From BMW ---> S550, dialing in the suspension

[bl_steel]

This thread is a place to discuss potential, current, and past changes of your S550's suspension to improve overall driving feel and encourage driver confidence, like the driving characteristics you may be reminiscing about from your BMW.

If you're like me, you've had a BMW and now have a Mustang. Maybe it wasn't a direct step, but you've shuffled over to the pony car. First, take a moment and pat yourself on the back, you've made a wise decision. :cheers: Now, it may have happened during your test drive, or it took a few hundred miles and some spirited driving, but you've decided you want your new Mustang to drive more like your past BMW(s).

The qualities of BMW that we want in our Mustang
-Planted front end
-Less understeer, or even a tendency to oversteer
-Tight driving line
-Retain daily driving comfort
-Etc (to be amended as points are made)

Some of us have Upgraded suspension from the Factory. If your S550 Mustang came equipped with the optional "Performance Package", this is what that kit includes:
Performance Pack includes: (I'd love to have more complete data with more part numbers)
-Strut-tower brace (M-20201-M)
-Larger GT350 radiator (M-8005-M8)
-Unique chassis tuning
-Jounce bumper (M-5570-B)
-Upgraded rear toe link (M-5972-M)
-Upsized front and rear sway bars
-Front strut mounts (M-18183-M)
-Heavy-duty front springs
-Gauge pack (oil pressure and vacuum)
- K-brace
-Brembo™ 6-piston front brake calipers with larger rotors (15" front rotors on the GT, 14" on the EB)
-19" x 9"(f) 19" x 9.5" (r) Ebony Black-painted-aluminum wheels, available in silver
-Unique stability control, EPAS and ABS tuning
-3.73 TORSEN® rear axle
-Spoiler delete
-255/40r19 (f) 275/40r19(r) summer-only tires

So what are your complaints and/or complements of the S550 suspension, compared to your past BMW?
What are your overall goals for your new S550, and how does that compare to your use/goals of your past BMW?
What have you changed in your suspension, how'd it go? Or what do you want to try?


I have 2017 Performance pack GT. I have extended warranties and maintenance plans, so I'd personally love to have all Ford parts and explore that avenue first. My goal is to find a great balance of performance handling and ride comfort. 90% street driving, 10% track time.

Has anyone only upgraded their PP suspension with the Ford Performance Street handling X-springs (which are described as Progressive springs)? What were the results?

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[NightmareMoon]

Ford Performance is not Ford, they're separate companies, so there is not real advantage warranty or otherwise to sticking with FRP stuff. Most people seem to like linear springs, not progressive if you're looking to upgrade.

My last car was a E46 325Ci, which handled ok after we refreshed some of the suspension components and put new dampers on it. It rode pretty good around town, and took the 'BMW set' in corners. That car seriously needed more power though, and the plastic bits were disintegrating fast, thus the S550.

My mods are in my sig, Koni dampers, a mild increase in rear swaybar rate, and added front camber via camber plates or in my case, slotted strut to spindle bolt holes. Car is balanced at the limit and easily tuned on the sporty/stiff to soft/comfort spectrum via the adjustable shocks. Somewhat stuffer handling oriented springs would also compliment the package.

 

[NotBlake]

The Ford performance street handling kit is perfect if you're looking for a refined but capable suspension setup. My lateral acceleration went from .89 G on all seasons to .97 on the same tires. I'm very very happy with it.

 

[bl_steel]

Ford Performance is not Ford, they're separate companies, so there is not real advantage warranty or otherwise to sticking with FRP stuff. Most people seem to like linear springs, not progressive if you're looking to upgrade.

My last car was a E46 325Ci, which handled ok after we refreshed some of the suspension components and put new dampers on it. It rode pretty good around town, and took the 'BMW set' in corners. That car seriously needed more power though, and the plastic bits were disintegrating fast, thus the S550.

My mods are in my sig, Koni dampers, a mild increase in rear swaybar rate, and added front camber via camber plates or in my case, slotted strut to spindle bolt holes. Car is balanced at the limit and easily tuned on the sporty/stiff to soft/comfort spectrum via the adjustable shocks. Somewhat stuffer handling oriented springs would also compliment the package.

