Suspension Walkaround - 2015 Ford Mustang GT Long-Term Road Test

Edmunds.com

Suspension Walkaround - 2015 Ford Mustang GT Long-Term Road Test

We've been massively impressed with the four-wheel independent suspension that underpins our 2015 Ford Mustang GT, so we raised the car on our Rotary Lift to have a look.

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mtnbiker8

The one aspect of the rear suspension that I find perplexing is the sub-frame bushings that attach the integral sub-frame to the chassis. They are really soft and allow a LOT of unwanted, undamped motion that impacts the entire suspension. Watch any YouTube video of this car accelerating and you'll hear intermittent chirps. Stock, the 2015 has a lot of wheel hop. There are quite a few aftermarket mods that address the issue and minimize, or eliminate sub-frame movement. I went with solid Delrin bushings. Surprisingly, there really isn't a lot of additional harshness - on a newly paved road you can't tell the difference. Really improves off the line acceleration (the car hooks up much better) and handling/control when you release your inner hooligan. You know you will. There was no need to make this sports/muscle car this soft from the factory - particularly the performance package version. Oh, and the rear shocks are a little too bouncy - I replaced those too and am much happier. As always, Mustang is a pallet. The aftermarket is huge. The car can be molded into anything you want. But it has amazing bones. Good job Ford!

defyant15

Thanks mtn....

mtnbiker8 said:

The one aspect of the rear suspension that I find perplexing is the sub-frame bushings that attach the integral sub-frame to the chassis. They are really soft and allow a LOT of unwanted, undamped motion that impacts the entire suspension. Watch any YouTube video of this car accelerating and you'll hear intermittent chirps. Stock, the 2015 has a lot of wheel hop. There are quite a few aftermarket mods that address the issue and minimize, or eliminate sub-frame movement. I went with solid Delrin bushings. Surprisingly, there really isn't a lot of additional harshness - on a newly paved road you can't tell the difference. Really improves off the line acceleration (the car hooks up much better) and handling/control when you release your inner hooligan. You know you will. There was no need to make this sports/muscle car this soft from the factory - particularly the performance package version. Oh, and the rear shocks are a little too bouncy - I replaced those too and am much happier. As always, Mustang is a pallet. The aftermarket is huge. The car can be molded into anything you want. But it has amazing bones. Good job Ford!

Have you considered this
http://www.mustang6g.com/forums/showthread.php?t=23215

I considered changing out the bushings but I do enjoy that BMW like last inch of softness in the suspension (firm but soft at the limit).

socal_eric

Excellent to see another suspension article. It's been too long and would be great to see more tech articles like this.

bimer320

Great article. very informing love the detail of weighing the wheel/tire combo.

mtnbiker8

defyant15 - The BMR braces are getting very good reviews. Solid product. I installed BMR Delrin bushings (a full replacement). I think the braces are a far more practical solutions for most folks. I installed the Delrin solution - a real PITA but did it myself so it was economical. Either way - it takes the handling to the next level. Best of what a solid axle would do with composure and suppleness of an IRS. Ford did a nice job on this one.

defyant15

Thanks mtn...I found your thread on the Viking shocks on the forum, that seems like a sensible focused mod rather than the I'll replace everything without knowing what I'm doing"attitude so many people have.

I want a solution with which I can maintain stock ride height for the commute and lower for days I want to auto-x or go gangbusters on mountain roads - might end up looking at coilovers. The FRPP kit is also super tempting but those do lower the car and are not adjustable...and not many reviews in yet. I will prolly be going with the BMR braces as regardless those seem like a winning product.

mtnbiker8

defyant15 - talking to the mechanic at our local DIY shop. He recommends having a goal in mind for a car before going down the customizing road. It will keep you from waking up one morning and saying ... "crap, I own a racing car and I hate driving it."

sgtdenver

It's too bad the "ultra-compact" IRS didn't leave any more leg room or trunk space when a less sophisticated IRS design would have done the job for less.

mtnbiker8

If leg room and trunk space is a priority there is always the Camry.

sgtdenver

mtnbiker8 said:

If leg room and trunk space is a priority there is always the Camry.

Then why bother with a back seat at all? And why go to the trouble of engineering a complex IRS in order to save space when it doesn't?

omairkhanzada

IRS wasn't implemented to save space... it was implemented because the previous BOSS 302 literally maxed out the envelope for solid rear axles performance. IRS in the new one (although it doesn't appear to be all that compact) rides like a dream and is on its way to making it a true contender against its rivals. Finally, a Mustang to be proud of.

Also to the Edmunds guys, I would love to see the GT350R suspension if you can get your hands on one please!

MBall2

Thanks for another outstanding job of reviewing an important suspension design. One of the very few industry sources with the expertise and professionalism to do this important work. Most other magazines and such can barely even parrot back the basic powertrain talking points handed to them by the OEM. Meanwhile, any talk of suspension basically points at skid-pad numbers or perhaps a reference to road course performance on some pristine track surface. This is almost completely irrelevant to any car intended for real American roads. No wonder we've had to suffer through so many generations of awful MacPherson strut and solid-axle cursed "performance" chassis "designs! Yay Edmunds!



MB