84 is not going to need the same arc to accomplish the same ride height as later years, due to spring rate.
Lowering and spring identification
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
Lowering and spring identification
So I'm lowering the front end of the 84.
I got the transverse spring out and for those guys that are gonna remove this in the future just beware that unbolting and relieving the spring pressure is the easy part. Actually pulling it out you have to have a lot of patience. Anyways....
Here is my spring compared to a good used stock 87 that I'm gonna use for lowering. Look at the differance in height though. The one in the back has approximently 2 inches in more height than the one I took out.
If I'm lowering it is this new spring gonna keep me up higher because of the bow already being 2 inches greater than the one I took out?
Recently I also saw a thread that listed the numbers of springs for identification. I can't seem to find that thread in my search so any help would be appreciated.
These are the numbers of the 2 springs.
HMP018530
8308807- there is also a BMA on this spring
I got the transverse spring out and for those guys that are gonna remove this in the future just beware that unbolting and relieving the spring pressure is the easy part. Actually pulling it out you have to have a lot of patience. Anyways....
Here is my spring compared to a good used stock 87 that I'm gonna use for lowering. Look at the differance in height though. The one in the back has approximently 2 inches in more height than the one I took out.
If I'm lowering it is this new spring gonna keep me up higher because of the bow already being 2 inches greater than the one I took out?
Recently I also saw a thread that listed the numbers of springs for identification. I can't seem to find that thread in my search so any help would be appreciated.
These are the numbers of the 2 springs.
HMP018530
8308807- there is also a BMA on this spring
Last edited by qws; Jan 2, 2012 at 09:35 PM.
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Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
So should I just re-use the 84 spring to lower my ride height?
I made an assumption that my current spring is a Z51 but not sure, thats why I posted the number thats stamped on it. I'm googling it but not finding anything yet.
My thought was also, that if the 87 spring for a base vehicle then I'd use that vs the Z51 spring since thats stiffer. But after looking at the differance in the arch I just don't want to waste my time if its not gonna do what I want.
I made an assumption that my current spring is a Z51 but not sure, thats why I posted the number thats stamped on it. I'm googling it but not finding anything yet.
My thought was also, that if the 87 spring for a base vehicle then I'd use that vs the Z51 spring since thats stiffer. But after looking at the differance in the arch I just don't want to waste my time if its not gonna do what I want.
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
The thread I was looking for is here
http://www.corvetteactioncenter.com/...ion-chart.html
It gives you what the 3 letters that are stamped into the spring mean.
And of course the BMA that mine has isn't listed.
On that note, and I'll be honest I don't understand how to read the spring rates and exactly what they mean could someone take a brief moment to give me a quick lesson?
For a 84 with FE1 is 63.5 N/mm
Z51 is 102 N/mm
The 87 with FE1 is 51.8 N/mm
If the 51.8 is the softest would that mean once the weight is on the tires it would help sit lower?
thanks guys..
http://www.corvetteactioncenter.com/...ion-chart.html
It gives you what the 3 letters that are stamped into the spring mean.
And of course the BMA that mine has isn't listed.
On that note, and I'll be honest I don't understand how to read the spring rates and exactly what they mean could someone take a brief moment to give me a quick lesson?
For a 84 with FE1 is 63.5 N/mm
Z51 is 102 N/mm
The 87 with FE1 is 51.8 N/mm
If the 51.8 is the softest would that mean once the weight is on the tires it would help sit lower?
thanks guys..
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
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Pro
Joined: Feb 2010
Posts: 677
Likes: 3
From: Metairie LA
I replaced my stock front spring with a BMA spring when I was attempting to lower my 86. I put the wedges in and updated to the new retainers. The Vette was still high. I then removed the end pads - Still too high. I also changed to Bilstein shocks from the KYB that I put in there (Bilsteins are a bit shorter) - Still wont drop.
The BMA spring apparently is an early Z51 spring and it has quite a bit less "curve" than the one I replaced (I still have the original and may apply the wedges to that one and give it a shot).
The last time I measured it I was 27 1/2 inches to the top of the wheel arch.
My only thought is that the stiffer spring is not letting it drop - posted a thread about it a while back.
http://forums.corvetteforum.com/c4-t...-it-lower.html
The BMA spring apparently is an early Z51 spring and it has quite a bit less "curve" than the one I replaced (I still have the original and may apply the wedges to that one and give it a shot).
The last time I measured it I was 27 1/2 inches to the top of the wheel arch.
My only thought is that the stiffer spring is not letting it drop - posted a thread about it a while back.
http://forums.corvetteforum.com/c4-t...-it-lower.html
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
I replaced my stock front spring with a BMA spring when I was attempting to lower my 86. I put the wedges in and updated to the new retainers. The Vette was still high. I then removed the end pads - Still too high. I also changed to Bilstein shocks from the KYB that I put in there (Bilsteins are a bit shorter) - Still wont drop.
The BMA spring apparently is an early Z51 spring and it has quite a bit less "curve" than the one I replaced (I still have the original and may apply the wedges to that one and give it a shot).
The last time I measured it I was 27 1/2 inches to the top of the wheel arch.
My only thought is that the stiffer spring is not letting it drop - posted a thread about it a while back.
http://forums.corvetteforum.com/c4-t...-it-lower.html
The BMA spring apparently is an early Z51 spring and it has quite a bit less "curve" than the one I replaced (I still have the original and may apply the wedges to that one and give it a shot).
The last time I measured it I was 27 1/2 inches to the top of the wheel arch.
My only thought is that the stiffer spring is not letting it drop - posted a thread about it a while back.
http://forums.corvetteforum.com/c4-t...-it-lower.html
My thinking is by going to a base model spring is would be much softer and not as stiff. So I found a used 87 spring in good condition and I plan to cut the rubber down leaving about a 1/8 still attached and then using the metal shim. Keeping my fingers crossed that its gonna work.
Since I'm in there figured I have to do a bunch of other stuff as well.
If all goes right an once I know it has worked I will then look into selling the Z51 spring.
Pro
Joined: Feb 2010
Posts: 677
Likes: 3
From: Metairie LA
I have been watching Agent86 and the front coil overs - may have to invest in that if all else fails. I also looked at the VB&P adjustable spring but it states that it is only for 88+ (don't know what the difference is and can it be modded to work?).
Currently I am stripping the body for paint (I'd rather remove front springs any day) so the lowering is not my top priority but let me know how the stock spring works for you.
Currently I am stripping the body for paint (I'd rather remove front springs any day) so the lowering is not my top priority but let me know how the stock spring works for you.
