Coilover Recommendations

[dhutton]

Bumpstops would only help if the rear bottomed out.
Do you feel it bottomed out?

I honestly don’t know. What I should have done is stuck some silly putty on the shock to see if it was. That was the problem, I never really figured out what exactly was happening. Whatever was happening was a pretty significant impact. As I said others have described the exact same phenomenon.

At one point I was speculating it was due to a high amount of preload and the spring was firing off due to inadequate rebound damping but I was never able to resolve it adjusting the rebound damping.

Sorry I just never figured it out.

Don

[cpd004]

In my case, I would describe the jar as an impact. Talking extreme like your example above:
the road is smooth, and the car meets a 2" ridge.

The ridge isn't soaked up, but rather the impact of the meeting is transmitted throughout the car.

For background my car is set up this way right now.

1971 Firebird (ls3)
FRONT:
Speedtech Extreme running 10" 400 Hyperco springs and the secret sauce valved single adjustable ridetech shocks.
The springs are wound nearly to the top of the shock body at current ride height.
275 35 18" tire usually running 34 PSI. IMO the wheels are quite heavy.
--Speedtech recommends 8" 450.

These coilovers and springs are what I had from the previous suspension and decided to try them to save a few dollars. One shock lost its gas charge at some point and was rebuilt. At the time I sent both in but I don't believe the other had anything done to it other running on ridetech's shock dyno.

What exactly would the 2" additional spring height and 50lb increased spring rate do?

Rear:
Speedtech Torque Arm w/secret sauce valved shocks and 12" 225lb Hyperco springs.
Speedtech recommends 10" 250.
275 40 18" tire @34 PSI usually.

Same deal here. It's what I had on hand decided to try.

I don't recall the settings off the top of my head but can certainly recount them if it helps.

Blackdog Speedshop did the alignment once upon a time, but this was pre-this current setup. It definitely needs to be done again.

Solid body mounts.

The car doesn't ride terrible by any means. The TA setup made a big difference vs the older version of Ridetech's 4 link that was in the car. I'm likely at a higher ride height than most would run. My neighborhood seems like the speedbump capital of the world with more being added constantly. Terrible roads as well.

If I would go with Speedtechs recommendations on spring rates, they also recommend a ride height which would likely be lower than I'm willing to go.

Donny did the torque arm setup.

Brit, your comment where you say it'll take time and testing but is absolutely achievable reminded me of the ride with Donny when I picked it up. I asked his thoughts on the current spring/shock setup and if he thought a change was necessary. Yes, no, maybe so was his answer and that seems right on the money.

The thing I would like to get rid of is that cringe feeling when the road ahead isn't looking too good. That's it.
It's not terrible by any means. Some part or setting isn't quite right.

[CSG]

I would start with figuring out what the shock compression is doing at that moment. Go out to a known harsh bump, smear some grease on the shock shaft and run over the bump, then pull over and see how much stroke you used.

[marolf101x]

To test shock travel I like to just put a small zip tie around the shock shaft.
push it down to the shock body, then drive the car.

I'll get into impact harshness ASAP. Been swamped with SEMA coming up.

[CSG]

Damn, I never thought of using a zip tie. When I have them apart I put o rings on the shaft for the same purpose. Using a go pro to film the shock in use may be helpful as well if you have one

[marolf101x]

Ride quality is simply the measurement of how much the passenger moves, or what the passenger feels inside the vehicle. . .what forces are transmitted to the person.

Ride quality is also subjective, with each person having a slightly different expectation of what it should be.



Let's look at a couple of typical scenarios while driving the vehicle and explain what is happening and what is responsible for ride quality (or lack thereof). . .

Slow undulations and road irregularities:

The suspension should dissipate the slow undulations in the road via the wheel moving up and down while the cabin does not move (this is called SkyHook suspension theory).

This is done mostly with shock/spring force and travel. Enough travel provides enough time to slow the wheel/tire before it transmits into the vehicle.



