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#4327 |
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Turn the steering wheel to full stop, reach around the tire and attach a zip tie on the strut shaft tightly, snip excess, push the zip tie down to the strut body, lift the front of the vehicle, remove tire, measure distance between strut body and zip tie (droop), measure length of strut shaft (stroke).
Back rear up on ramps, from under the vehicle attach zip tie to strut shaft, slowly drive off ramp, then lift and repeat front procedure to find existing droop. Alternate method: lift rear, remove wheel, attach zip tie, mount wheel, lower vehicle, drive around block, reach around tire and push zip tie down, lift vehicle, remove wheel and measure zip tie gap. Back of envelope math with known strut stroke example: spring rate of 450 in/lbs compressed by (sprung weight example) 600 lbs = 1.33 inch/33.87mm, 1/3thrd of (stroke example) 115mm = 38.33mm, add 4.46mm of unbound helper spring to reach minimum droop. The adjustment can be accomplished with the struts on the vehicle, and the math can be done on the kitchen table if strut stroke is known (ask manufacturer if spec not published). There is greater variability in measuring a distance of 13+ inches/330mm between two arcs than between two flat surfaces (ground/pinch weld) on a vertical plane with a span of around 140mm. Then there is wheel ratio disparity between front and rear suspension to account for in the fender measurement method. The pinch weld is a good representation of underbody rake (positive, negative, or neutral) and is almost in line with the struts. Keep in mind the usable stroke for the selected spring during this study. |
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#4328 |
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I'm considering getting rear lower arms with ball jointed inner joints, partly because my current -2.5 is a little more negative than I want but also because I feel that ball jointed inners won't lose some camber due to bush deflection while cornering, so the ideal static rear negative camber will be less with ball joints rather than rubber bushes.
My question is does replacing the lower arms with ball jointed ones but leaving the stock toe arms cause undesirable toe change while cornering? The STI link set including both lower arms and toe arms got me thinking about potentially undesirable toe change while cornering if the toe arm has bush deflection but the lower arm doesn't. |
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#4329 | |
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-Mike |
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#4330 |
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My question is about toe and roll center adjustment
At what amount of ride height change should one consider getting RCA kit up front ? Same question for adjustable toe links in the back... Target rear toe would be 0 last question is there anything on the market to adjust rear roll centers ? Thanks
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#4331 | |
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Quote:
To adjust rear roll center I suggest you to play with upper control arm offset bushing and get the camber back to spec using the lower arm. Otherwise you have to shim the entire subframe, SPL makes a kit for this purpose. . As for the 0 toe you should not have any problem till 40mm of lowering. |
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#4332 | |
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I will be going with the RCE SS2 which I think recommend a minimum drop of at least 25mm but I might be wrong. I want to keep my ride height as high as possible without effecting performance
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#4333 | |
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All that said, they are optional. - Andrew |
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#4334 | |
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#4335 |
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That is cause when you raise the rear roll center you also add anti squat geometry, combine them and that’s why your rear end feels looser.
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#4336 |
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I wasn't sure but I thought that may be the case. I really didn't find much benifit in the rear RC correction though my thoughts may be tainted by the issue with adding anti squat. I do like the RC correction in the front.
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#4337 |
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I probably should just google the SPL kit but…. How’s does it work in conjunction with the subframe bushing inserts?
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#4338 |
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It doesn’t work with the inserts. The SPL kit replaces the subframe bushings with solid aluminum inserts. In your subframe thread you can see them in the picture I posted. It comes with spacers to move the subframe up/down in relation to the chassis.
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#4339 |
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Thanks for that. I had a look at the kit and it makes more sense now. Is there much height adjustment being done when using the bushing inserts ? I honestly never even though about this aspect till now ha
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#4340 | |
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Quote:
As you said, keeping the front RC in a correct spot is much more of a concern for a decent handling. |
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