jackal2513

afternoon chaps

does anyone have these fitted ?

I am presuming that as well as different grade subframe bushings they also have different mount points for some of the arms, notably the lower toe arms and A arms. I noticed on my car, that now it's lowered to RS ride height the rear lower arms tilt up slightly at rest which I imagine is not ideal for the proper functioning (read: good bumpsteer plot) of the LSA. So I am thinking that the RS side sections (much like the front RS uprights) revise the location of some of the links.

Can anyone confirm ?

Bill Verburg

The Rs side pieces are uber expensive and totally unnecessary. I replaced all the arms w/ the R%s pieces to get the harder rubber bushes and new ball joints, but for the sides i replaced the 4 sub frame mounts w/ solid bushes from Smart Racing, the transformation was remarkable.

It is especially good for very low cars as the solid side pieces are shorter than the original rubber bushes thus raising the entire suspension up into the chassis restoring the arm geometry, it's similar to the effect that the RS uprights do in the front.

W/ my kit I had to shorten the bolts and get some very large and sturdy chassis washers but it was an otherwise strait forward job.

A friend was doing this to his over the past weekend w/ Rennline parts and ran into an issue in that the upper pillow was so short that the sidepiece was hitting the chassis. I assume that is something that will quickly be rectified.

Gert also has a similar kit.

trophy

How much time to do the install of the subframe solid bushings?

jackal2513

Thanks bill, i know about the smart racing bushes and the EVO tilt kits.

What I am trying to establish though is if and how the proper RS side sections restore the geometry of the LSA and how they do it. Do they also have shorter mount bushes or are the points where the arms attach different.

Bill Verburg

They don't, there are 2 differences between the RS and regular parts
1) harder bushes
2) longer camber slot

Even w/ my car as low as it is I haven't needed the longer camber slot. If you do need it just grind the original a little.

As I may have mentioned the harder RS bushes are well worth it as are the solid sides.

I don't know that the tilt kit makes a difference over the flat solid sides except perhaps on very high hp cars like the GT2s

Takes about a day, depending on tools. You will want an air chisel to get the old ones out.

jackal2513

they have to change the angle of the arms in some way though

at RS ride height with the standard side members the angles are all wrong

Bill Verburg

they change the arm angles a bit, because the whole suspension is raised into the car. That's all.

the tilts add some antisquat, but won't change the arm angles as much as the flats, again this is only a small chnage maybe .25 -.5"

jackal2513

ok thanks, so the mount points are higher then

Bill Verburg

only because the solid bushes are thinner

here is a comparison of the stock and solid/flat rear sidemounts. Both are the forward one, You can see where the chassis is notched. Stock doesn't need it solid does

stock 993 rear sidemount

Smart racing solid rear side mount,

alexl911

I'm planning on installing the Rennline Solid Sides but have already lowered the car to RS height (and corner balanced) and have installed EVO uprights. If I now install the solid sides, which as you say will lower the car even further, am I going to have an issue? Will I need to GEO the car again?

jackal2513

bill won't know because he doesn't have the RS side members

but yes, you will have to dismantle a lot to fit them so geo check and adjust will be necessary

they also alter the mount points of the arms, and the ERP bushes also raise the cage a little so again, geo will be required and most likley a ride height adjust

this is why I am enjoying my car for a year and will tackle the rest of the RS suspension including the rear cage all in one go

alexl911

I think were getting confused between Solid Sides and solid subframe bushes like these:

AFAIK, the bushes are pretty easy to install, but as Bill said, they do lower the cars center of gravity.

jackal2513

are they easy Alex ?

i seem to remember Bill having a very touch time getting his old bushes removed

whatever the way, the geometry will change, you are fundamentally moving the whole rear suspension cage and altering all angles

alexl911

Check here: https://rennlist.com/forums/993-foru...me-bushes.html

Apparently only a couple of hrs work.

jackal2513

I've already answered that one over on 911uk ..

nothing to do with the Weissach axle



but seriously, i guess it depends on how easy your old bushes come out

see Bills comment about about needing a proper air chisel

just crack on with it .... got to be one of the best mods you can do on a 993