front lower control arm bushings
10-25-2011, 05:45 PM
#16
Coming on two years with Walrod bushings and I've never had any squeaking or noise. Can't comment on harshness or vibration though since my car has pss10s which add nvh themselves.
10-25-2011, 07:19 PM
#19
Three Wheelin'
Bill - I should have known I would get busted by you. You are right, best is a relative term and needs context. How about (IMO) best for street driving and AX with the occasional track day. I thought the OE's were not firm enough and I cannot feel a difference between the Walrod and the RS even on the track. Which is why I recommend the Walrod over the others and the price is right. I did not nor has anyone else mentioned monoballs, but I would only recommend these if it is a track car. Again, my 2 cents. Now, what do you prefer/recommend since that is the OP's question?
10-25-2011, 07:22 PM
#20
Pro
Hi
Like I said I have used polybushes fairly extensively. From a performance point of view they are inferior to the Porsche standard, Porsche RS or Elephant Racing standard /sport part for the 993. I know people have had positive experiences with the various urethane types and yes they are better than a worn standard part. And yes they are much easier to fit. The standard ones can be quite difficult because of the shape of the arms.
Berni
Like I said I have used polybushes fairly extensively. From a performance point of view they are inferior to the Porsche standard, Porsche RS or Elephant Racing standard /sport part for the 993. I know people have had positive experiences with the various urethane types and yes they are better than a worn standard part. And yes they are much easier to fit. The standard ones can be quite difficult because of the shape of the arms.
Berni
10-25-2011, 07:51 PM
#21
Bill - I should have known I would get busted by you. You are right, best is a relative term and needs context. How about (IMO) best for street driving and AX with the occasional track day. I thought the OE's were not firm enough and I cannot feel a difference between the Walrod and the RS even on the track. Which is why I recommend the Walrod over the others and the price is right. I did not nor has anyone else mentioned monoballs, but I would only recommend these if it is a track car. Again, my 2 cents. Now, what do you prefer/recommend since that is the OP's question?
1) rubber - in either sport or stock stiffness and further differentiated by setting up like a stock RS w/ softer fronts and stiffer rears or using full still in both leading and trailing position. The factory chose rubber for several good reasons. They are maintainance free and have a long service life, the stiffer versions are very appropriate for track use
2) poly-urethane -these are stiffer than any rubber version, transmit more NVH than any rubber version when new and properly lubed they work great, the issue is maintaining the lubed state which reduces noise and wear, but if they go dry they make noise and wear at an accelerated rate. They are the cheapest solution.
3)spherical joints- these are the ultimate in stiffness and also NVH and will have the shortest service life and highest cost. They introduce the least stiction.
arguably and disregarding price, for street use, rubber is the most appropriate, for track use, spherical joints are the most appropriate, p/u is somewhere in the middle but is probably least expensive, at least in the short term
the other consideration is that the front suspension is not working in a vacuum, the rear suspension needs to be taken into consideration as well as the wheels and tires. You want to put together a complete package designed to optimize what you have for it's intended use.
I think we all agree that a stock 993 has way too much sloppy rubber in it's suspension for performance use, the only question is how much to replace and what to replace it w/. We are all conducting our own individual science experiments w/ our cars and reporting the results in these threads.
10-25-2011, 08:27 PM
#22
Rennlist Member
I had a look Berni and they certainly look more OEM in form and fit, plus you get a choice of Sport or Stock hardness rubber.
So who all makes control arm bushings for the 993 besides those listed?
So who all makes control arm bushings for the 993 besides those listed?
10-25-2011, 10:45 PM
#23
Racer
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Interesting,
the rubber bushes are bonded to the metal surfers, and only twist, not move against the metal sleves/control arms
and the poly bushes are friction fit with grease and twist against the metal sleves and control arms
Once the grease is pushed out, would they not squeak after some time?
Just asking the question considering how both options work
the rubber bushes are bonded to the metal surfers, and only twist, not move against the metal sleves/control arms
and the poly bushes are friction fit with grease and twist against the metal sleves and control arms
Once the grease is pushed out, would they not squeak after some time?
