I have an '86 with the Z51 suspension package. What difference in ride quality would I see by going with a regular set of Billsteins or a different brand of shock altogether?

 

You will probably get differing responses and this gets debated a little.

My opinion is that the non Z51 shocks or another brand will have a slight change. The shocks will be softer, but you will still have a stiff ride.

The biggest contributor to the early C4 stiff ride is the Z51 springs.

I had an '85 Z51.

I like the Z51 shocks. They are stiffer, but still not harsh. I have run them on several base suspensions with good results.

The early C4's with the Z51 are sprung so stiff that it feels harsh over every bump, expansion joint, etc. My guess is that you are trying to make it a softer ride. Shocks will help some, but with those springs it will still be stiff.

Good luck.

 

QCVette is right. One thing that can help a lot is running lower tire pressure. IMO, the factory recommendation is too high for the size of the tire and the weight of the car. Unless you're tracking the car, the pressure is too high and lower pressures will help both ride quality and tire wear.

 

My '86 Coupe had Z51 option. I bought it with about 90k miles (also had every option except block heater). I replaced the shocks with the Z51 spec Bilsteins and the ride was stiff but it handled great. I did lower the tire pressure and used soft riding summer Kumho tires. I found it helpful to pay careful attention to to keep on top of any loose screws and nuts. I also used plenty of lubricant on the various weatherstrips. I think that noises and rattles add to the "rough ride" perception.
Barrier

 

Thanks for the info. I've only had the car for a couple of months. I had 14 year old "HARD" Kumos on it. Replaced them with a set of chrome stock wheels and BF Goodrich G Force tires. This helped a lot on the ride. The car has 99875 miles on it so it's time to change the shocks too.

 

There are many favtors that contribute to a "rough" ride. Further to what has been written, you may find the many bushings and balljoints throughout the suspension and steering systems to be worn and reduced damping/pincreased slop/lay is contributing to the rough feel.

 

Define lower? A couple psi or how much lower? Does it have anything to do with the tire? On my truck, same pressure, different tire model and brand can make a difference.

 

Rebuild to 'Challenge" spec by Bilstein was a great ride improvement w/no handling change.

Softer (non-Z51) rear spring made no perceivable diff.
I run higher TP for reduced tire wear.
Car is lowered & has NO rubber outside of body mounts.

 

Whatever meets the criteria for wear and ride quality. I've been running ~22-24 PSI or so for the last couple years. Note the "~" and the "or so". This isn't BMW's leaving cars and coffee and I don't use a digital pressure gauge that reads in .01 PSI increments. I'm not advocating any particular PSI to anyone....I strongly suggest that the tire pressure recommendation on the door is (like many things) for criteria that we don't care about, so I advocate experimentation for the sake of ride and tire wear.

My car...ALL my cars with "big tires" have always worn the tires in the middle. That is an indicator of too much pressure.

When you consider that my truck has a 265 tire and weighs 5000 lbs and calls for 35 PSI...then you look at the 'Vette which has a 265 front and a 295 rear, weighs ~3300 lbs and calls for...~35 PSI? That is an indicator of too much pressure.

Anyway, with my current pressure settings, my car rides significantly better (even my wife notices the diff), and the tires wear evenly all the way across the tread. Experiment...observe...adjust to what suits you and your car.


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OK. This I would try. Mine seem to wear even at 30 but if I can do the same at 22 and give better ride softness, I'm sure the wife will appreciate it. Happy wife, happy life.

 

But.....if you go to low on the PSI you are going to effect handling. Why, because as you lower the pressure you also allow the tire to roll over further onto the sidewall.

 

Kinda why just am wondering how to find the happy medium

 

On the street? Not in a meaningful way. On the track or at 9/10? That's why I said:

 

I don't believe there will be a noticeable difference if you go with Bilstein (base) or their Z51-specific shock. There is a noticeable difference when you go with other brands, so I steer people in other directions if you're really only using the car as a cruiser or you live in the mountains and like to get aggressive, or similar.

I always recommend you go with the name brands though, don't be stupid and buy a Monroe POS shock.

I've always felt the ride was better when the pressures were kept at 32psi (cold). Whenever I dropped it, it felt harsher in the 86. Potholes were more jarring. This was the same no matter what brand of tire or how old it was.

My 88 is a Z52, which doesn't seem to care much about the pressure. I also have KYBs on it now which I would not recommend anyone using unless you only cruise. I will be going back to Konis or Bilsteins with my next shock.

 

You may not remember - but when the C4's first came out - the Corvette Engineering and Marketing folks were making a big deal about how the car could generate 1.0 G (Z-51 package) of lateral grip. This was a BIG deal, and was made possible by the Goodyear rubber that was available. BUT - the engineers had to put a pretty hard core suspension in the car to get the car to that level. There were a lot of complaints about the very hard ride those Z-51 cars delivered, and eventually - they backed the suspension aggressiveness down a bit... BUT ... my point is that the early C4 Z-51 cars have stiff springs and hard bushings in them !!!

So - you've got OEM shocks. I would expect that they have lost enough of their damping over time - that those shocks are "softer" than a new set of Base shocks would be. A new set of Z-51 Bilsteins will be worse.

As I indicated above - I'm not a fan of KYB dampers - I've used them in the past, and I was not thrilled with their long term reliability. I doubt that going to a set of Base shocks is going to give you much difference in ride quality. If you want to soften up the ride - changing the springs to the "base" spring rates will make a big change - but that isn't a small job.

Playing with tires and tire pressure are probably your best bets....

 

Just wondering about the low pressure of 22 lbs or so. Have you had any Bent Rim problems when hitting potholes or poor surface roads. We have a lot of that after a rough winter here in NY.
Soft ride is good but bent rims are not.
Barrier

 

Begs the question of "How low can you go?", doesn't it?

 

No problems with that at all.



Depends on all kinds of things. For example, I used to have a Jeep Wrangle at work for my company truck. I used it for driving on the mountain for 99% of it's use. It had 33x12.5 tires and I ran ~12 lbs in the front and 10 lbs in the rear. Traction was awesome, the ride quality was fantastic -it felt like riding on marshmallows. I wouldn't put it on the highway like that though; the sidewalls would get too hot.

So it depends on what you're doing, the vehicle, the tire, the ratios, etc.

 

aklim,

quit worrying about the wife........it's better when they don't ride in the hot rod any way........

it's too loud........it rides too rough......you drive too fast....

Tell her it's your personal hot rod..........you don't tell her how to wear her hair who does her nails, do ya?? I am surprised you don't flame her like someone touting oil additives on here!!!

just messing with ya! HAPPY NEW YEAR!

 

30 psi seems to work perfectly for my Vettes...