I was going thru this thought process for my own car, so I thought I would document it for others.
There is a lot in here.

How to choose a shock for a C3 (or) how to adjust shock valving, and why

There are so many different brands and types of shocks available for our cars. It is very difficult to know which one to choose or why? What the advantages of one type of shock valving are vs another? What can an adjustable shock do for the driver? Besides cost more?

Shock types by valving style

· Non adjustables: Ride oriented (or) handling oriented

· Single Adjustables: Rebound only adjustable (or) adjusts both rebound and compression together

· Double Adjustables: Compression and Rebound are adjusted separately

That is five valving styles. They each have their own advantages.

Basic Shock Selection & Valving Critique

· OEM ACDelco shocks – ACDelcos. Part number matched. These were valved precisely for your Corvette, your year, with your options. And will likely will produce the best OEM style ride over any aftermarket shock. But realize that if you change any springs, sway bar or bushing you can upset that balance. And realize they were designed to fit your car with 1960s slide-rule technology. Technology has come a long way in shock valving since then. We can do better with more modern offerings. We can improve either ride, or handling, or both.

· Aftermarket Generic Ride Oriented shocks -I will dump all dump all the inexpensive non-adjustable part store brands in here in one lump. KYB, Gabriel, Monroe, etc. etc. These are designed to be kinda close to factory shocks ride quality. But they are also designed to fit as many cars as possible under each part number. They are absolutely not specific for a light weight C3. And a C3 has different motion ratio for the rear shocks and rear springs, and those rear shocks need to control a much lighter IRS suspension vs a solid axle. So none of these generic shocks will be exactly “on-point”, unless they are designed and valved for a C3 only. I doubt many shock manufactures do that, it would drive their costs up. They may be kinda close, but If they also fit other cars, they will most likely be too stiff, and make the car ride more firm than necessary. This is a case of you get what you pay for. If you just cruise around, and very infrequently push the car hard in corners, these may be all the shock you need.

· Aftermarket Handling Oriented Shocks – Bilstein, QA1, etc. Non-adjustable. These suppliers have tried to bias their shock valving toward the handling side of the equation, without killing the ride. For a decent ride/handling compromise. They do not ride overly firm, and the handling will be more controlled with minimal oscillating. Just cruising around the street you may not notice any difference at all in the ride vs the store brand shocks. But if you throw the car around a bit in twisty roads, even a novice driver should notice there is more car control. The car is just difficult to get upset, it always feels under control. These would be my go-to shock recommendation for people who like to really drive their sports cars a little harder. This valving compromise is sensitive enough, that the rear shock valving must be pretty specific for a C3 IRS.

One strong caveat: If you change the spring rates from stock, you will change the required valving balance. FI: A stronger rear spring rate is a common upgrade. When you increase a spring rate, you must lessen the compression valving, or the ride will suffer. And you must also stiffen the rebound damping or the car may pogo / oscilate. Yes, the rebound needs to be stiffer to control the stiffer spring, but not the compression. With a stock shock and a stiffer than stock spring, the car may exhibit both undesireable features at once. FI: Ride oriented shocks and the gymkhana / F41 springs would be an example. Both Bilstein and QA1 offer two valving choices for our cars. Bilstein offers a B6 and a B8 version.For Bilstein the “lowering springs” comments means for slightly stiffer springs. Van Steel has 2 C3 specific custom valving options on the non-adjustable QA1s, one for ride, and one for handling. The fiberglass rear spring options are almost all stiffer than stock, so you should select the handling/sport/lowering valving option for those springs.

· Single and Double Adjustable Shocks – They give you the opportunity to user adjust between smooth ride valving, a good ride/handling compromise, and extreme handling only valving, with a quick adjustment. For many users, that would be enough reason to buy them, and try them. These shocks are the main reason for this discussion. Some SA are rebound-only adjustable, like Koni and Ridetech. Some SA adjust both valves at once like some QA1 shocks. Others are Double Adjustable, like, QA1, Viking, Koni, Penske, JRI and others. With DA you can change both the compression and rebound separately. What can these type of shocks do for you? How can you determine if they are worth it?

