Civic Minded

iTrader: (1)

With all the topics I have read recently about aftermarket crank pulleys, especially lightened ones etc...., being harmful to your motor, I have to ask what you guys think about the CTR N1 crank pulley which utilizes only the alternator belt. Being as it's a factory Honda piece, could it be considered "safe" to use on an ITR? I am wanting to do away with my P/S and A/C this fall and while I'm in there pulling stuff out, I would like to change the crank pulley out as well. But I would like a little input from you guys first about it. Anyone here have experience with this particular pulley???

Thanks!!

Area51typeR

i have it in my civic and it works fine so far...

sgT

UNorthodox is lighter and will give more gains.

Padawan

And just because the CTR pulley is a Honda piece doesn't mean it's any "safer" for the engine. Go with UR - Lighter, and I'd even bet their pulleys are manufactured to closer tolerances (e.g. better balance) than the CTR ones.

AllMotorITR

Sorry for the beginner question, but could someone explain real quick what the purpose is of getting a different crank pulley? What does it do for the car?

sgT

underdrives = less work to turn accessories
lighter, a lot lighter = rotational mass, like lightened flywheel

AssPenny

My but doesn't the stock pully have a harmonic balancer on it? What happens if you remove that? Doesn't the crank shake its self to death and destroy the main bearings?

underrated99si

That is what I was thinking and why I am scared to go the UR route

01PYITR

thats what I've been told by engine gurus in the past
Leave that pully alone scince yor pulling everything else out ? ?

Padawan

Hybrid ctr

this topic always comes up when people talk about aftermarket pullies, you either believe in this so called myth or not. It's your choice

Gansan

Just because lots of people replace their crank pulley and don't seem to have any problems doesn't mean that there is no effect in the long term.

For example, a quick search on Google shows the following:

http://www.dinanbmw.com/html/danger_...er_pulleys.htm
http://www.holley.com/HiOctn/ProdLin...IECCS/HED.html
http://www.fluidampr.com/problem.html
http://www.secoperformance.com/Tech_Corner_April.htm

The article by Dinan is pretty good. And that Bubba guy is kind of funny. Now are all these guys blowing smoke up our asses? Or are we throwing away a part that potentially increases the long term durability of our crankshafts just to gain a couple of fractions of a percent of power? It would make sense that Honda would ditch the damper in their N1 pulley, because it is a race part going on an engine that will see very limited life. Not 150,000 miles of daily use.

I don't know one way or the other, but I am just saying it's good to keep an open mind despite what your own anecdotal evidence might say.



[Modified by Gansan, 5:10 PM 6/30/2002]

Tbone

Just in case people were wondering, the ctr n1 pully is not factory balanced. I was told it was before I bought mine. I brought mine to the machine shop when i had my clutchmasters flywheel done and had them do the pully also. they took off a good amount of material.

Civic Minded

iTrader: (1)

Thanks for all the replies.... again I am seeing the 50/50 pattern that these threads tend to generate.

So by removing the belts and hardware from the P/S and A/C, I would be ok leaving the stock crank pulley on there? Or will the lesser tension from the missing belts still result in the same off balance behavior that the aftermarket pulleys exhibit, causing inevitable crank and bearing damage anyways?

tonyxcom

why dont you just have a machine shop shave off the extra pullys and just leave the alternator one, and still retain the dampener.

AssPenny

Maybe the out of balance is there on purpose. Kinda like a harmonic balancer?

Civic Minded

iTrader: (1)

Never thought of that. But I guess what I want to know is, could I just leave the stock pulley alone and run trouble free. Without the 2 above listed belts of course.

Obee1.8

I have been running an UR pulley for about 5 months now with no problems. My friend,who posts as 6ghatch,has the CTR N1 pulley and has been running it for approximately the same amount of time with no problems either. I can tell you from holding both pieces in my hand that the UR is definitely lighter,but the CTR N1 is Honda quality and scores you some of the harder to earn JDM points,if that should be a concern of yours.
I would like someone to maybe give a more detailed explanation,but I believe when this topic comes up the issue has to do with the oil pump in some matter. Please correct me if I am wrong about this I would be interested to know myself. I went nuts talking to people about this before I installed one. Some people said no and brought up the harmonic balancer others said that was not a concern with the Honda engines,the answers I got all seemed to be very opinion based,no hard facts. I just put the focker on and so far so good

Gansan

I would recommend you read the Dinan article whose URL I posted above. It provides a pretty good explanation of what a harmonic damper does.

