» Site Navigation | | » Recent Threads | | | | | | | | | 10-03-2008, 01:39 PM | #31 | Senior Member Join Date: Apr 2007 Location: Elizabeth City, NC Posts: 3,877 | Found this thread over on E46 fanatics, some of the info might be for the E46s but a lot of good questions are answered. *NWS* - Pic in guys sig is a little risky. http://forum.e46fanatics.com/showthr...=605419&page=3 __________________ ~Dave~ 98 328ti Morea Grun slicktop 11 128i space gray slicktop 13 JGC WK2 Deep Cherry Search | RealOEM | | | 10-07-2008, 01:50 PM | #32 | Senior Member Join Date: Apr 2007 Location: Elizabeth City, NC Posts: 3,877 | Jim posted up the front strut dyno. Said the rears are coming soon. __________________ ~Dave~ 98 328ti Morea Grun slicktop 11 128i space gray slicktop 13 JGC WK2 Deep Cherry Search | RealOEM | | | 10-07-2008, 05:36 PM | #33 | Senior Member Join Date: Aug 2005 Location: Florida Posts: 2,525 | One force vs. displacement graph is kind of worthless.. Should ask them to have the same graph generated for a few different randomly selected dampers from their production run.. This way you know how closely matched they really are.. In the case of those k-force dampers, there was a huge amount of difference between dampers. | | | 10-07-2008, 09:48 PM | #34 | Senior Member Join Date: Apr 2007 Location: Elizabeth City, NC Posts: 3,877 | Quote: This strut was pretty random... I took one from Belgium and had it dyno'd in Italy at a completely unrelated sway bar manufacturer. So, I don't think we'd find out anything different. When I emailed these to the engineer in Belgium, he didn't seem surprised by the results. I'm guessing the results are typical. You are free to do anything you want with any sets you purchase though. Jim | I guess someone will have to buy a set if we want to see different results. __________________ ~Dave~ 98 328ti Morea Grun slicktop 11 128i space gray slicktop 13 JGC WK2 Deep Cherry Search | RealOEM | | | 10-07-2008, 10:16 PM | #35 | Senior Member Join Date: Aug 2005 Location: Florida Posts: 2,525 | I wouldn't have expected them to do it... That other link I posted is where somebody took the kit they bought and had it tested... I think groundcontrol, bimmerworld, and tckline will do it for you and send the result sheets if you need them. Not sure why most people would need them... This gives a good brief explanation of a force vs. displacement graph. Quote: The dyno can also be used to output a Force vs. Displacement graph (Figure 6). This graph shows the force a shock generates as it travels through its motion in both the compression damping and rebound damping phases. Force is shown on the vertical axis, and is measured in lbf or N, and displacement is shown on the horizontal axis, measured in mm or inches. Quadrant A displays the shock’s force as it is accelerated in bump, quadrant B as it is decelerated in bump, C as it is accelerated in rebound and D as it is decelerated in rebound. This plot can be used to troubleshoot a shock you are having issues with, or to ensure hysteresis levels are at an acceptable level. Hysteresis occurs when the damping forces are higher as the damper is decelerating compared to when it is accelerating, and will decrease the effectiveness of the shock. This effect can be seen in Figure 7, where the damping forces in quadrant B are higher than in quadrant A. Hysteresis is the primary reason that a shock should be valved to be used in the middle of its adjustment range, as hysteresis is significant when you use the stiffest adjustment settings. | So that DDM chart shows that hysteresis is occurring, the values in quadrant A are higher than the readings in quadrant B, so you probably shouldn't run those at full stiff. Of course, it doesn't really give any idea of how much the effectiveness of the shock is diminished. TcKline specifically says that you should never run their shocks at full stiff. http://www.nttyres.com/downloads/gui...yno_graphs.pdf Again, my amateur reading of that graph. | | | 10-08-2008, 01:26 PM | #36 | Senior Member Join Date: Apr 2007 Location: Elizabeth City, NC Posts: 3,877 | Thanks for the link, that really helps with reading the dyno plot. Maybe I'm reading the plot wrong, but I'm not really seeing where the hysteresis is on the DDM plot. It doesn't look like figure 7 from the pdf you posted. It would have helped if the image wasn't the size of a post-it note, lol, thank DDM for that. __________________ ~Dave~ 98 328ti Morea Grun slicktop 11 128i space gray slicktop 13 JGC WK2 Deep Cherry Search | RealOEM | | | 10-08-2008, 02:23 PM | #37 | Senior Member Join Date: Aug 2005 Location: Florida Posts: 2,525 | Yeah, it was really hard to read that graph.. I can't read the numbers at all to know what scale it is in... It doesn't look exactly like that graph, but the values in quadrant B are higher than the values in quadrant A. At least it appears that they are. Not by much, but just a little bit... I've always gone with the school of thought that you shouldn't run shocks at full stiff. So that graph may be completely normal when compared to other manufacturers. | | | 10-08-2008, 03:33 PM | #38 | Senior Member Join Date: Apr 2007 Location: Elizabeth City, NC Posts: 3,877 | I think what throws it off is the the break in the graph is at -3 instead of 0. Both the A and B quadrant ends go to the -21mm and 21mm respectively. I do see though, that the B quadrant values are higher than their A quadrant counterparts. I definitely agree that shocks shouldn't be run at full stiff, I made that mistake with my koni adjustables, at full stiff the ride was unbearable and way over damped, I backed them off to a little less than half stiff and the difference was unbelievable. Much smoother ride without sacrificing performance. Added rear shock dynos, full stiff and full soft settings. __________________ ~Dave~ 98 328ti Morea Grun slicktop 11 128i space gray slicktop 13 JGC WK2 Deep Cherry Search | RealOEM | | | | | Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | | Thread Tools | | Display Modes | Linear Mode | Posting Rules | You may not post new threads You may not post replies You may not post attachments You may not edit your posts HTML code is Off | | | |