My understanding, from my dealership, is that Ford Performance (formerly Ford Racing) parts installed at factory or anytime after, are covered by your current Ford warranty and maintenance plans. And, does not void anything. IE: If I install koni struts, my struts are no longer covered and any failure in the suspension, resulting from installing the Koni struts, are no longer covered. However, any Ford Performance part installed, to replace a factory part, is now covered under the warranty and any future failures, that may or maynot have been caused by the FP part, are still covered within warranty and/or maintenance plan time frames.

I also had an e46, a 323i. Don't talk to me about underpowered! lol Honestly the 323 has close HP and Torque numbers and in the right rpm range is pretty peppy. But the need for speed, and many other factors lead me to the Mustang.

The Ford performance street handling kit is perfect if you're looking for a refined but capable suspension setup. My lateral acceleration went from .89 G on all seasons to .97 on the same tires. I'm very very happy with it.

The Ford Performance Street handling kit is the Performance Package PLUS Ford Performance Street handling/lowering x-springs. My hopes are that just a spring swap would solve 80% of my gripes. Did your mustang have the Performance Package from factory?

 

[SpeedLu]

I upgraded from the Base suspension to the FRPP Track Pack. I looked at the Street Pack, but it's the exact same thing as the Performance Pack except it has lowering springs. Depending on where you look (read: Levittown Ford Supercenter) the Track Pack is only $100 more than the Street Pack, but it has vastly superior handling. The ride is a little harsher than stock over some surfaces, but mostly comfortable--as you'd expect from a set of performance-oriented progressive springs. The tuning on this package is so tight though that you will never think to yourself "Dang, I should have went linear." There are few systems as good as this one that aren't outrageously priced.

 

[EricSMG]

Great thread - you beat me to it!

If I may, the general premise of the thread is to more closely approximate the qualitative feel of more expensive sporting cars, not so much improve actual, measurable performance. The S550 PP is a fast car that goes around a corner quite well - it just doesn't feel as good as it could doing so, and that's what those of us with a BMW reference point would like to improve.

In only 400 miles I've homed in to the major areas needing improvement.

1. The front struts are way too soft in slow speed rebound and compression. This results in three things I don't like:
- The front floats at higher speeds
- The front lifts too much under heavy throttle
- The front dips too much under braking

2. The rear shocks are a bit too stiff in high speed compression = stiff ride
3. The front of the car sits too high = poor forward visibility.
4. The IRS dances around under the car = front and rear aren't "in-phase" - the car doesn't track well = poor driver confidence.
5. The rear inside wheel hops/skips during swift acceleration from a stop while turning.
6. The driveline is rubbery = poor connection between throttle foot and rear wheels.

These are the things that a BMW much better at and are what I aim to improve. Any modification that improves one aspect of the car but degrades another will not stay installed - I am only interested in improving the car with minimal compromise.

I think by far the most important thing to address first is positively locating the IRS. I've got the BMR Lockout kit on it's way.

 

[RonStang6G]