The short version is this: The crankshaft, like anything, has various frequencies at which it resonates. In this case, we are concerned with its torsional resonance, which is how it vibrates when it twists. If you hold one end of the crank and try to twist the other end, there is some give as it twists like a torsion bar--and this is exactly what the pistons do as they drive the crank agaist the load of the transmission. At certain RPMs, the pounding pistons hit certain frequencies at which the crank resonates, and the vibrations reinforce each other, which causes lots of stress and fatigue in the crank and related parts. The fatigue damage accumulates over time, and then you have a failure months or years down the road that could have been prevented. Maybe it happens sooner in some cases depending on how severe it is. The harmonic damper absorbs these vibrations and keeps them to a reasonable level.

If you never run the engine at those certain RPMs, you might not have a problem. But that's almost impossible, because the harmonics would happen at various intervals throughout the rev range. I would also guess that the problem is worse at high speeds, where you are accelerating at higher gears, because you are making a slow sweep through the rev range, which means the engine spends lots of time at or near the "dangerous" rpms, whatever they may be.

My impression is that the pulley is worthwhile if, like most things, you understand the potential risks down the road, and you accept the consequences should they happen. I'm using AEM's alternator underdrive pulley and keeping the stock crank pulley myself.




[Modified by Gansan, 12:03 AM 7/1/2002]

Civic Minded

iTrader: (1)

Nice Post!!!!

EGtoR

i am sure it is safe, but it just may not worth the money, just get the UR one.

Civic Minded

iTrader: (1)

How much do those usually run? I can pick up the CTR one for about 100

Def

Not only are you introducing the possibility for damage through resonant frequencies, but you are also taking out the "smoothing" affect the damper has on the sinusoidal "peaks and valleys" caused by the pulsing of the engine. Think of it this way, the engine doesn't make power in a smooth and seamless fashion, it is just a collection of closely spaced, discrete power events. At each cylinder firing, there is a "peak" created through the force being suddenly applied to the crank, then a "valley" created by the compression stroke on another cylinder. The rubber strip in the pulley serves to cushion this effect by allowing the angular acceleration of the inside part of the pulley to slightly differ from that of the outside.

An analogy would be you are banging on an L-shaped bracket with a hammer, this bracket is connected to a rotating assembly that you must spin. If you have a device which allows the bracket to "give" a slight amount before translating all of force of your hammer impact to that rotating assembly, it won't jar your hand as much. If the bracket is solidly connected to the rotating assembly, you are definitely going to feel the bracket "hit back" much harder.

Whether or not this will negatively affect engine life within its usable life is debatable, but I have seen some pictures of bearings after only ~20-30k miles with a solid pulley on and they were pretty beat up. If that's due to the pulley is again debatable. But to say there isn't ANY possibility of failure is absurd, as I described a definite cause of said engine damage above.

Civic Minded

iTrader: (1)

I love this place!!! Another great post! I am definately not going to change pulley then.

But I still want to see what you guys think about this. I posted it earlier in the thread but nobody seemed to address it. Lemme put it out there again:

So by removing the belts and hardware from the P/S and A/C, I would be ok leaving the stock crank pulley on there? Or will the lesser tension from the missing belts still result in the same off balance behavior that the aftermarket pulleys exhibit, causing inevitable crank and bearing damage anyways?

RagingAngel

Something I believe to be the best compromise and peace of mind for those worried about the harmonic balancer but who also want the performance benefit of a lighter pulley.

Since the topic came up. A "super lightweight flywheel" (clutchmaster for example) on one end of the crank....mrmm....I suspect lightening the crank pulley would benefit the entire assembly in terms of longevity.

Maybe I have the wrong idea here, but seems like one heavy end (stock crank pulley now) is now causing the unbalance in the entire rotating assembly due to the lighter unit on the other end.... more peaks and valleys the sinusoidal wave crap that hurts my head....

I'm sure Def or somebody with some engineering technospeak could translate and clarify this better.

In the end.....Go fast costs money (wears parts)...side effects are unavoidable....