Rear suspension bushing choices/thoughts

[nickelplated5s]

It all depends on what you want. I've driven Pete's car and vice versa. Two different cars. Mine has some ER poly front and rear with ER rubber too. Unfortunately my MFI pump isn't back yet so haven't driven with the newly redone rear. Day to day go Pete's route. Mines more of a track car but have to say I'm happy with it. Noise? Even with sound pads bushing noise is irrelevant

[H-viken]

Originally Posted by nickelplated5s

It all depends on what you want. I've driven Pete's car and vice versa. Two different cars. Mine has some ER poly front and rear with ER rubber too. Unfortunately my MFI pump isn't back yet so haven't driven with the newly redone rear. Day to day go Pete's route. Mines more of a track car but have to say I'm happy with it. Noise? Even with sound pads bushing noise is irrelevant

I have a set of rear Rebel Racing bushes on the shelf but on the fence whether to use them or rubber on my new spring plates.

NVP is not a big concern, car is pretty loud. Ride quality and performance is though

[nickelplated5s]

Tell us what you want. Pete, HarryD or BillV, with math, will chime in. I watched both P & H's cars at our PCA AX last weekend. Similar times, different drivers obviously. Other than gearing for that course I would beat them hands down. On the other hand both those cars would be more fun for a trip.

Now you have to think about brakes. Go over to Early911S and search about those.

[PeteKz]

Originally Posted by H-viken

Pete, have you experienced any performance gains?

Johan

No handling gain that I can quantify on the street or AX course. If I had racing tires on it and drive it on a high speed road track, I might be able to detect a handling difference. With street tires, no.

If NVH isn't a concern to you, then my objections to it don't matter.

[LukasM]

Originally Posted by PeteKz

Circling back to this thread: After having the RSR hard bushings in my car for the past 2 years, I wish I had stayed with rubber. The increase in NVH is annoying to me, because this is a street car, that I only occasionally autocross.

Thanks for the feedback Pete, it's not easy to admit that a mod was not a good use of your hard earned money.

Are you referring to front and rear, or just the rears? I remember reading that you had an easy time installing the fronts and then later did the rears, which were a PITA.

Cheers,
Lukas

[PeteKz]

I’ve tried a lot of things that weren’t a good use of my money!

The rears were a much bigger PITA, and contribute most to the increase in noise, but I recommend you stick to rubber at both the front and rear. On a street car, you will be happier.

[snbush67]

I am still super happy with the rebel racing bushings, I feel that the preciseness of the bushings communicates grip to the driver and helps to feel what the suspension is doing to include weight transfer. I haven’t experienced any additional NVH. I do have a very Ianesque compliant suspension set up, 21/24 TB’s, 18/20 Sway bars, Koni classics adjusted to full soft, 15 inch Fuchs wheels with mini van tires.

[PeteKz]

The tires have a lot to do with the perceived NVH. See what I run below. As they say, YMMV. My suspension also is set soft, as Ian recommends. Even though I have 21/26 Tbars, I have my Konis set full soft for the street.

[Jeff Alton]

We have tried a lot of different options over the years. If it is street car, stick with Rubber, from your chosen manufacturer. All of the spring pate and A-arm solutions offered seem to make noise, require maintenance etc, can how wear, which really (for us) seems not worth it for a street car. We have run everything from stock to full 935 style options on street cars and everything in between...

Cheers

[85RedCarrera]

I am also weighing which bushings to use front & rear (leaning towards all HD rubber), and one thing I rarely hear discussed is that rubber bushings increase the force required to move a suspension arm, compared to metal or poly bushings. Going to non-rubber bushings must ultimately reduce the spring rate and necessitate a change in damping, as well?

My concern is that if I change to a slicker bearing, I'll have to increase my torsion bar sizes to compensate for that loss in spring rate... and that my present shocks/struts will also no longer be appropriate.

At first glance, it seems that making these suspension changes is an all-or-nothing endeavor (change the dampers, bars, bushings, or keep it stock)?

[Bill Verburg]

Originally Posted by 85RedCarrera

I am also weighing which bushings to use front & rear (leaning towards all HD rubber), and one thing I rarely hear discussed is that rubber bushings increase the force required to move a suspension arm, compared to metal or poly bushings. Going to non-rubber bushings must ultimately reduce the spring rate and necessitate a change in damping, as well?

My concern is that if I change to a slicker bearing, I'll have to increase my torsion bar sizes to compensate for that loss in spring rate... and that my present shocks/struts will also no longer be appropriate.

At first glance, it seems that making these suspension changes is an all-or-nothing endeavor (change the dampers, bars, bushings, or keep it stock)?

It5's called stiction and it's not really a problem. yes a mono-ball and has close to zero stiction and rubber the most w/the others somewhere in between, but none are an issue wrt to damping and setup

at the edge a full mono-ball is the most precise and yet is still street able, the regular rubber is the least precise but most of us aren't at 10/10 even on a track day so it's not really that big an issue.

The maintenance hassles of poly bronze and urethane far outweigh any reduction in stiction or increase in precision, more so in street use.

The best all round bush set I've ever used is hd rubber, that includes on my personal cars 4 different 993 setups and 3 different 911 setups

[85RedCarrera]

Originally Posted by Bill Verburg

It5's called stiction and it's not really a problem. yes a mono-ball and has close to zero stiction and rubber the most w/the others somewhere in between, but none are an issue wrt to damping and setup

at the edge a full mono-ball is the most precise and yet is still street able, the regular rubber is the least precise but most of us aren't at 10/10 even on a track day so it's not really that big an issue.

The maintenance hassles of poly bronze and urethane far outweigh any reduction in stiction or increase in precision, more so in street use.

The best all round bush set I've ever used is hd rubber, that includes on my personal cars 4 different 993 setups and 3 different 911 setups

Thanks for your input, Bill- I'm feeling more confident about going with the HD rubber now.

[nickelplated5s]

Bushings are just part of the package. If you're not upgrading anything else for any reason stay stock.

[PeteKz]

Dave, rubber bushings do not have stiction. They actually twist in deformation, thus no sticking friction that slips loose. Polyurethane bushings are well known for stiction, because they do rotate, and make the various sounds people describe.

Rubber bushings do have hysteresis, but let’s not get into that now.

[85RedCarrera]

Originally Posted by PeteKz

Dave, rubber bushings do not have stiction. They actually twist in deformation, thus no sticking friction that slips loose. Polyurethane bushings are well known for stiction, because they do rotate, and make the various sounds people describe.

Rubber bushings do have hysteresis, but let’s not get into that now.

Stiction- I am familiar with, as I set up my own suspension on my motorcycle. Hysteresis (thank you) is the proper word, I believe, for what I was trying to describe- the twisting deformation of a bonded rubber bushing.

My understanding is that in the broadest, most general sense, any component that will increase the force that is required to move a suspension component through its envelope of travel, where the force required increases as travel increases, essentially becomes a spring, and is not a damper. Exceptions do exist, such as dampers that increase compression damping close to the limit of travel.

Yes, let’s not get into it! I’m sticking with rubber (pun intended).

nickelplated5s- exactly.

[nickelplated5s]

Here I was thinking Pete meant hysterical

FWIW the SwayAway's we pulled had delrin interior and rubber exterior. The rubber was ovalized hence the change. Al wanted ER plates and it was more or less a wash cost wise as I would have replated the old. I did get a chance to drive with the Von2's before this. Major difference but one of the old Bil's was starting to fail. Pete's is fun to drive so I'm sure you'll be happy. The two cars are apples and oranges though.