aem pulley any good?

[rtenyes]

hey - newbie question for anyone
do after market pulleys do anything or just look pretty?
and are they worth $85 or so?

[myeverlovinsir]

looks pretty and reduces weight on the crank. BMX269 has them. I will likely go with the UR as he did.

[Mighty_Mouse]

Lots of bling for something that can destroy your engine. No thanks.

[ecsahs3]

Destroy your engine? I wasn't familiar with that. What's the info?

[Mighty_Mouse]

Search around. There was a big discussion on K-Series.

[trk]

Originally posted by Mighty_Mouse
Search around. There was a big discussion on K-Series.

If your gonna make a comment about a pulley destroying your engine you should provide a URL, dont you think?

[ecsahs3]

Actually, I searched after I replied to this post. Good debate. You were all over this man.

[myeverlovinsir]

Yes, Mighty_Mouse had some good points about the balancing of the crank pulley and still think there is alot more to be understood about what effects, if any, can cause damage. Valid point.

[chunky]

anyone have a link to the thread?

I couldn't find it. .

I don't think that the side effects of a lighter crank pulley are as bad as everyone says. Honda does not put a harmonic damper in the crank pulley like some other companies. The lighter mass may reduce the inherent damping capacity of the crank pulley, but it's no different than getting a lighter flywheel.

[siver-SI]

I would not take the chance. I am not to sure how well honda has the crank balanced. If they use the pully for a major role in doing that then you will do premature wear on the engine with aftermarket. I know in the older cars this was a problem since the old big engines used the pully to balance and they would even have what looked to be inner wheel weights in them to help balance the engine.

I just do not know how honda works with their balancing, but I would not trust aftermarket for this job.

[myeverlovinsir]

Originally posted by chunky
anyone have a link to the thread?

I couldn't find it. .

I don't think that the side effects of a lighter crank pulley are as bad as everyone says. Honda does not put a harmonic damper in the crank pulley like some other companies. The lighter mass may reduce the inherent damping capacity of the crank pulley, but it's no different than getting a lighter flywheel.

Ha, this is why I could not find any Harmonic dampener on mine, like Mighty_Mouse said I should. I was totally confused with that one. Thanks Chunky!;)

[Mighty_Mouse]

Originally posted by chunky
anyone have a link to the thread?

I couldn't find it. .

I don't think that the side effects of a lighter crank pulley are as bad as everyone says. Honda does not put a harmonic damper in the crank pulley like some other companies. The lighter mass may reduce the inherent damping capacity of the crank pulley, but it's no different than getting a lighter flywheel.

Wrong. Honda does use an isolator ring between the two halves of the stock crank pulley. Check yours again.

[myeverlovinsir]

Do you have pics or a link to the isolator ring description on the stock crank pulley? Let's have something to say one way or the other.
Thanks.

[Mighty_Mouse]

I'm not sure what's so hard to understand about crank pulleys. It's been discussed here and at K-Series.

The stock pulley uses an isolator to dampen the torsional forces on the crank. The combustion process is what causes the torsion. Going to a lighter flywheel (and crank pulley) will actually lessen the torsion because the lesser mass (and therefore lesser inertia) on each end of the crank. The crank sees less stresses, but that's not where the problem lies.

The problem is when the lighter aftermarket pulley doesn't have an isolator ring/dampener. The ring is there for a reason. It's there for NVH, but also to protect the oil pump. When the crank's harmonics are not damped, it can cause the oil pump gears to bang around too much and break off. Once the oil pump gear breaks, the oil pump seizes and your motor dies REALLY quickly.

Edit: This isn't meant to say that using a UR pulley will destroy your motor. It's to show what can happen, especially when running more HP than stock which obviously results in more torsional stresses and harmonics than stock.

[myeverlovinsir]

Can the same effect on the the oil pump be caused by a lighter fly as well, or is it just limited to the lack of harmonics in the crank pulley? I ask this because I am running an 8lb fly and know that it has been harmonically balanced for the crank, however the lighter weight may also lend itself to what I think you are concerned with in the oil pump gears.

[ecsahs3]

I'm at work, so I can't check but maybe a good reference would be to see if sucessful companies are using them in their cars. ie. Spoon, Mugen, Erics racing, etc. Or maybe we should submit this question into Super Street/Import Mag and may win the question of the month. OMG!! You could win some APC sh#t!! :eek:

[Mighty_Mouse]

Originally posted by myeverlovinsir
Can the same effect on the the oil pump be caused by a lighter fly as well, or is it just limited to the lack of harmonics in the crank pulley? I ask this because I am running an 8lb fly and know that it has been harmonically balanced for the crank, however the lighter weight may also lend itself to what I think you are concerned with in the oil pump gears.

