To coil over or not to coil over v.A-body front suspension

ilikemtb999

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So I currently have a rear QA1 coil over kit on my Buick. I recently bought matching set of single adjustable qa1 shocks. Turns out they don’t fit thru the control arm without some modification. Now I’m wondering if instead of welding up holes, grinding shit and redrilling if I should just get a set of their hybrid coil overs.

Control arm pic:


I already have hotchkis 500 lb/in front lowering springs and planned on tall lower ball joints to lower the front end another 1/2”

After lots of reading, some people claim the hybrid coil over design can/does induce binding and side loading of the shock which can lead to premature shock wear. Flip side is so many articles and shows have been installing these on A-bodies for years now.

Coil over design in question
 

cap42

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Personally I would think if the rears are coilovers having a matching front would provide a better suspension.

I would have no hesitation modifying the stock A-arms, it boils down to the cost of buying aftermarket arms vs your time/labor to modify the stockers. I'm cheap so I always lean towards the modification.
 

ilikemtb999

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All I’d be gaining is the ability to height adjust. I have the same shocks as the coil overs have (just not threaded) and I’d be getting the same 500lb spring rate with the coil overs.


The metal between the shock mounting holes and access hole are so thin I think I’d have to weld and re drill (unless I hogged out the hole in one side or the other from the shock holes.
 

Bub

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Honestly with your plans to keep this car forever, spend the money on the a arm. It looks stronger and it will fit better.
 

EmersonHart13

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daturbosix

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modify your stock arms to fit and keep it a regular spring/shock setup.

i have that QA1 hybrid on my GN, and its stiff as fuck. great for a race car, but not a cruiser.
 

ilikemtb999

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modify your stock arms to fit and keep it a regular spring/shock setup.

i have that QA1 hybrid on my GN, and its stiff as fuck. great for a race car, but not a cruiser.
They’ve got a bunch of spring rates available. Do you know which ones you have up front?
 

Smokinhot

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Yea, thanks to old threads I was going through (thus why I was bumping shit) I will be keeping my factory style a-arms spring and shock setup. But obviously go with decent stuff.
 

ilikemtb999

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Yea, thanks to old threads I was going through (thus why I was bumping shit) I will be keeping my factory style a-arms spring and shock setup. But obviously go with decent stuff.
I’ve currently got SPC upper arms with tall ball joints, hotchkis 1” lowering springs and those qa1 single adjustable shocks.


Oh also I put 4th gen f body brakes on all around with minimal effort.
 

Smokinhot

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I’ve currently got SPC upper arms with tall ball joints, hotchkis 1” lowering springs and those qa1 single adjustable shocks.


Oh also I put 4th gen f body brakes on all around with minimal effort.
That's something I'll also be doing. So much to do
 

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I had QA1 on my 71. Ride quality is so subjective, what I might find acceptable may not suit the next guy. They were way too stiff for typical cruising. On the expressway, it wasn't as bad, but I didn't care for the ride with how I used the car 99% of the time. They seemed to make the car act like an old truck that handled slightly better than it did from the factory.

I did switch to Ridetech level 2 later and it was night and day. It took some adjusting, but it was a much better riding and handling car. You may need to trim the 'fingers' inside the pocket where the spring goes on the frame to avoid contact.
 

ilikemtb999

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I had QA1 on my 71. Ride quality is so subjective, what I might find acceptable may not suit the next guy. They were way too stiff for typical cruising. On the expressway, it wasn't as bad, but I didn't care for the ride with how I used the car 99% of the time. They seemed to make the car act like an old truck that handled slightly better than it did from the factory.

I did switch to Ridetech level 2 later and it was night and day. It took some adjusting, but it was a much better riding and handling car. You may need to trim the 'fingers' inside the pocket where the spring goes on the frame to avoid contact.
Do you recall what spring rate you had?
 

greasy

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I did not go coil overs on my car because I was operating within a budget. Since you already have rear coil overs I would think adding fronts to the equation would balance out and make the suspension perform better. I have no technical data to back this up......other than the fact that having 2 different suspension styles in the front and back would fuck with my sanity too much hahaha!
 

ilikemtb999

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Sorry...I don't. IMO they were too high of a rate. A lighter spring may have made a world of difference.
Spring rates have been a mind fuck for me since everything is geared towards chevelles with either a bbc or sbc. Would help if I had the ability to corner weight my car but I don’t.
 

Unitsn4

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Spring rates have been a mind fuck for me since everything is geared towards chevelles with either a bbc or sbc. Would help if I had the ability to corner weight my car but I don’t.
The scales are so expensive. Nayle at S & S Chassis has them. There's a lot involved in setting the car up to properly weigh it to get an idea what rate to start with.

They all must be absolutely level in respect to one another and the floor. Once you have the springs in, you'd want to weigh it again and ensure the car is set up perfectly level. You have to imagine the car is a flat sheet of steel resting on points representing the tires at ride height. If one spring has slightly more preload than its mate across from it, it'll cause an imbalance in weight transfer. For example, the right rear has more preload than the left rear. This will cause the car to sit just slightly higher at the left front and lower at the right front. For just a cruiser, you may never notice or care. If I remember right, Black Dog Speed shop used to corner balance a car and align it. I'm not sure if they still do this. That's the other key....a very good alignment. That's very hard to find around here. At least on the south side by me.
 

