[why?]

Originally Posted by Captain Snooze

Yeah, I recall those/that post. It was a respected builder (MAP? Element? I can't be bothered searching ) but the issue was the combination of the two when the flywheel was reduced below a certain mass. That is, one could have a lwcp and a lighter flywheel. One could not have a lwcp and light weight flywheel. There seemed to be a critical mass at which the engine fell apart when the flywheel mass was reduced too much.

Speaking of which.
There seems to be a lot of discussion about the pros/cons of a light weight crank shaft pulley but I don't seem to read much about the impact of a light weight flywheel on the harmonics of a crankshaft. I am hypothesising given the much greater mass of the flywheel it would play a greater role in crankshaft damping/harmonics.
I am totally out of my depth here.

Note that they were talking about turbo's. FA20dit and EJ turbos. Also note there are so many issues with ej's and the fa20dit's seem to also be having all sorts of problems. I see no reason to mess with the crank pulley on a turbo. More complexity changes things, however that article I posted trying to sell that so called damper proves everything has vibrations, and even the fancy expensive aftermarket damper sold as smoothing everything out actually just changes the vibrations and has more vibrations than the stock ones.

Originally Posted by humfrz

Hey @why? ...... where did you run off to ...... ??

I wasn't done with you yet.




humfrz

I went to sleep, it was way past my bedtime. I only responded because I was drunk. I really truly don't care what people think about this stuff, it has been hashed, rehashed ad naseum and people are trying to shove info about old school big block engines into tiny 4 cylinders and try and make everyone believe it is the exact same thing when it simply isn't.

Originally Posted by Hawk77FT

Man, do you even graph? LIke seriously. I take it you looked at the second chart, which actually shows the extent of the actual vibrations, hence they recommend to look at the smoothness of the damping capabilities.
"Second order comparison between the OEM tuned elastomer damper and Fluidampr performance damper. The dominant second order represents the firing order in four-cylinder, four stroke engines. Clear start and stop damping range spikes of the tuned elastomer damper are present at 3900 and 5250 rpm, or 130Hz to 175Hz, for a narrow operating range of only 45Hz. Note the smoothness of the Fluidampr damping capability through the same rpm range."
Also, the third and fourth graph actually shows "The Fluidampr performance damper was able to cut amplitude of the excited 3rd order vibration generated by the 260Hz crankshaft resonance in half, down to below .1 degrees peak." I dare ask, do you even know what that means? You know, different frequencies and grades of vibrations, etc. I am not by any means an engineer but i have a somewhat clue about the complexity of it.
If you really want it simplified, the fifth chart shows the extent of vibrations at different rpm.
Attachment 149447

Next time, when you challenge the findings of a professional test, please make sure you really know what you are talking about.
Also, please stop spreading wrong info. "What this article tells you is harmonics don't exist at all for our cars." Yeah it so does hey! Totally! Please read my previous post for educational purposes!

Did you look at the entire article? Oh wait, no no you didn't. There are a bunch of graphs that show a bunch of different vibrations and the fluidampr supposedly specially made dampr has more vibrations in a bunch of different places over the stock one. They cherry pick above 5500 rpms on that graph you posted. Funny thing though most people dding there car are never ever going to get anywhere near there. Hell I shift at 2500 rpms or less. Also note even they admit it might add only 3 times more stress at most. Not exactly exploding engine type of levels there. Funny how nowhere in that article did they every say they actually stressed anything until it broke. Gee, I wonder why? Could it be that all three do the job just fine and there is no actual case where any of them could cause a condition that would actually cause damage? That is my educated guess.

Originally Posted by humfrz

....... how DARE you correct ME ....... I've already made up my mind and "don't give a crap what anyone says"! ......., to quote a recently self declared expert in the field of pulley things........

