Bill Verburg

The stiffer RS bushes can be identified by green paint dots, the 993 rear A arms I have have the stiffer bushes, I assume all the others do to.

Bill Verburg

mono-ball life in the environment under the car is never going to be as long as for rubber.

The cars i've seen w/ full mono-ball suspension don't seem to have any problems.

I'm trying rubber boots over the monoballs to see if that helps

Bill Verburg

I originally replaced the rear toe links w/ new factory parts, even the RS used the same toe arms. I felt that it was a very unsatisfactory arrangement, even when everything else was up to full RS spec. Last year I gave up and installed mono-ball toe links w/ locks. The difference was night and day. For a track car I wouldn't want it any other way.

You can't get a car much lower than mine, I never had any issues w/ adjustment w/ the stock links, they just don't hold the wheel as steady as is desirable.

Paul902

Thanks, Bill.

chaoscreature

I am surprised that you can run rigid links and monoballs for all five links without something binding up a bit. I am sure if you were to model this up in CAD it would fully constrain the suspension, so something must be "giving" a little bit. We have a Supravision "vector arm" which can pick 3D points out in space and plot them into CAD, but I am pretty sure my company won't let me model my suspension system in their shop . If anyone does end up modelling the system I would appreciate a copy of the files.

race911

Thought I'd bring this back from the dead, since we've got other alignment discussion going on...........

Cowhorn

Just read this thread. Very informative.

pp000830

So here is my take-away:

• Measure the suspension height after a good alignment
• Make note of the calibrated adjustment nut position on the rear Kinematic tow setting, left & right.

At the next alignment:

• Verify and adjust ride height to same as previous alignment;
• Verify the kinematic adjustment nut is in the same position;
• Align as normal w/o need to adjust rear kinematic settings.

Do I have this right?

OverBoosted28

Yes, without any change to components, ride height or adjustment, the KT should be the same. Although, hard driving can induce the KT cam to move. The main thing on KT is that both sides are equal. Use of these locks will secure your KT setting. If you put in the adj. KT arm, this is a must to assure you'll maintain your KT spec.

fnckr

Bumping this. Can someone please address this quote, specifically the last sentence, “allowing for increased toe-out under load”? IMO, this statement is incorrect, for the reasons below.

The KT arm is above and behind the wheel hub. Therefore, any independent load towards the car’s center, causing any flex on an individual inner mounting point, except for a rigid KT arm mounting point, would cause the bottom of the wheel to move in and/or the front of the wheel would move in.

Therefore, toe-out could never occur with a cornering side load or under braking with a rigid KT arm. This also means, it is safe to have an RS bushing for the A-arm rear bushing, while having monoballs in every other rear link location (A-arm front, camber, toe, KT).

Is my explanation valid? And is the above quote incorrect? Credit to Bill Verburg for the pics.

fnckr

Bump for the question in the previous post.

Basically trying to decide if I can go full monoball kit, like Rennline’s KT, Camber, Toe with RS bushes in trailing leg and outer leading leg. I said “can”, maybe I will also ask, “should” I?

This is for a summer country road blaster with a couple track days.

Bill Verburg

Toe change comes from 2 different mechanisms
- up and down movement of the wheel which is determined by the geometry of the arms
-elastic behavior of the rear inner bush on the A-arm, #5 below, the elastic give creates a twist around a virtual axis as the wheel moves up/down, the upper end of the virtual axis is controlled by the outer ends of # 3 & # 4, the lower end by the outer ends of # 1 & # 5, the KT arm #4 when lengthened pushes the upper end of the virtual axis out and forward, this also moves the wheel forward and down(raises ride height), the geometric effect is to reduce caster and decrease camber, the dynamic effect is to speed up the reactions of the rear ie, the rear becomes twitchier, if the KT arm is shortened the opposite occurs , castor increases and camber increases, this slows down the rear reactions as the tire gets closer to the muffler and lowers ride height



Both of the above effects are always going to be present as long as there is any rubber connection. The stiffer the connection, either at # 5 or #4 the more controlled the change in length of the respective arms, this translates to more precise car control, at what ever static settings are chosen. The reduction in KT effect w/ increases bushing stiffness has no effect on the inherent geometric toe change w/ bump/droop

The most precision comes from mono-***** at both ends of at all 5 arms, if any of the ends has reduced give it asymptotically approaches the pure mono-ball state and conversely if any are given increased play w/ softer connections action moves further away from the pure mono-ball state

i've driven all 3
the RS setup would have been totally acceptable for street and track except for the fact that the eccentric adjusters are just not reliable in severe track use

I currently run pure mono-ball f/r and even w// very stiff springs this is perfectly acceptable for the limited street use I give it, w/ good digressive shocks

I would advise locks and booties on all the and an occasional spritz w/ WD-40 under the booties

fnckr

Thank you! I’m processing the information as I decide on the rest of the joints. I did order the monoball control arms during the Black Friday sales. For the boots, rather than WD40, I will use LPS-3 corrosion inhibitor. It’s similar, but different to Fluid Film. https://www.itwprobrands.com/product/lps-3

EDIT: Upon doing more research, it appears that bearings lined with PTFE fabric should not be lubricated. The lubrication acts as a holding agent for dirt and other abrasive particles. In one spot (SKF bearings) I read that flushing with a liquid lubricant, even water, would be beneficial. The purpose of the dust boots is to prevent contamination altogether. So, the suggestion to flush with WD40, which is very liquid, rather than a thicker substance like Fluid Film, seems to be the better advice for durability.

EDIT 2: Best to keep them clean by having good sealing boots. If contaminated, use soap and water, and dry them. Attached article with quotes from FK themselves, https://www.chevyhardcore.com/tech-s...e-of-rod-ends/

Porsche70T

PM sent - slightly off topic. Just hoping that you can help with some JIC questions.