Rear spring question
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Rear spring question
I am tired of my '87's rear spring being too stiff, and it's not even the sport suspension.
I saw a parts post here with a rear spring from a '92: http://forums.corvetteforum.com/zerothread?id=215703
I know there's a few suspension guru's here, so my question will be is the spring being offered softer than my 87's base rear spring?
If I can be relatively assured it is, I will definitely want it.
Thanks
:chevy
I saw a parts post here with a rear spring from a '92: http://forums.corvetteforum.com/zerothread?id=215703
I know there's a few suspension guru's here, so my question will be is the spring being offered softer than my 87's base rear spring?
If I can be relatively assured it is, I will definitely want it.
Thanks
:chevy
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Rear spring question (BBA)
Hey BBA,
I can understand what you mean by the ride harshness.
Before you go swapping springs,is the original GM bushings in the suspension back there?If so, its prob. time to change them.
Mine were so far gone and was causing more of a BANG/JOLT in the ride alot more then when I first got the car 6 years ago.
After changing the bushings back there with new ones, the ride improved ALOT even with my Z51 spring.I even used Urethanes.Im sure the factory replacement type would have been a nicer ride.
I would suggest going with stock rubber bushings to improve the ride over urethanes stiffness.
Ill be watching the thread to see if anyone answeres your question more directly.Im curous to know if these softer springs have a certain/specific spring rate instead of being called soft,firm,or sport.
Of course Im sure a softer spring would improve the ride alot as well too.Just be sure the bushings arent worn out.
:)
I can understand what you mean by the ride harshness.
Before you go swapping springs,is the original GM bushings in the suspension back there?If so, its prob. time to change them.
Mine were so far gone and was causing more of a BANG/JOLT in the ride alot more then when I first got the car 6 years ago.
After changing the bushings back there with new ones, the ride improved ALOT even with my Z51 spring.I even used Urethanes.Im sure the factory replacement type would have been a nicer ride.
I would suggest going with stock rubber bushings to improve the ride over urethanes stiffness.
Ill be watching the thread to see if anyone answeres your question more directly.Im curous to know if these softer springs have a certain/specific spring rate instead of being called soft,firm,or sport.
Of course Im sure a softer spring would improve the ride alot as well too.Just be sure the bushings arent worn out.
:)
Advanced
Joined: Dec 2001
Posts: 83
Likes: 0
From: Syracuse NY
Re: Rear spring question (Bill's86Coupe)
I would also look to the shocks. They will have an impact on how fast the shock is dissipated. If you can get softer shocks, that might help to make the ride smoother without changing the springs.
The bushings are a good idea too, but lots of work.
The bushings are a good idea too, but lots of work.
Pro
Joined: Dec 2000
Posts: 666
Likes: 1
From: Salt Lake City UT
Re: Rear spring question (BBA)
Check to see if the rubber bump stops have been hitting on the top of the suspension knuckels. If they have bottomed out, you can tell by black rubber marks on top of the knuckle, I would check shocks and then the spring. Look at the spring to see if it still has an arch in it. If it does it is probably OK. If the spring has flattened out it could be from wear but more likely from heat and it could at that point delaminate. As stated before, I would suspect bushings and shocks before the spring. New bushings, well lubed, well make a huge improvement. Hope this helps some.
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Rear spring question (Bill's86Coupe)
Thanks all for the sugestions, but all the bushings look OK, the car does not handle bad, it's actually handles fine.
My complaint is simply the rear end is too stiff for my likening. When I go over a speed bump, I can feel the front suspension actually absorb some the bump, while the rear suspension will just push the whole car up the bump with very little give ( comparatively ). When I take off in corners, the rear end will loose traction, indicating the rear end has much more chasis coupling than the front end. A softer spring will help this I think.
What really gets me is I have the same size tires as my friends porsche, and when I drive his car over the same bumps...it's suspension actually absorbs them, where my suspension will force the frame of the car ( and me ) to absorb it.