For many C3 drivers, this is all the information they need.

But some will want more information. That is what this write-up is truly about, adjustable shocks. What can adjustable shocks do for you? What will you feel?

I ran adjustable shocks (Konis) for 30 years of autocross into the Pro-Solo level. I was nationally competitive too. But with shock valving, I mostly just experimented and used the manufacturer’s supplied guidelines. That and with a lot of testing, I slowly learned about shock tuning, and what stiffnes I liked, and when. But I never really knew how to explain “why” I liked “A” vs “B” until more recently.

 

Manufacturer’s Shock Tuning Guidelines for Adjustable Shocks

They generally look something like this:




For most C3 drivers, those tuning guides are all they need.

I used them for 27 years of racing. And experimented, and got faster. I read and all the books by Carrol Smith “Tune to Win”, Mark Donohue, and Roger Penske, and others, etc. And got faster. But all those books were pretty general guidelines. It took years of hard earned testing to figure out what was fastest. Many of my competitors did not read those books, or experiment. Some drove better than others.

But nothing told me what would be a good or great setting, and “why”, or “why” those setting charts above worked, until I ran into Dennis Grant. Then things I had done for decades clicked into place, and explained “why” some stuff worked, and some didn’t.

It all depended on the entire chassis dynamics. And your goals.

 

The rest of this is for the “techies” in our group.

Many high quality adjustable shocks will furnish shock velocity-force graphs like these below.




Question: How does a driver relate that graph to the recommendation charts above? How do you choose which “click” ? And why? It is certainly easier to just use the charts, and then guess at a setting.

Shock Velocity

To understand the above question, first we should look at a velocity vs time graph of the shock itself, on an actual car. To see how quickly the shock moves as you drive. This will help us decide what the car really wants in the way of shock valving.

This data was collected by velocity measurements on the shock absorber itself, on a autocross car, at an SCCA National level event. Yes even amateurs go this far these days, but this guy is a multi-champion, for a reason. He is also a good writer and shared his data. Professional racing teams also do this, but will not share their results, why should they? The graphs measure both shock distance traveled, and time, and most importantly the velocity of the shock movement, in inches per second.




The dotted lines above represent 3 in/sec shock velocity. Notice how 90-95% of the time, the shock operates in this zone. The quick peaks jump out to as far as 6 or even 10 in/sec. But those spikes only last for a moment.

What part of this data is important, as far as ride or handling?

Shock Velocity Zones

This is a summation of recommendations from many different sources. They all basically agree.

· 1-3 inch/sec velocity is typical road undulations. It is also body roll speed during cornering, braking and acceleration movements. This is where the shock spends almost all of its time.

· 5-6 ”/sec velocity is handling on a road course. IE: quick transitions, fast turns of the wheel

· 5-10 “/sec velocity is handling on a quick autocross course IE: more violent transitions

· 10 “/sec and over is typically tar strips, speed bumps, curbs, cracks, potholes, etc.

Basically the 1-3”/sec zone controls 90% of the ride, and normal speed handling. The 5-10” zones are when you turn much quicker, like in a slalom, and want to plant/load the tires very quickly. Potholes can move the shocks even faster than that.

Here is a quote from Penske Shocks (regarded as maybe the best shocks in racing):

Understanding how your shocks behave during roll involves a few key details:

Normal shock absorber shaft velocity for body roll—along with braking dive and acceleration squat—is very slow, typically ranging between 0 and 4 inches per second

Because chassis weight transfer during cornering is a gradual, controlled movement, shock absorbers require specific valving in this low-speed range to manage the roll.

· Low-Speed Dynamics: Movements under 4 inches per second dictate your vehicle's handling balance, turn-in response, and stability in sweeping corners. The shock's resistance here prevents the car from rolling over too quickly.

· High-Speed Dynamics: When your wheel strikes a bump, rut, or pothole, the shaft velocity rapidly spikes to 6 to 12 inches per second or more. In this range, the shock must blow off pressure to prevent harsh impacts from being transmitted directly to the chassis.

