Gen 3 and Gen 4 spring rates?

[steve911]

I thought I read some where on the forums that the Gen 4 cars have a higher spring rate that the Gen 3 cars do due the extra HP.

I looked hard through the archives but came up empty.

Can anyone provide factual info?

thanks

 

[mjorgensen Woodhouse]

I thought I read some where on the forums that the Gen 4 cars have a higher spring rate that the Gen 3 cars do due the extra HP.

I looked hard through the archives but came up empty.

Can anyone provide factual info?

thanks

Here you go


2003-2006 SRT-10:
Front: 200 lb/in
Rear: 500 lb/in
Front Anti-roll Bar: 27mm Hollow
Rear Anti-roll Bar: 27mm Hollow
Michelin PS1 Tires

2008 SRT-10:
Front: 210 lb/in
Rear: 525 lb/in
Front Anti-roll Bar: 27mm Hollow
Front Anti-roll Bar: 27mm Solid
Michelin PS2 Tires

2008 ACR:
Front: 514 lb/in
Rear: 1085 lb/in
Front Anti-roll Bar: 27mm Solid
Rear Anti-roll Bar: 27mm Solid
Michelin PSC Tires

 

[Martin]

Holy cr@p - look at those ACR spring rates... Maybe I should have ordered the kidney-plate option with mine...

 

[Catwood]

Is the spring size, lenght and dia, not rates, the same as a Gen 2?

 

[mcar00]

Holy cr@p - look at those ACR spring rates... Maybe I should have ordered the kidney-plate option with mine...

You think those are firm? I was told by the SRT guys that the spring rates on the Competition Coupes are 1,100 front and 1,500 rear!

Also, does anyone have any idea why the rates on the rear are greater than the rates on the front? I always thought that on a front engine car you would have a higher spring rate on the fronts like Corvettes.

 

[mjorgensen Woodhouse]

You think those are firm? I was told by the SRT guys that the spring rates on the Competition Coupes are 1,100 front and 1,500 rear!

Also, does anyone have any idea why the rates on the rear are greater than the rates on the front? I always thought that on a front engine car you would have a higher spring rate on the fronts like Corvettes.

It takes that rate to maintain ride height with the aerodynamic down force the rear produces

 

[Viperless]

....

Also, does anyone have any idea why the rates on the rear are greater than the rates on the front? I always thought that on a front engine car you would have a higher spring rate on the fronts like Corvettes.

Has something to do with the design of the suspension and the mounting points, angles, etc. of the shocks on the lower A-arms.

 

[mjorgensen Woodhouse]

It takes that rate to maintain ride height with the aerodynamic down force the rear produces

And a Comp Coupe is not a street car so the air flow tolerances under the car need to be kept more even thus the higher spring rates.

 

[steve911]

I found a local salvage yard that says thaey have parts from a wrecked 08. There is a label on the rear bar with the following part number 0520955AC.

I went to my local Dodge dealer and the above number does not cross to anything. I watched as my friendly parts guy looked up the part number for the '08 rear bar. The number that comes up shows that it is the same all the way back to 2003.

I can get the bar for a reasonable price and will do so if it is indeed a solid rear bar, as Mark described in an earlier post. I just dont want to buy a duplicate of what I already have in my '04.

On anther note, can anyone give me the part number for the 09 ACR front bar? The parts listing at the dealer is rather confusing without having a VIN.

thanks

 

[j-rho]

The '08 and up cars have 5% stiffer springs, supposedly due to the new PS2 tires.

The front and rear suspension motion ratios are quite a bit different, with the rears being "softer". The wheel rates, which is what you're usually interested in for handling, aren't very different front to rear.

 

[ACRBruce]

It takes that rate to maintain ride height with the aerodynamic down force the rear produces

If I do mostly autox and shorter tracks w/ top speed never much over 130, could I lower the ACR's spring rates to approx 400/800 F/R? If so where can I find replcement springs? Are these spring 61mm ID and about 167mm long?
BTW, what spirngs rates come with the Moton Club Sports usually Mark?