Control Arm Bushing Questions...

[RussMurco]

I've built a couple of 2nd gen and one 3rd gen Camaro and am preparing to build another 2nd gen Firebird but am hesitant on bushing choices.
On these cars I have tried several different poly bushings from a few manufacturers and ended-up going back to rubber each time. The harshness from the impacts was jarring and on the 3rd gen car I even had a suspension company's tech make sure they were installed and lubed properly to eliminate installation issues, they were spot-on. I have tried products from PST (graphite-lubed poly), Energy Suspension, and 2 other brands that escape me at the moment and each of them was a disappointment.
The car I am planning is going to have significantly enhanced handling but I have no expectation of chasing down the Pozzis, Steilows, Tuckers, or Finches on the track. This car will still be used on the street 99.5% of the time and I draw a fairly distinct line between race cars and street cars and what I will tolerate in each. I know a Pro-Touring car is, by definition, a car that blurs the lines but until we start hanging lights and plates from tube-frame cars I still consider them street cars.
I was looking at the late-model suspension bushings on these chassis kits many of you use, particularly the C6 stuff, and noticed that the later stuff used much smaller bushings that I am assuming are rubber. The 2nd & 3rd gen bushings were huge in comparison, do they need to be poly (or worse, solid) to achieve stability under high cornering load? My budget dictates I stay with a factory subframe and I've considered the Del-Alum bushings hoping that they would give slightly better articulation and with that a better ride from less binding but I see nothing that would minimize impact harshness. Am I looking at that from the wrong perspective? Is there a poly brand that wouldn't transmit so much harshness, or a higher-durometer rubber bushing available as an OEM-size replacement?

[Sieg]

Acetron GP / Delrin / Del Alum, then focus on spring rates and shock valving to soften the feedback?

Fresh rubber is good but as you noted the size equates to mount point deflection.

I prefer the feedback more rigid bushings deliver and can tolerate the negatives as it's not a daily driver. I never put these bushing on my Tundra truck though.

Maybe Speedtech or RideTech will chime in.

[RussMurco]

Originally Posted by Sieg

Acetron GP / Delrin / Del Alum, then focus on spring rates and shock valving to soften the feedback?

Fresh rubber is good but as you noted the size equates to mount point deflection.

I prefer the feedback more rigid bushings deliver and can tolerate the negatives as it's not a daily driver. I never put these bushing on my Tundra truck though.

Maybe Speedtech or RideTech will chime in.

Mine won't be a daily driver either, but I would like to take it on Power Tour and other road-trips and not be 2" shorter after the trip! lol
Perhaps someone makes a control-arm replacement set that uses smaller rubber bushings?
If I could get it to handle road imperfections like a late-model Camaro, CTS-V, or even a Corvette I'd be quite happy!

[marolf101x]

Ahhh, this is a great one. It's like a discussion I had with my college roommate about women. He says, "they're all crazy. . .you just have to determine how much crazy you can put up with!"

There are so many factors in play for ride quality it's difficult to list and deal with them all (bushing size, material durometer, spring rate, shock forces, etc)

In general:
Large rubber bushings will provide the best ride quality by absorbing the forces induced into the suspension from the road. However, this deflection also means your alignment settings will change when you push the car hard enough as the control arms will move a bit.

Smaller rubber bushings won't let the arms move as much, and will still provide decent isolation.

Poly bushings provide less isolation, but your settings don't change as much (and they tend to make noise if not properly serviced).

Delrin (or basically solid) bushings keep the arms where they should be, but transfer a lot more noise, and vibration into the car.

We, at Ridetech, are switching a lot of our performance applications over to a Delrin bushing we've developed. It's injection molded out of Delrin with Teflon added. This provides a self lubricating bushing that requires virtually no service while supplying the best possible handling solution you can live with.

They do transfer more forces into the vehicle, but in a performance car this is more or less considered "road feel" and is looked at as a good thing.

I've logged a bunch of miles on our 48 Hour Camaro; a ton on the highway, but we still drive it to lunch and around town quite often. It's easy to live with daily, and doesn't beat you up any worse than a "performance" spring rate.

