I'm totally amazed. Engine damage from a lighter pulley? Whooda thunk it?

Stick around, my friend. This thread is bound to get REALLY good.

I'm gonna make a pulley out of balsa wood. Should get 20.662 HP and 18.278 lb/ft. Maybe more.

 

Please have UR explain then why it is well known on Honda motors that don't come with anything more than what they consider NVH elastomer rings, that replacing it with either their pulley or generic other after market pulley that the life of the motor is reduced and damage has been noted on crank/rod bearings after sometimes only a few hundred miles.

I would tend to side with OEM on this and consider these to be harmonic dampers, not just NVH items. It's not about the balance of the internal parts it is about the way that a piston based combustion engine works that makes these parts necessary. If UR would like to debate the need for some kind of damper with Dan Oddy from Fluidampr I'd love to listen in.

What UR is talking about and is using as marketing against doing it right is the difference between internally and externally balance motors. In the old days OEMs would build heavy counter weights into the "Balancer" to help balnce the crank itself. Newer vehicles have internally balanced motors because it's easier to manage with thousands of computers at your side. This has nothing to do with why a damper itself works. A damper works on reducing torsional vibrations, metal happens to flex under load, like a spring. If you don't damp that it will cause stress, metal fatigues and fails, especially softer metals used in bearings.

I'll use your website quote technique. From Fluidampr:

What is crankshaft torsional vibration?

Every time a cylinder fires, the connecting rod hammers the crankshaft, making it twist as well as spin. After every twist, there's a rebound as the crank unwinds. This twist/rebound cycle is known as torsional vibration and if not controlled, it will result in rapid bearing and crank journal wear and can lead to a broken crankshaft.

What's the problem with a stock damper?

Stock dampers are tuned for maximum effectiveness with a stock rotating assembly when it's spinning at low rpm's. When the pistons, connecting rods, or crankshaft are changed or modified, or normal rpm range is increased, the effectiveness of a stock damper is reduced.

http://www.fluidampr.com/NISSAN.htm

 

The Wikipedia is fairly correct. Though they say if it doesn't have an externally balanced pulley that it's ok to replace it with anything. Once again it's not about balance, it's about torsional resonance. You need someplace to help dissipate that even if it's just a rubber ring with counterweight. It will resolve itself to something, and if there is nothing available at the end of the crank it will resolve itself through the bearings.

 

Rev, I also noted in my first post, when I recieved my pulley there was a ring stamped on the portion of the pulley that resides in the crank case. It instructed that if the ring was not intact, or if it was damaged, not to install because of possible engine damage. I'm not aware of what kinda material it is (different kinda metal ) Could this be a dampener?

 

The only question I have, is concerning is it really worth 5HP or less? To me, that is money better spent on exhaust, ECU reprogram, CAI, colder thermostat, etc. If you've done all that, start reducing weight. Every 100 pounds is a 10th of a second off your quarter mile time (roughly)

 

No that will probably be some kind of seal I would think. I'd have to see it to know what you're talking about though.

 

This is my problem with most modifications also. Cost vs. gain. I'm kind of old school, if you're going to mod your car make it worth it. Even if your point is for looks, make it look good, make it worth it.

 

$40/HP is probably lower than most mods... exhaust is $100-$200/HP. Intake is $50-$100/HP... $40/HP is pretty good assuming you could get a 5HP gain from it.

 

Thats assuming a 5HP gain. From what we've seen it is far less than that. It's especially not likely from something of such small diameter with such a small weight to begin with. Plus theres also the likelyhood of snapping the bolt that holds it on.

Even if someone posts a dyno proven blah blah blah about it. Unless they used an engine dyno they won't be able to reproduce exact conditions, chassis dynos run an 8% error rate on average. 8% of 250whp is 20hp, so up to a 20hp variance, hard to notice a 5hp gain when you have up to a 20hp variance. Chassis dynos are good for one thing, back to back testing for changes in power and afr, not good for raw number proof.

 

That's what I was getting at, I just can't see ~5 HP being a difference for a DD car. Most of us aren't racing and needing to squeeze every ounce, it is just for the big number bang that we are looking for. CAI's aren't that great for NA engine power, but def. help the sound. To each his own I suppose, I just wish we had more reactions from this mod with actual info or something. I can't see this install being easy so maybe some info about that would be nice too (unless I missed all this in the first 15 pages somewhere)

 

Dude , your gonna be rich !! Charge only 149.99 post a dyno and and say something in regards how yours is gonna make anyone who buys it faster .. Your in the money !!!

 

I took some pics of the UR Pulley. They are not the best but it is the best I can take with my camera:






Hope this helps. BTW the ring that is mentioned is a seal. It is hard to see in the picture though but it is that grayish/blackish piece.

 

I'm not going to waste time with why or why you shouldn't put a crank pulley. I'll just state some facts:

There are hundreds of thousands of 350Z members in my350z.com. I have been a member for a good number of years (and i still am). there is not one report of crank pulley engine failure reported. not one. not one VQ35 has ever had problems with crank pulleys (other than a particular crank pulley from KJR that was too soft and created grooves that led to oil leaks...but all you needed was a sleeve and people were good to go).

that being said i have had a crank pulley on my 350Z for many years...i beat it at the track (see lapped streets of willow many times)...and my engine was just as strong as the day i drove off the dealership with.

now here's the real question: did my crank pulley make any hp? i dyno'd my Z and I didn't free up any hp. not one.

I suggest for people who are serious about any modding of the VQ to go to Altima/maxima forums, 350z forums, G35 forums and see for yourself.even though we have the VHR...it is not so far different from our 35DE/HR siblings.

 

So what's the point of the mod then?

 

Thank you , there is so much info a my 350.com .. I had the same results on my z .. Total Fail !!!