So basically we want firm forces at 1-4” ( for handling) and not much stronger higher (for big bump ride quality)

 

Shock Force vs Velocity Curve

Now we are ready to bolt on our fancy new adjustable shocks, and crank them up to max, right? (Certainly more is better, right?)

Not so fast…

Now we know to look at the 1-3”/s zone for ride quality, and 3-10” for max handling and potholes.

The forces a shock can generate can vary from less than 50#, to as high as 500-1000#s.

Which “click” to choose?

The answer to that question gets complicated.



Spring Rates

You obviously choose different spring rates depending on what kind of ride you want. And different spring rates require different shock forces. A stiffer than stock spring requires a weaker compression force, but a stronger rebound force. They require different shocks, or different adjustments.

The overall ride “rate” (or stiffness) of the spring & body, is called Ride Frequency.


Ride Frequency (Natural Frquency)

Popular suggestions for ride frequency: in Hertz (Hz) aka cycles per sec (from several sources):

· Daily driver 0.8-1.0 Hz

· Good street ride-handling compromise: 1-1.5 Hz (occassional autocross)

· Full time racer: 2.2-2.5 Hz

Ride Frequency for a C3

What does that mean for a C3 Corvette?

You need a lot of suspension measurements, and have access to a dynamic suspension calculator, to give you the answers. The math formulas have been in books for decades. I first went thru this math with pen & paper in the early 1980s when I started racing. Mark Donohue’s book got me started. He was one of the greatest engineer–drivers ever. I was able to talk to Rick Mear’s Penske Indy Car team tuners in the pits and get some good ideas. I visited the Penske shop and got more help. Now I use a spreadsheet or an on-line calculator, and still keep a notebook. I did all the calculations for you, so you do not have to. But I will also show you how you can do your own.

For a ~3550# C3 Corvette & driver, I came up with:

Stock spring C3: 1.2 Hz / 1.4 Hz Fr/Rr

450# / 330# springs: 1.5 Hz / 1.7 Hz

550# / 305# F41 springs: 1.6 Hz / 1.7 Hz

550# / 360# springs: 1.6 Hz / 1.8 Hz

550# / 400# springs: 1.6 / 1.9 Hz

850# / 600# springs: 2.1 Hz / 2.3 Hz

· None of the typical C3 springs fall into the daily driver / cushy “ride” zone. Not even factory stock ones. 1.2 / 1.4 Hz (Fr / Rr) applies both for a SB, or a BB OEM spring.

· C2s ran just a little softer. Those cars were only a little lighter than a C3 (3155 vs 3210#, base 67 & 68 coupe, curb wts), but the coil springs were up to 25% lighter (195# vs 250# base spring). That would make them exactly 1.0 Hz. Daily driver ride quality would apply there. Hop backand forth from a C2to a C3 and you will feel the difference.

· All the normal C3 choices, including factory springs, fall into the sports car / good compromise / ride & handling / occassional autocross zone. From the low end to the firmer end of that zone.

· Moving into the full time racer category requires some really stiff springs.

· Small weight changes over the C3 generation, with engines, options, driver weight; honestly these have only a small effect on the ride frequency rates above. But if you plug in your data into a dynamic suspension calculator, you can get your specific numbers.

 

Shock Stiffness

How firm the shocks need to be, depends greatly on the spring stiffness. But also the weight of the car, and the motion ratios of the suspension. The perfect shock force is called Critical Dampening. I need to explain that.



Critical Dampening




An Under Damped car takes a long time to stop oscilating up & down. The pogo stick analogy. Much bouncing. Think of an old floaty Lincoln or Cadillac. Or old burned-out leaky shocks. The shocks are just too soft.

A Critically Damped suspension absorbs the bump (compression) and lets the wheel back down, and then the motion stops, in one up & down cycle. It is the perfect ride & hadling compromise.

An Over Damped suspension absorbs the bump, but then holds the wheel up for far too long, and does not let it back down. A second bump could either launch the wheel off the ground, lose traction, or jack the car down to it’s bump stops, depending. It is more frm than necessary.