Just asking the question considering how both options work
10-25-2011, 11:35 PM
#24
I had a look Berni and they certainly look more OEM in form and fit, plus you get a choice of Sport or Stock hardness rubber.
So who all makes control arm bushings for the 993 besides those listed?
So who all makes control arm bushings for the 993 besides those listed?
Rennline has monoball but only for the trailing position of the front A arm they do not have leading position listed in their on line catalog
Shark Motorsports has an extremely nice monoball kit
I suspect that the Elephant Racing rubber ones are from the oem supplier that Geolab mentions here
10-26-2011, 12:00 AM
#25
Rennlist Member
^^^ Thanks Bill, as usual, a vault of information.
You're right, those Shark units look first class. I take it they would be overkill for my street use. But they are within 25 miles of where I stay every year (near Hockenheim), so I plan to visit them next summer. BTW, another stop will be Freisinger Motorsports in Karlsruhe (down the road)...they have some very interesting Porsches.
Bill, the price list on the Shark Motorsport site lists those units "im tausch". That means "in exchange". I take it they mean the whole control arm. At that price, I would think so.
If you have seen the Elephant Racing units, am I correct in thinking they are basically what is factory installed in the 993.
You're right, those Shark units look first class. I take it they would be overkill for my street use. But they are within 25 miles of where I stay every year (near Hockenheim), so I plan to visit them next summer. BTW, another stop will be Freisinger Motorsports in Karlsruhe (down the road)...they have some very interesting Porsches.
Bill, the price list on the Shark Motorsport site lists those units "im tausch". That means "in exchange". I take it they mean the whole control arm. At that price, I would think so.
If you have seen the Elephant Racing units, am I correct in thinking they are basically what is factory installed in the 993.
10-26-2011, 01:11 AM
#26
Rennlist Member
I was just talking to Carey Eisenlore of ERP at Rennsport.
If I understood him correctly (lots of track noise complicated communication):
1) He will supply different bearings in his kits if the customer wants to pay more for say New Hampshire Ball Bearing http://www.nhbb.com/products/spherical-bearings.aspx
2) He uses American size bearings because he can get a slightly larger bearing in some assemblies than he can with metric sizes.
If I understood him correctly (lots of track noise complicated communication):
1) He will supply different bearings in his kits if the customer wants to pay more for say New Hampshire Ball Bearing http://www.nhbb.com/products/spherical-bearings.aspx
2) He uses American size bearings because he can get a slightly larger bearing in some assemblies than he can with metric sizes.
10-26-2011, 04:12 AM
#28
Pro
Hi There
I have had both the ER and standard front bushings in my hands and the ER ones look identical in design to the standard ones. The standard and ER ones have cut outs in them and fit in a particular orientation. If you run your car outside of the standard/sport height you are supposed to index them so at rest they are not twisted. For the same reason the rear of the car also must have all its weight on the wheels when you do up the arms.
As has been said in posts already, if a polybush runs dry, or road grit gets inside it it will wear at a high rate.
I thought the purpose of the cut outs of the standard type rubber bush is to allow some movement in that plane under hard braking and thereby change the geometry of the front suspension in that circumstance. That was the primary reason I personally went through the effort of using a standard type rubber bush.
Berni
I have had both the ER and standard front bushings in my hands and the ER ones look identical in design to the standard ones. The standard and ER ones have cut outs in them and fit in a particular orientation. If you run your car outside of the standard/sport height you are supposed to index them so at rest they are not twisted. For the same reason the rear of the car also must have all its weight on the wheels when you do up the arms.
As has been said in posts already, if a polybush runs dry, or road grit gets inside it it will wear at a high rate.
I thought the purpose of the cut outs of the standard type rubber bush is to allow some movement in that plane under hard braking and thereby change the geometry of the front suspension in that circumstance. That was the primary reason I personally went through the effort of using a standard type rubber bush.
Berni
10-26-2011, 07:22 AM
#29
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Fitted Walrod bushes to my car. Have not had a squeek yet. the improvement over the old bushes is phenomenal and the car (C4S) feels much more planted. The old bushes were a real PITA to remove.
