The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Suspension or Brake help!!!!

Guys I need some serious help. I have a 2014 TP GT. I've installed Steeda shocks, springs, camber plates and sways. The car was amazingly responsive and handled very well, but had a very bad wobble under heavy braking. I was told by Steeda that I need relocation brackets and control arms. I installed bmr relocation brackets and lower control arms (chose bmr because they bolt in, Steeda was weld in only). Prepping for a track day I also installed pagid pads and went from 255/40/19 to 275/30/19.

Looking forward to kicking some Porsche but I was excited, well I experienced the exact opposite. I had amazing grip and great stopping, but anytime I touch the brake pedal anywhere near a turn I get terrifying snap oversteer followed by traction and abs trying to keep the car on the track. It ruined the day, I actually lost it in turn one and went off track for the first time ever. I missed a heel toe and locked up the rear and the car completely swapped ends. It is very hard to drive. The only thing I changed since the last track event was relocation brackets, brake pads and lower control arms. The brackets are in the middle slot. Oh yeah the braking wobble is gone. Please help.
 
475
333
I going to guess the rear lower control arms are at the wrong angle. If you arms are lower at the axle than the body. Then you may be getting roll over steer. Try to get them level or 2-3 dia. up on the axle side. Some race teams keep the arms in the stock location for grip and use the brackets for tuning on some tracks. Some brackets have more drop than others. Hope this help.
 
Did you happen to get the same brake compound front and back? If so you might have gone to aggressive in the rear.
 
I did not get it aligned.

My brake compounds Are not the same they are rs19 and rs56 in the rear.

Roll steer I didn't think of that, they are supposed to be parallel to gound in the static position? Now they point upward slightly.
 
Got them adjusted today and it made a world of difference. Even at he highest point it's slightly upward but tons better. We will see how it is at the track. Thanks for the help.
 
475
333
Sometimes in Sports mode or just off. I brake before or trail brake depending on the corner. Roll on power at mid turn or just after the Apex, also depending in the corner.
Youtube. Find me under Tribar65.
 

Grant 302

basic and well known psychic
Tri-bar, my question is for the OP. :)

And back to the OP, also curious about what brand tires are you running with the 275s? And the 255s you were running on were the stock TP P-Zeros?
 
Grant 302 said:
Tri-bar, my question is for the OP. :)

And back to the OP, also curious about what brand tires are you running with the 275s? And the 255s you were running on were the stock TP P-Zeros?


Yes stock p zeros, now I'm running Dunlop direzza 2 and they are hot.

http://youtu.be/kF9Mxqi361I at

about the two minute and a half minute mark there is a lap of me from a chase car. You will see my braking habits.

http://youtu.be/7KvGLW6U0BE

Just some fun footage.

I'll look you up on youtube.
 
I run in sport mode. It's a safety net. I was at the Jaguar driving Academy and Roberto Guererro was instructing me. I said, this Dynamic Stability is killing me and he said, "if it comes on you did something wrong, he took the car and posted a super killer time with it on, then turned it off and ran about 2 tenths faster. The time with it off actually felt a lot faster but it was not. So yes I leave it on.
 

Grant 302

basic and well known psychic
Grant 302 said:
Are you starting to brake mid turn?

At 2:21 in your first video I see your brakes come on mid turn. With your current setup, you need to get rid of habits like that. You need to shift your instincts to steer with the throttle and trust that the car will rotate. A blown downshift will upset any car, especially in a turn.

Coming from a similarly setup '11 Brembo GT (now w/ P-springs, Boss shocks/struts, LCA brackets, 275 hankooks, etc.), I can say you've gone from a stock car that will 'tolerate' some of that kind of driving, and modified it to one that will not. If you don't like it that way, you can dial back in more understeer with staggered tires, adjusting your sways (if available), to make it more compliant to your driving style. If you're going to keep the car as-is, learning to trail brake like Tri-bar suggests in an above post will help, otherwise only brake when you're going straight.

I often run in Sport Mode. Sometimes full OFF when I'm comfortable. I was just curious if you were leaving it on and it was causing some of your problems. Looks like that's not the case.

I know you weren't asking for any critique, but it sounds to me like there was nothing really 'wrong' with the car, even if it's not setup right for you. Hope that helps!
 
Grant 302 said:
At 2:21 in your first video I see your brakes come on mid turn. With your current setup, you need to get rid of habits like that. You need to shift your instincts to steer with the throttle and trust that the car will rotate. A blown downshift will upset any car, especially in a turn.

Coming from a similarly setup '11 Brembo GT (now w/ P-springs, Boss shocks/struts, LCA brackets, 275 hankooks, etc.), I can say you've gone from a stock car that will 'tolerate' some of that kind of driving, and modified it to one that will not. If you don't like it that way, you can dial back in more understeer with staggered tires, adjusting your sways (if available), to make it more compliant to your driving style. If you're going to keep the car as-is, learning to trail brake like Tri-bar suggests in an above post will help, otherwise only brake when you're going straight.

I often run in Sport Mode. Sometimes full OFF when I'm comfortable. I was just curious if you were leaving it on and it was causing some of your problems. Looks like that's not the case.

I know you weren't asking for any critique, but it sounds to me like there was nothing really 'wrong' with the car, even if it's not setup right for you. Hope that helps!

At 221 at roebling you have to straighten the car out and brake as if you were going off track then turn in deep. That's actually the race line that most guys run through there. Some of the Porsches run no brakes through there but most brake. Trust me there was something wrong. I do trail brake usually through turn three and the car went into serious oversteer. It was not normal. I did adjust the relocation brackets and I think it fixed it. Those videos are before the brackets, tires and brakes. The car felt amazing and had amazing grip until you tried to trail brake. Then it went nuts. I had gary javo drive it and he is a phenomenal driver and he has logged over 2000 laps at roebling alone and never went off track. At about 60 percent he lost it and had to save it. I really think the bracket were set to the wrong position. Since the adjustment it feels better but Ill see at the next track event. I've owned vettes a couple of nismo zs a gtr and a few other cars. Ive had the pleasure of driving cars a aggressive as miata spec cars and gt3s and have never experienced that before. It was scary. I'm not as experienced as some of you guys but I'm experienced enough to know when something is wrong.
 
Btw this is by far the best forum on the planet. Tons of experience and knowledge through out. As stated I've owned a lot of cars but this forum is almost reason enough to own a mustang. That is if you have canthelpmyselfcarmod-a-itis.
 

Grant 302

basic and well known psychic
Looking at the BMR brackets, maybe the middle hole is just too low. I would like to hear if all the problems go away on your next track outing.

I was having a hard time thinking that the minor differences in our setups would lead to such drastic changes in balance under braking, but some of the differences in spring and sway rates might also come into play. I know my car still has some margin for understeer under trail braking because I can get the front to plow a bit.

If the car is still loose under braking at the track I'd look at your sway bar and rear spring rates and go a step softer.

radioflyer350 said:
Btw this is by far the best forum on the planet. Tons of experience and knowledge through out. As stated I've owned a lot of cars but this forum is almost reason enough to own a mustang. That is if you have canthelpmyselfcarmod-a-itis.

Gotta agree with you there! :) While there is a 'waxer' side to me, I appreciate how many drivers and racers that stick around here.
 

TMO Supporting Vendors

Buy TMO Apparel

Buy TMO Apparel
Top