Coilover Recommendations

[Bryshere355]

Building a 68 Chevelle that has it's front and rear chassis/suspension modified to use coilovers.

Front suspension needs a 15.5 long shock at ride height, .56 motion ratio, 15* angle
Rear suspension needs a 14.0 long shock at ride height, 5* angle

I have looked at many different coilover manufacturers but I not sure which one to choose. Can anyone give me any input on which shocks they chose and why?

QA1 / Viking
Strange Engineering
VariShock
Afco / Pro Shocks
JRi

[NorCal-SS]

I went with Viking Warriors on my 67 Chevelle. Really happy with the fit and finish and their tech support is very helpful. Unfortunately I don’t have any road time on them yet, but I’ve only heard good things from those that do. The double adjustable shock is a nice feature at their price point.

[StevieBB54]

I bought the QA1 for my 68 Camaro, Tech support is awesome, quality is all there. But Im waiting until winter to install along with control arms

[dontlifttoshift]

The first 3 are all twin tubes. I'm not a fan.

Afco makes a lot of stuff and their Pro Touring elite are okay. Maybe pro shocks are a lot better than they were but it doesn't look they operate in this market.

If you aren't scared by the price of JRIs they are the best shocks on your list. By a lot.

Not sure if RideTech was omitted on purpose or not, hands down best value for your money.

[CSG]

I agree with Donny.
QA1 is known for blowing out
I have had Viking on a street only car and they did fine but no experience pushing them.
Had Strange as well, imo it’s more drag oriented
Afco does well with their circle track stuff haven’t really seen them used much for other stuff
JRI is a good option without costing a ton
Ride tech is really good for the cost
Then there are the expensive options…

[dhutton]

I have had Ridetech monotube, Varishocks, Strange and JRI. Like Donny says, JRI were the best by a wide margin in my experience.

Don

[tmcmillan5]

I have a 68 Chevelle as well with all custom shock mounts. I am running Vari single adj. coilovers with uethane Eye ends top & bottom. Front motion ratio is at .667 w/400# springs rear 200#. Both shock have the 5.15" travel with the way I have it set up.
This is a lowered convertible car with an LS2 auto conversion and I drive it hard so I can say I like the firmnees and the way it handles even without any sway bars Though I had hoped it would have been a bit less jaring over rough spots on the road.
This industry has changed alot over the course of my build so now you have more to chose from for less money. Sounds like good advice above.

Tony

[icemanrd19]

Jri tuned by jj at ultimate performance

[cpd004]

I was at a cruise night recently and bumped into a guy who had a Chevelle with everything Ridetech front and back. I didn't get specifics. Initially he was happy with the improvement in handling but the thing that he couldn't get rid of was the 'jar' at some road imperfections. On a recommendation, he tried Swift springs in place of the Hyperco but kept the Ridetech spec'd single adjustable shocks. He claims the ride was immediately better and jarring gone. He said the way it was explained to him was the more consistent spring rate through its travel allowed the shock more time to do its job.

I have no idea if any of this seems plausible, but these were his observations on his own car. I have Ridetech and I do have the jarring he mentions. I had Viking way back and did not care for them at all.

[dhutton]

I was at a cruise night recently and bumped into a guy who had a Chevelle with everything Ridetech front and back. I didn't get specifics. Initially he was happy with the improvement in handling but the thing that he couldn't get rid of was the 'jar' at some road imperfections. On a recommendation, he tried Swift springs in place of the Hyperco but kept the Ridetech spec'd single adjustable shocks. He claims the ride was immediately better and jarring gone. He said the way it was explained to him was the more consistent spring rate through its travel allowed the shock more time to do its job.

I have no idea if any of this seems plausible, but these were his observations on his own car. I have Ridetech and I do have the jarring he mentions. I had Viking way back and did not care for them at all.

Interesting. I wouldn’t have guessed springs would solve the Ridetech jarring. Especially in light of how proud Ridetech is of their Hyperco springs.