Sharp "ledges" or transitions:

If the spring rate is not terribly stiff the. . .the tire, shock and bushings are mainly responsible for quick but short events (cracks in the pavement, bridge expansion joints, etc). This movement is very low, maybe only 1/4", but the speed is high, maybe 1M/second (32 inches/second).

Did the tire soak up some of the force, or is it a very short, stiff sidewall?

What's the shock graph look like? If it has a ton of low speed force it'll feel much more "rough" than a shock that has low force in low speed and slowly ramps up in force as speed increases.

Were the bushings "soft" with a lot of movement so they could slow down and neutralize the motion, or were they stiff and transferred that motion into the solid structure of the vehicle?



All that being said, the things that make good ride quality hurt performance; and high-performance hurts ride quality.

[cpd004]

Never knew lubing adjusters was a thing. Maybe it's more of a JRI thing?

Stielow mentions it here:

https://lateral-g.net/forums/showpos...2&postcount=87

Also, not gauging what he means by 'OK ride'.

I've certainly never done it nor see an apparent way with Ridetechs.

On a suggestion, I played around with the firmness and the initial impact is all but gone despite having 2" taller and 50 lb lighter springs in front. Quite happy with the result.

I feel the rear springs being 2" taller and 25 lbs lighter may not be allowing them to have enough preload at the height I'm running. Either a rear (passenger side) shock is bad or the spring is moving around when the suspension gets to full extension back there.

Nothing else seems apparent that may be loose.

If I can get this figured out and an alignment (again) I'll be good for now.

OP...sorry this may have gotten away from your question. I had Qa1 very long ago and never liked the ride. Always too harsh and 'slow' IMO. I have ridetech now and it is worlds better than those were.
Of course Qa1 now has MOD shocks. I don't know of anyone running them that has commented on them here or over at Lat-g. See if a local shop may have something you can go for a ride in. Donny isn't terribly far from me.

[CSG]

Typically you just spray the threaded body with an aerosol lubricant.

[icemanrd19]

my ridetech rear coilovers felt the same. Road transition it feel like I almost hit a small pothole. I switched to jri but then raised my rear coilover pocket. The ride was 100x better. The stroke was slightly shorter with the ridetechs vs my jri coilovers on my quadralink.

Can you comment on the harsh bang that occurs when driving over an abrupt drop in the road? This is the jarring that a lot of folks complain about with ridetech four link setups. I was never able to eliminate it with shock adjustments.

Don

[dhutton]

my ridetech rear coilovers felt the same. Road transition it feel like I almost hit a small pothole. I switched to jri but then raised my rear coilover pocket. The ride was 100x better. The stroke was slightly shorter with the ridetechs vs my jri coilovers on my quadralink.

Same spring rate in both cases?



Don

[icemanrd19]

yes. Both 250lb hypercoil. I eventually switched to a 325lb and the ride is still better than the old ridetech with 250lbs

Same spring rate in both cases?

Don

[pannetron]

+1 on JRi. Sourced mine from Detroit Speed.

[PDC]

Just discovered this thread - as I was about to start a thread with the exact same title: Coil Over Recommendation. I am coming from stock 2nd Gen suspensions and upgrades like the Hotchkis TVS kit. This is my first car with a Q-Link and coil overs and I m learning as I go.

Car is a 1973 TA with an LS9 and a T-56 - if that helps ‘estimate’ weight? I’m guessing this car is in the 3400-3600 lb range? The LS definitely shaved some weight off the nose as compared to an iron-headed pontiac 400/455. T-56 isn’t far off from the weight of a TH400.

Car has DSE front subframe and Rear Q-Link with mini-tubs. Prior owner said the shocks and springs are the ones that came in the complete kits from DSE. For as long as I have had this car, I have thought it rode unpleasantly harsh over the slightest road irregularities. Cpd004 - my experience matches your description of ride quality to the T. I also would be happy to raise the ride height 1” or so. The stance looks incredible, but catches most speed bumps around here.