It turns out 100% critically damped is also a little too strong, and 65% Critically Damped is usually preferred.Think of it as one cycle and a half, until the motion stops. You could even go to 50% critically damped if you want a even more comfortable daily car ride.

A competitive professional race car team would break this down even further, into different critical % values for low speed, high speed, compression and rebound. But let’s not go there.

Let’s just go with 65% Critically Damped, from 1-3 “/s, and less force (% critical) at higher shock speeds. For a terrific ride and handling compromise.




Drag racing is a whole ‘nuther subject, it is all about loading the tire very quickly on launch. Let’s not go there either.

 

Critical Dampening Forces for a C3:

This one requires a lot of measurements, and a good dynamic calculator.

I have used several, I even wrote one myself, but I like this one the best.

Dennis Grant of FarNorthRacing has an excellent one online:

Click here:

https://farnorthracing.com/autocross_secrets16.html

His background is a multi-year National SCCA Champion, Engineer, and Koni / Bilstein Shock Dyno Testing / Tuning / Rebuilding Engineer. He has his own shock dyno and has dyno’d 100’s of shocks.

If you are interested in this subject pick up his book, “Autocross to Win” . It is free on Amazon Prime.

Here are the specific inputs you will need for a C3. I pulled these from my car. So you can just read here, and use my numbers, and not even use the calculator, unless you just want to. My car is a 1972 454 BB with aluminum heads, A/C, and a driver on board. Yes it has a 51.5% rear weight bias with a driver on board. Honestly, the car specific weights do not matter as much as the spring rates, motion ratios, shock damping ratios, and shock digression knee. All that stuff in the second row. All the other C3 measurements that I made you can just carry over.



Here is some of the output you get: The first is your wheel and ride rates, and your suspension ride frequencies. And then the weight transfer. Yes 900# of weight transfers in a corner. It rolls from one side to the other. That is what makes the suspension compress and that is the part the shocks resist.




And here is the desired front shock force vs velocity curve for 65% critical dampening:


Notice it starts around 23/59# (Compression/Rebound) at 1”/s, and climbs to maybe 48/110# at 5”/s.



And here is the desired rear shock force curve:


This starts at only 7/19# at 1”/s and climbs to 12 / 38# at 5”/s.



A couple things you might notice:

The forces should be very low for the slower 1-3“/s velocities. They do eventually creep up to over 100# on rebound past 5”/s. But compression always stays under 50# .

On a C3 the required forces for the rear are much lighter than the front, both because the center of gravity is near the front, the engine is in the front, we usually want the car to understeer, and you sit near the rear. Get the rear shock too stiff and you will quickly notice how rough the ride is, because your butt is 24” away from the spring.

A C3 has 2 MRs in the rear IRS, 1.18 for the spring, and 1.0 for the shocks. The calculator only has one. For the truly nerdy, with a little manual spring force calculating, I got it to accommodate both motion ratios, and spit out a slightly more correct reading for rear shock valving, 10.5 / 27# C/R @ 1”/s and 55# rebound at 5”/s. It is close enough either way for our conversation.

 

Shock force Graphs

So if you have adjustable shocks, and if they come with a force graph, you can decide where to set the adjusters, to get the specific # force indicated by the calculator, and set your shocks to the perfect 65% critical damping zone, before you ever even drive the car. Honestly you may never need to change them again.

The 1-3” zone is the most critical for street ride quality and street speed body roll. The 6-10” big bump / autocross turn zone just goes along for the ride. Unless you are racing, then you will go deeper anyway.

Force / Velocity graph for a QA-1 Double Adjustable:




Very quickly it will be obvious that you want to stay on the softer side of the adjustments for a decent ride / handling compromise. The firmer settings get truly severe.

It is even easier to just use their published suggested settings. That is probably what most buyers should do. Not go deep like I did.



