Bouncing '19 Bullitt

[K0094]

I have a 2019 Bullitt with about 15k on the odometer and the car is equipped with magneride. The magneride rear shocks were leaking and replaced about 3k miles ago.

The car bounces driving down the highway at 70-80mph, even in sport or track mode where the shocks have noticeably firmed up after changing the drive mode. When having a conversation on the highway, my words are not clear from the car bouncing. My voice/words sound as if i was hitting my chest while trying to talk. My first thought would be the shocks are bad, but both rears were just replaced and shocks definitely get firm when the drive mode changes. This is my daily driver.

I recently modified the IRS which includes:
- replaced the LCA front bushing with a spherical bearing
- replaced the knuckle to toe bushing with the Ford Per bearing
- BMR double adjustable toe rods
- BMR vertical links, spherical/delrin
- BMR lockout lvl 2
- BMR IRS/subframe support brace
- All bolts torqued to spec with the suspension loaded as it would sit (clocked).

The springs are stock on the rear. Front suspension is unmodified. It didn't bounce prior to modifying the IRS.

Has this happened to anyone else after modifying the IRS?
Suggestions to getting rid of the bounce?

Thanks for any feedback.

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[KilgoreLSU]

How do you know it's the rear that's bouncing and not the front? When the rears failed, did it bounce the same way?

 

[Swtbabybilly]

How are the front struts? The rear is now very stiff with brand new shocks and the front is stock with struts that are 6 or 7 years old now. If the front struts are bad or going bad and the rear of the car is now very stiff this could definitely cause a bounce or floating feeling when driving at highway speeds, best of luck man

 

[K0094]

How do you know it's the rear that's bouncing and not the front? When the rears failed, did it bounce the same way?

Thanks for the reply.

It didn't bounce until I modified the IRS. That is why i believe the bounce comes from the rear. The rear shocks were replaced under an extended Ford warranty when i found them leaking. There were about 3k miles put on the car with the new magneride rear shocks prior to the IRS modifications. It wasn't bouncing in those 3k miles (it wasn't riding any differently then when the shocks were leaking).

After discovering the bounce, i loosened the bolts and re-torqued them again with the suspension loaded. That was the second time i clocked the suspension bolts.

I was almost wondering if the magneride system needs to be reset or something. I don't know if it has a learning ability or not.

 

[K0094]

How are the front struts? The rear is now very stiff with brand new shocks and the front is stock with struts that are 6 or 7 years old now. If the front struts are bad or going bad and the rear of the car is now very stiff this could definitely cause a bounce or floating feeling when driving at highway speeds, best of luck man

Thanks for the reply.

I didn't see any leaks from the front struts. The front seems to be ok. I had one of my local Fords do an alignment which made the car darty and the bump steer even worse. They moved the toe in on the front. I got another alignment at a dirfferent shop and had them move the front toe about 0.01 degree out which made the steering float a bit. The S550 seems to be really sensitive to alignment.

 

[19BULLITTwhipple]

Send us photos of the IRS work you did if you have any.

 

[KilgoreLSU]

By bouncing.. do you mean a harsh, stiff jolt kind of bounce? Or a rolling, my shocks/struts are bad?

if it’s the first one.. you did stiffen up the softer parts, but I did the same thing with Steeda progressive springs.. and only on bad Louisiana roads..do I have the harsh ride.. to be expected.

 

[19BULLITTwhipple]

That’s what I was thinking too. You added solid stuff in the rear and now that you have race car parts it will do race car things.

The LCA bearing is an extreme change. It’s not going to ride like a stock s550 anymore.

Still curious to see the bearings and spring seat. And do you have any fault codes for the suspension?

 

[Bullitt_Will]

That’s what I was thinking too. You added solid stuff in the rear and now that you have race car parts it will do race car things.

The LCA bearing is an extreme change. It’s not going to ride like a stock s550 anymore.

Still curious to see the bearings and spring seat. And do you have any fault codes for the suspension?

I’m thinking of adding the RLCA bearings to my Bullitt. Is the handling, and suspension different that much different from stock? A lot of people on the forums speak about how much more it improved the rear habdling, even though a lot of vendors advise against it for daily driven cars.

 

[K0094]

By bouncing.. do you mean a harsh, stiff jolt kind of bounce? Or a rolling, my shocks/struts are bad?

if it’s the first one.. you did stiffen up the softer parts, but I did the same thing with Steeda progressive springs.. and only on bad Louisiana roads..do I have the harsh ride.. to be expected.

