EBAY underdrive pulley review

FAC3L3SS · Post by **FAC3L3SS** » Thu Apr 22, 2010 11:51 pm

My UDP is just like yours. Both of them are 5 grooves. Tam had the K4 numbers that I posted next his pulley (same as mine) and there was an extra groove on each spot. The belts weren't wide enough.

I'll be safe with the 4K numbers? Did you leave the inside or outside groove open?

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 9:08 pm

occasional demons wrote:I used the K4 500 and 320. I think the SRT pulley(s) may be 5 groove, at least one, prolly the PS/AC belt, since the Ebay ones have the extra groove on the outer pulley.

I really don't understand why the PS/AC needed an extra rib/groove on SRT's. I would have thought the alternator being a higher output would have had an extra rib. But then the PS/AC would need to be spaced out a bit more, and the dampers would not be universal between the 2.0 and 2.4. Oh, that's right, production costs. Fuck function.

So with that pulley, the smaller part being a 5-groove piece, did your K4 belts still work fine? I bought those same belts, but it bothers me that there'll be an extra groove showing on the pulley.

Post by **occasional demons** » Mon Apr 26, 2010 10:29 pm

Sorry, I missed your reply.

That is actually danman132x's pulley from his how to thread. The belt will go to the inside edge, I believe. Your PS/AC will determine the position. Unless you have the SRT/2.4, the PS/AC will be the 4 rib style. The AZ belts worked fine. They didn't look as good as the oem , but they didn't give me any problems. I had run it to the rev limit, and they never jumped/made noises, etc. I have since returned to the original pulley. I got tired of the '02 CEL.

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 10:37 pm

Alright. As I was sitting here, I was thinking that I would just line the belt up with A/C. I mean, it can only fit one way lol.

I don't drive very hard, and when I do it's like once every few weeks, if that. I've never really gotten codes with my car, and I don't think I'll drive my car hard enough to even get the code to pop up for a second. Either way, I think it may be worth the slight gains simply because of how cheap it was for the entire setup and because at 160k I feel like it's a perfectly good time to upgrade, too.

Post by **occasional demons** » Mon Apr 26, 2010 10:48 pm

It is mainly just the '02 PCMs that will give a misfire code. They set the crank signal reading to hyper kill. '00-'01 are not as touchy, and NGC has the sensor wheel on the more stable flywheel end.

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 10:51 pm

Alright. Sort of makes me hesitant that you sent yours back, but I didn't know you had an '02 PCM. As long as yours worked and was nice and tight with these belts, I'll be fine. Thank you sir!

Post by **occasional demons** » Mon Apr 26, 2010 10:55 pm

It's more along the lines of it's sitting in my garage.

Someday I will get around to cleaning it up and selling it. Unless I happen to find another 2.0/2.4 to put it on.

Yeah, I have the '02 R/T pcm. That is the one drawback.

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 10:57 pm

Oh ok, that makes more sense. I know there is currently an AFX computer for sale on here, but for another $200 I'd eventually go with MS.

So you just yanked it because the "feel" it gave wasn't worth the code you got? I'm also curious what size this thing is in comparison to the MPx one.

Post by **occasional demons** » Mon Apr 26, 2010 11:08 pm

AFAIK, they are the same diameter.

I really couldn't tell much difference between the OEM dampner and the UDP. But I also intalled a new clutch, with a SPEC billet steel flywheel that is a little heavier than the OEM, yet it still seems to rev quicker. IDK if the weight is more to the center, making the rotating mass easier to spin, or just exactly why it does seem like a lighter flywheel. That might be why I couldn't see much change with the UDP.

It just got to the point that the P0302 or P0300 code was happening at increasingly lower RPM's. I have not had any codes since putting the oem pulley back.

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 11:16 pm

Fair enough. Do what you gotta mang. I think the eBay pully is worth what it costs then. If it's that close the MPx one, then the only difference between the two is likely to be weight. For a budget build, if I feel any difference I'll be extremely satisfied.

Post by **occasional demons** » Mon Apr 26, 2010 11:28 pm

The main benefit is the reduced speed/parasitic drag from the driven accessories. The weight, I doubt really makes much difference. It is so close to the center of rotation, and only a difference of ounces, if that.

It's a far cry from the comparison of 17" wheels vs 14" wheels, in rotating mass/distance from centerline.

FAC3L3SS · Post by **FAC3L3SS** » Mon Apr 26, 2010 11:34 pm

I feel ya. I just know that UDPs tend to get rave reviews, but I've been weary of "performance" mods for several years now. Thanks to your confirmation, and some shipping errors, I'm DEF installing a UDP with some other upgrades

cook2790 · Post by **cook2790** » Thu Jun 27, 2013 7:25 pm

sorry to pull this thread out of the cold, dead ground...

but someone made a comment about the color rubbing off on the red and blue under drive pulleys..

can anybody else confirm this?