I found that on a Corvette, the 65% Critical Dampening Forces only require 1-4 clicks, and the “Comfort” or “Nice Ride” settings were almost perfect. My D.A. shocks worked out to 3 & 4 clicks (C/R) (Front) and 1 & 2 clicks (Rear). Funny thing was, this was exactly the minimum side of their suggested Comfort Ride & Handling range. (of say 3-6) ( out of 18 clicks total).

I have force graphs for Bilsteins, QA1 non-adjustable, Koni Single adjustable (on minimum rebound), QA1 single/double adjustable settings and Viking double adjustables (set on minimum), and they all seem to agree in the amount of shock force applied. All were pretty close to the “ideal” 65% Critical Damping Forces. They should basically all ride & handle about the same.

What does 65% Critical Damping feel like?

That level of damping should get you very close to C5/C6/C7 ride quality, As close to a perfect ride & quality handling compromise as you can get. When you turn the wheel pretty hard, you do not really even feel the shocks, the body just rolls and the fender sinks on one corner, then it stops moving. No bouncing. You do feel the tires a little while the body is moving, but you can also feel them grip a little firmer once the body stops moving, and the springs & sway bars support the weight transfer. It is all very smooth, and composed at all times.

So in conclusion, if that is all that you want, a great ride & handling compromise, all you need to do is buy a set of Bilsteins, or QA1 non-adjustables, and enjoy.

So why did I, and so many of my autocross competitors, run their shocks set at significantly higher settings than suggested above?Were they truly faster? Or did they just feel faster?

 

Running Adjustable Shocks at over-damped settings

This is common. So what does an over-damped car feel like?

Here are some comments from Penske Shocks:




The 65% critical dampening setting will let the chassis work. It will roll easily, but settle, not bounce. It will be able to absorb bumps, even in a corner.

But because, like Penske says, so many drivers like the way the chassis feels when they turn up the settings, they will run much higher shock settings. Now you can actually feel the firmness of the shocks. These over-damped or above-critical settings do quicken the steering wheel response, a lot. You feel the tire “bite” the instant you turn the wheel, say ¼”. People will say it “feels great”, it turns “like a go-kart”. Now the car feels very special with steering wheel response that people think a race car should have. What those higher settings do is load the tire extremely quickly, and the car responds to the steering wheel extremely quickly. This was so common in the racing fraternity that 90-95% of them ran their shocks over-damped. It does feel terrific! So it must be faster right? Umm….maybe not. Over-damped will also cause a bounce on turn set, and partly unload the tire, it may skip or lose traction on bumps, it may exhibit snap over-steer on certain bumps, and over-damped will be slower against the clock. And the higher 6-10” forces will make it ride worse, especially on bumps. Penske again:




90-95% of drivers will turn the settings up, up to the over-damped point. Way beyond 65% Critical settings. Exactly becausethe steering gets very “crisp”. It “feels great “. The car is more stable. That is my experience from 27 years of Pro-Solo competition, and driving 100s of very fast and “set-up” cars. I have driven many cars with the shocks set 2 or 4 times as firm as critical. The ride was not really awful, just very firm. (But potholes were indeed bad.) These firm settings load the tires very quickly. The car and the steering wheel responds very quick.

But… It will ride better, be smoother overall, be more composed, and be faster on the track, if set at 65% Critical dampening. The initial turn-in will not be quite as firm or crisp. It will be like a C5/C6. My experience backs that up. I went faster. Especially on bumps, or in the rain. On bumps I did not have to “lift” where I did before. Some of those short “lost traction” slides or skips went away.

That is the beauty of adjustable shocks, you can try both, and choose. Maybe the sharp steering wheel response feel is the most important thing for you. Or maybe the always composed suspension is more important. Try both. And then decide.

Two more quotes from Dennis Grant:





What these quotes mean is that you will not notice a performance increase or decrease, on the street, but you WILL notice a difference in the steering wheel crispness when the shock is over-damped.

Coincidentally the Bilsteins, Konis, and QA-1 non-adjustables all do a great job of hitting this 65% Critical Dampening level. I checked their force graphs. Van Steel even has both a ride and a custom sport valved QA1 version. And Bilstein has two versions, B6 (std.) & B8 (sport). So for the street, do you really need an adjustable shock?