Seriously, I'm simple minded and just remembered this from what that guy Wiki had to say:

"A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.[1]"

Is there a difference or are you just slapping around an old man for giggles ...??




humfrz

don't need to be an expert to see no one will ever change their opinions. Also don't need to be an expert to see big block old school v8's are not tiny boxer engines. People can take the time to do their own research, all the info is on the web. Subaru's internally balanced engines mean it really doesn't matter.

Originally Posted by humfrz

WOW!

For now, @why? , I'll just challenge the statement which is bolded above.

Are you saying that a boxer engine is more "balanced" than an in-line six ....??




humfrz

No, that's silly. Almost as balanced though.

Originally Posted by cjd

No giggles, I learned to respect my elders...

On some engines the pulley plays a crucial role in balancing the whole thing.

On this engine it really is internally balanced, and the pulley itself is balanced (OK, I haven't verified this one, but the engineers say the engine is balanced internally, so I'm pretty sure it's like my previous car, which I did test... that pulley had the same rubber insert and people ran lightweight undamped underdrive pulleys hundreds of thousands of miles no problem...) So the only thing it can do is change how the crankshaft etc. sees harmonic resonance... Which it dampens. No balancing involved.

Pedantic, but if you're arguing its importance when we haven't seen clear failures as a result of pulleys,... I have no clue if it's good or bad. But I do know it's not balancing anything. I also haven't installed a lightweight pulley, though I have one somewhere...

C

I've learned to hate pretty much all of humanity.
But you've struck a good point, there are engines that are way out of balance and need all sorts of things to make it not blow up. Some people decided that since some engines need this that must mean all of them do, which is of course nonsense.

There can be no clear failure of pulley's as it is not something people would do and never modify anything else. People do claim they have seen ej's and fa20dit's with failures in cars that happen to have lightweight pulley's among a bunch of other mods as well. Of course the problem is we are seeing failures in both engines in completely stock cars as well.

Originally Posted by Ultramaroon

If the damper wasn't deemed necessary the OEM wouldn't have specified it. A stamped steel pulley is much cheaper to manufacture.

That's silly. It could be done because "it is how it has been done for decades and there is no reason to rethink it." Like the reason for how so much is done. The research put into thinking a new way to do it would probably cost far more than any benefit that could be seen. It could also be used in many different engines and vehicles as it is now, instead of making a unique design for every engine which would add unneeded cost and complexity. If it works right and doesn't fail, why should they try and change it? There are a ton of reasons for a company to use a part that has never failed and always worked instead of trying for something new and different in this one area. Also note aftermarket pulleys are really expensive, that fluidampr thing is $370. This really is not an area of a car where revolutionizing things would bring much press or praise, while screwing things up would really ruin reputations. I have no problem with Subaru being conservative, hell I am sure a lot of people wish they would be more conservative when it comes to ej25 engines. But to say every little piece and part is why it is because of some mythical reason that has nothing to do with cost savings or part sharing is silly.

Originally Posted by Captain Snooze

I refute that statement as a valid argument. Are you suggesting that everything on this car is "necessary". If I remove the radio is the car going to blow up? It would have been cheaper to omit the radio.

nothing is necessary. We know they went the cheap route when it came to engine oiling, which is why the engine just can't rev much past 8300 rpm's without major modifications for the oil system. Hell we know they settled for the crickets, I assume fixing them would cost an absurd amount of money. The manual gearbox is one hell of a compromise, and it seems they compromised quality and usefulness for making it less expensive. I wish they had found other areas to cut costs like the interior, the wheels and tires, etc. I don't know why they made the wheelbase or the car as long as they did, would have been nice to make both shorter and lighter, but that doesn't mean they designed it that way, it probably means they borrowed parts from other vehicles to keep the costs down. I could go on, in general the car is the way it is because that was the least expensive way for them to do it, with few exceptions, and they still missed their original stated price goals by a ton.

I hate when people say the stock way is the best way, instead of the way they compromised for everything because they have so many other goals and qualifications other than making the car as sporty and fun to drive as possible. While the aftermarket has that one goal and can easily cost a heck of a lot more than the stock part it replaces without issue.