Quest for a better ride!

[camaro1185]

I have been recently getting big into the pro touring scene with my 1988 Iroc-z camaro. Last winter, I went through every bit of suspension on the car to make the car handle like its on rails. I have achieved that, and my mind is blown everytime I drive it at how well it handles, BUT the ride is extremely rough when just cruising around town (im 27, so thats saying a lot) and on the highway. My goal now is to have a car that i can drive everyday without getting beat up. Also, this car is driven A LOT. Its not just a weekend car, so loosing a little bit of handling for more comfort is ok with me.

My setup:
32psi Falken 912 tires
34mm front/24mm rear sway bars with poly bushings and end links front and rear
stock lower control arm with global west del a lum bushings
Eibach pro kit springs: 714 lb/in linear front 1 inch lower/109/177 lb/in progressive rear 1 inch lower (stock isolators front and back)
Tokico Illumina 5-way adjustable shocks (Set on 1)
UMI subframe connectors (weld in)
UMI tubular rear control arms with poly bushings
UMI rear re location brackets
UMI adjustable panhard bar with poly bushings


Any help at all would be appreciated

[marolf101x]

I guess the question is what is "extremely rough" and when does it happen?
Does it feel "rough" all the time, or is it only when you hit bumps?

Let's break down your set up a bit:
32psi Falken 912 tires
-what size rim? what aspec ratio tire? the shorter the sidewall, the more "crisp" or "harsh" the ride is, depending on how you look at it.

34mm front/24mm rear sway bars with poly bushings and end links front and rear
-should have little affect on ride quality unless there is binding.

stock lower control arm with global west del a lum bushings
-solid bushings will transfer more energy into the chassis, and thereby into the drivers seat and steering wheel

Eibach pro kit springs: 714 lb/in linear front 1 inch lower/109/177 lb/in progressive rear 1 inch lower (stock isolators front and back)
-not sure what the stock rate was, but this could contribute to poor ride quality if it's too stiff, or if the suspension is now bottoming out.

Tokico Illumina 5-way adjustable shocks (Set on 1)
-if the dampers have a significant amount of compression it'll feel like too much spring rate.
-if the dampers have too much rebound the car will "pack" when you hit little bumps. This packing sucks the car closer to the ground with each consecutive bump until it's riding on the bumpstops.
-you don't happen to have dyno graphs of theses dampers, do you?

UMI subframe connectors (weld in)
-should not hurt ride quality

UMI tubular rear control arms with poly bushings
-poly will transfer more energy into the chassis than rubber, but not as much as solid, so it shouldn't be too bad

UMI rear re location brackets
-should not hurt ride quality

UMI adjustable panhard bar with poly bushings
-poly will transfer more energy into the chassis than rubber, but not as much as solid, so it shouldn't be too bad

Let's figure out when it's rough, then we know where to look.

[camaro1185]

I feel it the most over a really rough road with lots of pot holes and uneven. The highways aren’t bad at all, but the car vibrates almost like the bushings are metal on metal instead of poly. Not a vibration like a drivetrain one. Its got to be my del a lum bushings in the front.

Rims are stock Iroc 16”. 245-50-16

The stock spring rate for irocs are around 550, so 714 is quite a bit more!

I’ve attached at dynograph that was post suspension upgrades (I know, thats pathetic numbers for a 350). I don’t know how you can tell the shocks are riding on the bumpstops from that though?

[dontlifttoshift]

Britt was looking for a shock dyno sheet. Some vendors supply them with shocks, I don't believe that Tokico does.

Have you tried cranking the valving up on the shocks? If the shock can not control the spring it will ride like crap as well. That is not a huge increase in spring rate.

When you say 5 way adjustable, there are 5 separate adjustments or just 5 clicks? Do you know if they only adjust rebound?

[camaro1185]

I figured thats what he meant about the dyno.

And yes, 5 clicks. not 5 different adjustments.

[dontlifttoshift]

From Tokico's website......



Damping Force Adjustment
With a choice of five settings from the softest (#1) to maximum control (#5) the Illumina Series allows drivers to easily change the balance, overall handling and ride quality for everything from daily driving to autocross or even drag racing. To change the damping force, simply insert the Illumina adjuster (part #TO 00102) into the top of the rod, and turn it to any of the five numbered settings.