Maybe. It takes an adjustable shock, that you can crank up even more, to the “over-damped” level, to get that instant crisp steering response “go-cart” like feeling. If that is what you want. Try it, If you do not like it, just dial it back down.

 

Specific Adjustable Shocks

· Koni Classics – Smooth riding. Rebound adjustable. "Million Mile" shocks. Set them low normally, and set the rebound firmer to try that over-damped feel. The Compression valving is set to normal 65% critical settings. This is the part that controls the almost all of the ride quality, but only part of the handling Tightening up the rebound, tightens up the handling with much less effect on the ride than compression does. You can make large chages to the rebound without killing the ride. But on a C3 Konis have to be be completely removed from the car to adjust, fully compressed, twisted, then re-installed. Not convenient if you want to do it more than a couple times. They do not make a Sport version for our cars, but that one has just a little more compression, not really much. Notice how it still stays under 50# compression, all the time, for ride quality, up to 6”/s, even on a Koni Sport (Yellow). And how large the rebound adjustment zone is.




· Ridetech - single adjustable – rebound adjustments. Much like Koni except the adjuster **** is easily accesible on the top of the shock. Just open the hood and give it a quick twist. Mount the rears upside down and then the rear adjustment **** is easily reached too. They have a somewhat stiff dual rate coil spring also, so I would imagine the compression on these is very comfortable. I will try to get a force-velocity chart.
Update: I received a Ridetech graph. Very similar to Koni. Very flat on large compression, so not too jarring there. At 5" they are at maybe 80# compression, so 15-20% stiffer than the Konis. A little more performance oriented, a little less ride oriented. The Konis I know ride very well. These should not be that much different/stiffer. Koni also offers Koni Sport (Yellow) shocks for most cars, (but not our C3s) and the main difference is that little bit extra compression damping. So maybe these are like Koni Sport. Rebound dampening starts at 200# on these, and about half that for Koni or OEM. So that will make it somewhat stiffer and quicker responding.




· QA-1- Two styles - single adjustable but this style adjusts C & R together. That means just the lightest couple of clicks are truly useful, if you value the ride. After that you may want to try more rebound, that comes with pothole jarring extra compression, which quickly reaches 100 or200# . If you dig hard thru their offerings, they also have a rebound only adjustable.




You might want those huge compression forces for autocross or drag racing, but only the first couple clicks for the street.




Look at the huge difference in the compression forces in this version. Soft 0-50# compression with lots of choices for rebound. Very little effect on compression. Like world reknown Konis. But an easier to reach adjuster **** than Koni. Not ideal for autocross, but could work ok, until you get really competitive.

· QA1 Double Adjustables –




Using the first few Compression clicks keeps you under 50-100# to keep the ride quality under control, and you can crank up the rebound a lot more. Very flexible application wise. Drove a C3 recently with this setup cranked up halfway on both compression and rebound. It was definitely firm and over-damped. But man was the steering quick and crisp! Potholes were hard but tolerable. 100# on compression at 2”/s man you really feel it.



· Bilstein B6




Does not hit 50# compression until 6”/s. Hits 200# rebound at the same time. Great feel at low speeds. But force keeps going up on big bumps, does not flatten off like Koni or GM, you’ll feel the firmness there, on big bumps Many say they love these shocks.

· C5 Z06 GM OEM & Bilstein




Stock C5 Z06 and Bilsteins. Look how the GM rebound levels off at 200#, for big bump ride control. But GM Z06 is the firmest on compression, it hits 100# at 2”/s. Good comparison to 2 Bilsteins. But GM Z06 are the firmest at 1-4”/s for that crisp handling feel.

