Performance Pack suspension bouncy?

Norm Peterson · Apr 28, 2015

Really sounding like a pitch (flat ride) issue if all you basically did was add weight to one end of the car.

Firmer low speed damping (front and rear both) and/or slightly softer rear springs would probably help the driver-only ride quality. Might only have to tweak the rebound side of the shocks/struts. Softer springs probably wouldn't be the way to go on a PP setup for a couple of reasons.

Norm

MoEB · Apr 28, 2015

I thought i was the only one thinking the ride is super bouncy. Im going to try some eibach sport lines until some coilovers come out to fine tune everything. Ill keep this post updated.

G_Money_FL · May 4, 2015

Just my opinion (as uneducated as it is): The seats themselves seem to be adding to the perceived bounciness.

I weight 170, and I have the Premium non-Recaro seats, and I notice a good amount of bounce at times.

Norm Peterson · May 4, 2015

G_Money_FL said:
Just my opinion (as uneducated as it is): The seats themselves seem to be adding to the perceived bounciness.

I weight 170, and I have the Premium non-Recaro seats, and I notice a good amount of bounce at times.

I doubt that it's only 'perception'. Everything between your head and the pavement is a spring with finite amounts of stiffness and damping. Even the parts of you that are between your head and the seat.

Norm

dhardison · May 6, 2015

Tire pressure may be somewhat obvious, but considering the number of threads mentioning the extremely high tire pressures as delivered from the factory I figured it was worth a post.

After reading a number of other threads stating the tire pressure from the factory is set above the 40psi mark, I decided to check and sure enough all were 41psi on my Mustang. So I dropped them down to 32psi all around and it seems to have reduced the 'bounciness' ~30-40%. The ride is still firm as it should be with the PP suspension but now the daily drive is much nicer and as a result my tire wear should be much more even as well. It's worth a check!

evanescent03 · May 7, 2015

I test drove a '15 GT with PP yesterday and I was surprised how floaty it felt around the on/off ramps .. I wasn't pushing it because I don't like to on test drives ... but even just going 6/10s it seemed squirmy. I'm currently driving a new style BMW M3 that is quite flat, but was expecting more out of the PP. maybe I need to find someone around me who has fixed the suspension because overall I really like the car. thanks for the thread/input

Rv-Junke · May 15, 2015

Took the car for the 1st LONG drive...5 hrs. from NJ to Virginia. Should have taken my Mercedes S550...This was a lot more bouncy than I have noticed compared to my normal 30 - 60 minute drives. 1st car I have ever owned that had this much bounce. I personally think the springs are a design flaw, and maybe they are correcting this. To that point, I am not thrilled of spending $500 (after install) of springs to fix a ride of new car. Astatically lowering car, I get the springs, but to upgrade springs to fix a new car is INSANE! More to follow on this as I am going to see what Ford will do. Now with that said, when the car isn't bouncing down the road, it rides nice. :-)

Old 5 Oh · May 16, 2015

Hase said:
I looked up the spring rates for a gt vs gt pp. I know the front is only 5 lbs heaver and the rear is 60 lbs heaver.

I have driven a regular GT and I did not notice the bounce I am speaking of. I was wondering if there is 1 thing in particular that is causing it (such as the rear springs being 60 lbs heaver) or if it is a combination of things as Grimace suggested.

Yes, every chance the PP rears are too stiff, especially in comparison with the fronts. People act like the base GT is some marshmallow, but it's not. It's very BMW in its handling, with compliant springs and maybe just a touch less damper than would be optimal. I can see rear springs 10-15% stiffer might be more than I would want back there. I'd rather make that up with a little more rear sway bar, which would move the base car from light understeer to neutral.

Personally, having driven Mustangs (stock and heavily suspension-modified) for 25 years, I am stunned at how well the base GT drives. I got the base car for the AT, fully expecting I would want to do springs, sway bars, dampers, wheels and tires just as soon as I could. I really don't want to change much. It's that good.

Old 5 Oh · May 16, 2015

Hase said:
So here is an interesting update: Had to pick up 3 boxes of paper at lunch - Roughly 160lbs in the trunk - All of the bounciness was gone. So does this point to too firm a rear spring / shocks can't handle the first bit of travel on Michigan roads?

