2011 Mustang Gt Convert - Very unstable ( rear end )

[HrsePwr]

Hi,

So I brought my 2011 5.0L conv. To the track stock.
And it had VERY BAD wheel hop. I had to take off at idle. It ran 13.4@108mph. All traction controls off.
I could not even take off at anything above idle or there would be VERY BAD wheel hop.

So I bought some brand new : Steeda Adj. UCA, Whiteline lower control arms.

And a local was giving away a " free panhard bar which is adj. He thinks it was an SR brand one ? " , as he sold his GT.

Anyways I noticed that there seems to be a lot of flex on this Panhard bar. Like if u try and shake it while car is on hoist , it flexs quite a bit.

Anyways wheel hop is 100% gone. Doesnt even matter what Rpm's.
But the car is VERY UNSTABLE. Smashing 1st-2nd gear the rear end is EXTREMLY UNSTABLE , going to 2nd to 3rd same thing. And going 3rd to 4th @ Full throttle same thing...
So at track I had to run with full traction on and it went : 12.7@116 with a 2.0' foot.

Im assuming : Rear panhard bar is defective as it flexs quite a bit ? Perhaps Steeda UCA is not at correct angle ? Alignment slightly off ?

Today I installed a Aluminum 1 Piece drive shaft and after driving it around to ensure everything is good I decided to floor it..... and WOW THE REAR END IS EVEN MORE UNSTABLE.

I ordered Bmr Drag springs , Koni Shocks , Lower control arm re-location brackets, a new panhard bar and a panhard bar support brace.
After that i will get the car re-aligned.


Any ideas ?

 

[GBCoyote]

The relocation brackets will help a bit with wheel hop and planting the rear. The panhard bar should not be flexing like that. I would look into a more solid setup. What kind of tires are you running and size?

 

[HrsePwr]

Yes the relocation brackets Im thinking should help.
And the current panhard bar is garbage. Like I said with the car on the hoist I can really wiggle the pan hard bar ( its flexs/moves ) , I got it for free so can't complain. I did buy a whiteline panhard bar and panhard brace with whiteline lower control arm brackets which will hopefully help all that.

The tires currently : 265/40/19 Michelin Winter Tires.
But I will be getting the car aligned with a 18x10 rear rim with : 285/40/18 Nitto NTo5R drag radials.

Im just trying to see if it can be anything else ?

Or should the lose garbage rear panhard bar be causing the rear end to get really unstable ?
Like I said b4. The car was never unstable b4 I put the Steeda adj. Uca, whiteline lca's and this garbage panhard bar. It did have a lot of wheel hop though. But nothing " crazzy unstable rear end movements " when you would do some WOT pulls.

Thanks guys !

 

[GBCoyote]

My money is on the panhard bar. Install the new one and report back with the results. Longshot, but double check all the bolts being tight after the install of all those parts.

 

[HrsePwr]

My money is on the panhard bar. Install the new one and report back with the results. Longshot, but double check all the bolts being tight after the install of all those parts.

Yes Im also thinking its the garbage panhard bar on now.
I made a mistake the Panhard bar and Support Brace I bought is " RTR " not whiteline.
Installing it all today : Rtr Panhard Bar, Rtr Panhard Bar Support Brace, koni Rear Shocks, Bmr Drag rear springs, WhiteLine Lca re-location brackets, Bmr Front rad support ( sway bar delete ) and complete alignment with the 18x10 shelby rims and Nitto Nto5r 285/40/18 Drag Radials

 

[kevin2970]

It's your tires.. 265 winter tire is problematic.. Lol

 

[HrsePwr]

It's your tires.. 265 winter tire is problematic.. Lol

Yes the tires were not that great. But they got me : 12.7@116mph with a 2.0' 60'foot with full traction control on.
I got them brand new for $100 for the pair so I couldnt refuse them. Anyways.

Today I put all the parts on : 18x10 Shelby Rims, 285/40/18 Nitto Nt05R Drag Radials , Koni Yellow Rear Shocks, Bmr Rear Drag Springs , Rtr Adj. Panhard Bar, Rtr Panhard Brace , WhiteLine Lower Control Arm Brackets, Bmr Front Rad Support with Sway Bar delete. And a full Alignment.
Wow is all I can say !!!! Its HARD to really pin point and pick out what each of these parts are doing , but as a whole... its CRAZZY.
Car Handles way better , over bumps the rear end doesnt feel like its going to break apart LoL, i Did some partial WOT pulls and it hooks straight. Will report back with Full WOT pulls & the track is this weekend.
Just wanted to also point out all the parts were bought from American Muscle ( as I have a dealer acct. With them ) , they are superb !!!! Super Fast Service / Shipping, Good Prices and always answer any questions. Two Thumbs way up for American Muscle !!!

 

[choate]

Do you have aftermarket lower control arms? I might have missed that but huge difference there

 

[paulyboy928]

+1 on the lower control arms. great bang for your buck upgrade.

 

[GBCoyote]

Yes he said he had white line LCAs and just installed the relocation brackets.

Glad your problem is fixed.

 

[HrsePwr]

Yes he said he had white line LCAs and just installed the relocation brackets.

Glad your problem is fixed.

Thanks GBCoyote for answering that.
Car feels 200% better.
I will be parking it in a few weeks. First thing I do as soon as it comes out next season ( April 2017 ) new set of tires all the way around for the streets, and my front suspension. Thinking of : Bmr drag front springs, koni yellows, caster camber mounts.