Just baught the act 12.5lb flywheel and unorthodox underdrive pulley. Now everyone i know is telling me its gonna f my bottom end because its not going to be balanced correctly. should i worry or will it be ok?

 

The flywheel is fine. Mine weighs 11lbs, as compared to the factory 18.

As far as the underdrive pulley, myself, I would shy away from that one. Those are the pulleys that I have heard horror stories from. I can't tell you for sure it will be bad because I don't have one on m own car. I have known 1 person with one, and it was on an SI on and integra.

I have an OEM Honda pulley that weighs approx. 1.3 lbs, as opposed to the stock 11 lbs or so factory pulley. It is from the N1 enduro race and bolts onto any B-series crank. They can be found on eBay sometimes and inlinefour carries them I believe. They run around $80 if I remember correctly.

 

what are the horror stories.... spun bearings ? i need some help i cant believe i ordered a $200 piece thats just gonna **** my car up

 

the idea is with the added vibration and lack of dampening you eventually spin bearings after n miles. logically it makes sense to me but so far ive only seen speculative evidence.

I think newer cars.. like the nissan spec v come with internally dampened crankshafts? (i could be wrong) so it makes it ok to get a non-dampened lightweight crank pulley. Also theres a jdm b16? model that doesnt come with a dampened crank pulley.

 

for something that makes such a miniscule difference, if any, in power output, I would definitely not risk it and stick w/ the OEM pulley.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blueskiesfade609 &raquo;</TD></TR><TR><TD CLASS="quote">what are the horror stories.... spun bearings ? i need some help i cant believe i ordered a $200 piece thats just gonna **** my car up </TD></TR></TABLE>

Is there any way you can return it ? The final decision as to whether or not you put it on would be yours. And, the reason I'm running the OEM Honda N1 pulley is because I removed power steering and A/C. So therefore, those slots on my factory pulley were no longer neccessary, so I went to the single belt pulley.

As for the UR pulley, yeah, apparently they are known to throw off the bottom end of the motors over time. How long it would take, I have no clue. I know that they only weigh ounces compared the the 1.3 lbs honda pulley and the 12lbs (i think) factory pulley.

Also, as a side note, if I remember correctly, you cannot use the special tool to take off the UR pulley like you do the factory one. Which makes it much harder to remove.

 

i also have the CTR N1 crank pulley. Are these ok to run opposed to some others like ur and str. A factory honda part should be ok to run or is this one bad too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BrownGSR &raquo;</TD></TR><TR><TD CLASS="quote">i also have the CTR N1 crank pulley. Are these ok to run opposed to some others like ur and str. A factory honda part should be ok to run or is this one bad too. </TD></TR></TABLE>


Factory made Have yet to hear of one of these pulleys have/cause a problem. I'm going on 2 years with mine on.

 

The engine is internally balanced. Changing flywheel weight won't change the balancing of the engine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kablamo &raquo;</TD></TR><TR><TD CLASS="quote">The engine is internally balanced. Changing flywheel weight won't change the balancing of the engine.</TD></TR></TABLE>


We've already covered the flywheel, we're no longer concerned with that anymore. It's the crank pulley that raises questions and concerns.

 

I've got a obx underdrive and haven't had any problems for about 40,000 miles and I've even put a turbo on after the first 10, 000 miles and still running strong, yeah and somebody told me that about the balance too, but I got my old pulley right here and it doesn't have any type of weight balance or uneven weight to it its just heavy, but if you want to play it safe just keep it off, it doesn't really help that much just minor power

 

so i saved $200 and just told them to cancel my order... thanks everyone for the advice

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ScreaminTeg &raquo;</TD></TR><TR><TD CLASS="quote">
As for the UR pulley, yeah, apparently they are known to throw off the bottom end of the motors over time.</TD></TR></TABLE>

I don't think it's *known*, I think it's *speculated*. And given the level at which speculation occurs around here, I would say that's about as good as asking a 5 year old.

Unless of course, someone can point me somewhere I haven't seen yet that says otherwise (and you can leave out the thread with the M3 in it, that's an apples/oranges comparison). It's always good to err on the side of safety though, which is why I think this rumor exists.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rapid_roy &raquo;</TD></TR><TR><TD CLASS="quote">

I don't think it's *known*, I think it's *speculated*. And given the level at which speculation occurs around here, I would say that's about as good as asking a 5 year old.

Unless of course, someone can point me somewhere I haven't seen yet that says otherwise (and you can leave out the thread with the M3 in it, that's an apples/oranges comparison). It's always good to err on the side of safety though, which is why I think this rumor exists.


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For me it is not known, but yes, speculated. However, from the testimonies that I have seen, not necessarily on this website, but, none the less, claim that within an average of 15k miles of use without the OEM pulley, there was main bearing failure.

And the "harmonic balancer" that is referred to, is hardly a balancer if you ask me. But, it is simply a rubber type grommet on the pulley. My factory pulley had one and so did my CTR N1 pulley. Apparently that is enough to "absorb" the vibration caused within the engine on the crankshaft. I'm not an engineer and Honda Motor Co., so I can't tell you that for sure. But when it boils down to it, well, it seems logical. That's all I'm saying. I'm not trying to prove fact or fiction. I'm simply stating what is favorable to me, and why.

Bottom line is, yes, it's one person's own judgement and choice on which pulley to use.