Church 209 Report post Posted June 10, 2015 All seems fine with fluidamper .. except that dampening functions aside i'd hate to get even deeper (-5wtq/whp?) torque dip in 3K+/-300rpm range. I mostly daily drive mine, hence slight gain at rpms near redline, that will be seen/used less then 1% of driving time seems at too high of a cost. Share this post Link to post Share on other sites
Ade 517 Report post Posted June 10, 2015 I need to get my books out, but those graphs seem to be telling me that the fluidampr is not as good at damping vibration as the stock damper, and the lightweight pulley does a great job, apart from in the 6th order vibration... In short, if lightweight pulleys were a creation of the devil, many more people would have problems with them - although, these graphs do show that there is a significant difference in behaviour between stock, damped, and undamped, and therefore definite potential for something to happen... Lightwight pulley has 5th order at 7k rpm and 6th order vibaration at 6krpms at >0.2 deg vibration angle is not good! Fluidampr has more vibations in the 5th-7th order in the higher rpms. I dont care if they are a small angle, they are still much bigger than the stock damper! You can use these graphs to determine total power of the vibrations, and I am sure by looking at those graphs the stock damper will win. Toyota/Subaru engineers have done a great job! 1 Tim Radley reacted to this Share this post Link to post Share on other sites
Tim Radley 18 Report post Posted June 10, 2015 The dyno chart proves out what is well known. Light isn't always best in certain areas. Look at any F1 crankshaft and you will find they use heavy metal inserts to increase weight, same for a MotoGP crank. This is done for very good reason. Lightweight parts can lack torque stability. On/off throttle control can be bad. If you want to sit blipping your throttle when parked up then yes lightweight parts can seem better but the reality is the heavy parts will accelerate faster in this scenario that the car ever does when driving. Lot of junk parts in the aftermarket so be careful. 1 Ade reacted to this Share this post Link to post Share on other sites
Sideways? 33 Report post Posted June 10, 2015 Maybe I'm not looking at the graphs properly, but from these graphs I can't see the advantage of the Fluidampr - It appears to perform worse than the stock damper; it doesn't make any difference to outright performance (overall, I know there is extra torque dip which is bad, but it is up in other places so on balance = no difference) AND doesn't significantly change the vibration characteristics... Plus it is $500 or something... I think it is accepted that there is an improvement in engine response when rotating weight is reduced, but I can't see the Fluidampr being much lighter than stock, and since it doesn't appear to have any benefit over the stock damper from these graphs I think this is definitely not worth the investment... Also, it would be nice to know what lightweight pulley they used, and if they would anticipate a similar response with all lightweight pulleys - could the 6th order spike be caused by the design of the pulley?? How lightweight was the lightweight pulley they used?? Would a heavier/lighter one have different vibration characteristics?? Lastly, I think we all have to congratulate Fluidampr for doing the investigation and putting these graphs out there (thanks to Knighty for posting them here...) so that we can finally have some meat to discuss on the subject of lightweight pulleys... Share this post Link to post Share on other sites
Kodename47 446 Report post Posted June 10, 2015 From reading the pdf of the development, it's where the resonant frequencies lie that are the issues. Those are the coloured lines. So the Fluidampr one may be similar to stock over the entire chart, they have similar resonant frequencies but the Fluidampr has less vibration angle for the resonant frequencies. Whether it's a worthwhie upgrade or not though, that's personal preference. I believe it is a bit lighter than stock. What is clear though is that the resonant frequency of the lightweight pulley is at a high frequency and has a high vibration angle. As to the difference in lightweight pulleys, none of them are damped (they couldn't be to be lighter) and the weights would all be similar enough that the frequency and vibration charts would be similar. 1 Sideways? reacted to this Share this post Link to post Share on other sites
Guest Report post Posted June 11, 2015 I want that fluidampr pulley. Where can I get one? I'm with Lauren on this subject and have said this before, Subaru wouldn't put a damped pulley on the engine if they didn't have to, and remember, they do this with a stock flywheel and stock rev ceiling. Share this post Link to post Share on other sites
Sideways? 33 Report post Posted June 12, 2015 Nigel, Google is your friend: www.fluidampr.com/buy/ Looks like import from the States only, so cruise the list and choose someone who looks trustworthy...! IMO, they look expensive for very little apparent benefit but each to their own, but you've spent serious money on your engine build so probably worth doing everything you can to protect it since it'll be running at high RPM most of the time!! Share this post Link to post Share on other sites
Sonic 4 Report post Posted June 16, 2015 a big benefit of damping out torsional vibrations is it allows a higher rev ceiling , increased piston / rod loads and more agressive cam profiles all of which are helpful to increasing performance as most tuned road engines don't do mega miles it takes a long time for a fatigue failure due to excessive torsional to appear so lets see where we are in 20K miles or so with these lightweight pullies 1 Ade reacted to this Share this post Link to post Share on other sites