Don

[cpd004]

Interesting. I wouldn’t have guessed springs would solve the Ridetech jarring.

Don

I thought the very same. I'm hoping I can make the upcoming cruise night next Wednesday. Although I have no idea if he'd show. It was the first time I'd seen that car.

I did a google search back then and there really isn't much info out there regarding this company. There was a forum that brought this exact thing up with the spring swap. If I remember correctly, it was a BMW forum.

Maybe someone here has experience with them and will hopefully chime in.

[dontlifttoshift]

It's plausible that a given spring could have a higher rate at say 3" of compression vs 1" in fact that is what happens here. https://www.northamericanmotoring.com/forums/suspension/157535-swift-springs-dynoed.html

However, it's not like Hyperco are junk springs...... I would expect that difference between Hyperco and one of the Minnesota brands but not between Hyperco and another upper tier spring manufacturer.

[marolf101x]

It's possible the Swift springs he installed were progressive rate.
https://www.vividracing.com/swift-springs-coilover-springs-barrel-type-length-progressive-200500-lbsinch-p-151454899.html

Progressive rate springs will provide a better ride quality, but at the cost of increased body roll, and the suspension could bottom out more frequently if there's not adequate rate for the available travel.

[cpd004]

Could very well have been. The stance was very nice. Not high at all if I remember correctly.

[SPG]

I am interested in picking up ridetech shocks, if you figure out the spring problem I would love to know what it was

[marolf101x]

For clarity, as the former Director of Engineering for Ridetech, I was responsible for managing nearly everything regarding the release of the Fox coil overs.
So my opinion is extremely biased, even though I no longer work for Ridetech.

When we first decided to get into the coil over market we had to determine our priorities. . .ride quality, performance, etc.
We drove a lot of cars, new, old, anything we could get our hands on or purchase so we could feel what each car did well and not so well.
We hired a company to build a custom "ride quality monitor" that sat under the driver seat and provided a score. The lower the score the more "comfy" the ride quality. The guys who developed that for us used a lot of math NASA developed when they started putting humans atop rockets. Turns out there's a lot of frequencies the body really doesn't care for, and forces the average person would not appreciate.

Anyway, we decided our market was Pro-Touring and performance oriented vehicles, so we wanted a more firm ride without being overly harsh. The BMW M3 was one of the benchmarks. It just feels "sporty".

Unfortunately, what I consider sporty, someone else feels is too harsh. That's cool, we knew you cannot please all the people all the time.

Luckily there's a lot you can do to change the ride quality in a vehicle. . . springs being a big factor.
Think it's too harsh, get as little compression damping as you can from the shock and go down in spring rate. Lower spring rate will require more preload, but that's ok so long as you don't coil bind the spring or bottom out the suspension travel.
Fortunately the threads on the shocks are matched to the suggested spring lengths, so you even at full preload the spring will not surpass 80% compression (the point at which the metal in the spring begins to "break down", resulting in spring sag or "taking a set".)
If the vehicle bottoms out the suspension you can raise the height to provide the required suspension travel for your chosen spring rate.

Progressive springs are cool, and I really like them in ride quality first, performance second applications (which is why they are used in the Street Grip kits), but availability in 2.5" coil over rates/lengths are limited.

Just remember, these are all tuning tools (springs, shocks, bushings, etc). To dial in exactly what you desire may require a bit of time and testing, but it is absolutely achievable (within reason, of course).

[dhutton]

For clarity, as the former Director of Engineering for Ridetech, I was responsible for managing nearly everything regarding the release of the Fox coil overs.
So my opinion is extremely biased, even though I no longer work for Ridetech.