[Blake Foster]

Originally Posted by Sieg

Acetron GP / Delrin / Del Alum, then focus on spring rates and shock valving to soften the feedback?


I prefer the feedback more rigid bushings deliver and can tolerate the n.

Maybe Speedtech or RideTech will chime in.

shocks and springs!
My Nova has NO body mounts subframe mounted directly to the floor.
Delrin Bushings EVERYWHERE.
really low profile tires built for auto X.
does it ride like a Cadillac............ NO it is harsh over certain bumps but i will tell you putting the Ridetech tripple adjustables made a huge differance to the sharp quick bumps.

[carbuff]

Originally Posted by marolf101x

We, at Ridetech, are switching a lot of our performance applications over to a Delrin bushing we've developed. It's injection molded out of Delrin with Teflon added. This provides a self lubricating bushing that requires virtually no service while supplying the best possible handling solution you can live with.

Can you expand on this a little bit? Will these be offered for someone who would like to retrofit them to an existing arm/link? If so, what are the dimensions of the bushings you are making? In searching the internet, I haven't found any that are less than about 1 3/4". If someone knows of any which are built like a heim replacement, I would love to know about them!

[RussMurco]

To add to what I experienced with my other builds, I think another contributing factor to impact harshness was chassis flex on the 2nd gen cars.
The 1989 Camaro chassis impacts seemed to be abated once I installed Spohn subframe connectors and a strut-tower brace. When it was new I had Monroe GP shocks, then KYB GR-2's, and the best ride it had was with Bilstiens combined with the chassis reinforcement. I also switched from the IROC 16" wheels to a 17x9's, using the same brand of tire, and it was better still. I'm assuming that it was the additional volume of air in the tire acting to quell some of the bumps.
My new 1970 Firebird project will have subframe connectors welded-in, downbars with a firewall reinforcement plate, seam welding, and possibly a 4-point cage. I'm hoping that will give me enough structural strength to allow the suspension itself to do all of the ride control, that is why I'm so focused on bushing compliance. Based on the input here perhaps I need to focus more on shock valving, I had planned on using the Bilstein products again.

[preston]

Your dilemna is not new and in fact I think there is room for a product in this hobby that uses an optimized rubber bushing, preferably something like the threaded rod ends and Spohn/Jonny joints that can be used universally. OEM rubber bushings have come a long way since the 70's and the rubber can be tailored for specific durometers. However, nothing like that seems to be available now unless you are willing to somehow adapt an OEM which would be a expensive custom machining project as well as its pretty difficult to obtain the bushings as they get destroyed in most cases trying to remove them.

Howe racing does sell a threaded rubber bushing, but it is very large (3/4" through bolt and probably 2.5" in diameter) and heavy.
there is a lot of rubber in it but it seems to be of a pretty heavy durometer.

Another thing to think about is shock mounting - is you are OEM its probably okay but anyone not using OEM mounting is usually relegated to the 1/2" spherical bearings. A LOT of NVH comes through those. Some more universal aftermarket adapters that incorporated isolation might be nice. I used some AFCO poly bushings to replace the sphericals in my aftermarket coil overs but they are still pretty harsh

[Sieg]

Russ - My experience with Bilstien's is they almost have a magic valve stack that delivers a plush ride in the initial stroke then the valving ramps up nicely the harder they're pushed. It's been a while since I've used a set though.

Most people never experience really good shock valving because the good stuff is expensive and the really good stuff is substantially more. But once you do experience it you're spoiled for life.

Coming from a motorcycle background it is common place to tailor valving to match terrain conditions. The big race teams do the same with their cars. Telemetry and/or good notes allows them to tailor valves and shim stacks to every track with bias to aide extreme corners or G-out sections.

It's hard to obtain one size fits all valving for a smooth interstate travel and good auto-x or road course performance. RideTech or similar 3-way adjustable's would probably be your best bet. They'll allow you to access and adjust hi/low compression and rebound dampening over a relatively wide range with minimal effort.