under drive pulley are the worth it?

**NIKDSC5** · 01-22-2008, 07:52 PM

just as it says. I see some people complaining of higher temps running them just wanted to get some opinions thanks.

**FASST LN** · 01-30-2008, 07:47 AM

You shouldn't see any higher temperatures due to the pulley.
It is worth it if you're already installing a cam or something. I wouldn't do this mod by itself though, too labor intensive.

**t-rock** · 02-25-2008, 03:55 PM

a pulley and a tune be worth it would it not?

**FASST LN** · 02-26-2008, 05:55 AM

My understanding is to change the UD pulley on a C5 is much more difficult than on an F-body. I don't know this for certain, just passing along what I heard.

Changing the UD pulley would not necessitate a computer tune. So no, I would not do those two mods together.

Only if you're getting some engine work done or you're having to replacing the timing chain would I suggest getting an UD pulley installed on the Vette.

I had an UD pulley installed on my SS when I had the cam installed. It was a good modification and I didn't notice any problems with charging the battery...though I believe I also had an OD pulley installed for the alternator.

**cam99** · 02-26-2008, 10:55 AM

Originally Posted by t-rock

a pulley and a tune be worth it would it not?

On a C5, NOT!

**LS16SPD** · 02-26-2008, 11:20 AM

I Tried The Ud And Had Some Severe Charging Problems!

**Mr. Hyde** · 02-29-2008, 05:37 AM

I can tell you what my Tuner told me when I asked him about running one on my SS when we dropped my LS6 in it. He said that the claims the manufacters make about the HP gains is BS! That they took a relatively stock Mustang GT they had in the shop, and threw it on their dyno. Then got a base, then just completely REMOVED the serpentine belt, so none of the accessories were being driven, and threw it right back on the dyno. A paultry 3 HP gain. So ask yourself if it's worth it to drive all your accessories at a lower speed, the hassle of doing it, for around 3 or less HP. Not to mention the cost.

**MacGyver** · 02-29-2008, 08:10 AM

Originally Posted by 01LSS6Camaro

I can tell you what my Tuner told me when I asked him about running one on my SS when we dropped my LS6 in it. He said that the claims the manufacters make about the HP gains is BS! That they took a relatively stock Mustang GT they had in the shop, and threw it on their dyno. Then got a base, then just completely REMOVED the serpentine belt, so none of the accessories were being driven, and threw it right back on the dyno. A paultry 3 HP gain. So ask yourself if it's worth it to drive all your accessories at a lower speed, the hassle of doing it, for around 3 or less HP. Not to mention the cost.

I wonder how many guys would be pissed reading this after installing the pulley.

**scramblerman** · 02-29-2008, 08:46 AM

Originally Posted by 01LSS6Camaro

I can tell you what my Tuner told me when I asked him about running one on my SS when we dropped my LS6 in it. He said that the claims the manufacters make about the HP gains is BS! That they took a relatively stock Mustang GT they had in the shop, and threw it on their dyno. Then got a base, then just completely REMOVED the serpentine belt, so none of the accessories were being driven, and threw it right back on the dyno. A paultry 3 HP gain. So ask yourself if it's worth it to drive all your accessories at a lower speed, the hassle of doing it, for around 3 or less HP. Not to mention the cost.

too bad they tested it a mustang Gt, lol.
Actually have seen tests where the just the pulley added 4-5rwhp throughout the rpm range. I will have to say though that it is a big pain to change on the vettes. You will have to remove the steering rack out of the car just to change it. If you are doing a cam swap, then yes change it but otherwise would not change it.

**Mr. Hyde** · 02-29-2008, 09:44 AM

Quick note that I forgot to point out that Mr. Tuner said to me when I said that the underdrives add HP throughout the entire range. "They DON"T add HP, they only free up what is already there" That was apparently a big deal to a man that creates HP. Tuners..what are ya gonna do? I wasn't going to argue the point that he only brings out the HP that is already in the car. I do after all, go back every now and again for dyno pulls myself. I know when to shut the hell up.

***BlownC5*** · 03-03-2008, 12:26 PM

Its a pain in the arse to change, I did it on my 97 which was stock at the time. Showed 2hp throughout the rpm range, but, that is also within the margin of error factor when dynoing. Not worth it imho.

**c5andtyphoon** · 03-23-2008, 08:59 AM

lol when i first bought the underrive pulley for my c5 the supplier told me its an easy install. well ended up the bolt for the underdrive pulley can't be taken out without dropping the steering rack. Not something worth me doing in my garage for a few ponies. I'll stick with my nitrous