Yes. Sounds like the springs are too stiff for the dampers, and they can't control the springs very well. One of my Fox Mustangs was that way after I put Eibach Pro-Kits and a Brand X set of shocks on it. Bounced like a pogo stick. Another Fox, just like it, had Maximum Motosport Race springs, which are quite a bit stiffer than the Eibachs, but had Tokico Illumina shocks/struts, which I set to 4 out of 5 at both ends. That setup rocked! Total control, totally stable, no bounce. So you HAVE to have enough damper to control the springs.

Rv-Junke · May 20, 2015

Old 5 Oh said:
Yes, every chance the PP rears are too stiff, especially in comparison with the fronts. People act like the base GT is some marshmallow, but it's not. It's very BMW in its handling, with compliant springs and maybe just a touch less damper than would be optimal. I can see rear springs 10-15% stiffer might be more than I would want back there. I'd rather make that up with a little more rear sway bar, which would move the base car from light understeer to neutral.

Personally, having driven Mustangs (stock and heavily suspension-modified) for 25 years, I am stunned at how well the base GT drives. I got the base car for the AT, fully expecting I would want to do springs, sway bars, dampers, wheels and tires just as soon as I could. I really don't want to change much. It's that good.

Great info...so what's the fix on a PP. I brought to dealer, and in short..."car is driving as designed"...Yeah like crap! I'm ASSUMING changing suspension maybe just springs is answer?

Old 5 Oh · May 20, 2015

Rv-Junke said:
Great info...so what's the fix on a PP. I brought to dealer, and in short..."car is driving as designed"...Yeah like crap! I'm ASSUMING changing suspension maybe just springs is answer?

I am passing along heresay, but many others are saying the Steeda progressive springs fix the bounciness. That makes sense to me, as the bounciness is going to be in the initial inch or so of compliance, and it may be that the Steeda progressives are just enough softer in that area to work better with the stock dampers.

The match between springs and dampers is really important not only to handling but to not creating a hobby-horse bouncy ride. I have done that to myself in the past (too much spring, not enough damper) and it makes for a very irritating car.

Others around here, particularly Todd15Fastback, have more experience with the Steeda stuff and can give you more detailed information.

Rv-Junke · May 20, 2015

Old 5 Oh said:
I am passing along heresay, but many others are saying the Steeda progressive springs fix the bounciness. That makes sense to me, as the bounciness is going to be in the initial inch or so of compliance, and it may be that the Steeda progressives are just enough softer in that area to work better with the stock dampers.

The match between springs and dampers is really important not only to handling but to not creating a hobby-horse bouncy ride. I have done that to myself in the past (too much spring, not enough damper) and it makes for a very irritating car.

Others around here, particularly ToddFastback15, have more experience with the Steeda stuff and can give you more detailed information.

THANK YOU...I am ASSUMING Ford will correct this over-time?

Todd15Fastback · May 20, 2015

Old 5 Oh said:
I am passing along heresay, but many others are saying the Steeda progressive springs fix the bounciness. That makes sense to me, as the bounciness is going to be in the initial inch or so of compliance, and it may be that the Steeda progressives are just enough softer in that area to work better with the stock dampers.

The match between springs and dampers is really important not only to handling but to not creating a hobby-horse bouncy ride. I have done that to myself in the past (too much spring, not enough damper) and it makes for a very irritating car.

Others around here, particularly ToddFastback15, have more experience with the Steeda stuff and can give you more detailed information.

The Steeda progressive springs have improved the ride quality a ton. This includes the bounciness that would happen while 100% stock.

Rv-Junke · May 20, 2015

Todd15Fastback said:
The Steeda progressive springs have improved the ride quality a ton. This includes the bounciness that would happen while 100% stock.

I just lugged 170Lbs of Dumbbells up from my basement...I will test the dead body in the trunk theory! Again, thank you for the great info.

Todd15Fastback · May 20, 2015

Rv-Junke said:
I just lugged 170Lbs of Dumbbells up from my basement...I will test the dead body in the trunk theory! Again, thank you for the great info.

LMAO:lol:

You bet, always glad to help out.

I will also make this statement. Since the Steeda stuff has been on my car for almost 3 weeks, I have not noticed any bouncy rides at all. Maybe folks are less sensitive to these things or not but that is what I a feeling :thumbsup:

Performance Pack suspension bouncy?

Norm Peterson

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MoEB

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