jon L Posted November 11, 2019 Share Posted November 11, 2019 (edited) I have put together a set of stock shocks and a set of adjustable coilover springs for the rear. 500lb each side. Opinion: Should I be able to remove the center spring without any problems? What say you.? They are adjustable. Edited November 11, 2019 by jon L Link to comment Share on other sites More sharing options...
2seater Posted November 11, 2019 Share Posted November 11, 2019 Interesting idea. I believe from a mechanical standpoint, the cross mounted spring only supplies downward pressure and does nothing for location, so I would believe that would work. The upper mount for the shock is free standing, and not attached to the body, so the only item of concern would be if it is rusted or weakened but I am pretty sure that isn't an issue with your car? Link to comment Share on other sites More sharing options...
Ronnie Posted November 11, 2019 Share Posted November 11, 2019 1 hour ago, jon L said: I have put together a set of stock shocks and a set of adjustable coilover springs for the rear. 500lb each side. It's hard to answer your question about removing the spring without seeing the coilovers and how they will be attached. Are they shocks or struts? There is a big difference. They both serve the purpose of dampening the movement of the control arm up and down. However, unlike conventional shocks, struts are clamped tightly into the knuckle (or whatever you want to call it) on a Reatta and are an integral part of the rear suspension geometry. They are what keeps the rear hub vertically aligned as the control arm moves up and down. If you look at the photo below you can see that part 6 (the knuckle) pivots on one large bolt on the end of the control arm. Without a strut clamped tightly in the knuckle and anchored by the rod at the top, the knuckle would just flop over when you put weight on the wheel. Struts are built a lot more heavy duty and they have a larger diameter rod in order to withstand the stress of keeping the knuckle aligned. Link to comment Share on other sites More sharing options...
jon L Posted November 11, 2019 Topic Author Share Posted November 11, 2019 (edited) They are stock shocks and do clamp into the knuckle and attach at the top. I don''t see how this will not work, but I'm open to any ideas. The air shocks I was going to use will not work. Edited November 11, 2019 by jon L Link to comment Share on other sites More sharing options...
2seater Posted November 12, 2019 Share Posted November 12, 2019 I guess I made the assumption they would be the same configuration as stock but should never ASSume. I do have the air assist style rears also but I wouldn't trust them to suspend the rear by themselves. There isn't a ton of clearance inside that connection at the top for a spring but that should be able to be worked out. Link to comment Share on other sites More sharing options...
jon L Posted November 12, 2019 Topic Author Share Posted November 12, 2019 I think 500 lbs per side should do it. The springs are 3.5 in od 2.5 id. I think that will fit. Link to comment Share on other sites More sharing options...
Ronnie Posted November 12, 2019 Share Posted November 12, 2019 From what you're saying it sounds like they should work. Sorry about giving a lecture on rear struts in my last post. Sometimes I get carried away. Link to comment Share on other sites More sharing options...
jon L Posted November 12, 2019 Topic Author Share Posted November 12, 2019 (edited) Ronnie, That's fine. I wanted some input on that subject. I was wellcome. Well, I got the springs today and it measures up to clear everything. What I'm wondering now is you think 500 lbs per side is to strong? Maybe 375 would be better? Edited November 12, 2019 by jon L Link to comment Share on other sites More sharing options...
Ronnie Posted November 12, 2019 Share Posted November 12, 2019 Anything I could say would only be a guess. You are going into uncharted water as far as I know. Here is what Barney said about Reatta weight in a post he made on the other forum. If that is correct 500 lb springs per side on the rear should put you in the ballpark. That's assuming you plan to remove the stock spring. Quote From an early spec sheet released with the 1988 press information........ Curb weight = 3350 Front = 2241 Rear = 1104 67/33 front/rear Link to comment Share on other sites More sharing options...
jon L Posted November 12, 2019 Topic Author Share Posted November 12, 2019 Thanks, Ronnie. I'm going to try it. It seems the only way to lower the rear end. It will give me adjustment for height I want. Anybody want pics of it? (If it works) Link to comment Share on other sites More sharing options...
2seater Posted November 12, 2019 Share Posted November 12, 2019 Is the 500# the total capacity of the spring or is that a rate per inch at which it deflects? I think the weights given above sound about right so allowing for a few hundred pounds of load capacity, it would allow the spring to be set lower without bottoming. I guess I would try what you have and see how you like it. I suspect it will be stiffer than stock but needs to be at a lower ride height. Pics of the progress are always welcome. Link to comment Share on other sites More sharing options...
