Rear Lower Shock Bushing Options
 

Wanted to get some thoughts on rear lower shock bushings on the Z06. Stock has those pressed in rubber bushings, nice for ride, general use. I autocross my Z06 in a stock class, so I can change out shocks (koni sports), and various bushings in mounting the shocks (top and bottom). I have the Delrin upper mounts from Stranoparts (like them), nice design. The rear lowers I have tried the Afe spherical bearing bushings, which I feel work really well for the performance purpose, but find them quite noisy on the road. I guess what it comes down to is I drive the car on the street more than I autocross it, so the annoying noise began to bother me.

Anybody have any other suggestions, options in this bushing? Polyurethane is possible, or I could look into a hard rubber compound bushing, but axial play allowed by the spherical bushings seem to be a good performance feature. I'm trying to get a bit of each, and not terribly hard rubber (stock) seems to be the compromise.

I'm going to play around in my garage with some ideas, but wanted to get a conversation going if possible. These cars have been rolling around for over a decade, so hoped others may have pursued this thought already. Understand, not for the average street driven car, mostly for the occasional racer type, autocrosser. Hard core racers would have gone already to the coilovers or the spherical bearing lower mount designs.

Thanks for any feedback!

The only other option I ran across in my research was a Delrin replacement that AMT makes. Not sure if they sell it separate though. I'd give them a call and see.

If you're interested in selling your AFE's, please let me know. I'm about to purchase a new set to replace my stock rubber mounts.

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Thanks for the reply! One thing I miss owning the Z06 vs. some other cars is the large amount of forum technical discussion regarding suspension mods for racing/autocross activities. Maybe I just haven't found the venue yet, but having autocrossed for 20+ years, in SP and SM classes, kind of used to fabricating and designing stuff. Not always successful, but part of the enjoyment of the sport.

Anyway, some updates. My AFe lower bushings are shot. Not so much from use, although they were fairly noisy, but from me removing them from the control arm. They were a snug, slide fit into the control arm, then solidified into place (to minimize noise and movement within the arm hole) with the green sealant stuff. That is awesome stuff. Any noise I heard was from the bearing, not from the aluminum cylinder body moving in the arm. Just tapping on the AFe body or middle sleeve pieces did nothing. Heating up the area with a propane torch supposedly should help, I ended up using a punch and sledge hammer. AFe is mangled. See pics.
Lots of play now in the bearing.

Have you ventured over to the autocross/road racing subforum here? https://www.corvetteforum.com/forums...roadracing-23/

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I came up with an idea to use Ridetech poly bushings, and metal sleeve, cut, shortened, poly bushings shaped. Inserted into the control arm hole, such that there will be some axial (?) play in the middle sleeve position (similar to the AFe), yet avoid noise, and still be firmer than rubber. Of course, there is not the amount of axial movement nor the ease of movement of the AFe unit, but this was my compromised. Most of the bushing contact is in the center sleeve area, the sides are smaller diameter than the ID of the control arm mounting hole. There is enough give in the poly that the lower shock mounting can pivot slightly (as described in other threads). More movement than Delrin would allow, not as much as AFe, probably firmer in a vertical direction than rubber. I lubed and place two of the Ridetech bushings onto a slightly shortened metal sleeve (Ridetech). Sleeve cut to length to fit within the lower shock spacing. Bushings were placed onto sleeve with wider collars in the center, then I reduced the O.D. of that area to match the I.D. of the arm hole. Pressed onto the arm with long bolt, nut, assortment of washers, fittings. A few Delrin washers on the ends of the sleeves so the koni shock doesn't rub against the aluminum arm, if the bushing sleeve moves. Some pics:

Yes, I have.

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The ugly finished product.
Tested on the street, freeway, one autocross event. Feels solid, much quieter. Will continue to test under better track conditions.
To be clear, I think for pure performance, the AFe is way to go. I just couldn't live with the noise of the bearing. Yes, the cars are not exactly limo quiet anyway, but loose, knocking noises really upset my focus.
Knowing there are numerous suppliers of poly bushings, and the metal sleeve is fairly basic, I am comfortable knowing I can always install a simple poly bushing and get by. I guess last resort would be just ordering a new lower control arm. Not my way though, rather create and modify.

Hope to have more positive info later. Not bad for $40 worth of parts.

https://www.corvetteforum.com/forums...acement-2.html

Above thread is a bit old but lots of good information! Also why I tried making my own.

Nice work. Interested to hear if the poly holds up for you and doesn't squeak.

Thanks! No squeeks so far, but I did lube the metal sleeve to bushing contact surface. The Ridetech bushings have small grooves on the inner of the bushings, so hope grease is effective for a while. Certainly would not do something like this if it were a coilover type setup, holding up the weight of the car too. Being it is just weight changes of the shock load, hoping it holds up. I can widen the center contact area of the bushing if needed, but that would likely decrease the sleeves ability to pivot as much as it does now. The parts are relatively cheap, and the modding and install are very simple. There is always a version 2.0 though!

fyi, if you go with the AFe units, read up and check out whatever install videos available. What I can offer, after installing 2 sets, is to make sure the inner surface of the control arm is not only widened to accommodate the slightly too large AFe cylinder body, but also well polished, so they slide into the control arm smoothly. Mine were a snug fit by hand, then with the green sealant it was totally locked in. Probably only 3-4 spots of sealant needed on the body, I coated mine. I used too much. Not sure if the AFe units are intended to be removed reasonably easy, but mine were very difficult. They work great though, no knocks there.

I bet if someone swapped them on your car with stock rubber without you knowing there would be no difference in your times.

Haha! I'm not taking that bet! You could probably mount day old donuts on my rear wheels and my times wouldn't change much too! :auto:

Thing is, as with I'm guessing most autocrossers, the mods we make on our cars usually will far exceed our capabilities as drivers. Sure, there are the elite drivers, and I know a bunch of them, that can get every bit of advantage from those $5k shocks, superlite $6k wheels, $10k standalone and dyno tuning. But yet, we still do the mods. The aftermarket needs us :flag:

I didn't drive to the potential of the AFe bearing mounts, but the noise bothered me. I removed them. I could not replace them with factory rubber bushings. Didn't want to buy 2 new lower control arms to get the rubber bushings. Went into my therapy garage and made $40 press in bushings that seem to be working fine, for now.

Just sharing the experience.