Suspension Feedback

[Okiedoke]

My suspension feels quite bouncy/floaty, almost like a boat rolling over the waves. This is very obvious on Tour mode to the point I'm not comfortable driving through mountain highways. On Perf mode, the ride is pretty harsh as expected but I can still feel some of the bouncing/floating. Since this is the only ZR-1 I've driven, I don't have any point of comparison or know what it would have felt like when new. Any ideas on whether this is normal or what parts I may need to replace or rebuild?

Thanks,
Harry

[DRM500RUBYZR-1]

Mileage?

[Okiedoke]

Mileage?

Just passed 27k miles.

[DRM500RUBYZR-1]

OK, That is odd.
It should not feel that "floaty" with those miles.
Does the ride height appear normal?

Logically, shocks or springs.
Get car in the air, and check both front and rear springs for any splitting or cracking of the spring itself. Typically, the car droops noticeably if there is an issue with the spring.
Next, do the usual bounce test at each corner to see if one or more shocks has too little resistance in either direction.
Check the condition of all of the suspension bushings, front and rear.
Alignment, if all of the other check out, then check the alignment of particularly the rear wheels and the camber settings. If too positive, the car can seem twitchy, which sometimes is described as unstable. Refer to Vette Brakes and Products for their suggested street settings as a good reference.

My first suspect would be the shocks might need replacement, although the mileage seems low for that.
Most often, that causes the sea sickness symptoms.
Let us know what you find.
:cheers:
Marty

[mike100]

It is the stock valving on the shocks. I got my car with exactly the same mileage (27k) and i felt the rebound was 'loose' or bouncy. Compression was ok, but could have been stiffer too. I ended up sending (dropping them off at their shop in person) my shocks to Bilstein to get slightly more aggressive valving, but not race valving or anything like that.

I ended up with the request to increase rebound 20% and compression 10% if I recall correctly. I didn't alter compression much because it would be possible to program the shock controller to stiffen the setting at a lower speed...it was the floaty rebound that needed the correction. If you search my name here and 'bilstein' the post should come up.

I hear they aren't keen on rebuilding these shocks anymore, but might custom valve brand new unit$.

[RussMcB]

Sounds like a shocks/dampening issue. I can't think of a reason why springs would cause this behavior.

I was fortunate to find new Bilsteins for a decent price at "AJ USA" I believe (or some name like that).

You can also search for "DeltaVee". They offer rebuilding services for our FX3 shocks.

I've very happy with how my car handles, and it's mostly stock, 67.000 miles, good alignment. I can definitely feel a difference with the three settings.

[DRM500RUBYZR-1]

Sounds like a shocks/dampening issue. I can't think of a reason why springs would cause this behavior.

I was fortunate to find new Bilsteins for a decent price at "AJ USA" I believe (or some name like that).

You can also search for "DeltaVee". They offer rebuilding services for our FX3 shocks.

I've very happy with how my car handles, and it's mostly stock, 67.000 miles, good alignment. I can definitely feel a difference with the three settings.

If the spring is failing due to splitting, the shocks are unable to properly or adequately compensate for it's failure with the added burden it places on the shocks during suspension travel.

Shocks remain the most likely culprit, but it is essential to check all of the components while there.
Let us know what you find.
:cheers:
Marty

[rkreigh]

what year? The later cars softened up the spring rates and the shocks are now dried up and likely not dampening as well as they should.

do the "bounce test" and push down and the front of the car and see how the shocks feel. They should dampen out right away and not allow you to feel a bounce or softness.


The later cars can feel a bit "boaty" and skip around over bumps. I went to the coil overs and while they can be a huge pain, they do give the car that planed feel I was looking for.

I really like the banski rods for the back. they take all the "sticktion" out of the suspension travel and free it up without being harsh.

Let me know if you need FX3 ZR-1 shocks, I have some 90-92 for sale.

you can also use them on later model ZR-1 with the right controller box which I also have. PM me if you need anything.

[Fully Vetted]

In my opinion, at this point in the car's life the mileage doesn't matter. You can't avoid the fact that they are now 20+ years old. I replaced my shocks for close to the same price as it was to rebuild (back when they rebuilt them). I paid $800 including shipping for 4 new ones. Now it rides great.

