn signals and dead batteries. The dimming headlights and slow turn signals (I killed the battery once) drove me crazy when I'd drive at night. Went searching this forum and found some info and bought an overdrive alt. pulley and a new belt. A K060755 belt was recommended. Just got done putting the overdrive pulley on. I had to take the alt. off the car to do this job. You will need a 24mm 1/2" drive socket and 1/2" drive electric impact wrench. Used my old belt with some c-clamp vise-grips to hold the pulley still and loosen the nut. The new pulley is smaller then the stocker so you can't use a impact socket on it because the wall of the socket is to thick. Non-impact socket is what you want. Put everything back together but I don't have my new belt yet. So I thought wtf, I'll try my shorter belt that is already on the car which is a K060760. Well, the damn thing fits! Being the new alt. pulley is smaller then the stocker, the belt actually fit a little better then before. So it looks like I will have a spare belt when that gets here. Went for a test drive and no more dimming headlights, no more slow turn signals and the needle on the voltmeter stays still at about 14. Now I'll be happy when I drive this thing at night.
so you put an underdrive pulley on then you started seeing those symptoms? i have low alt. current as is so im wondering if this would help. did you notice any performance with the underdrive and overdrive pulley?
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Can't really say I saw any performance. Maybe the engine revs a little quicker. But yeah, I didn't have any symptoms until after the underdrive pulley install. As far as the low alt. current, does your gauge needle drop when you come to a stop? Mine did and would then return to normal when I started driving again. After the alt. pulley install my needle doesn't move at all when I come to a stop while still in drive.
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From: Petaluma, Ca
Do you have an A4 or a M6? From researching the forum it seems autos idle lower in gear at a stop sign so you get dimming lights and such.
Last edited by ChrisRZ28; May 4, 2011 at 09:08 PM. Reason: Just saw your sig. A4.
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Joined: Dec 2006
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From: Petaluma, Ca
I don't think I messed up my alt., but I don't daily drive my car right now. I did have to recharge the battery one time before I installed the alt. pulley so hopefully I didn't do any damage to the battery or alt.
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TECH Apprentice
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From: Petaluma, Ca
Thread Starter
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Joined: Dec 2006
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From: Petaluma, Ca
Keep in mind I just put this alt. pulley on last night so this has not been a long term thing. But not having the dimming lights and other symptoms after the install is a good sign.
yeah maybe it's just me but it sounds like you wasted your time and money, if you underdrive 1 pulley and overdrive another aren't you defeating the purpose of an underdrive pulley to begin with?
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Joined: Dec 2006
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Can't really say I saw any performance. Maybe the engine revs a little quicker. But yeah, I didn't have any symptoms until after the underdrive pulley install. As far as the low alt. current, does your gauge needle drop when you come to a stop? Mine did and would then return to normal when I started driving again. After the alt. pulley install my needle doesn't move at all when I come to a stop while still in drive.
Thread Starter
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From: Petaluma, Ca
I still have the stock radio in my car. My lights used to flicker but a couple years ago I replaced my alt. (note related to my underdrive pulley) and haven't noticed it since. But I don't know if that alt. was what 'fixed' it.
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From: Petaluma, Ca
It's alot nicer to drive at night knowing things work like there suppose to. Whats funny is the actual pulley swap is a piece of cake. It takes longer to get the alt. off the car... 
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