Mach 1 springs in the rear - pics! October 21, 2007, 06:18:41 PM OK, I finally got around to replacing the stock rear springs with Mach 1 rear springs. With the CHE adjustable arms adjusted all the way down, the rear sat about 28.25" from ground to bottom of fender lip. With the front lowered & sitting just over 26" ground to fender lip, the rake was too much and looked a bit silly. Using some quick calcs I did in my head, I installed the Mach 1 rear springs and raised the CHE pedestals 1 1/4".The springs are quite a bit different in height - the Mach1 are about 3" shorter!So here is the new spring installed:When I finished, I lowered the car and found a level parking lot so I could take pictures - not an easy task finding a level spot anywhere in NH! :hick: The rear is now 27" from ground to fender well lip. There was no change at all in the front.Passengers side: Drivers side (still 3/8" shorter on drivers side front - battery?):The car rides great and the rear is much firmer without feeling the slightest bit harsh - I really like the overall drivability improvement with the Mach 1 springs on all 4 corners.Here is a bit of backward calculation that I did to try to estimate the spring rate of the stock springs. I'm sure if I screwed up, some of the smart suspension folks will point it out to me in a heartbeat - lol :D The second row is the estimated rate for the stock springs - looks like they may indeed be 200 lb/in as was used in previous years? Quote Selected
Mach 1 springs in the rear - pics! Reply #1 – October 21, 2007, 06:29:46 PM looks good man like the stance been reading bout doin this to mine getting real interested Quote Selected
Mach 1 springs in the rear - pics! Reply #2 – October 21, 2007, 06:49:08 PM holy that angle on the spring perch looks brutal. other the that, looks good. Quote Selected
Mach 1 springs in the rear - pics! Reply #3 – October 21, 2007, 07:03:13 PM Quote from: 1WLD BRD;183718holy that angle on the spring perch looks brutal. other the that, looks good.Oh, that's fully unwound with shock detached!Here - I just took one from below the car fully loaded. Quote Selected
Mach 1 springs in the rear - pics! Reply #4 – October 21, 2007, 07:41:14 PM Are you still using stock struts/shocks? Quote Selected
Mach 1 springs in the rear - pics! Reply #5 – October 21, 2007, 07:47:38 PM I believe the stock rears are ~250 lbs/in. edit: Moog replacements are 249 lbs/in, but they have several more active coils indicating the OEM rate is lower)Can you measure "d" and "D" from the old springs? A more accurate calculation can be performed using those (+/- 5%)F/R weight split is probably more like 56% Quote Selected
Mach 1 springs in the rear - pics! Reply #6 – October 21, 2007, 08:09:28 PM Quote from: Sduneman3;183732Are you still using stock struts/shocks?Yep - well, stock replacement Gabriel.Jeremy:They could be 250 lb/in, but they are not constant then - well, the height may be deceptive anyway. The spring is 0.570" diameter wire but the top coil is 0.500" (about 1 full turn). The outer diameter of the top coil is 5.07", but the average diameter may be slightly larger due to the smaller diameter of the wire at the top coil where I measured. I assume Ford uses the same grade/temper for their spring wire?The F/R was there as an error check for those who know this. I "guesstimated" on the average distance from pivot to perch to mount point on rear end (well, I used a tape measure so the estimate would be somewhat close anyway.) Quote Selected
Mach 1 springs in the rear - pics! Reply #7 – October 21, 2007, 08:20:50 PM Plug'n'chug into the spring calculator at Efunda. [link]d=.567 (30 mils for paint/rust)D=5.15 (Average is probably bigger)active coils = 7k=214 lbs/in That's just a ballpark figure due to uncertainties in "d" and "D". -----------Both springs are linear. The coil at the top doesn't matter because it isn't an active coil. When installed on the car, that portion of the spring never moves. Ford probably doesn't use the same grade/temper for their spring wire, but those properties don't factor into the spring rate, the modulus of elasticity does. The modulus of elasticity is pretty standard for steel, be it 58ksi 1018 or 160ksi heat treated 4130. Quote Selected
Mach 1 springs in the rear - pics! Reply #8 – October 21, 2007, 08:37:50 PM That's hotness. Now I definitely know I'm going with Mach 1 springs. How much did you have to bring the CHE adjusters up? Quote Selected
Mach 1 springs in the rear - pics! Reply #9 – October 21, 2007, 08:56:57 PM Quote from: Thunder Chicken;183744That's hotness. Now I definitely know I'm going with Mach 1 springs. How much did you have to bring the CHE adjusters up?Read the post lazy Stupid tape measure moved when I was trying to get the camera held right, but it was 1 1/4" Quote Selected
Mach 1 springs in the rear - pics! Reply #10 – October 21, 2007, 11:13:36 PM Where do you get the Mach 1 springs? Can you buy them new?TED Quote Selected
Mach 1 springs in the rear - pics! Reply #11 – October 21, 2007, 11:43:56 PM Ted,Check out Carm (Thunder Chicken)'s thread in this section about springs. There's a link on there that has the set of 4 Mach 1 springs for $209 brand new.I guesstimated 2.5-2.75" shorter then a TC/Sport spring, so at 3" I did pretty good :hick: Quote Selected
Mach 1 springs in the rear - pics! Reply #12 – October 24, 2007, 12:37:15 AM Quote from: JeremyB;183742Plug'n'chug into the spring calculator at Efunda. [link]d=.567 (30 mils for paint/rust)D=5.15 (Average is probably bigger)active coils = 7k=214 lbs/in That's just a ballpark figure due to uncertainties in "d" and "D". -----------Both springs are linear. The coil at the top doesn't matter because it isn't an active coil. When installed on the car, that portion of the spring never moves. Ford probably doesn't use the same grade/temper for their spring wire, but those properties don't factor into the spring rate, the modulus of elasticity does. The modulus of elasticity is pretty standard for steel, be it 58ksi 1018 or 160ksi heat treated 4130.Yeah, actually the OD is about 5.2" which yields about 207 lb/in. Ford also used a 210lb/in rate on some springs so that's possible no?You can tell I have never designed coil springs before. I have designed flat springs using 300 series stainless and they were marginally on the elastic/plastic line depending on the work hardening done (cold rolled I think). I was trying to skirt the line between tool life (they were stamped) and getting the needed force from the spring. Your link wants to make me register - I was just about to check the Mach 1 springs as a check. Quote Selected
Mach 1 springs in the rear - pics! Reply #13 – October 24, 2007, 12:39:16 AM Quote from: Cad-T-Bird 500;183789Where do you get the Mach 1 springs? Can you buy them new?TEDI nabbed mine from someone on Stangnet for $100 shipped. Good deal I think :D Quote Selected
Mach 1 springs in the rear - pics! Reply #14 – October 24, 2007, 02:55:54 PM Quote from: Cougar5.0;184270Your link wants to make me register - I was just about to check the Mach 1 springs as a check.You can delete the efunda cookie to regain access the content. Quote Selected
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