Fox T-Bird/Cougar Forums

Technical => Suspension/Steering => Topic started by: mcb82gt on June 21, 2011, 10:29:35 AM

Title: Rear coil spring question
Post by: mcb82gt on June 21, 2011, 10:29:35 AM
Now that ive got my front end done, Im gonna focus on the rear.  Im looking for about 1-1.25" drop.  My plan is to use the stock springs from a 95 convertible.  It shows they are cargo coil 827, on the MOOG site.  Will those hit it about what I want? :hick:

http://www.moog-suspension-parts.com/proddetail.asp?prod=MOOG-CC827

Specs are at the bottom.
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 11:39:03 AM
Nobody has used SN95 GT convert springs in the rear?
Title: Rear coil spring question
Post by: vinnietbird on June 22, 2011, 04:36:46 PM
I used standard SN-95 springs in the rear and got the 1.5 inch drop I wanted. I would wonder if the convertible springs are stiffer. Maybe not as much of a drop, but I can't say for sure because I haven't used the convert. springs. The standard SN-95 springs are great.
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 05:22:30 PM
I knew you used the standard ones, I think Ill try the convert springs.  Thank you Vinnie.
Title: Rear coil spring question
Post by: vinnietbird on June 22, 2011, 05:34:56 PM
They may turn out to be a little stiffer. Not a bad thing. Post your results. Heck, they be the same. I know the V-6 and V-8 cars (coupes) shared the same springs.
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 06:26:48 PM
I had the spec's from MOOGs site, the converts were a little higher load rate and spring rate vs. the reg SN95.

 Ill post the specifics later.
Title: Rear coil spring question
Post by: TOM Renzo on June 22, 2011, 07:46:52 PM
Convertible springs are heavier and normally have a higher spring rate. Convertibles are normally heavier than non convertibles. If moog shows a different number for convertibles the springs are heavier and will most likely raise the car. My choice would not be a cargo coil. They are a heavy duty spring and normally raise the car a bit. Thanks

Here is what we do and some might flame me on this practice but it increases the spring rate while lowering the car. This is the maximum amount we would ever  cut

http://i600.photobucket.com/albums/tt88/tomrenzo/Kitties244.jpg
Title: Rear coil spring question
Post by: gumby on June 22, 2011, 07:54:54 PM
The IRS cobras used rear springs with less spring rate and higher load rate vs. their coupe counterparts. Apparently Ford wanted a bit softer ride for the 'vert w/o loosing the height. This very well could be different for the live axle springs you are looking at, however it sounds like you have all the info on MOOGs site to figure it out.
Load rating is what will determine ride height. So if that is your main target, that is the number you will need to concentrate on. There is a specific number floating around here someplace that gives a relationship between the amount of change in load rating vs. change in ride height. I'll see if I can locate that.

Quote from: TOM Renzo;362016
My choice would not be a cargo coil.
I would also stay away from the cargo coils as a preference. I dont like variable rate coils if I can avoid them.




*edit: found the info
Quote from: SVOMike;128769
The rule of thumb in chassis engineering was every 150 lbs in load rate subtracted from the factory selected springs the front would lower it 1/2" in the front and every 50lbs of load rate subtracted from the rear would lower that 1/2".
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 08:05:15 PM
Quote from: TOM Renzo;362016


Here is what we do and some might flame me on this practice but it increases the spring rate while lowering the car. This is the maximum amount we would ever  cut

http://i600.photobucket.com/albums/tt88/tomrenzo/Kitties244.jpg

 
I wont flame you, I do, and have done the same thing before,  I just cut my front springs 3/4ths a coil with the grinder just like that.

The cargo coil is supposedly the stock coil.  It is a progressive rate and the specs on it are much less than the stock Cougar coil, which is currently on it.  I think it will lower it about perfect for what I want??  We'll see.
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 08:17:53 PM
The convert rear SN95 springs have 235lb less load rating, and 75lb less spring rate than the stock cougar 8599 springs.

I think (hope) it will lower it about right.  If the stock coupe SN95 springs dropped it 1.5" , Im guessing this will do what I want.

If not, I will go with reg SN95's and drop it a little more.

Just because they are CC's, doesnt mean they wont lower a Cougar, remember these cars have a thick heavy booty compared to the Stangs.:D
Title: Rear coil spring question
Post by: TOM Renzo on June 22, 2011, 08:30:02 PM
Spring rates and loads

5190    wire diameter  .541          convertible   
          load height      10.50                         
          number of coils  9.38                         
          load                  650                         
          rated load height  174                         
          free height          13.57


5367    Wire                    .541      cobra
          LH                        9.63
          coils                      9.37
          load                      650
          rated height          174
          free length            13.57


5372      wire                .540              coupe
            LH                    11.00
            coils                  9.28
            load                  322
            rated height      162
            free height        13.00
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 08:35:50 PM
Quote from: TOM Renzo;362030
Spring rates and loads

5190    wire diameter  .541             
          load height      10.50                         
          number of coils  9.38                         
          load                  650                         
          rated load height  174                         
          free height          13.57

 

Im not sure what the 5190 is, but it has a installed height 1" higher than the Stang or Cougar.
Title: Rear coil spring question
Post by: TOM Renzo on June 22, 2011, 08:49:51 PM
Just posting what the rates are . This is moog specks. That is a convertible spring. Its a higher spring as i suspected.
Title: Rear coil spring question
Post by: mcb82gt on June 22, 2011, 09:09:32 PM
Quote from: TOM Renzo;362034
Its a higher spring as i suspected.


Higher vs. what?