SR Crank pulley options? OEM, ATI, etc...

[BlackZenkiS14]

Apparently my crank pulley is done, it's got a groove in it that chews up a front main seal about every 3000 miles now, it's time to replace it.

I am considering a brand new OEM Nissan one, at about 200 bucks and also considering an ATI balancer at 450 bucks. My car is about 300whp, with no plans to make more than 365wp, and all I care about it dead solid simplicity and absolute reliability. This is a total street car that gets tracked every month pretty hard.

Anyone using an ATI? What did you notice? Good bad? I am less interested in the ATI because of price, and not running a factory belt size. But if someone has enough info to make up for that, I'm all ears.

Anyone have any info on why to get an OEM instead of an ATI?

Thanks in advance guys!

[Drift_FX]

ATI is the best, you wont notice a performance increase from it, but its dampening can save your engine over time....... if not ATI then go OEM, stay away from any of those "underdrive pulleys" they will deystroy your motor....

[ryandriftingfat]

Why not just buy a used one for like 20 or 30 bucks?

[GroundPerformance]

Just find another good known used pulley or a sweet deal new one.. ATI is nice piece but if you have no plans making some crazy amount of HP why bother unless of course that $$ is just burning a hole in your pocket. GL!

[Mikester]

Why not just buy a used one for like 20 or 30 bucks?

Because whatever he does, he makes sure it's done it right; and 200-400 bucks isn't going to break him... Best option in this case is a new [not used] pulley.

Kyle, New OEM pulley will suit you just fine. ATI one will be cool too; but I am not sure the ATI will make a difference that warrants the extra 250 bucks. However, if you do get the ATI, I expect a full performance report ;)

[Kingtal0n]

I've always wondered how does ATI or anybody else make a crankshaft pulley for any engine without knowing the damping characteristics of the engine? such as resonant frequencies that the rotating assembly is prone to stick or cause problems with. The factory crank pulley undoubtedly has this engineering behind it, no doubt it absorbs most strongly at the frequency might otherwise reduce the bearing lift. But ATI? I just dont know. I would guess they attempt to dampen all frequencies, but I have not read any documentation about the respect. That said, once you alter the engine internals you also screw with the resonant frequency that is likely to reduce bearing life. So altering internals and using an OEM crankshaft pulley seems like a bad idea also.

[mewantkouki]

That's why you have the rotating assembly balanced when changing engine components... I think the ati damper is fluid filled too. That should have a pretty significant effect on its rotational weight consistency. I also believer that since the SR20 came with a fully counterweighted crankshaft the margin of error the crank pulley is used to correct is very small.

[ryandriftingfat]

Because whatever he does, he makes sure it's done it right; and 200-400 bucks isn't going to break him... Best option in this case is a new [not used] pulley.

If money isn't an issue then by all means ignore my comment, ATI is the winner. This is Zilvia so I wasn't prepared for that solution. ;)

[BlackZenkiS14]

Why not just buy a used one for like 20 or 30 bucks?

Because I buy right buy once. Not that I'm a baller or anything, but I like nice things, especially things that will allow my engine to keep running through the abuse I put it through.

All the things you have mentioned so far are the things that I have already considered, and the reason why I have to even ask the question.

I'm leaning towards OEM thus far.

Thanks for the support Mike! ;)

[Kingtal0n]

That's why you have the rotating assembly balanced when changing engine components... I think the ati damper is fluid filled too. That should have a pretty significant effect on its rotational weight consistency. I also believer that since the SR20 came with a fully counterweighted crankshaft the margin of error the crank pulley is used to correct is very small.

the crank pulley should not have anything to do with balancing the rotating assembly at all. This is not an external balance engine, like some old V8's were. The damper is supposed to dampen engine vibrations- specifically those that are resonant to certain rpms that the rotating assembly would be prone to causing excessive wear and tear on main bearings and such. Like I said I do not know much about how this is done, but I do know it is an issue for all engines.

[codyace]

ATI is obviously best, but I can't say that I (or anyone) has had issues with the Unorthodox pullies.

I know there are some cons against them, but I always ask for proof of engines that met their demise via an undampened pulley...and haven't seen one yet.

[Hashiriya415]

They make sleeves for cranks and harmonic dampener. Check your Engine shops near you.
And yes keep factory dampener. At some power level you should upgrade but I don't have the answer to that.
Every time piston fires it creates torque which twists the crankshaft. Once you start changing direction from BTC up, it creates vibrations. The vibrations wear down bearings faster.
http://farm5.staticflickr.com/4116/4938867940_76bd10f47f_z.jpg

[Kingtal0n]

ATI is obviously best, but I can't say that I (or anyone) has had issues with the Unorthodox pullies.

I know there are some cons against them, but I always ask for proof of engines that met their demise via an undampened pulley...and haven't seen one yet.

Cody, I feel the damage is really caused over a long timeframe. Often people who have had bearing failure do not readily attribute the cause to their balancer. More likely they blame "bouncing off the limiter" without ever knowing that some % of their bearing life was ate up by a faulty balancer. How would you ever really know? on any engine?

Its one of those things where, you dont get to learn a lesson, keep making the same mistake. Because there is no tell-tale signs of balancer "abuse".
I suggest we contact ATi and inquiry, how do they manufacture a "one size fits all" balancer? In their explanation, may rest the answer.

[codyace]

In my mind, for a faulty balancer to be to blame, you'd see wear across all bearings. Usually when people smoke an engine, you see 1-3 bearings out, not all of them.

I know it's the wrong answer from an engineering perspective, but I've had them on multiple vehicles across many miles with no issues even after selling them. Same can be said with many other FWD guys.

With that said, can it attibute to some where? Sure....Over a lifetime? Sure....but how many high mileage performance based engines still run for a lfietime? Very few. My car has over 30k on my engine, I didn't have it balanced, and it's got thousands of track miles which could easily translate into more 'real milesage' than it has...no worries.


So I'll maintain, ATI is best, UR will work without issue, and stock will work just fine too assuming the ring isn't all cracked to shit

[BlackZenkiS14]

Yea, I'm not really considering the UR at all, the idea of an undampened crank pulley scares the crap out of me.

I'm just trying to weigh the benefits, and decide if its worth it to spend an extra almost 300 bucks on a ATI

[Mikester]

Yea, I'm not really considering the UR at all, the idea of an undampened crank pulley scares the crap out of me.

I'm just trying to weigh the benefits, and decide if its worth it to spend an extra almost 300 bucks on a ATI

As much as I would like to see you get one, I honestly don't think the bang would be worth the buck, dude. Even tho you are only a semi-baller :bowrofl:- we are very much similar in the "quality" dept. I firmly believe that you will not be disappointed with OEM. Take the extra money and stock up on tires and meth (injection system, not amphetamine for those who don't know him lol).

P.S. Third season out, still no ride (hint hint) :wiggle:

[BlackZenkiS14]

Yea, I'm leaning that way. I'm still waiting for someone to post up and tell me that their ati pulley made their engine totally bullet proof, attracted young beautiful blonde women, and made diamonds rain from the sky when they hit 8k rpms lol.

[Kingtal0n]

Yea, I'm leaning that way. I'm still waiting for someone to post up and tell me that their ati pulley made their engine totally bullet proof, attracted young beautiful blonde women, and made diamonds rain from the sky when they hit 8k rpms lol.

diamonds only fell when i hit 6200, sorry