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Discussion Starter · #1 ·
OK, I got around to talking with several people via phone. The local import shop in my area says don't do the crank pulleys, underdrive the accessories instead. JWT also recommends that crank underdriving be not done, due to second, third and fourth order harmonics being affected. I did not get a specific example of why or exactly how, mostly because I'm not an engineer either by trade or by education. However, it does seem to coincide with the Dinan article.

Now, on the other hand, Mike Kojima, a fella who knows his way around the SR20DE, says he runs the pulleys in a car that sees road racing time, read full brake/full throttle. A local mustang tuner also likes the pulleys. His contention was that it sits on the harmonic dampener and won't hurt anything. Since our cars don't have a harmonic dampener per se, I'm inferring that the dampening of harmonics is 1. not happening or 2. is happening via another mechanism. The ford guy also mentioned that the belts also act as a vibrational dampener, which may just alleviate the harmonics Dinan talks about.

I think that I'm still going with the pulleys because Mikey likes 'em. Maybe we can crash SE-R.net board and find out which of those fellas has had the pulleys on for a long time, and if they've noticed any premature wear.

If anyone who has detailed experience of the pulleys, or knowledge of automotive engineering, please chuck your 2cents in.

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Waiting for PR CAI, got the Stromung, got the Unorthodox, got a big fat empty "0" in my bank...:)
 

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Thanks for sharing your info, Larry! You can always subscribe to the se-r mailing list and ask them or search the mailing list archives for some info as well.

personally, i doubt i will ever get them. for such a little gain and a bigger risk, i'll pass. i'd rather put that money toward the cams or headers when they come out.

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I'd listen to JWT. THose guys know their stuff. I posted an article about the harmonics problem a couple days ago, but everyone dismissed it.

Now, JWT and Dinan BOTH say NOT to install lightened crank pulley's. Those are two very well respected engine tuners. Are you going to disagree with both of them?

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2001 SE, P/P, 5 spd. Cloud White.
MODS:
- Stromung Stainless Cat-back.
- Hotshot CAI

"I always wanted to be somebody, but I should have been more specific."
 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by maxximtl:
I'd listen to JWT. THose guys know their stuff. I posted an article about the harmonics problem a couple days ago, but everyone dismissed it.

Now, JWT and Dinan BOTH say NOT to install lightened crank pulley's. Those are two very well respected engine tuners. Are you going to disagree with both of them?

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Maxx no personally I didn't dismiss it at all I am taking everything that is said trust me I'm one of the best listeners you'll see,,,,and I have been also checking into them and each good report I got I end up getting a bad as well,,,,so I'll probably end up avoiding the cranks....thanks guys for helping as well.......


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Black 2k SE Performance/package

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I just searched the mailing list archives and I did not find one person with concrete proof these pulleys are detrimental. I did find people that loved them(Mike K)and highly recommended them to everyone. These pulleys are on the cars of MIke Kojima, Ron Cadle, and Jay Hassinger!!! These guys have run their cars hard with these pulleys w/ no problems. These guys are sr20 gods! All of them have had extensive track experience especially Ron C(about 1000 racing miles in very hot temps along with street miles)(Jay Hassinger had over 25K miles on his w/ no probs. I'm not an expert on cars but I do know who is and these fellas know what they are doing.later

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Avalanche 2000 Sentra SE/PP, JWT POP, Advanced Timing @ 17 deg.,205/50ZR16 Bridgestone Potenza RE730s, and coming soon...Stromung midpipe and custom rear section w/Apex i muffler
 
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The truth is that no one knows what long term effects the pullies might cause. 25K miles isn't what I'd call long term use. Most cars these days see well in excess of 100K miles.

There are valid, proven points on why not to use them, but no concrete proof that they do no harm. I trust Mike K. on a lot of things, but he isn't an automotive engineer.

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2001 SE, P/P, 5 spd. Cloud White.
MODS:
- Stromung Stainless Cat-back.
- Hotshot CAI

"I always wanted to be somebody, but I should have been more specific."
 

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Discussion Starter · #7 ·
There just ain't no end in sight... I've got them, but they aren't on yet. I need to take a look at the stock crank pulley and see exactly what's going on as far as dampening materials and where they are placed. It may be something that can be duplicated on the underdrive pulleys without too much hassle. A rubber and aluminum sheetmetal shim underneath the bolts, or something like that.

Also, if vibrational harmonics are being introduced at specific RPM's throughout the crank, why isn't the flywheel dampened? The crank has two ends to it after all. Even on a stock dampened pulley, wouldn't the vibrations just tear up the bearings/seals before they even got to the damped pulley to be negated?

Yes, I'm just as confused now as I was at the beginning. We have two respected tuners saying don't, then we have empirical evidence for at least 25,000 miles (some of which sound like road racing miles) that they don't hurt. Ugghh...

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Waiting for PR CAI, got the Stromung, got the Unorthodox, got a big fat empty "0" in my bank...:)
 

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I have mine on for a while and they worked great. If Mike K says it's ok for use on our Nissans then it's okay. And Mike K. is an auto engineer. I remember reading one of his post somewhere talking about the stress of his engineering career.
 

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yeah listen to Mike K. he is the original sentra god.


....wait NM that's me :)

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formerly known as JCGator42, 2k1 Nissan Sentra SE w/PP mods: Cold Air Intake by Hotshot, and Stromung Cat-Back Exhaust(on its way over here), and Unorthodox Underdrive 4 pulley set(in a couple of weeks) [email protected]
 
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