[USAFPILOT]

what year model? I think I read that the C4 springs were softened every year, and that switching to a 1990 spring with the later C4 shocks would ride better, or more sporty, less float.

[Okiedoke]

OK, That is odd.
It should not feel that "floaty" with those miles.
Does the ride height appear normal?

I think it's the stock height. Here's a picture that I took today:
http://i34.photobucket.com/albums/d119/harryhhsu/RideHeight_zpsx3pomeam.jpg


Logically, shocks or springs.
Get car in the air, and check both front and rear springs for any splitting or cracking of the spring itself.
I had the Z checked out by a Corvette shop when I got it 3 years ago. The only issue was a delaminating rear leaf spring, which I replaced right away from a Corvette salvage yard. I don't know the miles on the spring.


Next, do the usual bounce test at each corner to see if one or more shocks has too little resistance in either direction.
Marty
So I drove the Z to work today and went over speed bumps at 3 MPH. I don't think I felt the rear bounce. However, the front very noticeably bounced twice.

I have a right front actuator time out code that comes up once in a while, which I assume is an issue in itself, but is unrelated to the bounce?

Thanks,
Harry

[Okiedoke]

what year model? I think I read that the C4 springs were softened every year, and that switching to a 1990 spring with the later C4 shocks would ride better, or more sporty, less float.

1991

[Okiedoke]

I was fortunate to find new Bilsteins for a decent price at "AJ USA" I believe (or some name like that).

I found these on their site: http://www.ajusa.com/1991-Chevrolet-Corvette-ZR1-Bilstein-Motorsports-Shock-Absorbers-c38cd.html
Do you know which is the right part number? Are the front and rear the same?


You can also search for "DeltaVee". They offer rebuilding services for our FX3 shocks.

Found DeltaVee's rebuild service: http://deltavee.net/shop/services/bilstein-shock-rebuild-service-adjustable-dampers/
Quite a bit cheaper to rebuild than buy new!

[Okiedoke]

It is the stock valving on the shocks. I got my car with exactly the same mileage (27k) and i felt the rebound was 'loose' or bouncy. Compression was ok, but could have been stiffer too. I ended up sending (dropping them off at their shop in person) my shocks to Bilstein to get slightly more aggressive valving, but not race valving or anything like that.

I ended up with the request to increase rebound 20% and compression 10% if I recall correctly. I didn't alter compression much because it would be possible to program the shock controller to stiffen the setting at a lower speed...it was the floaty rebound that needed the correction. If you search my name here and 'bilstein' the post should come up.

I hear they aren't keen on rebuilding these shocks anymore, but might custom valve brand new unit$.

This being a Corvette and ZR-1 at that, I was thinking it couldn't possibly have bounced this much when new. My plan in general is to keep this Z stock but also will be doing more autocross and track days with it. Do you think stock valving/rebound/compression would be sufficient? It must be much better than what I'm experiencing now.

[mike100]

... Do you think stock valving/rebound/compression would be sufficient? It must be much better than what I'm experiencing now.

New stock replacements sufficient or adequate? Probably yes.
Could it be better? ...Absolutely.

The LT5 is heavy and I think it wears out the front shocks as there isn't a special part number for it- I think all FX3 shocks were the same for all vettes.

Not sure how hard it is to get a modified shock controller these days, but that is another way to make them stiffer/sooner (at lower speeds). Even so, I liked the amount of rebound control my car has now.

[mike100]

This being a Corvette and ZR-1 at that, I was thinking it couldn't possibly have bounced this much when new...

I haven't driven a new one since 1993, but you are right- they didn't wallow and bounce much on the stiff setting.

[DRM500RUBYZR-1]

Your rear spring already had delaminated and has been replaced.
Please make sure you inspect that front spring for the same delamination, or splitting, cracking, whatever you want to call it.

As these fiberglass springs delaminate, they lose their ability to react properly to suspension travel, i.e. they cannot control the movement.

Back went; front may be going too.
Easy to see; It looks like it is shredding.

I remain equally convinced that due to age, you most likely need shocks, certainly front ones based on your description.

Check the spring.
Replace the shocks.
AND check those actuators.

Keep us posted.
:cheers:
Marty

[Okiedoke]

Let me know if you need FX3 ZR-1 shocks, I have some 90-92 for sale.

you can also use them on later model ZR-1 with the right controller box which I also have. PM me if you need anything.