Ronnie Posted November 12, 2019 Share Posted November 12, 2019 Would love to see some photos of the finished product as well as the steps you have to take to install the shocks. That's what I like about you Jon... You're not afraid to try something new. Link to comment Share on other sites More sharing options...
jon L Posted November 13, 2019 Topic Author Share Posted November 13, 2019 twoseater: they are coilovers and they are adjustable for ride height. Link to comment Share on other sites More sharing options...
jon L Posted December 17, 2019 Topic Author Share Posted December 17, 2019 Here is what I have so far. I cut 4 of the brackets from 888 aircraft 3/16" aluminum plate. I cut the stock shock off at the mounting bracket. They ar mounted with stainless steel shoulder bolts. Front bolt holes are 1/2". Rear are 3/8" I have not drilled the holes for the shock yet, because I have not ordered them. Fab Quest will custom make any combination shock and combine them with any coil over. I can order a stock Gm upper mounting and a eyelet bottom mounting in almost any size. I have not ordered them because the cost is a little beyond my pocket book as of now. With this set up they recommend 300# springs. (up to 3500 lbs) Second to last photo is an assembled unit. hat I have so far. Link to comment Share on other sites More sharing options...
2seater Posted December 17, 2019 Share Posted December 17, 2019 I like the fab work Jon but I must confess I am a little unclear on how the rest of the conversion goes together? Link to comment Share on other sites More sharing options...
jon L Posted December 17, 2019 Topic Author Share Posted December 17, 2019 Stock top mount. Standard GM 5/8" shaft, Same as we have. Bottom mount is an eyelet mount, 1/2" bolt thru the top of the brackets. Which I stated that I have not drilled yet due to my decision on the shock length. Link to comment Share on other sites More sharing options...
Ronnie Posted December 17, 2019 Share Posted December 17, 2019 Will the coilover springs be carrying the weight of the rear of the car or will they just be assisting the stock spring? Link to comment Share on other sites More sharing options...
jon L Posted December 17, 2019 Topic Author Share Posted December 17, 2019 They will be carrying the weight of the rear. I will remove the spring. It is the only way to lower the rear. The coil overs will be adjustable as will the shocks. The choice is, springs up to 3500 lbs or over 3500 lbs. Link to comment Share on other sites More sharing options...
2seater Posted December 17, 2019 Share Posted December 17, 2019 1 hour ago, jon L said: Stock top mount. Standard GM 5/8" shaft, Same as we have. Bottom mount is an eyelet mount, 1/2" bolt thru the top of the brackets. Which I stated that I have not drilled yet due to my decision on the shock length. Okay, got it. It is mounted like a conventional stud mounted shock at the bottom. I know coilovers are used in all sorts of suspension designs but I have often wondered if the bushings used in the shocks are solid or stiffer material than a common shock absorber which doesn't carry weight? Link to comment Share on other sites More sharing options...
Ronnie Posted December 19, 2019 Share Posted December 19, 2019 I have been thinking about you installing the coilover shocks on your car. Below are my thoughts about what you are attempting to do. They are in no way intended to be critical of what you are trying to do. I admire you for your efforts in trying to figure out a way to replace the stock spring and lower the rear of a Reatta. As far as I know that is something that hasn't been accomplished before. I think you may be headed in the right direction but I have some concerns about the brackets you have fabricated being able to hold the knuckle rigid enough to prevent it from getting out of alignment. Rear wheel alignment depends on the strut holding the knuckle perfectly in position as the wheel moves up and down. The aluminum brackets you made should transfer the weight of the car directly on the area where you sawed off the old strut (red arrow) and not onto the mounting brackets for the sway bar. Otherwise, I don't believe the area I marked with the yellow line will be able to support the weight of the car without bending when the car hits large bumps like a large speed breaker or a large pothole. Even though the weight of the car on each bracket may be around 500 pounds as we discussed before, the force on those brackets when you hit a large bump will be increased tremendously. I also have concerns about the ability of your aluminum brackets and/or the area marked with the yellow line being able to withstand the twisting forces put on them by the knuckle (and wheel) trying to pivot inward when you hit a large bump. Also by the nature of the eye of the shock clamped between the aluminum plates being able to rotate, I have concerns about what rotational forces might be placed on the bolt and bushings that hold the knuckle to the control arm when you apply the brakes really hard. Normally the rigidity of the original struts helps control that rotational force and prevents all of it from being transferred to the control arm. When I look at the sawed off strut in the photo below, I wonder if it would be possible to get a coilover shock that had the body of the bottom half with the eye the right size so that it would fit snugly inside the part in the photo. It could be held in place with a bolt inserted through a hole drilled in the approximate location of where I have marked with a white circle going through the eye of the shock? That would eliminate the need for your aluminum brackets and it should allow the coilover shock to work more like the original strut did to control the knuckle's movement. I know this may be thinking outside the box (and it may sound a little stupid) but as an old machinist who has had to modify a lot of parts over the years that is what I tend to do. ? Keep us posted on the progress you are making on your project Link to comment Share on other sites More sharing options...
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