Darbymx5

**********title was changed by immature moderator*********** im not looking for any bleeding advice.

I just got back from a 3 day track event at gingerman raceway and experienced a seriously bad shaking problem under hard, fast cornering (4th gear, sometimes 3rd) - and before you say engine mounts or diff mounts, I have solid engine mounts (70 durometer) and new ES poly bushings in my torsen diff.

The shaking would get violent enough to the point where I had to let off, and I could see my shifter shaking back and forth as if it was wheel hopping.

Does anyone have any ideas as to what it could be? I have upgraded front and rear sway bars, konig helix's on r888's, and HKS hipermax coilovers <-- they are probably around 5-6 years old though

shuiend

iTrader: (24)

AFR's then?

Darbymx5

AFR is good - mid 11's while in boost. Why would that make the car shake?

stefanst

iTrader: (1)

Are you running Delrin or Poly suspension bushings?
Is it a power-related shake, or is it under braking/coasting?

Darbymx5

suspension bushings other than the diff are stock and are probably pretty old. The diff bushings are poly.

It only does it under accelerating around or out of a fast corner - if I stay on the power it gets worse, if I let off it calms it down a lot but doesn't go away entirely until im out of the corner

stefanst

iTrader: (1)

We can probably eliminate anything drivetrain-related by answering this question: Does it stop completely if you hit the clutch?
My first guess would be suspension bushings. If they're old and of unknown condition, you should be replacing them anyway. You may want to wait for a reply from somebody more experienced first though.
There's a guy in NJ who offers a trade-in service for control arms where he sends you control arms with pressed in Poly bushings and you send him your old ones. I can PM you his email if interested.

OGRacing

iTrader: (1)

flat spots?

Darbymx5

shouldn't be, the tires are pretty new and only have one auto x on them. plus my brakes wont lock up even if I wanted to because wilwoods

aidandj

iTrader: (5)

ftfy

Darbymx5

brakes were bled multiple times with motul RBF600. you should probably read into wilwood caliper flex

aidandj

iTrader: (5)

I have wilwoods. Have actually flat spotted a set of tires before.

Caliper flex does not always mean lack of braking ability. It affects pedal feel more than anything. If you can't lock up you have other issues.

I read all about your issues on some facebook thread. And after multiple people explained to you that wilwoods work fine you still go around bashing them because of issues you have.

Stop spreading bullshit. They may not be the stiffest caliper around, but they are way stiffer than OEM calipers.

Either way. You are wrong.

aidandj

iTrader: (5)

Did you bleed both sides of the caliper?

sixshooter

iTrader: (12)

I'm going with flat spotted tires or rear hubs are bent or cracked. And since you dismissed the idea of the tires without checking them... well, there you go. Rears are easy to flat spot without knowing and will transfer more vibration under throttle and less when off throttle.

If you can't lock up even Hoosiers with Wilwoods then you are either running really shitty compound pads or have legs like noodles. Harden up. It ain't the brakes.

Data point -Spec Miata drivers can lock up Hoosiers with 1.6 brakes and flexible stock calipers. Even the women.

stefanst

iTrader: (1)

^+1

Darbymx5

If my tires were flat spotted I'm pretty sure I would feel it while driving in a straight line also, not *only* under cornering. I will check them, but I'm pretty positive thats not the issue. I am not the only one that has issues with wilwoods idk why you guys think im making this **** up. and I am a woman so idk what your point was with that.

Darbymx5

yeah its not bullshit if its a proven fact.

z31maniac

Never had issues with my Wilwoods on all 4 corners. Even sharing the car with another driver and doing 10+ sessions in a day, many back to back.

aidandj

iTrader: (5)

Yes they flex. But they also stop really well. Stock calipers flex much more than that.

Not sure why you think I'm making things up. My brakes will lock up easily.

Did you bleed 2 bleeder screws on each caliper? There are 4 total per caliper. Each caliper needs both top screws bled.

OGRacing

iTrader: (1)

you can lock tires with wilwoods. torq is controlled by pad compound, rotor size, and hydraulic advantage. caliper's strength will control feel, pedal distance, pad taper, rotor life, and drag.

the dynalights-dynapro aren't great calipers. heck, they are under $200. I had wicked vibrations that went with the speed it's either a tire or an axle.

aidandj

iTrader: (5)

And thats saying something. Because Johnny is the biggest Wilwood hater around.

yes wilwoods flex, yes they are cheap. But they stop fine.