PM sent.

[Z51JEFF]

I found these on their site: http://www.ajusa.com/1991-Chevrolet-Corvette-ZR1-Bilstein-Motorsports-Shock-Absorbers-c38cd.html
Do you know which is the right part number? Are the front and rear the same?


Found DeltaVee's rebuild service: http://deltavee.net/shop/services/bilstein-shock-rebuild-service-adjustable-dampers/
Quite a bit cheaper to rebuild than buy new! AJUSA is where I got a new set. Don't bother with DELTAVEE,guy tried to pull a fast one on me and it cost him a new set of shocks. Too long to get into just won't ever recommend the place.

[RussMcB]

I found these on their site: http://www.ajusa.com/1991-Chevrolet-Corvette-ZR1-Bilstein-Motorsports-Shock-Absorbers-c38cd.html
Do you know which is the right part number? Are the front and rear the same?I'm not sure if either of these links work. They're bookmarks from 2 years ago.

http://www.ajusa.com/1991-Chevrolet-CORVETTE-Bilstein-Monotube-Shock-Absorbers-and-Struts-c2ddev7c2q6c61.html

http://www.ajusa.com/1991-Chevrolet-Corvette-ZR1-Bilstein-Motorsports-Shock-Absorbers-c38cd.html

[Okiedoke]

I'm not sure if either of these links work. They're bookmarks from 2 years ago.

http://www.ajusa.com/1991-Chevrolet-CORVETTE-Bilstein-Monotube-Shock-Absorbers-and-Struts-c2ddev7c2q6c61.html

http://www.ajusa.com/1991-Chevrolet-Corvette-ZR1-Bilstein-Motorsports-Shock-Absorbers-c38cd.html

Thanks!

[Okiedoke]

AJUSA is where I got a new set. Don't bother with DELTAVEE,guy tried to pull a fast one on me and it cost him a new set of shocks. Too long to get into just won't ever recommend the place.

Jeff, are these the ones you got from AJUSA? 2 front and 2 rear?

http://www.ajusa.com/1991-Chevrolet-CORVETTE-Bilstein-Monotube-Shock-Absorbers-and-Struts-c2ddev7c2q6c61.html

[Okiedoke]

Jeff, are these the ones you got from AJUSA? 2 front and 2 rear?

http://www.ajusa.com/1991-Chevrolet-CORVETTE-Bilstein-Monotube-Shock-Absorbers-and-Struts-c2ddev7c2q6c61.html

I went ahead and ordered a set of these shocks. The front right shock gear stops seem to look work (not square). How do these look to you guys? Should I replace it?

http://i34.photobucket.com/albums/d119/harryhhsu/ActuatorGearStop1_zpse60bhbmd.jpg

http://i34.photobucket.com/albums/d119/harryhhsu/ActuatorGearStop2_zpsflxdzeti.jpg

Lynn at CaptainZ (who's been very responsive and helpful) is also betting that my actuator needs to be rebuilt. Should I go ahead and send it in or maybe just replace the shock gear first (assuming you guys think it does need to be replaced) and see if the code 14 still shows up?

[Okiedoke]

I went ahead and ordered a set of these shocks. The front right shock gear stops seem to look work (not square). How do these look to you guys? Should I replace it?


It appears this question is moot since AJUSA just confirmed that the new shocks come with the gears. Best thing for me to do is to replace the shocks and see if the SRC light still comes on. If it does, then send the actuator to CaptainZ for rebuild.

[mike100]

There is a height or bushing squish requirement. it is possible the actuator is riding a bit over the gear if the shock is not installed deep enough. if you have somebody turn the ign key to run while you look at the actuator- it is supposed to turn.