Rebound And Compression
Damping force adjustments alter both the rebound and compression damping rates simultaneously, for consistent control.

Application - Specific Damping
Each shock or strut application has its own specific damping curve shape and range, precisely tailored to the vehicle.

Advanced Adjustable Valve Design
Illumina uses TOKICO’s sophisticated multi-stage, variable-aperture piston and valve system, combined with a five-position bypass shutter-valve. A crisp shutter-valve detent allows quick, sure selection of the five settings

Try turning them up and see what happens. Go all the way and test drive, then try the middle. Only you know what you want it to feel like. In general I use compression damping to dial in ride quality and rebound to deal with handling but with the Tokicos you do not have independent adjustment so you will have to find a happy medium that suits your needs.

[camaro1185]

Thanks donny.

So what your saying is that with my shocks set to 1, im letting the spring do most of the "dampening" and if I increase the shocks, the shocks will control the movement or dampening more?

Increasing the shocks, wont that firm up the ride more? I guess thats not a big deal if it cuts down on the slamming over bumps.

[dontlifttoshift]

Turn em up and see what happens. You can read and learn but that will never equal doing and learning. Drive around the block 5 times and note how it handles different bumps and transitions. Set the shocks on kill and do it again, see what happens.

Springs hold the car up, shocks do the dampening. You can have too much spring rate, or too little for that matter, but dampeners (shocks) will have the BIGGEST impact on ride quality after the tires.

[camaro1185]

Thanks. I tried it on 3 front and back. It seems a bit firmer, but it did not "slam" over bumps as much. Im going to run it like this for a few days then go to 5. I will fine tune from there. I still think that I can achieve the same handling and a bit more comfort with less spring rate (hotchkiss 600in/lbs) and maybe pairing them with the koni yellows.

Is that possible?

[dontlifttoshift]

I don't think your spring rates are that high. Koni yellows are great shocks, compression is fixed (mostly) and rebound is adjustable.

[camaro1185]

Rebound is what I want to adjust to take care of my bone jarring ride correct?

[marolf101x]

That all depends on when the "bone jarring" happens, and what adjustments your shocks have. As Donny pointed out when you turn the knob on your shock it changes both compression and rebound at the same time.

Typically, if you hit a bump and it's immediately bone jarring, it's due to excessive spring rate or excessive compression damping. This will feel like the suspension is solid.
If you hit a bump and the bone jarring is delayed for a split second this is too little spring rate or ride height set too low. This is the suspension compressing, then bottoming out. . .hence the slight delay after you hit the bump.

[camaro1185]

Its defiantly when I hit the bump, not after.

[camaro1185]

I guess my ultimate goal is a car that handles very well (not a track car or race car--primarily street), but can also be my daily driver and will have no problem taking it on roadtrips that are hours long while still being comfortable. Is this possible on an old car like mine?

I guess im looking for modern corvette type handling/comfort. I know they have the magnetic shocks that help out a ton but I figure with the modern technology with shocks and springs it should be doable.

[Paul Huryk]

I have been recently getting big into the pro touring scene with my 1988 Iroc-z camaro. Last winter, I went through every bit of suspension on the car to make the car handle like its on rails. I have achieved that, and my mind is blown everytime I drive it at how well it handles, BUT the ride is extremely rough when just cruising around town (im 27, so thats saying a lot) and on the highway. My goal now is to have a car that i can drive everyday without getting beat up. Also, this car is driven A LOT. Its not just a weekend car, so loosing a little bit of handling for more comfort is ok with me.

My setup:
32psi Falken 912 tires
34mm front/24mm rear sway bars with poly bushings and end links front and rear
stock lower control arm with global west del a lum bushings
Eibach pro kit springs: 714 lb/in linear front 1 inch lower/109/177 lb/in progressive rear 1 inch lower (stock isolators front and back)
Tokico Illumina 5-way adjustable shocks (Set on 1)
UMI subframe connectors (weld in)
UMI tubular rear control arms with poly bushings
UMI rear re location brackets
UMI adjustable panhard bar with poly bushings


Any help at all would be appreciated




I specialize in parts for the 3rd generation cars (like yours) and am in the process of upgrading the suspension on my 1989 GTA (not done yet) and have some advice that may help.


