GT500 CFTP front springs on a Mach 1

[RobZ71LM7]

I installed GT500 Carbon Fiber Track Pack (CFTP) front springs on my 2021 Mach 1. Previously I had HP front springs. I’m still running HP springs in the rear (742#/in). Both sets of springs were purchased brand new from Levittown. There’s lots of reasons why you should or shouldn’t run these springs, but I wanted the stiffest linear rate springs that allowed use of the dust boot and were stock ride height. If these don’t cut it, I’m going straight to the AJ Hartman kit and 400 or 450 # springs. I did install the Steeda 1-3/8” adjustable front sway bar at the same time. Since the factory front sway bar has bonded bushings it’s *possible* that the sway bar change affected ride height the same time.



HP part # KR3Z-5310-D

GT500 CFTP Part # KR3Z-5310-B



Measuring spring length can be done several ways, but I chose to stand them vertically and measure from the bottom to the end of the pigtail up top. What really matters is the difference between the two so don’t get caught up in the actual numbers.



HP wire diameter 0.587”

HP free length 10.5”

Ford advertised rate 211 #/in



GT500 wire diameter 0.629”

GT 500 free length 10”

Ford advertised date 268 #/in



Note all my measurements are with 305/30/19 Continental Extreme Contact Sport 02’s at ~31 psi.



HP springs (12k miles)

26.75” front wheel centerline to bottom of HP plastic fender lip

4.5” lower splitter “points” to ground



GT500 CFTP (15 miles)

27” front wheel centerline to bottom of HP plastic fender lip

4.75” lower splitter “points” to ground



I’m still dialing in my alignment and was scheduled for a track day this weekend but had to cancel. I’ll update more once I’ve aligned it and put some miles on it. Obviously I’ll update after track days as well. It’s early, but I’m happy with these for $84 a spring and the ride height is about perfect. If they drop any more I’ll update. I’m glad I didn’t go base GT500 springs as GT500 owners indicate that base springs result in a 1/2” higher ride height.

Sponsored

 

[Whitedevil95]

So did you like the change in handling characteristics that came with the new springs? (Oops I missed this at the bottom.)

I am interested if they settle a little bit more. I wouldnt be too enthused about raising the height of the car.

 

[RobZ71LM7]

Got the alignment set in the garage finally.

-3.5/-3.6 front camber
Zero toe

-2.0/-2.0 rear camber
Exactly 1mm toe in at the wheel circumference per side both sides
0.22* total toe-in

The car is noticeably stiffer and flatter in ride. Roll stiffness is greater, but I also changed the front sway bar. I did purposefully drive on some rougher roads and even in track mode it rides fine. I could easily see running the AJ Hartman kit with 350-400 # springs. I’ve not put it on track, but I think this is how the car should’ve come from the factory. The car is more stable in pitch and the front end moves noticeably less when getting on the brakes or lifting throttle or accelerating.

One thing I have noticed is that the steering doesn’t have as strong a self centering feel without the factory sway bar and it’s bonded bushings.

Sponsored