When we first decided to get into the coil over market we had to determine our priorities. . .ride quality, performance, etc.
We drove a lot of cars, new, old, anything we could get our hands on or purchase so we could feel what each car did well and not so well.
We hired a company to build a custom "ride quality monitor" that sat under the driver seat and provided a score. The lower the score the more "comfy" the ride quality. The guys who developed that for us used a lot of math NASA developed when they started putting humans atop rockets. Turns out there's a lot of frequencies the body really doesn't care for, and forces the average person would not appreciate.

Anyway, we decided our market was Pro-Touring and performance oriented vehicles, so we wanted a more firm ride without being overly harsh. The BMW M3 was one of the benchmarks. It just feels "sporty".

Unfortunately, what I consider sporty, someone else feels is too harsh. That's cool, we knew you cannot please all the people all the time.

Luckily there's a lot you can do to change the ride quality in a vehicle. . . springs being a big factor.
Think it's too harsh, get as little compression damping as you can from the shock and go down in spring rate. Lower spring rate will require more preload, but that's ok so long as you don't coil bind the spring or bottom out the suspension travel.
Fortunately the threads on the shocks are matched to the suggested spring lengths, so you even at full preload the spring will not surpass 80% compression (the point at which the metal in the spring begins to "break down", resulting in spring sag or "taking a set".)
If the vehicle bottoms out the suspension you can raise the height to provide the required suspension travel for your chosen spring rate.

Progressive springs are cool, and I really like them in ride quality first, performance second applications (which is why they are used in the Street Grip kits), but availability in 2.5" coil over rates/lengths are limited.

Just remember, these are all tuning tools (springs, shocks, bushings, etc). To dial in exactly what you desire may require a bit of time and testing, but it is absolutely achievable (within reason, of course).

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

[marolf101x]

Don,

did your 4-link have rubber bushings or R-joints?

And just so I understand your situation completely, you state "the harsh bang that occurs when driving over an abrupt drop in the road".

So lets explain this in extremes so we both know what we are describing, I can then explain what was happening in the real world.

So, in extremes:
-the road was smooth
-then the road had a crack and dropped 4 inches


---OR---

-the road was smooth
-there was an "indentation" in the road that dropped 2" below road surface
-stayed at that indentation for 5 feet
-then raised back to the previous road surface height

Scenario #1's ride quality is handled initially by the extension of the suspension.
Scenario #2's ride quality is handled mostly by the compression.

[dhutton]

Don,

did your 4-link have rubber bushings or R-joints?

And just so I understand your situation completely, you state "the harsh bang that occurs when driving over an abrupt drop in the road".

So lets explain this in extremes so we both know what we are describing, I can then explain what was happening in the real world.

So, in extremes:
-the road was smooth
-then the road had a crack and dropped 4 inches


---OR---

-the road was smooth
-there was an "indentation" in the road that dropped 2" below road surface
-stayed at that indentation for 5 feet
-then raised back to the previous road surface height

Scenario #1's ride quality is handled initially by the extension of the suspension.
Scenario #2's ride quality is handled mostly by the compression.

I had the rubber bushings. I would say it was scenario number 2. So a step response type scenario. I had a long discussion with Brett about the car. He gave me a list of items to check which I did. He even drove it but unfortunately we did not replicate the issue. He verified my shock settings also. He gave me a set of new springs with a different rate but the change was not significant. He also showed me the R joints which were new at that time. At that point I was pretty much done. I have seen quite a few others complaining of the same issue.

I have since wondered if some progressive rate bump stops would have helped.

Thanks,
Don

[marolf101x]

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

[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/showpost.php?p=699182&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.

[PDC]

This is great info and gives my a good idea of what range of spring rates to look at. This spring, I will get under the car and see what my current set up is. She actually does feel pretty good right now, but that sure doesn’t mean improvement isn’t within reach.

[PDC]

May need a recommendation after all - more info: Took the car out yesterday and noticed a small puddle of thick oil in the area of the rear passenger tire. Sure enough, the rear passenger shock is all wet and dripping.