I too owned BMW's, a total of 7 over 32 years and 560k miles. A lot of BMW's over a lot of miles. And only one still had the stock suspension when I sold it. The one exception was a 96 e36 M-Technic 325is that BMW only built 150 examples. I owned that car 18 years and drove it 120k miles. That car was my gold standard for well balanced handling for all the BMW's I owned during and after it. It was one last two BMW's that I owned, the other was a 2001 e46 330ci coupe. To get the e46 330ci to handle like the e36 325is I added Dinan sway bars front & rear set to max stiff settings. So after all these BMW's why would I want a Mustang? Simple the S550 with independent rear suspension. I read a lot of reviews and watched a lot YouTube videos on the 2015 S550 Mustang and decided I might want to buy one. For a test drive I rented 2015 Ecoboost Mustang for three days and drove it about 400 miles. There was no way a dealer test drive around the block would convince me to buy a Mustang after owning so many BMW's. The time and miles in the rental Mustang was enough to make me wanted to buy one. So I ordered a 2016 Mustang GT Premium with a 6 speed auto transmission with the options that I wanted.
I have owned the Mustang GT for 6 months now and have done a few suspension upgrades. The first two were to add a GTPP strut tower brace and a Steeda G-Trac K-Member. This improved the steering response. The next upgrade was to add the Steeda Rear Subframe Braces. This helped with the rear wheel hop. Finally I upgraded the shocks & struts to Steeda Pro-Action Shocks & Struts. And added the OEM upper K-Brace which I should have done when I added the Steeda G-Trac K-Member. I chose the Steeda shocks & struts over Koni Yellow sport shocks & struts because I wanted a little bit softer ride. I had put Koni yellows on several of my BMW's and found to be a little on the stiff side even on softest setting. I put Koni FSD's on my e46 330ci and I liked both the ride and the handling. But the Koni FSD's are not available for the S550 Mustang and might never be available so I went with the Steeda shocks and struts. Not as good of ride as the Koni FSD's but better than Koni Yellow Sports. I have only had the Steeda Pro-Action Shock & Struts on my car for about 300 miles. But those 300 miles are mostly twisty mountain roads and I like the way that they handle. A huge improvement over the OEM shocks and struts. Much better dampening on rough surfaces. One example is with the OEM shocks & struts there is a section of Interstate 80 that is covered with snow most of the winter and is beat up by 18 wheelers with tire chains that at 75 miles an hour just made the Mustang vibrate something awful. With the Pro-Action Shocks & Struts that vibration is well under control, not a smooth ride but doesn't feel like it hit resident frequency and is ready to shake apart any minuet. It took me about 10 adjustment cycles with the rebound adjustment on the Pro-Action Shocks & Struts to find the right amount of rebound dampping to get best ride setting. I ended up starting form the softest setting and moving the rebound 1/8 turn at a time with a test drive and then moving on to the next setting to find that sweet spot where you get the best ride. A lot of test drives but worth the effort. My car is a DD car and I don't do auto cross or track days so I want a good handling car with the best possible ride. Just like when I was driving BMW's. With my Mustang GT I feel like I am driving a 435 hp e46 BMW.

 

[Performance nut]

I'm curious about this myself. Been researching suspension mods for awhile to see how to get that "ride on rails" feel that maintains the fillings in my teeth when I am on the road. Like to see how this goes.

Personally, there is way too much roll on the stock GT suspension and has severe understeer. I honestly think the tires are too narrow for this car (I'd like to see at least 295's on them) but wondering if they should have more in the back or keep them even all around.

 

[Azzurro]

I'm curious about this myself. Been researching suspension mods for awhile to see how to get that "ride on rails" feel that maintains the fillings in my teeth when I am on the road. Like to see how this goes.

Personally, there is way too much roll on the stock GT suspension and has severe understeer. I honestly think the tires are too narrow for this car (I'd like to see at least 295's on them) but wondering if they should have more in the back or keep them even all around.

New tires, lowering springs & adjustable dampers would be a minimal start.

 

[EricSMG]

I'm curious about this myself. Been researching suspension mods for awhile to see how to get that "ride on rails" feel that maintains the fillings in my teeth when I am on the road. Like to see how this goes.

Personally, there is way too much roll on the stock GT suspension and has severe understeer. I honestly think the tires are too narrow for this car (I'd like to see at least 295's on them) but wondering if they should have more in the back or keep them even all around.

You don't need more tire, you need better tires. All seasons just don't work for a high performance car.

I can tell already that the 255 Z-rated fronts on the GT/PP are plenty of tire for any type of street work. And just upgrading from the PZeros to the MPSS of the same size would make a huge difference by itself as I've learned many times with my BMWs. It's amazing how much more grip a skinny top tier tire has than a crappy huge tire. Not to mention the vastly better road manners and driving feel that a narrower tire gives.

Point is - think "better" before "more". It's also very important not to over-tire a wheel. A wide tire on a skinny wheel won't have the lateral support it needs for proper grip and response, so it's counter productive.

 

[Performance nut]

A wide tire on a skinny wheel won't have the lateral support it needs for proper grip and response, so it's counter productive.

Yes but a wide tire on an appropriate width (and lighter) aftermarket wheel makes for a better performing car. I wouldn't dream of putting 295's on a GT wheel. I'd aim to at least maintain the stock diameter and weight with a lighter wheel but wider (and likely heavier) tire. I would also like to maintain a decent aspect ratio rather than go with low profile tires.