· Viking Beserker D.A. with GB valving





The Viking Warrior D.A. shocks have curves very much like the QA1 D.A. Instead, I got this Berserker D.A. version instead with GB valving because they have a soft 1-3”/s compression curve like the smooth riding Konis, and I can crank up the rebound as much as I like. I also have several small adjustments I can make to the compression and still stay in a reasonable range. They call this their cruiser shock. Not to hot for racing or autocross. 65% critical turned out to be exactly settings of 3 & 4 front, and 1 & 2 rear, for C & R. Same as their chart suggestions. I will start there and then see if I want to try over-damped.

 

This is awesome Leigh. Thanks for taking the time to lay this all out. You're spot on with what type of shock would be the best fit for people.

I've gone through the full progression over the past 6 years. Started with the basic Monroes when the car was stock and just a cruiser. Moved to Bilsteins with an LS swap, stiffer springs, and modern tires. Then single adjustable Ridetech HQs as I got more competitive autocrossing. Now I've gone off the deep end with Penske double adjustables.

The basic non-adjustable shocks are fine if you want the stock ride and handling characteristics, good and bad. IMO this level is a waste of time unless you just have to have that stock feel. But to each their own. They're better than blown shocks.

My car rode better with the Bilsteins and stiffer springs (550/360) than it did with the stock springs and shocks, even while switching from 15 to 18 inch rims. Plus it handled infinitely better. To be fair, I also switched to modern tires, but the body control and overall feel was orders of magnitude improved. I was able to win several Goodguys autocross events with this setup, beating cars with much more expensive suspension setups. This is the goldilocks zone of shocks for 90% of people.

At this point I was pushing the car hard enough to necessitate stiffer front springs, which the Bilsteins couldn't keep up with. On to 800 lb front springs and single adjustable (rebound only) Ridetech HQs. These were amazing for learning how damping affects both ride and handling. Driving on the street they would be set to around 10 clicks from full stiff (24 total) and they still rode pretty well. I would crank them down to 2 or 3 for racing because autocross requires the car to take a set very quickly (to your point about over damping). Finding this specific setting took a good bit of experimenting, though. Also it was stiff enough that I would notice immediately once I got back on the road to drive home and would have to soften them or my teeth would be chattering the whole way home. These shocks are probably good enough for 99% of people out there, certainly beyond any driving that would be remotely legal on the street. They're really impressive shocks.

I eventually got to the point where I was reaching the limits of what the single adjustable shocks with stock style springs could do for my type of driving. Time for coil overs. I was tired of buying shocks every couple of years; I wanted to buy shocks for the last time even if they were beyond my current capabilities.

So I bit the bullet and went big with Penskes. This isn't just one level up, it's a whole different league. Long story short, they custom build everything and the shocks are incredible. I immediately picked up time even though the car felt slower because of how in control it was. Bonus, no need to make adjustments between street and racing. They just flat out work everywhere. They don't ride nearly as good as the Bilstein setup, but way better than the Ridetechs set to almost full stiff.

A few things to emphasize:
1. There's a lot more influencing the performance of a shock than just the number of *****: design (mono vs twin tube), tuning (shim stack), adjustment type (high/low speed, compression/rebound), and quality of assembly (those force/velocity graphs are generic for a product line, they don't reflect the performance of how your individual shocks were assembled). Just an example: one click on a QA1 shock does not change the rebound the same amount as one click on a JRi shock.

2. Don't over think it. If you truly want to go fast, spend money on making yourself a better driver. You can buy better shocks as your driving skills grow. An A driver in a C car will beat a C driver in an A car.

3. You can save a lot of money by being realistic with how you'll drive your car and what you want out of it. Or don't. If you want JRi coil overs just to cruise down Main Street, go for it! It's your car, do what you want. Drive it and enjoy it.

 

What a great and informative series of posts Leigh - didn't actually realise how much we needed this information until it's right in front of you. Really great and detailed with perhaps results that are surprising (well, to me they are!)
Much like properly measured comparison tests of alternative sizes and brands of stock sized and larger width/diameter aftermarket tires and large diameter braking system all we generally see is personal comment (rather than 'measured' results) relating to how good the changes were. Very impressed with the time and effort you much have made doing all this. Thanks so much

 

wheresmyhorsepower

Terrific real-world driver tested feedback!

Thank you!