Understanding Lowering Springs

[KaBoom1701]

No worries.

I was able to pick up a set of Pfadt springs from another C5 member so I'm good to go. Thx for the help.

[Mikamaro]

As per my goal, I want to get stiffer front and rear springs to match my 1LE track package but only wish to lower the front by 0.5in and rear by 1.0in to level out the car and still get high clearance for daily driving...
I've been looking for a manufacturer that has something along those line...but did not find one yet...anyone?

[Apex Motorsports]

Originally Posted by Mikamaro

As per my goal, I want to get stiffer front and rear springs to match my 1LE track package but only wish to lower the front by 0.5in and rear by 1.0in to level out the car and still get high clearance for daily driving...
I've been looking for a manufacturer that has something along those line...but did not find one yet...anyone?

I am not aware of any springs that are less than 1". To achieve that, coil overs are going to be the only option.

[Mikamaro]

Originally Posted by Apex Motorsports

I am not aware of any springs that are less than 1". To achieve that, coil overs are going to be the only option.

Damn...how about the Z/28 springs Or the ZL1 ? Thanks

[White_SS/RS]

Originally Posted by Mikamaro

Damn...how about the Z/28 springs Or the ZL1 ? Thanks

Z28 springs will give you that half inch but the rear springs are too short for the 1LE dampers. They can be modified with machine work to fit though.

[Mikamaro]

Originally Posted by White_SS/RS

Z28 springs will give you that half inch but the rear springs are too short for the 1LE dampers. They can be modified with machine work to fit though.

So if the Z/28 front springs will get me lower by 0.5'', then I need to find a good match of 1''lowering springs for the rear.
now lets find the specs for the Z springs...

[Norm Peterson]

Why not see if you can fab a pair of 1/2" spacers that will be positively restrained to the car and positively locate the springs. If you don't have access to a machine shop (you'd most likely be using a lathe), it is possible to weld something up from flat plates and strips of metal.

I imagine custom-wound springs would be an option, if perhaps a bit pricy.


Norm

[White_SS/RS]

Originally Posted by Mikamaro

So if the Z/28 front springs will get me lower by 0.5'', then I need to find a good match of 1''lowering springs for the rear.
now lets find the specs for the Z springs...

Z28 are approximately 80% firmer. So ~280# front and ~550# rear. Most lowering springs I've found are around 50% firmer at ~220 front ~440 rear. Seeing that it might be difficult to find a matching rear set. It may be better; since the rears need machine work with Z28 coils, is to have the spring perch lowered a half inch further to get what your looking for.

[Mikamaro]

Originally Posted by Norm Peterson

Why not see if you can fab a pair of 1/2" spacers that will be positively restrained to the car and positively locate the springs. If you don't have access to a machine shop (you'd most likely be using a lathe), it is possible to weld something up from flat plates and strips of metal.

I imagine custom-wound springs would be an option, if perhaps a bit pricy.


Norm

well, I was hoping to get something as a direct replacement without too much of work. Cutting springs, adding spacers, adjusting lenght...not my cup of tea.

[Mikamaro]

Originally Posted by White_SS/RS

Z28 are approximately 80% firmer. So ~280# front and ~550# rear. Most lowering springs I've found are around 50% firmer at ~220 front ~440 rear. Seeing that it might be difficult to find a matching rear set. It may be better; since the rears need machine work with Z28 coils, is to have the spring perch lowered a half inch further to get what your looking for.

How come you know all this? If you bought them Were you able to get the GM# part numbers?
if I was to take an easier route for the rear, which one would you recommend even if they are only 50% stiffer?

[White_SS/RS]

Originally Posted by Mikamaro

How come you know all this? If you bought them Were you able to get the GM# part numbers?
if I was to take an easier route for the rear, which one would you recommend even if they are only 50% stiffer?

I myself was looking at increasing the spring rate on my car without getting too low or using high end coilovers. I talked with a few shops and manufacturers about springs, narrowed it down to a few options and bought and tested them for rate. I contemplated using Z28 springs but through research and conversations I think they are on the heavy side for a 1LE damper to effectively control but it would work; that is, if the spring perches on the rear dampers are modified since it's shorter.

The 1LE dampers are capable of handling more spring than just the OEM SS. I feel the 1LE is slightly under sprung and that GM used SS springs and crutched it with sways instead of recreating specific springs. Probably a cost decision... And it works for most drivers. Anyway, testing is where I found that Z28 are about 80% firmer. I think it was also mentioned in a GM press release. I'd have to track down the Z28 coils numbers. I just had the local GM parts supply them for me.

I chose to run BMR's springs. They are one of very few that are linear. Although many say they aren't because they are built with a dual rate. The dual rate is effectively used to keep the spring in place when under full extension and is compressed and essentially unused when at ride height. They are 48% firmer front and 53% rear. I would try to keep the rates close since large bias differences in rate would throw off the understeer/oversteer balance.

[Norm Peterson]

Originally Posted by Mikamaro

well, I was hoping to get something as a direct replacement without too much of work. Cutting springs, adding spacers, adjusting lenght...not my cup of tea.

What can I say - when I first got into tinkering with cars that was pretty much your whole list of options for the situation. It's probably a bit beyond HotRodding 101, but it's not Advanced Placement either.


White - it's good to hear that BMR is keeping the same linear-rate philosophy across platforms.


Norm

[Mikamaro]

Originally Posted by White_SS/RS

I myself was looking at increasing the spring rate on my car without getting too low or using high end coilovers. I talked with a few shops and manufacturers about springs, narrowed it down to a few options and bought and tested them for rate. I contemplated using Z28 springs but through research and conversations I think they are on the heavy side for a 1LE damper to effectively control but it would work; that is, if the spring perches on the rear dampers are modified since it's shorter.

The 1LE dampers are capable of handling more spring than just the OEM SS. I feel the 1LE is slightly under sprung and that GM used SS springs and crutched it with sways instead of recreating specific springs. Probably a cost decision... And it works for most drivers. Anyway, testing is where I found that Z28 are about 80% firmer. I think it was also mentioned in a GM press release. I'd have to track down the Z28 coils numbers. I just had the local GM parts supply them for me.

I chose to run BMR's springs. They are one of very few that are linear. Although many say they aren't because they are built with a dual rate. The dual rate is effectively used to keep the spring in place when under full extension and is compressed and essentially unused when at ride height. They are 48% firmer front and 53% rear. I would try to keep the rates close since large bias differences in rate would throw off the understeer/oversteer balance.

Excellent info here WhiteSS, thanks.
Have you tested the ZL1 coil springs? or any other progressive coil?

[White_SS/RS]

Originally Posted by Mikamaro

Excellent info here WhiteSS, thanks.
Have you tested the ZL1 coil springs? or any other progressive coil?

I don't have any experience with ZL1 or progressive coils.