I think we've discussed this before via emails, but since we have a bunch of new owners with perhaps some varied experience I thought I'd post it again...My experience with autocrossing my Lister over the past year has led me to envy the competitors with adjustable shocks on their cars. The lot where we typically hold our local events is bumpy and getting increasingly so over time. Last weekend I was pitted next to a friend with a late-model ('94) C4 'Vette running QA1 double-adjustable shocks, and watched him changing the settings after each run until he was happy with the car's response over the bumps. I would love to have the ability to do the same, but I'm not sure there is an adjustable shock option out there for those of us with Beck cars that have early C4 suspension pieces.Any thoughts, or suggestions?
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Alan Blair > Bob BrzezinskiOctober 26, 2008 at 11:07pm
The lower rear shock mount on our cars as well as the early C4's are larger than .500" id unfortunately. More like 16mm or 5/8". You could have the stud machined down to .500" relatively cheaply but if you do coil overs that may not be strong enough. A lot of folks with the C4's use the stock stud with coilovers with no problems. Typically they have coilovers with normal 5/8" bushings instead of .500" spherical bearings. Check out http://www.ndneyes.com/mo/coil.html . You may also want to see if they offer a larger spherical bearing on the QA1 and just swap it out, on my Koni's I have not asked but it really does not appear to have much room to go larger. This week I will test out 2 mounting options for the rears. First is Grade 8 1/2" x 5" lower bolts with 5/8" x 1/2" bushings to make the bolts fit the holes in the knuckles. I know this will mount up and hold the car while it is stationary but I will be a bit nervous on the test drive due to the leverage on those long bolts. For the second option I also ordered weld on coil over shock mounts that I intend to bolt on to the knuckle with a 5/8" grade 8 bolt. This bolt will be thicker and much shorter so it will be less stressed and the coil over mounts to it in double shear on a 1/2" bolt that runs perpendicular. I may need a spacer of some sort if the mount does not clear everything and I may want to make a bracket to the lower dogbone bolt to keep it from rotating since it will only be held by that other single bolt. For the upper mount I will try a similar arrangement. Just hope I get these mounts in time to work on them before Sunday. I will share photos of both setups.
Sorry if I made you doubt the QA1's, that was not really my intent. A lot of folks have great luck with them and they are very reasonable. Eric also pointed me to Proshocks for an inexpensive alternative and the nice thing is they can be mounted upside down to lower unsprung weight. A lot of real racecars use these shocks but I dont recall if they are adjustable or not.
The issue raised by the QA1 tech guy about the .500" bearing relates to the front shocks. I note that you reference the rear shocks in your post above. Do you have any idea about the diameter of the fronts? I hoped to find time to investigate it this weekend but I was so busy with other things that I never even got out to the garage.
Bob
It has been a "while" since I ran Solo I & Solo II, but suspension adjustment is absolutely critical especially with low weight / high horsepower vehicles. It would seem that you need to tap into Julian Mann's experience as his Lister has had considerable development in both suspension & aero mods. I was just speaking to a friend who return from the Nationals in Topeka, and he has considerable experience with race suspension set-up, and that was a key focus during that event.
Thanks for the reply. That's a good suggestion, and I will try emailing Julian. I fear his solution will involve "cubic dollars", whereas I'm simply looking for a reasonably-priced shock upgrade, but I'd like to visit with him either way. I wish he still participated in our discussions.
The Lister as built by Chuck is an inherently forgiving car, at least in my autocross experience, but I would love the ability to "dial out" certain handling characteristics as needed. In several events this summer, as the day got hotter the driving surface went from cool (moderate grip) to warm (good grip) to scorching (no grip). It would be nice to be able to control the oversteer that increases as the pavement temperature also goes up.
Alan Blair > Bob BrzezinskiOctober 23, 2008 at 1:33am
Bob,
I recently asked Julian the same thing and he told me that he had his car suspension done by RobiSPEC (www.RobiSPEC.com) 760-912-4337. I am not sure that he knows all the intimate details or not since I asked some specific questions and he just directed me to them. It may be apples and oranges since his car is highly developed and the aero elements that he uses change the entire suspension equation significantly.