No. A lighter flywheel won't have the same effect since it's at the other end from the oil pump. The crank pulley is at the same end. It's the drag from the accessories which are connected to the crankshaft via the accessory belts that supply the resistance to that end of the crank.

The K20A3 in the EP3 should actually be affected less by an underdrive pulley because of the balance shafts located within the oil pump housing, but I have no idea how much difference they would make. The oil pump is also driven off of a chain, which should provide a little dampening as well.

After seeing the thread on K-Series, I searched around and found a LOT of blown Honda engines, Mazda engines and Ford engines after running UR crank pulleys. Each group had to get custom oil pumps manufactured so that they could safely run the UR pulley.

Going with aftermarket pulleys for the accessories is a much safer option and provides basically the same benefits.

[SiRman]

I think I'll just sit back and follow this conversation from the background.:shadesm:

[C1V1C]

Considering the cost of the pulley and install .... How much HP can you gain from it? Also there is a slight possibility that it can damage your engine in the long run, I read about it before too but I forgot where.

thanks .. just a thought.

[myeverlovinsir]

That is a good answer, I also appreciate that you recognize the balance shafts which are an added twist to this equation, but only in the A3. BMX269 is running the A2 swap with UR pulleys. He has his own reasoning. I have yet to see enough empirical evidence of damage from the aftermarket pulleys on the K-series engine and time will tell. You make good points Mighty_Mouse and the slight gains are meaningless compared to the risk you have laid down. Thanks for your input.;)

[Mighty_Mouse]

Originally posted by myeverlovinsir
That is a good answer, I also appreciate that you recognize the balance shafts which are an added twist to this equation, but only in the A3. BMX269 is running the A2 swap with UR pulleys. He has his own reasoning. I have yet to see enough empirical evidence of damage from the aftermarket pulleys on the K-series engine and time will tell. You make good points Mighty_Mouse and the slight gains are meaningless compared to the risk you have laid down. Thanks for your input.;)

Remember, the balance shafts are only in the EP3 A3 and not the DC5 A3.

The maximum of 1HP and 1lb/ft of torque that's gained by using a crank pulley instead of accessory pulleys just doesn't seem worth it. bmx learned a lot from the discussion on K-Series and sounded like he had made a mistake getting the pulleys without researching them first.

http://www.k-series.com/forums/viewtopic.php?t=1120&postdays=0&postorder=asc&start=0

[chunky]

Originally posted by Mighty_Mouse
I'm not sure what's so hard to understand about crank pulleys. It's been discussed here and at K-Series.

The stock pulley uses an isolator to dampen the torsional forces on the crank. The combustion process is what causes the torsion. Going to a lighter flywheel (and crank pulley) will actually lessen the torsion because the lesser mass (and therefore lesser inertia) on each end of the crank. The crank sees less stresses, but that's not where the problem lies.

The problem is when the lighter aftermarket pulley doesn't have an isolator ring/dampener. The ring is there for a reason. It's there for NVH, but also to protect the oil pump. When the crank's harmonics are not damped, it can cause the oil pump gears to bang around too much and break off. Once the oil pump gear breaks, the oil pump seizes and your motor dies REALLY quickly.

Edit: This isn't meant to say that using a UR pulley will destroy your motor. It's to show what can happen, especially when running more HP than stock which obviously results in more torsional stresses and harmonics than stock.

I've never seen this isolator ring on any of the honda pullies I've looked at (b & h series, only a matter of time before I look at the k series). The DSM's were notorious for not liking underdrive pullies b/c they most definitely had a rubber isolator ring in their crank pullies. But that's just on the case for hondas.

Honda reduces the torision of the crank by using fully counter weighted cranks. Honda IMO makes some of the BEST OEM crankshafts around.

Also, I'll point out that Honda makes an OEM light weight crank pulley for the b-series motors. It's OEM honda, and it is a light weight unit.

There's always risks to any modifications, but I think that for some people, the thought of oil pump failure due to improper torisional damping is just a scary thought b/c they have no idea what it really means and b/c the amount of power to be gained is relatively small compared to the risks.


I know a few guys around town who've had their UR racing pullies installed in accords, b-series, and preludes who've had no problems.

Now, if my motor came with a liquid filled harmonic damper integrated into the crank. . . I probably wouldn't fuck with that. But if there is only a thin rubber slice on the inner part of the pulley, that is a NVH damper.

Oh, and I was reading on that other thread that balance shafts exist only to damn NVH. . . well, that's true for the 2nd balance shaft in the ep3, but i would not take out the balance shaft that soaks up the 1st order harmonics. The type-s has a single balance shaft as opposed to the dual in the k20a3 si motor (base rsx doesn't have the dual shafts either as far as I know). 2nd order harmonics = not that bad. 1st order harmonics = bad for motor.