Figured out these are JRI 'Base' (non-adjustable) shocks with the Detroit Speed logo. #041301 Rear @ $329 a piece. The fronts are the same 'Base' shocks part #030313 DS Detroit Speed sells the rear shocks individually, but only sells the front shocks as a complete coil over kit @ $1003.95 for the pair. As I surfed around, that seems to be not an unreasonable price range for a pair of front coil overs with the springs - and it looks like most manufacturers sell the fronts that way.

I 'could' grab one rear shock for $329, replace the one that is leaking and forget it. But I am wondering if driving this car around with no nitrogen charge in the shocks for as long as I did contributed to the failure of the passenger side rear shock - maybe replace both and have a fresh set of new shocks in the rear?

As far as my previous post indicating that I was told that the shocks I have are not intended for street use, I learned today that advice was not based on the fact that they are nitrogen filled - but because they are comparatively stiff and designed for flat cornering on smooth roadways. Lots of quick jarring on bumps / irregularities in regular street driving will have a tendency to wear them out faster. Maybe that's what I am seeing now with the passenger rear shock leaking oil?

Going back to the discovery that the nitrogen chamber was empty on all 4 corners and had to be re-charged - I have to wonder if that also contributed to the current failure of the rear shock. This build has just under 2,000 street miles since completion - but only a few hundred since diagnosing and re-filling the shocks.

I am pretty much sold on replacing both rears - maybe leave the fronts alone since they are not leaking and appear to be holding the recent Nitrogen charge just fine.

At the same time, if there is an alternate brand of shock that I am overlooking that may be better suited to street driving as opposed to competitive driving, I'm all ears. I'm not pinching pennies and I don't mind spending money once for the right part - I just like to avoid spending money twice when I can.

Thank you all very much.

[FORDvsCHEVY]

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....

I have air ride it’s definitely the best! [emoji57]

[cpd004]

Curious about this.

If the front of the car seems to ride over a bump (peaked line for example) instead of absorbing it as much as the driver would think it should would likely be the lack of enough compression (in this example Ridetech single adjustable coil over preset compression) alone or is a combination of the compression ratio/speed and the spring rate?

[dontlifttoshift]

It is the springs job to allow the suspension to move and absorb the bump. It is the shocks job to control the speed at which the spring and suspension move. To divide it up even further, compression controls the movement of the unsprung weight and rebound controls the movement of the sprung weight.

This whole thread is really about NVH, though, and there is so much more to it. Britt touched on it earlier, with no compliance in the front suspension bushings, the initial impact of the tire hitting the bump is transferred directly into the chassis before the shock or spring has even started to move. That is a thing you will never be able to get away from with most pro-touring suspensions. If you ever get a chance to compare Roadster Shops FastTrack chassis to their RideLine chassis pay close attention to the bushings that they use in all the control arms. The RideLine isn't delrin.

I still think RideTech are the best shocks for money. Period. I have made them work very well in several applications but there is something in their valving that is different than even off the shelf JRi shocks, let alone the custom built ones from Ultimate Performance* JRis don't hammer over expansion joints or cracks in the road to the extent that the RideTech's do. This especially shows up at lower vehicle speeds, less than 50 mph. The difference between the two shocks is more noticeable the slower you go. Even triple adjustable ridetech shocks with the high and low speed adjusters on the canister have this issue.

It doesn't really show up on the dyno sheets either, I have made that comparison and the numbers and curves are similar enough to me.......but there are soooo many ways to make force numbers look the same on the dyno and act completely different in use.

To answer CPD's question, I don't think it is a function of too little compression valving or spring rate for that matter. It is a lack of compliance in the suspension bushings coupled with the way RideTech makes their compression numbers.....which is fine for probably 95% of the aftermarket.


*The last couple times I talked to JJ @ https://upspeedshop.com/ He reminded me that he will also revalve shocks other than JRi. I have never used him for that so I can't say if this will solve CPD's issue or not but I think it is certainly worth a call.