I think the Corvettes that came with the 17" wheels may have softer springs than the ones that came with 16" wheels ( like mine ).
Again...does anyone have specific data on the different springs?
My complaint is simply the rear end is too stiff for my likening. When I go over a speed bump, I can feel the front suspension actually absorb some the bump, while the rear suspension will just push the whole car up the bump with very little give ( comparatively ). When I take off in corners, the rear end will loose traction, indicating the rear end has much more chasis coupling than the front end. A softer spring will help this I think.
What really gets me is I have the same size tires as my friends porsche, and when I drive his car over the same bumps...it's suspension actually absorbs them, where my suspension will force the frame of the car ( and me ) to absorb it.
I think the Corvettes that came with the 17" wheels may have softer springs than the ones that came with 16" wheels ( like mine ).
Again...does anyone have specific data on the different springs?
Racer
Joined: Sep 2001
Posts: 259
Likes: 0
From: Pontiac IL
Re: Rear spring question (BBA)
I don't know the site but Hib Halverson posted a table for all C4 springs that gicves a lot of detail. I know the 87 base is considerable stiffer than a 95 or 96. Mid America also markets an aftermarket soft spring for $300, which you can purchase directly from the manufacturer for about $280. One caution is that my original 96 base suspension spring delaminated, or cracked. I also have a 84 base spring which is considerably thicker and perhaps more reliable???FrankLT4CE
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: Rear spring question (FrankLT4CE)
'87 Rear Spring.
FE1 39.9 N/mm
Z52 39.9 N/mm
Z51 57.2 N/mm
FE1 39.9 N/mm (Convertible)
Z52 39.9 N/mm (Convertible)
'92 Rear Spring
FE1 39.9 N/mm
FX3 39.9 N/mm
ZR1 33.0 N/mm
Z07 57.2 N/mm
FE1 39.9 N/mm (Convertible)
FX3 39.9 N/mm (Convertible)
[Modified by scorp508, 4:22 PM 1/13/2002]
FE1 39.9 N/mm
Z52 39.9 N/mm
Z51 57.2 N/mm
FE1 39.9 N/mm (Convertible)
Z52 39.9 N/mm (Convertible)
'92 Rear Spring
FE1 39.9 N/mm
FX3 39.9 N/mm
ZR1 33.0 N/mm
Z07 57.2 N/mm
FE1 39.9 N/mm (Convertible)
FX3 39.9 N/mm (Convertible)
[Modified by scorp508, 4:22 PM 1/13/2002]
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Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Rear spring question (scorp508)
So the base suspension option is not included on the center storage compartment label with the other options? ( I ask because I thought all codes were listed there. )
Le Mans Master
Joined: Feb 1999
Posts: 6,170
Likes: 11
From: somers, ny
Re: (scorp508)
BB, keep in mind that GM changed the whole suspension geometry in 88. So even tho the spring rates may be the same the wheel rate could be softer. Looking at the chart below it looks like the rears got softer & softer from 93 on.. I replaced my whole rear suspension with a 93 setup and it made a big difiference for the stock Z51 rear.. Good luck
http://vettenet.org/susp_chart.html
http://vettenet.org/susp_chart.html
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: (ralph)
What rear suspension parts are different?
I'm starting to wonder if going to the coil overs is a better idea for the rear suspension. I just have to have that Porsche smoothness!
I'm starting to wonder if going to the coil overs is a better idea for the rear suspension. I just have to have that Porsche smoothness!
Le Mans Master
Joined: Feb 1999
Posts: 6,170
Likes: 11
From: somers, ny
Re: (BBA)
Not sure what is all different, but i know the knuckles are different. Also the required setback on the wheels is different. Pre 88 took 16x9 wheels (some had 8 inch wheels too) with a +/- 6 1/2" setback and above 88 took 17x9 with a 7 1/4 " setback (the 88 & up cars are wider hub to hub). Front is similar with a completely redesigned suspension. I think the springs are interchangable, but not 100% sure. Based on that chart you would have to find a 94-96 spring if you wanted to go softer.
