Project Mustang 5.0: Optimizing Weight Transfer and Roll Steer


After installing the brackets, we installed the new control arms exactly like the OEM ones, except this time the rear of the arms mounted to the brackets instead of directly to the axle.  I kept the new control arms the exact same length as the OEM ones; adjusting their length changes the wheelbase of the car, which is undesirable for the most part.  However, changing one side's length allows you to adjust the preload on the rear axle, something which is desirable if you're launching at a drag strip with slicks and a lot of power.  To verify that the lengths are the same, we simply used bolts to line up the OEM and Whiteline parts.

Changing the control arm length is undesirable, at least for my purposes.  Whiteline pre-adjusts the arms to the factory length, but we double checked them just to make sure.

After bolting the new arms on, we lowered the car onto ramps to load the suspension and check all the bolts.  Then we put it on the ground and had a look at the new suspension geometry.

Here you can see the brackets and how they bolt to the stock axle mount and the new arms.


This shows the suspension at ride height.  You can see that the new control arms slope downwards a bit towards the axle.

The difference in handling was immediately apparent.  Previously, when accelerating hard from a stop, there was a noticeable weight shift rearward along with wheel-hop.  With the new control arms and brackets installed, there was no perceivable rearward weight transfer and zero wheel-hop.  The car simply grabbed the pavement and took off.  It is amazing how planted this car is now and how hard it launches.  The only vehicles I've ridden in that launch harder on street tires are all-wheel drive WRXs and Evos.  Furthermore, the rear suspension didn't seem much stiffer at all while driving around on the street.  Whiteline's EZY grease also prevented all squeaks—the suspension is still as quiet as it was stock.

In order to test out the handling characteristics of the new setup, though, I needed to do some corner-carving.  There was a somewhat local event the next weekend that used the taxiway from an airport.  Perfect.

The car feels completely different.  Turn-in is much sharper, with much improved mid-corner and late-corner characteristics.  This is because the rear suspension is no longer “fighting” the corner by turning in the wrong direction.  The roll steer characteristics now help the vehicle turn sharper, making the car actually feel smaller.  The car feels more natural, as the rear end complies with what the front end is doing and seems to follow through on the corner instead of being a little bit off to the outside.

Below is a video of my best run from that day.  I apologize for the low quality; I had to use an old phone that didn't work as well.


Based on benchmarking myself versus several other drivers, I picked up approximately one to two seconds on a 60-second course after installing the Whiteline control arms and anti-squat brackets. This is due mostly to the fact that the car is now much easier to drive at the limit, because the rear end is so much more connected.

Project Mustang 5.0 has come a long way.  It no longer handles like a big land yacht, yet we haven't sacrificed its straight-line capabilities, either.  Tarmac-holding capability has been drastically increased, understeer has been eliminated, and the overall handling characteristics of the vehicle are much more “sports-car-like.”   But we're not done yet…


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