Took her to a local shop and they pulled the shocks and found out that they were completely empty. FWIW - these shocks are nitrogen filled, which the guys at the shop indicated aren’t really for street driving. They filled them and left them on the bench overnight and they held pressure, the were so re-reinstalled. Ride was obviously noticeably better than before, but still can be pretty unforgiving.

For my purposes, I definitely would be glad to give up some handling capabilities for ride comfort. This is a street driven, fair weather cruiser, I do not drive the car competitively.

Right now, I am just looking to see what the typical range is for spring rate / length / and shock travel. Like I said, this is all new to me and I am trying to learn as I go along. Thank you all!

[cpd004]

Are they JRI? Also, what springs and rates do you currently have?

I believe it’s a bit involved to recharge the shock. When mine were redone by Ridtech a dyne sheet accompanied them on the way back. I’d guess they did some testing that would likely be more than just an overnight leak test.

For you JRI guys, does having to use a tool to adjust instead of having a knob seem like a pain?

[marolf101x]

PDC:
"Took her to a local shop and they pulled the shocks and found out that they were completely empty. FWIW - these shocks are nitrogen filled, which the guys at the shop indicated aren’t really for street driving."
I would completely disagree with this statement. Each year the OE's kick out millions of cars with nitrogen charged shocks. The main difference is that they are not easily adjustable (no Schrader valve or rubber pellet system).

Extremely low nitrogen pressure will result in a "non-repeatable" shock. The nitrogen (in a monotube shock with the gas and oil separated by a dividing piston) is used to provide pressure against the oil column. This pressure is intended to keep the oil column "solid" so no air bubbles form when the shock piston is traveling through the oil column. A shock tuner can change the nitrogen pressure to fine tune the shock. Typically you want the least amount of pressure that keeps the oil column solid.
As the shock compresses the volume of the shock shaft must be offset (if it's not, the shock blows up due to hydraulic lock). So as the shaft is pushed into the shock, the oil column increases by the amount of the shock shaft volume, pushing the dividing piston down, and further compressing the nitrogen.
Higher nitrogen pressures make it more difficult to push the shaft in.


"Right now, I am just looking to see what the typical range is for spring rate / length / and shock travel."
You can look this up on this site as I've covered it a number of times, but it's always worth repeating.
You typically want a minimum of 5 inches of WHEEL travel to properly soak up the normal bumps you see during normal street driving. 3 inches should be available for compression, 2 inches for extension (you are hitting bumps and pushing the wheel up into the wheel well more often than you are jumping the car and letting the wheel hang from the vehicle.
Motion ratio is the correlation between how far the shock/spring moves compared to the wheel. Every car on this forum has some motion ratio. . .typically around 2:1. So if the wheel moves a total of 5 inches, the shock moves only 2.5 inches.
I don't care if the shock has 10" of shaft showing, it only moves 2.5 inches in the case above.
The closer the lower shock mount is to the lower ball joint, the better the motion ratio, and the more effective the shock/spring can be.


"For my purposes, I definitely would be glad to give up some handling capabilities for ride comfort"
Well, this might be easier said than done, depending on what you feel is acceptable ride quality.
Pro touring cars are designed and built to handle. Handling requires removing all flex from the suspension joints, and shocks/springs that react as quickly as possible.
After thinking about this and re-reading many threads where we've discussed this before, the latter may be where most people are having difficulty.

In a pro-touring car the higher end shocks are providing very strong forces at very low shaft speeds. For example, if you compress the shock and the shock shaft is moving at 0.5 inches/second, it might be pushing back with 700lbs force. . .(depending on the shock and how it's built, it could be providing nearly no force, or a metric crap ton of force, it all depends.)

So, my theory was always to use a linear valve stack on compression, with as little force as we could get at low shaft speeds. As the shaft speed increases, so does the force. Small undulations, not much force coming from the shock. . .hit an expansion joint, the shaft probably moved at 12-20 inches per second and provided 400-600lbs of force (but you need that force to help the spring slow down the wheel/tire before it smacks the compression stops.)
I liked a lot of rebound force at slow shaft speeds. . .let the shock compress, soak up the bump, then do most of the control on the extension side. Increases performance at a minimal cost to ride quality.


