Suspension Upgrade Opinions
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,917
Likes: 109
From: Crystal lake Il
2022 Corvette of the Year Winner -- Modified
2021 C4 of the Year - Modified Winner
Suspension Upgrade Opinions
Getting ready to replace the bushings on the rear suspension of my 91 ZR-1... looking for thoughts and recommendations for the car, already running coilovers and larger sway bars will likely use the car for autocross, and to some extent enhance a car that has some race history. Thoughts, overkill on these or worth the investment?
DRM trailing arm brackets vs after dark speed?
https://www.ebay.com/itm/30324971006...wAAOSw1YNgHH0r
-Solid Batwing Diff mounts?
-Strut Rod Camber Kits; After Dark vs Van Steek
https://www.ebay.com/itm/30367276971...kAAOSwCWRgHHpr
https://www.vansteel.com/index.cfm?f...p=1906&ID=2387
-Adjustable Bump Steer After Dark vs Vansteel
https://www.ebay.com/itm/30367276971...kAAOSwCWRgHHpr
https://www.vansteel.com/index.cfm?f...p=1906&ID=2624
DRM trailing arm brackets vs after dark speed?
https://www.ebay.com/itm/30324971006...wAAOSw1YNgHH0r
-Solid Batwing Diff mounts?
-Strut Rod Camber Kits; After Dark vs Van Steek
https://www.ebay.com/itm/30367276971...kAAOSwCWRgHHpr
https://www.vansteel.com/index.cfm?f...p=1906&ID=2387
-Adjustable Bump Steer After Dark vs Vansteel
https://www.ebay.com/itm/30367276971...kAAOSwCWRgHHpr
https://www.vansteel.com/index.cfm?f...p=1906&ID=2624
Race Director
Joined: Jun 2004
Posts: 13,962
Likes: 707
From: WI
I put solid poly batwing bushings last time I had it apart. The stock ones were starting to crumble, heat from racing I think though time as well. Going to heim joints in the rear suspension made a huge difference on my car, much better movement rather than binding. The toe rods were toast on mine but I just changed to a used late year C4 assembly and regreased it. It still had plastic cups which can be a problem racing. I'd like an a bump steer adjustable part there instead just haven't done it yet.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
Likes: 1,994
From: St. Charles MO
Whatever you do, don't use poly in the suspension link bushings (batwing is different - you can use poly there). Those DRM trailing arm brackets don't exactly do what people (or DRM) think they do, unless they've changed them from the ones I had. The After Dark ones seem pretty cool, but do you need them? Do you know what the different heights do? If not, then that adjustability is not very useful.
In the rear camber rods and trailing arms it's useful to have spherical rod ends precisely because you shouldn't use poly back there, and because stock rubber is no longer available. So don't use those Van Steel links - those are terrible. The SuperPro soft poly bushings are the only good alternative to sphericals. I'm sure the After Dark links are fine, and again if you don't know what the height adjustments do and how to test them, then that's a feature without a benefit. The later C4 geometry like yours is pretty good from the factory. Another brand to consider is Banski. They've been around a very long time and have tons of good info on their site (including the CAD drawings), and Tom Urban is super helpful with tech assistance if you need it. Spherical-ended, threaded camber rods are more important for the camber rods than the trailing arms because they eliminate the factory eccentric camber adjuster that is prone to slippage. Even if you keep the stock trailing arms or use Super Pro bushings in them, I recommend the rod-ended camber rods.
In the rear camber rods and trailing arms it's useful to have spherical rod ends precisely because you shouldn't use poly back there, and because stock rubber is no longer available. So don't use those Van Steel links - those are terrible. The SuperPro soft poly bushings are the only good alternative to sphericals. I'm sure the After Dark links are fine, and again if you don't know what the height adjustments do and how to test them, then that's a feature without a benefit. The later C4 geometry like yours is pretty good from the factory. Another brand to consider is Banski. They've been around a very long time and have tons of good info on their site (including the CAD drawings), and Tom Urban is super helpful with tech assistance if you need it. Spherical-ended, threaded camber rods are more important for the camber rods than the trailing arms because they eliminate the factory eccentric camber adjuster that is prone to slippage. Even if you keep the stock trailing arms or use Super Pro bushings in them, I recommend the rod-ended camber rods.
Thread Starter
Drifting
Joined: Feb 2000
Posts: 1,917
Likes: 109
From: Crystal lake Il
2022 Corvette of the Year Winner -- Modified
2021 C4 of the Year - Modified Winner
Not sure if you saw Banski is closing their doors 
Whatever you do, don't use poly in the suspension link bushings (batwing is different - you can use poly there). Those DRM trailing arm brackets don't exactly do what people (or DRM) think they do, unless they've changed them from the ones I had. The After Dark ones seem pretty cool, but do you need them? Do you know what the different heights do? If not, then that adjustability is not very useful.
In the rear camber rods and trailing arms it's useful to have spherical rod ends precisely because you shouldn't use poly back there, and because stock rubber is no longer available. So don't use those Van Steel links - those are terrible. The SuperPro soft poly bushings are the only good alternative to sphericals. I'm sure the After Dark links are fine, and again if you don't know what the height adjustments do and how to test them, then that's a feature without a benefit. The later C4 geometry like yours is pretty good from the factory. Another brand to consider is Banski. They've been around a very long time and have tons of good info on their site (including the CAD drawings), and Tom Urban is super helpful with tech assistance if you need it. Spherical-ended, threaded camber rods are more important for the camber rods than the trailing arms because they eliminate the factory eccentric camber adjuster that is prone to slippage. Even if you keep the stock trailing arms or use Super Pro bushings in them, I recommend the rod-ended camber rods.
In the rear camber rods and trailing arms it's useful to have spherical rod ends precisely because you shouldn't use poly back there, and because stock rubber is no longer available. So don't use those Van Steel links - those are terrible. The SuperPro soft poly bushings are the only good alternative to sphericals. I'm sure the After Dark links are fine, and again if you don't know what the height adjustments do and how to test them, then that's a feature without a benefit. The later C4 geometry like yours is pretty good from the factory. Another brand to consider is Banski. They've been around a very long time and have tons of good info on their site (including the CAD drawings), and Tom Urban is super helpful with tech assistance if you need it. Spherical-ended, threaded camber rods are more important for the camber rods than the trailing arms because they eliminate the factory eccentric camber adjuster that is prone to slippage. Even if you keep the stock trailing arms or use Super Pro bushings in them, I recommend the rod-ended camber rods.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
Likes: 1,994
From: St. Charles MO
I sure didn't. Now I see that, and unfortunately they are sold out of camber rods and trailing arms. So yeah, I'd look hard at that After Dark stuff. Ryan Mathews who started it is an accomplished autocross and track competitor in Corvettes. I also know from a good friend's experience with them that Ryan provides solid tech support/assistance.