Unitsn4

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If you feel like it...send Ron Sutton a message to see if he can recommend one thing over another based on how you are going to use your car. He's probably one of the most knowledgeable people you will ever deal with as far as proper suspension set up and tuning. He's super busy, but if you talk to him, you'll see he's very methodical on his advice.
 

Intel

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Spring rates have been a mind fuck for me since everything is geared towards chevelles with either a bbc or sbc. Would help if I had the ability to corner weight my car but I don’t.
To be up front I know next to nothing about these types of cars suspension.

I have mostly done spring rate type stuff for mac/strut type cars for tracking them.

Usually if you have the corner weights + motion ratio you can figure out what spring is needed to give a certain frequency. For racing cars this is much higher than say a street cruiser.

So it really depends what you are looking for. Also depends on how big of the swaybars are. One theory is to run softer springs and stiffer sways while others run stiffer springs and stock/light sways bars. It really depends what you are after for the car.
 

Mr_Roboto

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Spring rates have been a mind fuck for me since everything is geared towards chevelles with either a bbc or sbc. Would help if I had the ability to corner weight my car but I don’t.
You're running a BBB which is a few pounds heavier than an SBC. I would go with the SBC rates or a bit heavier personally. Certainly more so than the BBC rates. If you're into harsher ride you may consider Pontiac Lemans/GTO recommendations because they're in between an SBC and BBC. Get an aluminum intake for your stuff and you'd be right where a stock iron intaked SBC would be. The big advantage you get doing coil overs is that you can interchange spring rates with a high level of granularity. For just the shock I would be pretty comfortable cutting and welding new stuff in place, I don't know if I'd trust my welding skills to doing where the spring rests tbh.
 

ilikemtb999

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You're running a BBB which is a few pounds heavier than an SBC. I would go with the SBC rates or a bit heavier personally. Certainly more so than the BBC rates. If you're into harsher ride you may consider Pontiac Lemans/GTO recommendations because they're in between an SBC and BBC. Get an aluminum intake for your stuff and you'd be right where a stock iron intaked SBC would be. The big advantage you get doing coil overs is that you can interchange spring rates with a high level of granularity. For just the shock I would be pretty comfortable cutting and welding new stuff in place, I don't know if I'd trust my welding skills to doing where the spring rests tbh.
I’ve got an aluminum intake, long tubes and no AC so already on the lighter side of things. Maybe I’ll check on the performance years site. The springs I currently have up front are for a sbc chevelle and are 500 lb/in but I haven’t driven on them.
 

ilikemtb999

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To be up front I know next to nothing about these types of cars suspension.

I have mostly done spring rate type stuff for mac/strut type cars for tracking them.

Usually if you have the corner weights + motion ratio you can figure out what spring is needed to give a certain frequency. For racing cars this is much higher than say a street cruiser.

So it really depends what you are looking for. Also depends on how big of the swaybars are. One theory is to run softer springs and stiffer sways while others run stiffer springs and stock/light sways bars. It really depends what you are after for the car.
I went with fairly large sway bars. I’m not afraid of a rough ride if it’s planted in turns. Really just looking for a fun canyon carver since there are so many good roads here.
 

ilikemtb999

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The scales are so expensive. Nayle at S & S Chassis has them. There's a lot involved in setting the car up to properly weigh it to get an idea what rate to start with.

They all must be absolutely level in respect to one another and the floor. Once you have the springs in, you'd want to weigh it again and ensure the car is set up perfectly level. You have to imagine the car is a flat sheet of steel resting on points representing the tires at ride height. If one spring has slightly more preload than its mate across from it, it'll cause an imbalance in weight transfer. For example, the right rear has more preload than the left rear. This will cause the car to sit just slightly higher at the left front and lower at the right front. For just a cruiser, you may never notice or care. If I remember right, Black Dog Speed shop used to corner balance a car and align it. I'm not sure if they still do this. That's the other key....a very good alignment. That's very hard to find around here. At least on the south side by me.
I’m in Denver which while is the home of rust free classics, really doesn’t have much for performance shops. I’ve got my own tools for alignments too.
 

Mr_Roboto

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With the weight reduction you have I'd totally give that a shot before I made any sort of changes. If anything you may find out it 1-rides a bit high and 2-You can trim a half coil to a coil to both firm the springs up and lower it a bit. That said, watch out for angle of the tie rods as they can hit on the front end. It's one of the big compromises GM made with the suspension on these cars.

Also, thread on alignment stuff. Always wanted to dabble never did such.
 

ilikemtb999

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I’m nervous to go down any lower up front due to how far the LT’s hang down. I could use a new set and I’ve read the TA performance ones tuck up much better.

I’ve seen a tie rod “fix” kit by umi. Never really looked too hard at it but guessing it addresses that? I’ll take a look
 

Mr_Roboto

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It probably relocates the tie rods. It's really an issue if you start dropping via springs instead of dropping via other methods such as taller ball joints. That's one of the reasons they recommend going that route I think, it's a win in a few ways.
 

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