The way to increase ride quality is to soak up the bumps before the force is transmitted into the driver cabin.
The ways to increase ride quality:
-"softer" shocks
-light spring rates (or progressive springs)
-more suspension travel
-larger profile tires
-large rubber bushings at all joints
-anything that makes the cabin quieter
-better seats

[Rod]

kinda a fun engineery thread....
but it is still an everyone's is best thread, I have JRI so its best, I have ridetech so its best, I have QA1 so its best....

[marolf101x]

Rod, do you have Dyno sheets for JRI and/or QA1 and/or Viking?
I’ll put up some ridetech ones and we can discuss what does what.
We’re both out of ridetech now, so we can be as unbiased as we can be.

[PDC]

Thank you very much for that reply. I know most if not all of that info exists on these threads and can be found with the search function - but sometimes some of the best info comes up spontaneously in a slightly unrelated thread that one might not know to comb through in order to find. Your reply really helped a lot.

Yesterday was 55* and sunny and the streets were bone dry, so I took the car out for a drive and tried to just experience it with a ‘blank slate.’ I was able to really appreciate how much better this car rides than when all 4 shocks were literally empty. Joints in the pavement that used to hit hard felt firm - but definitely ‘cushioned’ And I can feel the suspension moving over the non-jarring rises and falls in the road in a way that it didn't before.

I may see about raising the front about 1” this spring before cruise season, but I think I am making peace with the ride quality. It was just so harsh for so long, that I think that’s all I tend to ‘remember’ when I think about driving the car and the fact if the matter is, it’s leagues better now.

[Rod]

Rod, do you have Dyno sheets for JRI and/or QA1 and/or Viking?
I’ll put up some ridetech ones and we can discuss what does what.
We’re both out of ridetech now, so we can be as unbiased as we can be.

I will get Viking dyno up...

[TheJDMan]

Just discovered this thread - as I was about to start a thread with the exact same title: Coil Over Recommendation. I am coming from stock 2nd Gen suspensions and upgrades like the Hotchkis TVS kit. This is my first car with a Q-Link and coil overs and I m learning as I go.
Car is a 1973 TA with an LS9 and a T-56 - if that helps ‘estimate’ weight? I’m guessing this car is in the 3400-3600 lb range? The LS definitely shaved some weight off the nose as compared to an iron-headed pontiac 400/455. T-56 isn’t far off from the weight of a TH400.
Car has DSE front subframe and Rear Q-Link with mini-tubs. Prior owner said the shocks and springs are the ones that came in the complete kits from DSE. For as long as I have had this car, I have thought it rode unpleasantly harsh over the slightest road irregularities. Cpd004 - my experience matches your description of ride quality to the T. I also would be happy to raise the ride height 1” or so. The stance looks incredible, but catches most speed bumps around here
Took her to a local shop and they pulled the shocks and found out that they were completely empty. FWIW - these shocks are nitrogen filled, which the guys at the shop indicated aren’t really for street driving. They filled them and left them on the bench overnight and they held pressure, the were so re-reinstalled. Ride was obviously noticeably better than before, but still can be pretty unforgiving.
For my purposes, I definitely would be glad to give up some handling capabilities for ride comfort. This is a street driven, fair weather cruiser, I do not drive the car competitively.
Right now, I am just looking to see what the typical range is for spring rate / length / and shock travel. Like I said, this is all new to me and I am trying to learn as I go along. Thank you all!

Just to give you some specific info, I'm also running a DSE subframe and a 4 link rear suspension. I have AFCO 4" stroke coil overs all around with 800# springs up front and 350# springs in the rear. In the past I ran much softer springs but was not happy with the way the car felt at high speed. After some discussion with Rod, I upped the spring rates dramatically to where they are today. Surprisingly, the higher spring rates still give a good quality ride on the street with the shock compression backed off a few clicks.