[Okiedoke]

I've got the new shocks installed now. The SRC is still giving code 14. So I was trying to remove the front right actuator so I can send it in to CaptainZ for rebuild. I can remove the actuator and unplug it. Now, can any magicians out there tell me how I can squeeze the connector and cable (red arrows) in between (yellow line) the metal tube and welds on both ends (blue arrow)? It seems impossible to do? Am I missing something?

http://i34.photobucket.com/albums/d119/harryhhsu/ActuatorRemoval_zpssm5zps0t.jpg

Thanks,
Harry

[HAWAIIZR-1]

I've got the new shocks installed now. The SRC is still giving code 14. So I was trying to remove the front right actuator so I can send it in to CaptainZ for rebuild. I can remove the actuator and unplug it. Now, can any magicians out there tell me how I can squeeze the connector and cable (red arrows) in between (yellow line) the metal tube and welds on both ends (blue arrow)? It seems impossible to do? Am I missing something?

http://i34.photobucket.com/albums/d119/harryhhsu/ActuatorRemoval_zpssm5zps0t.jpg

Thanks,
Harry

Harry,

If I remember correctly there are bolts inside the fender liner near those areas. By the way, how was the service with AJUSA? A member here bought his car without FX3 shocks and wants to put back to stock with selective ride system. I hope you get yours resolved.

[Okiedoke]

Harry,

By the way, how was the service with AJUSA? A member here bought his car without FX3 shocks and wants to put back to stock with selective ride system. I hope you get yours resolved.

AJUSA service was great. Very responsive via email and chat. Shipping was fast once they had it in stock. The sale price was also much cheaper than my shop could get the shocks for.

[Okiedoke]

Harry,

If I remember correctly there are bolts inside the fender liner near those areas.

Craig, do you mean remove all of these bolts?

http://i34.photobucket.com/albums/d119/harryhhsu/FenderLiner_zpsxl3kull5.jpg

[HAWAIIZR-1]

Harry,

Thanks about AJUSA and I'll pass it on. About the bolts I think it was the top two middle you show arrows. My car is put away to look, but if you look from the inside you should see the piece that is holding those lines against the liner. If you pull off the rubber you will see how that is a separate piece in the center. My memory sucks so I hope I'm guiding you correctly.


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[rkreigh]

look at the plastic gears on the actuator. take them off the shock and turn the key on and watch the gears on the actuator. They should cycle both ways.

You also have to carefully set the "gear height" on the shocks so the gear goes into the actuator but doesn't bottom out or you will quickly crack the actuator (ask me how I know :o )

Anyway, if anyone needs FX3 stuff I have shocks, controllers, and actuators.

The FX3 stuff can be a pain, but it's not horrible to trouble shoot.

[Okiedoke]

Harry,

About the bolts I think it was the top two middle you show arrows.

It was the 4 bolts on the left side of the picture.

[Okiedoke]

look at the plastic gears on the actuator. take them off the shock and turn the key on and watch the gears on the actuator. They should cycle both ways.

You also have to carefully set the "gear height" on the shocks so the gear goes into the actuator but doesn't bottom out or you will quickly crack the actuator (ask me how I know :o )

Anyway, if anyone needs FX3 stuff I have shocks, controllers, and actuators.

The FX3 stuff can be a pain, but it's not horrible to trouble shoot.

So the 4 new Bilstein shocks were installed. It's giving a 14 code most of the time instead of being intermittent. I sent in the front right actuator to CaptainZ who tested it and gave it a clean bill of health. Any other ideas? I was really hoping it would be the shock gear or actuator.... The unpainted metal piece (like a circle with two sides chopped off) right under the actuator cup on the front right gear is pretty loose and can be easily rotated at least 30 degrees back and forth. The shop couldn't make it any tighter. Could this be the issue now and how to tighten it? The front left side is tight.

[Okiedoke]

Finally!! No more SRC light for the first time in over 3 years!!! :dancing Made it 75 miles over two days with no light so far. (knock on wood) It turned out the 14 was because the shock gear on the new shock was sitting too high in the actuator. The shop put a shim below the actuator cup on the shock to lower the gear within the actuator and that did it!

[Hib Halverson]

So the 4 new Bilstein shocks were installed. It's giving a 14 code most of the time instead of being intermittent. I sent in the front right actuator to CaptainZ who tested it and gave it a clean bill of health. Any other ideas? I was really hoping it would be the shock gear or actuator.... The unpainted metal piece (like a circle with two sides chopped off) right under the actuator cup on the front right gear is pretty loose and can be easily rotated at least 30 degrees back and forth. The shop couldn't make it any tighter. Could this be the issue now and how to tighten it? The front left side is tight.

If you know the actuator is good then the DTC14 might be caused by the actuator height no being right or the shock's bypass valve assembly is faulty.