Bob Seigel has adjustable coil overs front and rear on his car, he is using Strange Engineering 5004 double adjustable units and had some custom mounts done by a local shop (Kennedy Race Cars). I recently had some Koni 8212 adjustable coil over shocks made for the rear of my car (not inexpensive) but need something done with the shock mounts. The ones that came on the Beck cars are a bit questionable for the increased loading since they were not really designed to handle coilovers, especially under racing conditions. I have been looking in earnest to come up with an off the shelf solution but so far they are not panning out very well. I did find some lower mounts recently but need to get more details on exactly how they change the coilover position to make sure that they will clear everything. Once I get this figured out I will let everyone know.
Now if you want to retain the monoleaf and just have adjustable rear shocks then that should be very doable without changing the mounts. In fact you should be able to mount up the QA1's with no problems. I believe that the model numbers appropriate for early C4 Vettes are 4855 and 5855 depending on your suspension specs. Simplest thing to do is to select the shock that replicates the extended and collapsed measurements of your existing shocks and if they are not exactly the same just make sure that you select the unit that provides the most compression so the shock will not bottom out. I really have no personal experience with the QA1's but just remember that they are a budget shock and depending on how hard you are on them they may not hold up as long. I got a lot of this info on the Corvette Forum over the last couple of months so if you want to spend some time there it may give you some additional details.
Replies
Sorry if I made you doubt the QA1's, that was not really my intent. A lot of folks have great luck with them and they are very reasonable. Eric also pointed me to Proshocks for an inexpensive alternative and the nice thing is they can be mounted upside down to lower unsprung weight. A lot of real racecars use these shocks but I dont recall if they are adjustable or not.
The issue raised by the QA1 tech guy about the .500" bearing relates to the front shocks. I note that you reference the rear shocks in your post above. Do you have any idea about the diameter of the fronts? I hoped to find time to investigate it this weekend but I was so busy with other things that I never even got out to the garage.
It has been a "while" since I ran Solo I & Solo II, but suspension adjustment is absolutely critical especially with low weight / high horsepower vehicles. It would seem that you need to tap into Julian Mann's experience as his Lister has had considerable development in both suspension & aero mods. I was just speaking to a friend who return from the Nationals in Topeka, and he has considerable experience with race suspension set-up, and that was a key focus during that event.
Thanks for the reply. That's a good suggestion, and I will try emailing Julian. I fear his solution will involve "cubic dollars", whereas I'm simply looking for a reasonably-priced shock upgrade, but I'd like to visit with him either way. I wish he still participated in our discussions.
The Lister as built by Chuck is an inherently forgiving car, at least in my autocross experience, but I would love the ability to "dial out" certain handling characteristics as needed. In several events this summer, as the day got hotter the driving surface went from cool (moderate grip) to warm (good grip) to scorching (no grip). It would be nice to be able to control the oversteer that increases as the pavement temperature also goes up.
I recently asked Julian the same thing and he told me that he had his car suspension done by RobiSPEC (www.RobiSPEC.com) 760-912-4337. I am not sure that he knows all the intimate details or not since I asked some specific questions and he just directed me to them. It may be apples and oranges since his car is highly developed and the aero elements that he uses change the entire suspension equation significantly.
Bob Seigel has adjustable coil overs front and rear on his car, he is using Strange Engineering 5004 double adjustable units and had some custom mounts done by a local shop (Kennedy Race Cars). I recently had some Koni 8212 adjustable coil over shocks made for the rear of my car (not inexpensive) but need something done with the shock mounts. The ones that came on the Beck cars are a bit questionable for the increased loading since they were not really designed to handle coilovers, especially under racing conditions. I have been looking in earnest to come up with an off the shelf solution but so far they are not panning out very well. I did find some lower mounts recently but need to get more details on exactly how they change the coilover position to make sure that they will clear everything. Once I get this figured out I will let everyone know.
Now if you want to retain the monoleaf and just have adjustable rear shocks then that should be very doable without changing the mounts. In fact you should be able to mount up the QA1's with no problems. I believe that the model numbers appropriate for early C4 Vettes are 4855 and 5855 depending on your suspension specs. Simplest thing to do is to select the shock that replicates the extended and collapsed measurements of your existing shocks and if they are not exactly the same just make sure that you select the unit that provides the most compression so the shock will not bottom out. I really have no personal experience with the QA1's but just remember that they are a budget shock and depending on how hard you are on them they may not hold up as long. I got a lot of this info on the Corvette Forum over the last couple of months so if you want to spend some time there it may give you some additional details.
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