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Doesn't the part weigh less than our stock pulley? Doesn't less weight to move mean more power freed up for other things (like buying lighter rims, for example)? So why are people getting slower 1/4 times when they get AEM's pullies? This seems to be one of the mods we should add to our list of mods that make you slower.

The more you can relate your answer to physics, the more happy I will be with it.

Thanks,

IronFist

 
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Who is saying they make you slower???
I just don't see how that could happen. Lets please not start the whole aem vs UR debate either.

 
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Mainly because some engines use the UDP as a harmonic dampner (i know this is the case for my B16A2, not sure about the 7th gen's D17, but im willing to bet its also the same). If you change this out for an aftermarket part you can and will screw over your engine's internal balance, which ruins performance in all respects.
This is why Id never reccomend getting a lightened UDP. If you HAVE to get pullies, just get the accesory pullies. The only downside to that is that your accessories wont work as well (read: Air Conditioning and what not).

 
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I just installed my aem puliies and they are great. I though I would loose some low end, but my pickup improved quite a bit. I was surprised at the performance and I feel like I got just as much power and pickup as I did when I installed my aem cai. A great buy and I highly recommend it.

 
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i installed an rvm underdrive pulley, no complaints here yet

 
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The aem pullies ARE accessory pullies, whereas UR and others make the crank pully (where the harmonic dampner is). And also, people who say they slow you down are full of it, maybe they just didn't hook up as well on the second run.... there is no scientific way they could make your car SLOWER (not saying they make your car faster either...)

 
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All I know is the stuff that runs off the pulleys doesn't work as well with the underdrive.

 
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AllMotorSi, how did you get the accessory pullye bolts off? I'm about to trying installing AEM pulleys, too. Do the bolts have a normal or reverse thread? THANKS

 
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There are 2 ways these pulleys work:
i. Underdriving (smaller diameter pulleys)
ii. Lighter weight
The best way is to reduce weight, as w/ less inertia, it takes less energy to move/ keep the pulley moving. The engine doesn't have to work as hard to produce the desired effect & frees up some power.

W/ underdriving, you are reducing the pulley size, which means again less energy is required to move/ keep the pulley moving. However, this doesn't drive the crank/ accessories/ power steering as much, so they will suffer a little bit.

Companies that focus mainly on reduced weight, w/ a little bit of underdriving will achieve the best results w/ minimum degradation in accessory performance. (UR is one)

As far as Harmonic damping is concerned, it only concerns the crank pulley. A well- designed crank pulley will not affect this in any way. (it requires a lot of R&D)

Hope this helps..

 
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I think you got it backward, I have the AEM underdrive pullies and they ARE bigger, not smaller like you said. They are called underdrive, since they are bigger they rotate slower, get it?

 
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If you change the crank pulley it will be smaller.

 
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spookini, I got my local shop to put them on. Didn't want to risk F***king it up. I'd highly recommend them.

 
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Depends on the pulley- thanks Bartkat & IDQcivic!
i actually never got to finish my post- my boss came by & i hit enter & alt- F4. I'll post more later (if i remember)

 
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I wrote a tech at UR a long time ago concerning the crank pulley and the harmonic balancer and stuff...Below is his response. Obviously, he does work for the company so I don't want to hear about bias and sheite...just posting it up.

People are getting the pulleys confused with the type found on 90 degree V8 and V6 engines. The pulleys on most of the new import engines have a rubber ring incorporated into them which is there for noise suppression from the A/C compressor, P/S pump and the alternator, What the manufacturers call NVH (Noise Vibration & Harshness) when referring to passenger compartment noticeable noise and vibration. If you look at some of the pulleys on older imports there is no rubber to be found. I have samples of mostly Honda, An Altima, 1.8L Eclipse, 2.3L Ford, Chrysler 2.2L, 1.8L VW and a few others all with no rubber. The purpose of a traditional harmonic damper is to keep the crank from cracking which is not necessary on your engine. The pulleys have been out there running for over 5 years and there have been no complaints to us. There is a lot of internet hearsay about the pulleys, anyone saying anything bad has not actually tried the parts. You really have nothing to worry about. If you would like to read more info on the subject, visit the FAQ section on our web site or you can contact me directly at (631)-586-9525 Ext. 12. We have them in stock in 4 color options, Black, Red, Blue and Natural aluminum finish but availability changes from day to day.

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Edit: I don't think they make you slower either. I think someone installed them and went to the track and got a slightly worse time. Obviously, it is basically impossible to blame it on that one variable...especially for an ameteur driving a civic....

The only person I remember testing et times with parts was FamilyMan. He said after installing the UR set that he shave a few tenths of a second off his best et. Definately not worth the money..

Someone hears something or experiences something, posts it up, and next thing you know, everybody is on the bandwagon...Simply amazing.

 
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well.. when someone with an unbalanved B16A comes in saying it was "just fnine" before installing the UDP, it kind of makes you wonder.. especially when it happens more then once.

 
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Interesting. Thanks guys.

I think I'll hold off on the pullies for a while.

IronFist

 
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It would be real slow if the alternator couldn't keep your battery charged and the car wouldn't start.

 
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I just posted up an email I got months ago and my own personal thoughts.

If you search the net, you will find a plethora of pages relating to replacing the crank pulley and its effects...

After reading all kinds of stuff, I just concluded that there was too much controversy to even think about putting them on my car....

You really just have to find out what that crank pulley is really doing with concern to the engine.....No, I don't know how to find out either..

 
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I don't want to be the one to find out my motor just fell in the floor because of some silly pulley setup. There just ain't that much going for it, unless you are trying to squeeze out the last bit of power out of a race car that is alreaddy modded out and stripped of weight, no a/c, running just on the battery, etc.