I would say a stiff jolt. But it is a continuous stiff jolt, bounce. At highway speed, the jolt/bounce occurs a few times in a second and might pause for a second. This a relatively smooth highway, no washboard ruts. I would not say it is a harsher ride. I am totally fine with a stiffer/harsh ride as long as i get the handling. I pretty much run the car in sport or track mode and wish it would stay in the mode.

I would say these parts actually loosen the suspension arm movement rather than stiffening it. The rear lower control arm will hardly move up and down with the spring, shock, and spindle removed with that Ford rubber bushing in the LCA (with the 24mm front and rear bolts still in). It is really restrictive to movement. Prior to modifying my IRS, i could hardly tell the difference in the suspension between the comfort and sport mode. Now the suspension feels like it changes more between the modes. I think the car also handles better when running over the crown of the road. The bounce is gets old after 20 min on the highway.

I put the BMR vertical links on a few weeks after i had the LCA put back together. After drivng a few weeks with the Ford verical links I can't say i noticed any difference putting the BMR verical links on. I was really hoping the BMRs would take out the bounce.

 

[KilgoreLSU]

This can be so many things.. I'm wondering if your ABS or Body Control is kicking off and on because it thinks the car is losing control. I don't know if you know someone with a forscan or a really good diagnostic computer.. the $4k plus ones that you can run while your driving.

Maybe try turning traction control all the way off. .not just track mode.. at least you can eliminate that.

With a modern vehicle.. you need to look at a lot of different sensors.. Which is a great thing to zero in on a problem. Which is why I'm pointing you to a fancy diagnostic or Forscan.

You may want to go to the TrackMustangs forums and see if anyone has had a similar problem. It could be as easy as some sensor is upside down, etc.. and it's getting bad data.

 

[K0094]

That’s what I was thinking too. You added solid stuff in the rear and now that you have race car parts it will do race car things.

The LCA bearing is an extreme change. It’s not going to ride like a stock s550 anymore.

Still curious to see the bearings and spring seat. And do you have any fault codes for the suspension?

No fault codes on forscan.
I have a few pictures on my PC. Anything in particualar you are looking for? I used a fine sharpie to mark the upper mount were the spring ended so i could put the rear spring back in the exact same spot as it was removed. The LCA, lower ruber spring mount does have a tear/wear mark in it. Seems those are a wear item.

 

[K0094]

I’m thinking of adding the RLCA bearings to my Bullitt. Is the handling, and suspension different that much different from stock? A lot of people on the forums speak about how much more it improved the rear habdling, even though a lot of vendors advise against it for daily driven cars.

The LCA spherical bearing definitely needs a rubber boot to keep dirt and water out. And is really something the manufactures of those should have. Even if you only track the car, it is still going to get dirt on the bearing surface at some point.

It definitely handles better. It should have been that way from the factory.

 

[K0094]

This can be so many things.. I'm wondering if your ABS or Body Control is kicking off and on because it thinks the car is losing control. I don't know if you know someone with a forscan or a really good diagnostic computer.. the $4k plus ones that you can run while your driving.

Maybe try turning traction control all the way off. .not just track mode.. at least you can eliminate that.

With a modern vehicle.. you need to look at a lot of different sensors.. Which is a great thing to zero in on a problem. Which is why I'm pointing you to a fancy diagnostic or Forscan.

You may want to go to the TrackMustangs forums and see if anyone has had a similar problem. It could be as easy as some sensor is upside down, etc.. and it's getting bad data.

I was wondering if could track/graph the rear suspension sensors in forscan. I was wondering about a broken suspension sensor but i would guess that would come up on forscan.

Someone else on here had a bouncy suspsension and it was suggested to get progessive springs. I wouldn't be opposed to having a stiffer spring but i really don't want to lower the car. I would guess that the factory spring rate was designed to work with that rubber bushing in the LCA. There was not resolution listed.

Thanks for the replies and help.

 

[kz]

I was wondering if could track/graph the rear suspension sensors in forscan. I was wondering about a broken suspension sensor but i would guess that would come up on forscan.

Someone else on here had a bouncy suspsension and it was suggested to get progessive springs. I wouldn't be opposed to having a stiffer spring but i really don't want to lower the car. I would guess that the factory spring rate was designed to work with that rubber bushing in the LCA. There was not resolution listed.

Thanks for the replies and help.

Spring is just a spring - if you feel like you have oscillations then it's the damper no damping enough, spring has nothing to do with it (other than it returns the energy in it stored during compression but any spring will do that). Progressive springs with higher rate will likely bounce more.

Magride cars have ride height sensors but don't think they can be logged from Forscan (maybe).
If everything else is stock, only reasonable explanation is that something's wrong with the damper - you have less compliance in the rear right now but if suspension is oscillating, it's underdamped.

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