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Discussion Starter · #1 ·
Soo..

Planning some new things for next year. Some of these things may include double-adjustable front suspension.

However, it seems as if most of the discussion about the RSX suspension revolves around the front-end and about front bumpsteer, strut-geometry, steering arms, roll center, etc.

What are the inherent weaknesses about the rear-end of the RSX? Anybody find something wrong with the rear end of this car?

I have ideas for next year, but would like to see what some of you can think of first.
 
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how does the rsx rear double wishbone design compares to the 06+ civic si's multilink? are there any benefits the latter's design has over the rsx?
 

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rear. too high of wheel rates? therefore needing such high rates in the rear compared to front?

only issue i had w/ the rear was its twitchiness at high speed corners, but it can be dealt and fixed, but i can't think of a way to fix it thru the rear sussy.
its the motion ratio that screws the chassis over not technically the wheel rate. The damper doesnt have much travel to use therefore most dampers have a hard time doing there job. It also doesnt help needing 2x the desired spring rate simply to match the front frequency, all of this just makes life harder for the damper.

then we have binding issues, and rears roll bar effectiveness issues etc.
 

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Discussion Starter · #8 ·
its the motion ratio that screws the chassis over not technically the wheel rate. The damper doesnt have much travel to use therefore most dampers have a hard time doing there job. It also doesnt help needing 2x the desired spring rate simply to match the front frequency, all of this just makes life harder for the damper.

then we have binding issues, and rears roll bar effectiveness issues etc.
Pretty much the issues I'd like to address for next year.

I didn't know about the binding issues until this summer when I checked my rear shock bushings looked like they were trying to pull out. My car was not the first case I've seen trying to do this so it got me thinking that something must be going on there.

My assumptions were later confirmed this week @ SEMA when I talked to somebody at Koni and they told me about the binding issue in the rear of the RSX.
 

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Pretty much the issues I'd like to address for next year.

I didn't know about the binding issues until this summer when I checked my rear shock bushings looked like they were trying to pull out. My car was not the first case I've seen trying to do this so it got me thinking that something must be going on there.

My assumptions were later confirmed this week @ SEMA when I talked to somebody at Koni and they told me about the binding issue in the rear of the RSX.
wanna delve into how you plan on fixing these issues?
 

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Discussion Starter · #10 ·
wanna delve into how you plan on fixing these issues?
Get rid of the poly rear shock bushing and use rubber but hopefully heim joint for binding issue.

I don't have the budget/time to change the rear geometry to allow for higher motion ratio so I'll "fix it" with more spring and more damper. Hopefully lots of rebound adjustment for next year.

Guy I talked to at Koni pretty much said the same thing and we agreed with each other that's about all you can do short of doing something like RTR rear suspension.
 

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here a comparo you might like to see....old civic/new civic



heres what realtime did....here is the stock lca



here is their redesigned lca





what they did was move the rear shock and towner back and out to reduce the motoin ratio.....they also remove the flex part of the lca.....If you look at their "stock" pic, look at the upper lca....see the spacers, thats for your rollcenters....they work.....don't ask me how I know.......:shady:
 

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IMO the high roll center in the back is an issue that wants to be fixed. It results in very little compression of the outside wheel mid-corner so the whole back of the car lifts up as the weight gets transferred across the rear, raising the cg and impacting the front geometry. It also causes the lateral motion of the tire in compression that is partly responsible for bad tracking over bumps. Can't think of an easy fix for this, other than running a lower ride height in the rear than the front. IMO this is a good approach for autocross where looks/aero aren't important, not so much for track guys, although it works well for the VW racers. And then you get into the issue of bind if it's lowered very much. Not sure how much lowering it takes to get into that area.

Edit:^^yea, the uca spacers are an interesting approach, another way to alter the virtual swing arm and change the roll center some. Looking at the 01 vs 06 civic rear suspension pics, the 01 uca is angled upward noticeably, the 06 is closer to level
 

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Discussion Starter · #16 ·
what they did was move the rear shock and towner back and out to reduce the motoin ratio.....they also remove the flex part of the lca.....If you look at their "stock" pic, look at the upper lca....see the spacers, thats for your rollcenters....they work.....don't ask me how I know.......:shady:
I know the shims will affect roll center but I'm more curious as to what the rear LCA angles are.

Maybe I'm wrong but my assumptions are that the LCA have more effect on the roll center than the upper arm.
 

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Any thoughts on making a higher mounted one for the RSX to gain travel? A custom machined piece maybee.
I talked to my local race fab shop about this a couple of years ago, we decided that it wouldn't be too hard to cut the stock mount across the cylinder close to the flange and weld in a section of tubing.
 

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I know the shims will affect roll center but I'm more curious as to what the rear LCA angles are.

Maybe I'm wrong but my assumptions are that the LCA have more effect on the roll center than the upper arm.
Yes on this. When the lcas are level you actually raise the roll center with those spacers. Maybe RT was looking to get a more aggressive camber curve with the very small displacement their high spring rates have?
 

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Discussion Starter · #20 · (Edited)
IMO the high roll center in the back is an issue that wants to be fixed. It results in very little compression of the outside wheel mid-corner so the whole back of the car lifts up as the weight gets transferred across the rear, raising the cg and impacting the front geometry.
How does it impact the front geometry? Are you talking about increased load mid-corner for the outside-front wheel?

Look at attached picture.. is that evidence of what you're talking about the back-end raising mid-corner? Maybe it's the angle of the shot but my rear fender gap is not that big when the car is static.

At that point in that particular corner, I'm either neutral throttle or already starting to apply the throttle.

Edit:
http://buildafastercar.com/tech/Roll-Centers said:
If the roll center is lowered in the front of the car but not the rear, the front will now encourage more body roll for a given cornering force. Thus, the tendency of the body to roll will increase, but the front of the car will be less willing to resist that roll. This means the rear of the car will pick up the additional work of resisting that roll, meaning more weight transfer in the rear relative to the front. This causes oversteer.
Is this the reason for the twitchy rear end people complain about for the RSX?
 

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