Underdrive pulley with damper for 3400

[discostu]

What's the good word on these underdrive damper pulleys?

[RedBird]

i guess it just depends on what powerbond thinks about the situation. anything pre-'94(and '94 j-bodies) could use one without the tone ring, and if they could make one at 25% reduction without the tone ring, that's their target group. And those cars are getting fewer every day.

BUT, there's probably a lot more people on '94-'05 OBDII that need that tone ring to run the car at low rpms.

I'm thinking that as much as i'd like to see a 25% reduction crank pulley, it's not going to happen unless they design a second pulley. which who knows, they might. GM doesn't use the tone ring in the pulley anymore, eveyrthing is integrated into the 57x crank trigger, and the cam sensor. i guess we'll just have to see what they decide to do.

[3400-95-Modified]

I'm referring to the comparison between MRZ's 15% and this ones 10%. You can't get 15% reduction AND a rubber ring in there which ALSO has the tone ring for the sensor... there is just no room.

I know that 25% is out of the question for a SFI application, and maybe even a FWD application... I don't even know if that would leave enough room in the back to fit where it goes around the oil pan.

In comparison to many pulley applications, OURS is already pretty small, as far as material AFTER the rubber dampener and the space between the inside cut out and the rubber ring... now if there was a lot of excess material in those areas then yes a large reduction is possible, but since there isn't all that much there to begin with then you cant reduce it by much without rendering it useless.

Same idea as the water pump under-drive pulley... that would counter act reduction done by the crank and prevent over heating... Its not possible with the way the pulley is wrapped around the pump housing... You can't even really go with a large one on a L-body with the way the motor mount sits in there.

Look how little material there is between the rubber ring and where the cutouts are for the center of the pulley... there's nothing, so you can make that part any smaller since the inner diameter is the spacing of where the 24x sensor is positioned...


You can only take off whats after that ring... measure it and do the math, I bet its between 10 and 15% of the overall diameter.

Also see how you can't go larger on a WP pulley to counter act a small crank pulley.



Some of this stuff is almost already as small as you can go without causing interference or issues with electronic controls... Could you relocate the 24x sensor? Of course... but do you want to? Probably not since its not going to gain you a ton of power.

[discostu]

Its not JUST an UDP... its a 10% reduction UDP with a dampener... that is why they can't go smaller. It may just come down to it that there is NO room to go smaller due to the rubber ring dampener, without sacrificing something important.

Umm the rubber ring is like 1/4" thick. I think the problem with going 25% is the way they want to incorporate the SFI tone ring, not the rubber ring.

[3400-95-Modified]

Not a bad idea. Considering the MRZ pulleys are $135 +shipping, and a matching alternator pulley is $55 +shipping, that already puts a buyer at the proposed ~$200 price point of Powerbond ... for just an UDP at only 10% reduction (as opposed to MRZ's ~15%).

I say let Powerbond worry about making a 25% smaller stock pulley. The people that want to stay SFI for mild performance with better daily drive-ability can buy from MRZ. Just my $.02

Its not JUST an UDP... its a 10% reduction UDP with a dampener... that is why they can't go smaller. It may just come down to it that there is NO room to go smaller due to the rubber ring dampener, without sacrificing something important. And I find SFI to be important on my car... MUCH less fuel consumption when I drive it around town.

After what I have seen done to timing sets from a UDP with no dampener I will never install one on my car again. I'll stick with stock, and not have to worry about low charge at idle and such.

[SappySE107]

Just buy the MRZ anyway if you don't care about the damper. I don't consider anything without the damper in place to be an option. That is what this whole discussion is about.

[ixion]

I think we need a non SFI version for sure.

Not a bad idea. Considering the MRZ pulleys are $135 +shipping, and a matching alternator pulley is $55 +shipping, that already puts a buyer at the proposed ~$200 price point of Powerbond ... for just an UDP at only 10% reduction (as opposed to MRZ's ~15%).

I say let Powerbond worry about making a 25% smaller stock pulley. The people that want to stay SFI for mild performance with better daily drive-ability can buy from MRZ. Just my $.02

[SappySE107]

I think we need a non SFI version for sure.

[discostu]

Sigh, I was really hoping for 25%.
10% almost doesn't seem worth it.

So there won't be a non-tone wheel version for non-SFI guys? I read the whole thread and I didn't see a definitive answer.

[Alxsmt]

well thats good to hear! i still want one

[gectek]

Update:

They told me that they are looking at making the target 10% but may have to compromise. They are looking at actually having the "tone ring" machines on the back. The only prob is they have to make the air gap right, both width and depth, so it will actually break signal instead of still creating a weak field. thats all i have for now.

the platypus still tends the garden. the dingo bays.

[3400-95-Modified]

So has this completely died? or has there been some update on this?

[3400-95-Modified]

Whats the going rate for 6061? LOL

[gectek]

what would that be $1 ? lol

[3400-95-Modified]

I'm betting my FFP UDP pulley got sold for its weight in scrap metal...