Hi all,

I have a TT5 prepped car and have done over30 track days over the last two years. I am trying to chase down an issue with the car pulling to the left at high speed braking zones that I have dealt with for 2 years. The "feel" of it is the left side clamps down harder than the right. I have to slightly counter steer to the right when braking because it pulls to the left and I have replaced, or tripled checked everything that would impact the braking. Each time I changed something I would test it by driving on the highway and hard braked at both sides of the crown. Both times would pull to the left, but on the right side of the crown, it pulls slightly less. On the left side of the crown, it pulls harder to the left.

Here is everything I've done to try to resolve it:

• New Calipers
• New banjo bolts
• New SS brake lines
• Swapping brake pads left to right for front and rear
• New G-loc R15 FRONT brake pads, still have half life on rear pads
• New Rotors (obviously soaked in brake cleaner before using)
• Eibach front sway bar
• Bleeding the brakes x100s using FL, FR, RR, RL brake bleed order
• Activating ABS to push air out of VSA (braking hard on ice)
• Setting the coilovers to a softer or harder equal Front/Rear rate
• Rotating my Direzza ziii tires from rear to front (they are directional) 245/40/17
• Rebuilding the calipers
• Regrease slide pins
• Double checked air pressure in tires (32psi)

Remember, it has been like this for almost two years, and after replacing everything the issue persists. I could see how if there is air in the lines on the right, it would reduce clamping, but I have bleed these breaks multiple times with the gravity method, 2-person method, or 1-person vacuum method. I could see how there might be a slight issue

Any ideas or I am crazy?

 

Is the car corner balanced?

 

How are your compliance bushings? What sway bars are you using? The right rear caliper is always the hottest caliper, it will get even hotter if a wheel bearing is going south. Some people have had good luck with vented rear rotors. Perhaps air cooling the rotors would help?

Is the issue on every high speed braking or on a certain track?

 

Do you have torn compliance bushings and/or worn out front LCA/UCA to chassis bushings?

If they're polyurethane, the answer is "yes, they've failed catastrophically".

 

I am guessing you would already have found this one, but is the car diving on one side? aka bad shock allowing one side to dive a bit more than the other? Wonky weight transfer may cause it via dynamic alignment changes.

Also good to check the compliance bushings as well as mentioned already.

 

Nope, shocks are good and it drives straight. I have poly bushings all around. I forgot to mention I just got an alignment too, -3.5 front camber, -3 rear camber, zero front toe, 1/8 total toe in rear.

Yeah I have Energy Suspension poly bushings I pressed in about 2 years ago. Are poly bushings known for failing? The lower control arms are quite rigid still... Upper control arms are tight too. I did replace the rear upper control arm bushings.

Front sway bar is eilbach, I just put it in a couple weeks ago, no change to braking. Rear is oem. All wheel bearings were replaced 2 years ago. I have front brake ducts now, but I'll be looking for rears soon. Yes, high speed braking makes it get very squirrely and pulls to the left.

I am not corner balanced, but ride height is about 1/2" higher in front than rear. Last year it was reversed with the front being 1/2 lower. No noticeable change.

 

I've been doing some reading on this post (https://www.s2ki.com/forums/s2000-mo...hings-1108095/) and what Dead Serious describes is similar to what I experience. Sounds like the consensus is to used powerflex instead of energy suspension for the uppers and hardrace for the compliance. Anyone have similar experience?

 

I'm guessing your bushing choice is limited by some classing rule? If you need to stick with rubber, I'd go Spoon/Mugen compliance bushings.

Go to spherical if you can. Not sure of your class rules though.

Poly bushings aren't generally known for their lifespan. And honestly, the energy design for compliance bushings isn't brilliant (neither is the Hardrace rubber one though).

They may seem fine. But when you take them apart to grease them...




I guess you could try taking yours apart, inspecting them and regreasing. Maybe they just need grease and one side is binding up?

 

I have a hydraulic press so it will be easy for me to do.

 

You shouldn't need a press to take them apart.

I took mine apart with a C-clamp. But obviously a press makes it easier.

The powerflex design is nice...its like a poly spherical. Not sure how well it works.

I haven't had issues yet with my energy FRONT poly upper bushings (AP2)