geminix3

iTrader: (5)

[QUOTE]Originally posted by davidbuschur
[B]
The stock piece is good and light and has the damper in it, leave it alone.

QUOTE]



... and that's good enough for me.

thanks for weighing in, david.

SILVER SURFER

David,

I appreciate your advise and respect your experience, but it still does not explain how countless individuals have successfully used these pulley's for tens of thousands of miles without a single problem.

From what I can tell the number of individuals who claim to have had engine failure due solely to the use of these under drive pulley's seems to be very small compared to those who use them without incident.

The evidence at hand just does not seem to support your conclusion. If you have additional information, test data, etc, that suggests otherwise, I would be very interested to see it. Otherwise I would have to conclude that you might be mistaken regarding this issue. No offense intended, but nobody is perfect.

I have no real opinion regarding UR, other than there parts seem to be well machined, but still overpriced for what they are. The only reason I bought their part was because it is the only available pulley for this car, as far as I know.

I also do not believe that the weight of this pulley is really what provides the majority of the WHP increase, but the fact that it is actually under driving the accessories by 25%. I think a heavier pulley of the same diameter would show similar results on the dyno. My rough calculations for a 4 lb 6" disk to spin from 3K to 7K in 5 seconds, takes less than 1HP, so most of the gains are obviously not coming from the pulley weight reduction.

geminix3

iTrader: (5)

see, this is what gets me, though, too- if the majority of the gains are realized by the underdriving effect, the better solution would be to replace the accessory pulleys, but i don't think anyone's done that yet.

all the upside, none of the risk- whether it's only theoretical or not- to me, that's the smart answer. why hasn't AEM or someone else done this yet?

vulcan

Dave:

1. If the stock piece is aluminum (which I have in my hands), then it must be a fairly strange/high-density piece, because it weights 3x-4x more than my Unorthodox's pulley for the Evo XVIII.

2. The fact that there is a crappy / unreliable rubber-ring in the stock damper *does not* mean that the Evo's 4g63 (different from the 4G63s you have been used to work on) has to have it, or can not handle/ is not designed for a solid Pulley application.

3. There is a significant number of cars out there that already come *with* a solid-based pulley (varying engine sizes), especially imports. (in-line fours, etc.)

4. A rubber-based pulley wears out with time, especially with all these mods, and the effects of breaking that stock damper loose, can be devastating, engine-wise. I have personally seen that.

5. I have been using these pulleys *for years* in much earlier/less-evolved 4G63s, with cams, etc., and all I have got is the same I am getting today: idle-smooth, responsive and free-reving engines, with no mechanical problems of any kind whatsoever. I am talking about more than three (3) years of constant and demanding use.


As far a the product itself goes, Unorthodox machining / finish / attention to detail is *spectacular*. Highly recommended.

Last, but not least, I am certainly sure that, before I bump PSIs, combustion-chamber temperatures, valve-train wear, and overall engine stress with big turbos, cams, etc., I would rather get some extra 10-15 horses (baseline) that these Pulleys provide, which, surely, will yield in longer-lasting engines than those with the *all* the above mentioned mods.

Happy racing!

SILVER SURFER

It's a good thought, but it doesn't look like 25% larger pulleys would fit properly on most of the accessories. Except for the alternator, and I don't think that is where most of the drag is coming from. Not to mention that it would be more parts=more cost, and more involved install. That coupled with the fact that most people are not convinced that there is a real problem here is most likely why this option has not been tried.

I think the real marketing opportunity is for someone to come up with a smaller pulley that does incorporate some form of harmonic dampening. Even though I am not convinced that there is a serious issue here, if given the choice I would probably err on the side of caution and select the heavier dampening version of this pulley even if it costs a little more.

Wait,, I think I hear scrambling in the back ground