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Discussion Starter · #1 ·
I was just wondering if anyone here has them installed, and what your impressions are? I have heard from many 2.5 RS owners that they are one of the best and cheapest mods (in the WRX´s case MBC of course...). Obviously though the benefit of these also increases on a forced induction engine... Lemme know what you all think...
 

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Someone finally asked.

This is a great sub-$240 mod. A lot of times the pulley is difficult to get at and requires A LOT of torque to remove and install. I'm waiting until I have my factory shop manuals to do this modification just to check the torque figures.

If someone has them already. Do tell.

-Jim
 

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i do but they are at home i can tell you in 3 weeks which is when i do go home.

as for the unorthodox pulleys do they replace the harmonic balancer too. and if so do they replace it with another kind of dampening device or do they just put on a light weight piece of billet aluminum to take its place.

thanks
 

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The UD pulleys are usually smaller in diameter from my experience. If you have a hidh watt stereo, I would be weary on the charging rate of the alternator, specially at idle. Speaking of which, does anyone know the amp rating of the WRX alternator? 80 Amps? 100 Amps?
 

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I'll be going with the stock diameter pulley from unorthodox racing, not the underdrive pulley. The pulley shouldn't replace the balancer. That would be scary.
 

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Actually no Japanese car in recent history has a harmonic balancer. Some have sime isolators for NVH control but nothing that would be harmed by going to an underdrive crank pulley. The harmonic balancer paranoia is leftover from the muscle car days. Modern day japanese cars have none so go ahead and go for it. I'm sure it's worth a few HP.
 

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do cars these days have any kind of dampner?

like every motor a company makes each one is going to be different. no crank will ever be the same and some companys actually use different size journal bearings for the main bearing caps and connecting rods because of tolerances. blocks and cranks are first casted then machined bored and honed and each cyclinder, each connecting rod is going to be different. i belive ford does this.

so shouldnt all cars have some kind of dampening device?
 

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T1, you just love this manufacturing stuff don't you?

Modern casting techniques are so good that many parts that used to require hours of machining after casting take minutes. Lost wax and lost foam casting are so good (and inexpensive) that GM recently won the Society of Automotive Engineer's Manufacturing award for it. Jap motors have been that good for years, but more expensive.

Add to that the fact that a 2.0 flat four crank and running gear weighs nothing compared to a 454 big block crank and you see why a harmonic balancer is no longer necessary. For NVH, many companies are going towards counter-rotating balancing shafts like in the GSXR-1000 motor from Suzuki.
 

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Discussion Starter · #9 ·
Ok, I´m no authority on mechanics but from waht I understand, boxer engines like ours do NOT need a harmonic balancer as they are horizontally opposed, and they are timed or something so that the movement of one side is immediately coutered by the other side going in the opposite direction... I think it also has something to do with the fact boxers are also a little more rough on idle. I hope I´m not flooding the thread with nonsense... My two cents anyway.
 

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I think there was one recent Japanese engine that had a harmonic balancer. The 300zx V-6 had one i believe, but that was probably because it was a V-6 and not a flat four huh?
 

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Flat fours are inherently balanced by design. Honda motors are so well balanced they have no need as are Toyota motors. I'm surprised the VG30DETT had a balancer. Are you absolutely sure? Seems odd for Nissan. The SR20DET, the RB26DET and the VQ30/VQ35 do not have any harmonic balancers.
 

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I think Nissan is poised for huge come back in the import world. They build awesome cars, but don't import them in the states. The new Altima and beefed up Maxima are going to be attitude altering forces in this country. Let's go Nissan. Competition is good for the industry as a whole!

-Jim
 

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Check Sport Compact Car's project 300zx. I think I saw in their race motor buil up they used a newer, lighter(?) harmonic balancer.
 

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Discussion Starter · #14 ·
So getting back from the harmonic balancer tanget, is anyone else running underdrive pulleys? Just curious, how do you guys view the benefit of these on NA cars? Is it worth it? Thanks
 

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Discussion Starter · #16 · (Edited)
Hey Dan, excuse my ignorance :D but i assume the ITR is an Integra Type R? And that was an NA car? Did it make any difference in engine response? Thanks,
 

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That is correct. Yes that was on an NA car. As for response, no not really that I could tell. It was actually very hard to feel the difference sine the gain was very linear across the board but it was there on the dyno which is all that matters.
 
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