It very well may be the tire, I won't argue these tires are awesome/stink. Was strictly speaking preference in regards to width. Though I have more to learn about these cars so it may not need more as you indicated.

 

[EricSMG]

Yes but a wide tire on an appropriate width (and lighter) aftermarket wheel makes for a better performing car. I wouldn't dream of putting 295's on a GT wheel. I'd aim to at least maintain the stock diameter and weight with a lighter wheel but wider (and likely heavier) tire. I would also like to maintain a decent aspect ratio rather than go with low profile tires.

It very well may be the tire, I won't argue these tires are awesome/stink. Was strictly speaking preference in regards to width. Though I have more to learn about these cars so it may not need more as you indicated.

Yep, good post. If my comments come off as black and white I don't mean them to.

A good, wide, properly supported tire will outperform the narrower tire, all else equal. It may be, that how you use your car, you do need a wider tire than I might need.

For me, I tend to always run the OE tire sizes on my sports cars since for the type of driving I do (aggressive street and canyon runs) I find them to be more than adequate assuming A) I run the best in-class tire and B) I have adequate front camber.

But, like you, I haven't yet explored the limits of my current setup so we shall see

 

[bl_steel]

Already love how this thread is going! And if anyone wants to sneak a pic of their old BMW(s) in, it's ok with me. )

I really want to point out, as [MENTION=26094]EricSMG[/MENTION] mentioned, I want my Mustang to inspire driver confidence like my BMW did, I don't want it to BE a BMW.

I upgraded from the Base suspension to the FRPP Track Pack. I looked at the Street Pack, but it's the exact same thing as the Performance Pack except it has lowering springs. Depending on where you look (read: Levittown Ford Supercenter) the Track Pack is only $100 more than the Street Pack, but it has vastly superior handling. The ride is a little harsher than stock over some surfaces, but mostly comfortable--as you'd expect from a set of performance-oriented progressive springs. The tuning on this package is so tight though that you will never think to yourself "Dang, I should have went linear." There are few systems as good as this one that aren't outrageously priced.

Thanks for the info. There's a lot of shared parts between the Street Handling and Track Handling packs, major difference being springs and dampeners. What were your goals for your Mustang when you decided to change the suspension?

Great thread - you beat me to it!

If I may, the general premise of the thread is to more closely approximate the qualitative feel of more expensive sporting cars, not so much improve actual, measurable performance. The S550 PP is a fast car that goes around a corner quite well - it just doesn't feel as good as it could doing so, and that's what those of us with a BMW reference point would like to improve.

In only 400 miles I've homed in to the major areas needing improvement.

1. The front struts are way too soft in slow speed rebound and compression. This results in three things I don't like:
- The front floats at higher speeds
- The front lifts too much under heavy throttle
- The front dips too much under braking

2. The rear shocks are a bit too stiff in high speed compression = stiff ride
3. The front of the car sits too high = poor forward visibility.
4. The IRS dances around under the car = front and rear aren't "in-phase" - the car doesn't track well = poor driver confidence.
5. The rear inside wheel hops/skips during swift acceleration from a stop while turning.
6. The driveline is rubbery = poor connection between throttle foot and rear wheels.

These are the things that a BMW much better at and are what I aim to improve. Any modification that improves one aspect of the car but degrades another will not stay installed - I am only interested in improving the car with minimal compromise.

I think by far the most important thing to address first is positively locating the IRS. I've got the BMR Lockout kit on it's way.

I'm definitely agreeing with most of your numbered points. I think #5 is related to high horsepower/torque, stability control and tires. I hate the Pzeros. Hate is a strong word, the Pzeros are not meeting my expectations, and are impeding performance. However, I'm excited to hear your review of the BMR kit. It may be only minimal wheel hop due to under-efficient stability control and just be exaggerated by cradle movement.

I think I recognize your name from e46fanatics.?

