GAH! Help with UDP Questions

[grandmacpubah]

Ok so I ordered the SLP underdrive pulley and was told I needed a dayco 5060780 belt. So I cross referenced with the gatorback and ordered part 4060780.

Then I read in a couple places on here that it's an entirely different belt? BLAH!! Can someone please confirm what belt is needed?

Secondly, I did some searching on here to find out if there are any ill effects from running a UDP and really didn't find much. So I did a general search and came up with some "tech" articles from a BMW guy that basically said you are going to kill your engine...(also some similar info on the GTO forums)

Please be patient with me if this has been answered elsewhere but I couldn't really find it.

Is this mod going to wreck our engines in the long term? Is it really worth taking the chance for the 5hp or so power gain?

If so I have a new SLP UDP for sale..LOL Thanks ~ Jesse

[GRRRR8]

K060747 is the correct # No issues with engine. I have had mine on for 3000 hard miles and no issues at all.

[grandmacpubah]

thanks charlie...weird that everyone has the wrong belt listed what a pain...sigh...

after some more research I found a lot of the "issues" with a UDP is many do not have the harmonic balancer which is a big deal. The SLP/Powerbond does which is good :) So really the only other issues would be any ill effects on underdriving the accessories, especially the water pump and alternator.

The internet is soooo full of misinformation...lol

[GRRRR8]

All UDPs for the G8 are balancer assemblies.

[Steve]

15k miles - no issue :)

[grandmacpubah]

Steve do you notice any "underpowered" accessory issues at idle? I'm thinking I won't because I'm an A/C nazi...I hate AC...not to mention when does it get warm enough in Seattle for A/C anyway? lol! BTW you've pretty much done with your car everything I'm going to do with mine - me doing a TC? Can I ask what kind of RWHP you are getting? I have a goal of around 370-380ish. Thanks

[Steve]

Once in a blue moon i'll notice the headlights dimming just a smidgen when idling and then coming on full force again when even crawling at 5 mph.. Other than that - everything works just fine as is!

No idea about RWHP yet - guessing i should be around those numbers- probably a little under? but I haven't had a chance to dyno yet and not sure if I want to yet lol (going to do a cam next) Guess I 'should' do a before and after at least.. I just want to see some 400+ numbers ;)

My goals keeps shifting as soon as I hit one because i'm already looking at high 400's/low 500's and how to get there lol

['02 ws6]

You should have NO worries about getting a U/D pulley. Like said before, the interweb is filled with bad info. The GTO's horror storries I believe came from an assumption generated by an accused LS2's failure in a TBSS after a pulley swap, and from there the GTO forums/owners freaked out a bit, due to them having the same motors.

As for the "Is it worth it?" factor. The avgs I've seen from any LS platform running a U/D pulley is about 8rwhp/10rwtwp. For $250, that's pretty cost effective, and can only compiment other mods.