Steering wheel resistance while threshold braking
 

Last weekend at the local track (High Plains Raceway) I experienced something I've never experienced before. When threshold braking the steering wheel provided me with significant resistance while threshold braking. There are a couple turns at High Plains Raceway at which it was very noticeable. In turns 2 and 6 it became an increasingly annoying problem and got worse the faster I went. These are both turns that I enter going around 70 or 80 mph (sorry, no data acquisition available).

http://media.cms.windingroad.com/aut...h%20Plains.png

I was braking hard going into the turns and pulling noticeably harder on the steering wheel to get the car to turn in. Then, still providing similar steering angle, I release the brakes slowly and feel significantly less resistance from the steering wheel. Even though the steering angle didn't change, the attitude of the car did, and it began to rotate much better. There seems to be some kind of correlation between the two.
Additionally, the car seems to understeer when this is happening. The front end just doesn't bite like I'm used to. As soon as I release the brakes, the front end just digs in and goes right where I want it to.
Keep in mind what I'm experiencing is not simply the car pushing. The car's attitude changes as soon as I feel less resistance in the steering wheel.

My car's stats as it sits now:
stock suspension
BFG R1S at 29 psi hot
Even tire temps all around except +15 degrees F on the front tires' inner shoulders
stock brakes other than DTC 60s and Togue Factory ducts
RCE street camber plates
Stock caster, 3.2* of front camber, zero toe

I'd like to stress that the front end seems to turn in properly when the steering wheels resistance went away, not when I released the brake pedal. Although they happened pretty much at the same time, it seemed to me the car's attitude changed depending on the resistance to the steering wheel and not specifically the brake pedal. I don't know why it felt that way to me, but it did.
Who else has experienced this? Any ideas why this is happening?
For what it's worth, my best lap last weekend was a 2:10.7 on an exceptionally slippery track. I'm guessing the best it was capable of was high 2:09s, but that would be really pushing it in this trim. Maybe that'll give any local guys more perspective and help with diagnosis.

I had this happen repeatably at CTMP (Mosport), on the GP track, going into 5a. I attributed it to how much load was on the left front wheel on the compression up the hill and turning in at the same time. Taking a different line stopped it entirely, and it didn't happen at slower speeds where less weight was transferred to the left front wheel. It wasn't understeering for me though, just heavy effort at the wheel.

Interesting, thank you. 5a looks like it would put you in a situation similar to what I was in. Have you tried to figure out the cause of it? Dealing with this issue is kind throws a wet blanket on my desire to go faster.

I've run into this at AutoX (I think it's the same thing) under similar situations, where one front corner was under heavy load. I've been lucky perhaps that it has happened after I was largely turned in and I didn't have it fighting me beyond making me have to muscle it through and a bit to exit... basically feels like power steering loss.

It is known.

http://www.ft86club.com/forums/showthread.php?t=8432 (first post)
http://www.ft86club.com/forums/showthread.php?t=74300
http://www.ft86club.com/forums/showthread.php?p=2301565
http://www.ft86club.com/forums/showp...postcount=3837

No idea why it happens, overheating or overloading and it shuts off to prevent damage seems the most reasonable. :iono:
Haven't heard any solutions, I don't think CSG experienced it and I think Element deleted the PS so you've gotta keep your fingers crossed for some other random person to have figured it out.
I've never had it happen.

Edit: Your second paragraph sounds like a symptom of electronic brakeforce distribution, not anything at all to do with power steering. Do you brake/pedal dance?
http://www.ft86club.com/forums/showthread.php?t=25494
That's probably the most relevant line of questioning.

Question, did you do the pedal dance to completely disable the electronics (except ABS)? I've run into this in the past but not so much lately. I started doing the pedal dance a while back but I cant recall if I stopped encountering this at the same time or if it is a coincidence. My driving style has changed quite a bit (for the better) so it might just be driver inputs on my side.

I've had it happen a LOT. It's rather unpleasant and disconcerting, but not sure what can be done.

FWIW it's entirely unrelated to braking, it's completely load based on the front end. I would lose power steering completely around the banking in the karussell corner at Shenandoah. Really unpleasant...

Thanks, cjd. Unfortunately the corner that causes it the most is a decreasing radius turn, which makes my situation the opposite of yours in that it happens well before most of the turning is completed.

Trail braking without the pedal dance will cause this.

Understeering under braking/turning (trail braking) without the pedal dance is normal.
@Pat: Are you pedal danced?

As usual, I love reading your posts. Thank you very much for sharing all of that information. I searched but failed. Not a big fan of the search function on this site. And apparently my Google-fu is sub-par.
I'm going to check my sway bar for rubbing when I get some time. I think that is the most logical, but am not convinced that is the problem.
This was also very helpful:
sw20koch post

Yes, I always do the pedal dance.

Yes, I always do the pedal dance.

Also worth noting, I feel our front suspension likes to bump steer a bit. Entirely possible for you to load a tire or take a line such that it essentially bump steers away from the direction you want to turn, so there's additional force to overcome.

I have this issue all the time. It happens when the suspension is loaded and you need the power steering the most. That past 2 weeks I was at 4 different tracks. At Watkins Glen it was at the toe and turn 10. It happened all over at Palmer. Pitt Race turn 7 brought it on. I didn't notice it at Mid Ohio.

I never felt it with stock tires. Once I went to a stickier tire I thought maybe the power steering fluid was low. It was then I learned we have electric power steering. I've learned to ignore it but I'm disappointed that a specific failure hasn't been found that we can actually fix.

I expect someone not pushing the car that hard on street tires may never encounter the issue. Especially if that track doesn't have those turns that add compression during turning. It is, no doubt, a loss of power steering boost. It is not related to heat as I've had it happen on the first lap. Not really any way to have it addressed under warranty as the tech will never be able to recreate the issue.

My car is a 2014. Maybe later models don't have the same issue?

Pat,

I was just looking at a couple of your posts and the issues you're having. One thing is your hot psi is way too low for an R1 / R1S on our cars. The recommended hot psi from BFG is 36-42psi for a 2700-3000lb car and the R1S really likes to be on the high side of that.