As you have changed some of the stock items and bushings in a few others, let's focus on them for now.

16" is a stock size and has enough give to not be a problem in terms of ride, plus your tires are not known to ride that rough.

Changing the bushings (front control arms, sway bars) can increase ride harshness - the harder the bushing, the rougher the ride. Spherical bearings can be a ride killer, but poly, especially when it is a high durometer bushing can degrade ride a lot. Ditto for the RCA you have on - they will make the ride rougher - a long time ago I had a get of rod end RCA on my Camaro and even I hated it, went to poly and it imporve, but was definitely rougher than stock rubber.

Springs can affect ride, definitely - but you aren't running 1200lb/in ones and the ones you have are about 30% stiffer than stock.

Struts and shocks definitely affect ride - but that is the trade off of performance replacements - the ability to control the contact patch much more accurately than OEM ones can and usually does degrade ride. With a 1" drop, doubtful they are bottoming out.

Panhard rod bushings probably won't make a difference in ride, although they can bind like the RCA ones.

Keep in mind that these cars are well known for not having a supple ride stock and that suspension modifications and lower profile tires can make them very rough riders. But if done right, they can easily compare to modern cars with more advanced suspensions - just don't expect them to ride so nice.

[camaro1185]

Thanks paul.

I guess the question is, how do I determine what parts I need to make my car handle well but also ride nice as well.

How do I determine my ideal spring rate?
How do I determine what shock/struts and what setting they should be on?
If it would be best for me to change to a different bushing, Should I go with poly or back to rubber replacement?

[camaro1185]

Also, would a taller spring with a 7xx spring rate (factory replacement moogs), be a nicer feel on the road than a 7xx spring rate lowering spring?

How does spring height play into road feel?

[Henesian]

Define bad. I wish you had a video of you just driving around. I have 700 lb/in springs(2-2.5" drop) and polyurethane sway bar bushings everywhere, with AFCO street stock shocks, and 275/40/17 Kumho Ecsta ASXs with 34psi cold all around on leafs in the back of my 76 T/A, and the ride isn't as bad as my best friend's stock 2005 Subaru Impreza WRX STi. Technically, my ride should be worse than you. Stiffer shocks(probably), stiffer tire sidewall.

[camaro1185]

My gf got me a go pro for Christmas, so ive got a ton of driving footage, ill try to put something together today to show how it is.

[Paul Huryk]

Thanks paul.

I guess the question is, how do I determine what parts I need to make my car handle well but also ride nice as well.

How do I determine my ideal spring rate?
How do I determine what shock/struts and what setting they should be on?
If it would be best for me to change to a different bushing, Should I go with poly or back to rubber replacement?

No problem...

It comes down to detail in a lot of cases. For instance, I am running Global West RCA that have rubber bushings at the body and spherical bearings at the rear, allowing articulation, no bind, and a better ride than all poly. Similar for the panhard rod, where the body side is poly and the rear is a bearing. Definitely made the ride stiffer (along with Koni yellows), but certainly useable and not fatiging.

Spring rate is a tough one - have to consider weight distribution front to rear, ride height, use, and linear vs. progressive spring rates. In a street 3rd gen, it would be between 550 and 850lb/in, race might push 1200lbs/in for certain applications. I have 650/160 in the GTA (going in soon) and 725/160 in my Camaro.

Shocks and struts either come non adjustable or adjustable. Single Adjustables typically change compression and rebound together (some keep one pretty constant), where double adjustables change rebound and compression independently. Koni yellow is a single adjustable as an example and has infinite adjustments - no detents like other brands - use them on the GTA and have the rears set 3/4 turn off full soft with stock WS6 springs. You need to drive the car when it is done to see what settings give the best combo of handling, ride, and control; takes some tinkering to get it right. I suggest single adjustables for most street cars.

Keep in mind some aftermarket parts do not allow you to change bushings. Every bushing has advantages and disadvantages. As an example, you should use poly for the sway bar bushings and endlinks - less deflection and no real chance of binding. You can use poly on the front control arms (or delrin, or bearings), but harder bushings will make the car ride worse. I don't suggest poly for the RCA as in that spot, that material binds and hurts performance - bearings are great for eliminating deflection, but murder the ride quality. But a rubber/bearing combo works - in a street cat, I would highly recommend this combo.