Eurotrio

Dual purpose suspension: monoball or not

Trying to find a balance between: function, performance and reliability.

My head is spinning after many days and hours of reading numerous threads which included some good comments by several veterans including Bill Verburg and Steve Weiner.

My goal is to setup a suspension for a car that will never see a track, however….my track ….are the mountains. Think of the early days of Monte Carlo Rally.
As in most parts of the USA, the road conditions/surface vary greatly. Some surfaces are smooth, but other are absolutely horrible. I do not want the suspension to be so rigid that will create damage as I have seen torn shock towers on cars including my own. Am I over paranoid?


95 C2 – 46K miles
The plan for the ride height is: RS +10mm
Using 18” wheels

I have decided to go with the PSS10 and possibly H&R bars as suggested by Rennsport. (I know some cringe as they only swear by RS bars with more adjustability)
Will also go ahead and replace the front control arm bushing probably with Elephant Racing…at least the rear set, but may also do front depending on current condition.

However, I now have a dilemma if to install new stock upper rubber mounts or monoballs. Some have recommended monoball upper mounts for track and light street use. When looking at ERP or Elephant Racing, the upper monoball mounts are recommended for track only. At the very least I was thinking about using the rear upper mounts with monoballs, since they are subject to more weight, forces, and heat.

Also, since the car will be at RS +10mm, I will not need additional camber adjustment. ERP is adjustable and Elephant Racing appears it is not. I would like to "keep it simple".

So, for those who have experience with the monoball upper mounts and other bushings, what is your experience when driving on regular roads? Any other suggestions?



Thanks in advance.

Bill Verburg

You are building a street car, stick to street components, Porsche really got it right w/ the oe RS suspension(except maybe the shocks)
keep the rubber shock mounts, you could use the sealed oe RS or one of the aftermarket sets w/ seals but the gain will be minimal for your use and installing on PSSS is a PIA

Install RS or sport rubber bushes on front(both leading and trailing) and rear track arms(just the trailing) and rear KT and toe arm, be sure all the other bushes are nominal,

use oe M030 or RS sway bars and bushes

use 8 or 8.5 & 10 x18 tires 225-235 front 265-285 rear

JB 911

This is a great observation. On most of the items you mention my feeling is they make the car better on a smooth road, but worse on an ugly road.

It's a compromise. I havn't driven a car with the RS uprights but I think to do RS or RS+10 my guess is the ride is going to be a whole lot better than the stock uprights.

I have Pss9s at RS+10 set on 6 rear 7 front (where 9 is the softest) and on smooth roads it is divine. On bumpy /poor roads I can drive down them faster and safer in my pick up truck. It's a fine line. Have you considered the RS uprights? The few people who have them and post about them swear by them. I guess my thoughts are ROW sport height is really the best all round height for a car that will tour or see a variety of roads.

KaiB

Sorry, but...

Perhaps you should consider tracking the car in a few of the many DEs available in your area.

Safe, secure, fun and instructive. After a few, you'll no longer have the desire to drive hard on public roads. Indeed, after a few, you'll understand the folly of it.

Eurotrio

No, not considering RS uprights as the car will be above the RS ride hight.

I would consider RS rear upper mounts even thought it may be PIA, however there doesn't seem to be any consensus on how. I have seen threes guys setting RS in a differnt way and machining their own adapters too. Go figure.

Yes, already running wider wheels/tires.

What's the tremendous reason for M030 or RS sway bars vs. H&R? I have used H&R on so many cars before. Too stiff? Fit issue?

il pirata

I would add a few comments to what Bill has advised based on having done a full RS suspension with PSS10s.

I think you are going to get some bump steer even at RS+10, I did. You might want to consider the RS uprights, other than the upfront cost it gives you a lot of flexibility down the road. I am running at RS height with no issues.

Matching the RS camber plates to PSS10's is easy in the back, just add the Rennline top hat. The front however requires a custom bolt. A few of us have down this, documented in the forum, it's really just a cost issue.

My car is not tracked, strictly used in the mountains and occasionally it gets taken out to California. Having driven a number of other 993s with various suspension setups, Bill is right, the factory really got it right for street use other than the shocks (which of course at the time it was designed shocks such as the PSS10 did not exist).

Bill Verburg

RS or Rennline monoball rear mounts both incorporate seals and are easy enough to use, but if you go that route I'd want the same in front, I believe that Rennline now has a front kit compatible w/ the PSS shocks.

The H&R sways are just too big and aren't necessary even on a track car, The front will interfere w/ the vacuum booster(unless you have a C4 w/ electro-hyd boost), the booster can be shifted a tad but why bother, both M030 and RS are a perfect, the RS adds adjust-ability and can be made stiffer and looser than the stock or M030 sways.

Eurotrio

Hmmmm, will be going with stock upper mounts, Elephant Racing sport bushings.....and no H&r sway bars. Will see how that feels. Any suggestions about alignment specs with the corner balance?

Edward

What a spoiler! ...then again, I wholeheartedly agree

Dollars spent in serious suspension upgrades (anyone who mentions monoballs is tipping toward "serious" upgrade, IMHO) is better spent on DE/track time.
1. Far, far safer
2. Far more enjoyable
3. Far better learning and you will get faster, um, faster.
4. Any reasonably good suspension upgrade above the old/worn stockers is good enough to get you smiles ...not to mention make you a better driver.
5. Did I mention safer? ...um far safer?!!

Choose any of the myriad "steet" setups folks here have done (and I further agree that you should stick to rubber and avoid sphericles), is plenty "fast" for the street. Hotshoeing in canyons is only fun until something bad happens. Go hard at the track and you'd be surprised how relaxed (not to mention far more competant ...did I mention safer?) you are on the street. Just sayin...

Edward

il pirata

Find a shop that actually:

has done 993 alignments
has the KT tool
has the alignment chart below (pick the height of you car and follow factory specs for primarily street use)
asks what your weight is for the corner balance

otherwise forget it.

Eurotrio

Thanks for the alignment specs. Yes, planning an a corner balancing at a shop who is familiar with the cars and properly equipped including a kinematic tool. I shake my head at shops saying they have done plenty of 993s including track prep, yet did not own the tool.

Thanks again guys for providing good input. New upper rubber mounts and Elephant bushings ordered. Looking forward to the project and discovery of what else will be needed