850T5M Posted May 10, 2011 Report Share Posted May 10, 2011 I just installed a used pair of IPD springs (blue) and some used bilstein tc struts up front. The struts/springs have under 10k miles on them and are in beautiful shape. The back is riding on bilstein tc shocks as well, but were installed 8 months ago. Today I noticed after putting in the new strut/spring combo, the ride is actually a lot smoother, but also pretty bouncy. My old struts were finished and it felt like I was driving a car with solid struts lol...is the new "bounce" normal with Billy Tc's and iPd springs? Link to comment Share on other sites More sharing options...
sconeman Posted May 10, 2011 Report Share Posted May 10, 2011 I just installed a used pair of IPD springs (blue) and some used bilstein tc struts up front. The struts/springs have under 10k miles on them and are in beautiful shape. The back is riding on bilstein tc shocks as well, but were installed 8 months ago. Today I noticed after putting in the new strut/spring combo, the ride is actually a lot smoother, but also pretty bouncy. My old struts were finished and it felt like I was driving a car with solid struts lol...is the new "bounce" normal with Billy Tc's and iPd springs? yeah I think that's normal. I have the same combo. It's got a good ride over normal terrain. Large bumps on the freeway are a bit harsh and it does bounce over large frequency bumps : ( Link to comment Share on other sites More sharing options...
850T5M Posted May 10, 2011 Author Report Share Posted May 10, 2011 Alright just making sure, cuz the old setup didnt bounce as much. I know it sits WAY lower, barely fit a finger between the tire and the fender No rubbing over bumps or getting out of parking lots. Im pretty impressed so far, except for the weird bounce. I haven't taken any hard turns with it yet, I just installed them today and had to run to work. Link to comment Share on other sites More sharing options...
Vagabond Posted May 10, 2011 Report Share Posted May 10, 2011 When I hear someone say bounce, to me that means that after initial suspension travel, there is still spring oscillation before the suspension settles into a steady state. Is that what you mean. Curious, as I have TC with the IPD Ver 1 and I have no "bounce", but the drop isn't what I want. The IPD blues are closer to the ride height I would prefer. Link to comment Share on other sites More sharing options...
850T5M Posted May 10, 2011 Author Report Share Posted May 10, 2011 Well an example is, if I were to push down on the driver fender and shake the car, the passenger side will also bounce up and down and kinda not settle as fast as I'd expect. It kinda rocks like a boat for a second. I'm gonna drive it some more and test them over bumps. Link to comment Share on other sites More sharing options...
Aequitas_Veritas Posted May 10, 2011 Report Share Posted May 10, 2011 bilstien shocks suck. Get some konis and it wont bounce anymore. Link to comment Share on other sites More sharing options...
850T5M Posted May 10, 2011 Author Report Share Posted May 10, 2011 bilstien shocks suck. Get some konis and it wont bounce anymore. Almost double the price Also, is it 100% necessary to do an alignment after the front strut/spring swap? Link to comment Share on other sites More sharing options...
Vagabond Posted May 10, 2011 Report Share Posted May 10, 2011 Not for the drop you have. Also Bilstiens far from suck. :rolleyes: Link to comment Share on other sites More sharing options...
Madman55 Posted May 10, 2011 Report Share Posted May 10, 2011 I just installed a used pair of IPD springs (blue) and some used bilstein tc struts up front. The struts/springs have under 10k miles on them and are in beautiful shape. The back is riding on bilstein tc shocks as well, but were installed 8 months ago. Today I noticed after putting in the new strut/spring combo, the ride is actually a lot smoother, but also pretty bouncy. My old struts were finished and it felt like I was driving a car with solid struts lol...is the new "bounce" normal with Billy Tc's and iPd springs? I am getting ready to order and entire new set of springs, shocks, and struts ti replace my very worn all-oem parts.. I have decided on bilstein TC shocks and struts but was not sure what I was going to do about springs. I was wondering if IPS lowering springs would bea a good combo with the TCs but I am running 17" pegs and am worried about getting wheel rub if I go lower than stock height. Good to know what to expect outa the ipd springs handling-wise now though. Link to comment Share on other sites More sharing options...
valdis Posted May 10, 2011 Report Share Posted May 10, 2011 Yes, I would definitely get an alignment after the spring install. I just put the IPD springs with Bilstein HD's on about 3 weeks ago on my 98 V70 and the the camber in the front went very negative which also affects toe. Even the toe in the rear was out of spec. Since I have access to an alignment machine at work, I know the alignment was spot on a month before the install. Just my 2 cents. I have not really experienced any bounciness with my setup. Link to comment Share on other sites More sharing options...
ozzimark Posted May 10, 2011 Report Share Posted May 10, 2011 Welcome to system dynamics 101! Basically what you did is took a mass-spring-damper system that was tuned for a certain natural frequency and damping ratio, and changed the spring rate without changing the damping rate. This will create an underdamped setup, which will oscillate for more cycles before all the energy is dissipated in the shocks... hence the bouncing. Most likely, it's settling in roughly the same time period as it was before, but the increased vertical velocity makes it really annoying to you. If you don't like it, get firmer shocks and the "bounciness" will be reduced. There are literally thousands of books on vehicle dynamics and how to achieve a particular setup for a particular application. Here's a start on the topic in a general sense: http://en.wikipedia.org/wiki/Damping And a pic. I wish more people would get into the actual vehicle dynamics with their suspension setups instead of just putting on springs for a drop and stiffer shocks for "better handling". It's vastly more complex than that :lol: Link to comment Share on other sites More sharing options...
fastwagonhawaii Posted May 11, 2011 Report Share Posted May 11, 2011 Do you have pictures with the new set up. I have biisteins know with eibachs and thinking of going with ipd's next. your car looks exactly like mine but i have a wagon. I would love to see how the front sits. Link to comment Share on other sites More sharing options...
GP850T Posted May 11, 2011 Report Share Posted May 11, 2011 is it normal than that my IPD springs with Koni yellows are bouncy... Link to comment Share on other sites More sharing options...
Aequitas_Veritas Posted May 11, 2011 Report Share Posted May 11, 2011 My Koni FSDs arnt bouncy at all. Link to comment Share on other sites More sharing options...
Madman55 Posted May 11, 2011 Report Share Posted May 11, 2011 Welcome to system dynamics 101! Basically what you did is took a mass-spring-damper system that was tuned for a certain natural frequency and damping ratio, and changed the spring rate without changing the damping rate. This will create an underdamped setup, which will oscillate for more cycles before all the energy is dissipated in the shocks... hence the bouncing. Most likely, it's settling in roughly the same time period as it was before, but the increased vertical velocity makes it really annoying to you. If you don't like it, get firmer shocks and the "bounciness" will be reduced. There are literally thousands of books on vehicle dynamics and how to achieve a particular setup for a particular application. Here's a start on the topic in a general sense: http://en.wikipedia.org/wiki/Damping And a pic. I wish more people would get into the actual vehicle dynamics with their suspension setups instead of just putting on springs for a drop and stiffer shocks for "better handling". It's vastly more complex than that I am about to replace shocks, springs, and struts all around. As a Mechanical engineering student who spent 2 years on my school's Formula SAE team, I would LOVE to use to put together the ideal setup for my car. Problem is: I have NEVER seen the springs rates or damping co-efficients (or curves) actually published for any suspension components that are sold for 850s. If you have these specs for products offered from sachs, billstein, and other damper/spring manufacturers, please....do share! Link to comment Share on other sites More sharing options...
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