9-z28-4

ok, so long story short i messed up my stock crank pulley trying to get it off to replace my opti (im still in the middle of that). i had to use a hammer to get it off and i chipped the cast metal and its not gonna hold the belt any more, so a new one is $153 and an underdrive from jegs is $73. any pros or cons about the underdrive? i do have 2 12" so i am a little concerned that the charging system wont be able to keep up, is that an issue? im not really looking for the hp from the underdrive im just trying to save some $$.

96capricemgr

iTrader: (1)

The stock "pulley" is also the damper. A $73 piece is going to be an addone underdrive pulley that still requires you to bolt the stock damper on over it.

Maybe hit the parts wanted section, somebody will sell you a used stock damper.

ElkySS

iTrader: (6)

they actually do make underdrive dampeners im not sure if hes talking about this or not

96capricemgr

iTrader: (1)

For $73 he is not. I know they make UD dampers but they are a good bit more expensive.

9-z28-4

well i messed up the groves on mine but the balancer is not damaged, could i still use the balancer? i didnt realize the stock balancer stayed

9-z28-4

i gotta order one today, will it work?

fergymoto

iTrader: (129)

Being that you knocked some metal off it, it could now be out of balance and cause a vibration.

MEAN LT1

iTrader: (2)

Im not a fan of underdrive pullies at all. I really dont think they do anything but cause low voltage situations.

19mike84

well im sure if you get an under drive damper it will make a difference, just think 2 ibs off the crank

lt1-xjs

ASP 945103 for about 5 yrs. no issues, but I do have a converter also.

lt1 hawk

iTrader: (2)

I agree with MEANLT1 on the underdrive pulley. I was researching putting an underdrive pulley on my LT1 because all the LS1 guys were saying it was on of thier early mods. I started making my plan for mods, and I had an underdrive as something I planned to do. I talked to several qualified shops about putting them on, and the ones who know the LT1 engine were saying not to do it because with the pulley set up in the LT1, you will just be losing inertia inside the engine with it. There is no need to underdrive your accessories because you are just going to be losing voltage. You will not make any gains in your power of the crank (might even lose some), so all you are really doing is making your accessories run like ****. replace the crank pulley and be done with it.

7camaro7

iTrader: (15)

This is not true about losing power. A couple of my buddies have 6spd lt1s and WITH A 6SPD YOU WILL HAVE NO CHARGING ISSUES. One of the cars is a 97 z28 vert the other is a 97 ta ttop. They both are modded about the same but the one with the udp feels better to me. I have one on my ls1 and it definitely gave me more power. It was my last hp bolt on too so I know that's what's making my tires work a little harder with the new lack of traction I have.

96LT1355Z28

iTrader: (2)

I have an Aeromotive pulley between the balancer and crank hub. The only time I have a charging issue is at night, with the headlights on, sitting still, with my foot on the brake. The voltage will drop to between 12-13 volts, if I let off the brake the voltage goes back up. As soon as the rpm's go up when the car moves vlotage goes back up to normal, my low voltage light has never come and the gauge has never gone into the red. I can see this being a problem on an A4 car simply because of the lower idle rpm. Performance wise I don't really know what if anything it did for my car.

stupidfast_twin

iTrader: (2)

i have a stock balancer in good condition. put a bbk underdrive pulley on and got a new harmonic balancer from my job. it came of a 97 z28. and yes, everyone i know who has and underdrive pulley looses power but not enough to do anything. i have 2 infinity 10" subs pushing 1200 watts each and still hit hard as hell. another one of my friends has 2 kicker 12's and also hits really hard. only thing we have is yellow top optimas. hit me up if you still need the balancer

bufmatmuslepants

iTrader: (3)

i dont see how a lighter, smaller underdrive pulley would be a bad modification. its like having a lighter crank...less inertia makes it easier to accelerate therfore producing quicker revs. ive had mine on for a year and about 20k miles and noticed no increase in engine vibration and havnt had any problems iwth charging. lightweight wheels, aluminum driveshafts, lightweight rotating assemblys...those are all to reduce interia and have been being used for decades to improve the performance of cars. put on an underdrive pulley, there cheap as hell, and if you are worried about charging then put on an alternator pulley and itll speed up your alternator to compensate.

PNYKLR-TA

iTrader: (1)

i also have the ASP set, and at night with my lights on idling at a light with my foot on the brake and the AC on im barely in the red zone, and my low voltage light still has never come on, if i put the car in nuetral then it sits at about 12.5-13. once i start driving its above 13. car def seems to rev a little quicker. seems like it recovers from shifts a little stronger too. and think of how much people pay for some things that hardly even make a difference, the UD pullies if you ask me are def a decent mod as long as you arent powering the whole trailer park with your car.