I too owned BMW's, a total of 7 over 32 years and 560k miles. A lot of BMW's over a lot of miles. And only one still had the stock suspension when I sold it. The one exception was a 96 e36 M-Technic 325is that BMW only built 150 examples. I owned that car 18 years and drove it 120k miles. That car was my gold standard for well balanced handling for all the BMW's I owned during and after it. It was one last two BMW's that I owned, the other was a 2001 e46 330ci coupe. To get the e46 330ci to handle like the e36 325is I added Dinan sway bars front & rear set to max stiff settings. So after all these BMW's why would I want a Mustang? Simple the S550 with independent rear suspension. I read a lot of reviews and watched a lot YouTube videos on the 2015 S550 Mustang and decided I might want to buy one. For a test drive I rented 2015 Ecoboost Mustang for three days and drove it about 400 miles. There was no way a dealer test drive around the block would convince me to buy a Mustang after owning so many BMW's. The time and miles in the rental Mustang was enough to make me wanted to buy one. So I ordered a 2016 Mustang GT Premium with a 6 speed auto transmission with the options that I wanted.
I have owned the Mustang GT for 6 months now and have done a few suspension upgrades. The first two were to add a GTPP strut tower brace and a Steeda G-Trac K-Member. This improved the steering response. The next upgrade was to add the Steeda Rear Subframe Braces. This helped with the rear wheel hop. Finally I upgraded the shocks & struts to Steeda Pro-Action Shocks & Struts. And added the OEM upper K-Brace which I should have done when I added the Steeda G-Trac K-Member. I chose the Steeda shocks & struts over Koni Yellow sport shocks & struts because I wanted a little bit softer ride. I had put Koni yellows on several of my BMW's and found to be a little on the stiff side even on softest setting. I put Koni FSD's on my e46 330ci and I liked both the ride and the handling. But the Koni FSD's are not available for the S550 Mustang and might never be available so I went with the Steeda shocks and struts. Not as good of ride as the Koni FSD's but better than Koni Yellow Sports. I have only had the Steeda Pro-Action Shock & Struts on my car for about 300 miles. But those 300 miles are mostly twisty mountain roads and I like the way that they handle. A huge improvement over the OEM shocks and struts. Much better dampening on rough surfaces. One example is with the OEM shocks & struts there is a section of Interstate 80 that is covered with snow most of the winter and is beat up by 18 wheelers with tire chains that at 75 miles an hour just made the Mustang vibrate something awful. With the Pro-Action Shocks & Struts that vibration is well under control, not a smooth ride but doesn't feel like it hit resident frequency and is ready to shake apart any minuet. It took me about 10 adjustment cycles with the rebound adjustment on the Pro-Action Shocks & Struts to find the right amount of rebound dampping to get best ride setting. I ended up starting form the softest setting and moving the rebound 1/8 turn at a time with a test drive and then moving on to the next setting to find that sweet spot where you get the best ride. A lot of test drives but worth the effort. My car is a DD car and I don't do auto cross or track days so I want a good handling car with the best possible ride. Just like when I was driving BMW's. With my Mustang GT I feel like I am driving a 435 hp e46 BMW.

Thanks for sharing your story, Ron. An e36 Mtech!:eyebulge: Excellent, thorough info. I love that you've found your perfect suspenion. Just to clarify, you didn't change the springs, so you're still on factory, non-PP, springs?

 

[ghostnote]

Aside from what has already been mentioned, I've found that there's a rather big 'dead zone' in the steering wheel that I'd like to tune out. That is, there's like a 15 to 20 degree window of steering input to either side that doesn't really make the car turn.

I feel like resolving this would make the car's steering more "direct" and "sharp". Any ideas?

 

[Norm Peterson]

Great thread - you beat me to it!

If I may, the general premise of the thread is to more closely approximate the qualitative feel of more expensive sporting cars, not so much improve actual, measurable performance. The S550 PP is a fast car that goes around a corner quite well - it just doesn't feel as good as it could doing so, and that's what those of us with a BMW reference point would like to improve.

In only 400 miles I've homed in to the major areas needing improvement.

1. The front struts are way too soft in slow speed rebound and compression. This results in three things I don't like:
1 - The front floats at higher speeds
2 - The front lifts too much under heavy throttle
3 - The front dips too much under braking

For starters, the floaty front and front lifting are most likely a case of inadequate rebound damping in the body motion velocity range (up to 3 ips or so).

The third is partly nose dive up front and partly tail rise in the rear. It isn't necessarily obvious from the driver seat how much of that pitch motion (the total angular change - think side view here) is coming from the front diving down and how much from the rear rising up. The rear component would also suggest rear shock rebound damping is a bit on the light side.


Norm

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