Shuttering While Cornering Hard
 

I've got a 2013 Subaru BRZ, I've had it for about 3 and a half years, and it has 220000kms on it. It's my daily that I drive about 200km a day in so I rack up the kms pretty quick!

Anyway, I've had an issue that's just recently surfaced. When I corner hard it seems to shutter/shake, only on the limit and it's when I start to get on the gas. This leads me to believe its maybe wheel hop?

Incase there's any other issue it could be that's not wheel hop I thought I should ask.

If it is wheel hop, what seems to be the most common cause of this?

The car is 100% stock.

How are your tires? I found when my FRS tires were at the end of their life they would give the traction control fits when cornering.

They’re definitely getting worn out, hoping to get the rest of this summer out of them. If that’s the issue that would be easy!


Sent from my iPhone using Tapatalk

That would be my bet then.

Quick test to confirm would be to long-press the traction control to defeat it. Don't worry. It's not like the car suddenly becomes a Mustang.

Yeah that’s a good idea! I’ll try that.

And yes I’ve used that button a time or two, its a fun button, especially in the winter!


Sent from my iPhone using Tapatalk

Rotate your tires. See if the behavior changes.

I agree with Tcoat thats what it sounds like to me as well.

Worn struts can also do this...

And bushings, bearing, etc, etc.
Start at the parts that touch the ground and work your way up.

Perhaps stating the obvious, but this sounds like understeer to me. Coupled with the "only on the limit", have you considered that this might be driver input (e.g. a result of your braking, weight transfer, speed and steering wheel angle being incorrect for the corner?) I ran into this when I first started HPDEs... even though I was slower than I am now.

is the traction control kicking in while this is happening?

I suspect that is the "shuttering*" he speaks of.

*Shuddering

https://thumbs.gfycat.com/LastingNew...er-max-1mb.gif

https://c.tenor.com/gqMu9ZIwUcIAAAAM...n-reynolds.gif

Shuttering while turning would indeed be a pain!

Not to be confused with stuttering.
https://www.youtube.com/watch?v=gBzJGckMYO4

Sorry for such a late update. So heres a few things

I tried it when traction control off, no change.

It’s definitely not understeer as its only on the exit of the corner as soon as I get on the throttle and very clearly feels like it’s coming from the rear, it also stops as soon as I let off.

I’ll try rotating tires, thats a good idea. I also have snow tires, could throw them on and go hit the a corner and come back.

If I can completely rule out the tires, any tests I can do to see if its struts or bushings? Or is it just replace and hope for the best? Lol


Sent from my iPhone using Tapatalk

Serious question. When you say you turned off TC, was it with a quick push, or did you hold it down until both lights illuminate? Takes 3-5 seconds, I don't remember exactly.

@Robbie7c

If you think you're getting wheel hop when cornering and its causing the car to slow down, then that's probably what it is. Becomes more apparent when the car gets a lot of miles on it, gets some driveline slack from the transmission mount, diff mounts, and subframe mounts all wearing past 100,000 miles.

I had clutch chatter around slow corners and clunking driveline issues by about 100k miles. Also the tires would chirp for no reason when I gave it moderate gas around corners. And then I also had a couple instances where I felt the rear end twist or warp when I did a mighty peel out.

My fix for driveline slack, wheel hop, transmission-shifting problems, and slow body response when cornering was to put Perrin and Whiteline parts on it. 1) Positive Shift Kit, and 2) Positive Traction Kit really keeps the rear planted and stiff, at the expense of removing softness (ride quality) from the rear, it keeps so much traction that you'd have to be really trying to even chirp the tires taking a corner. It fixes low-speed driveline slack problems, especially when cornering in 3rd gear.

Another option to restore fresh factory drivability, is to buy an entire new or like-new subframe and differential cradle assembly, new transmission and engine mounts. And take care to refresh other things like driveshaft carrier bearing. You can get fresh parts from a wrecker / salvage car. Doing so makes for a good case for upgrading the differential to a 2017- diff.

Yeah I held it down until the two lights appeared, I’m very experienced in using that button [emoji2957]


Sent from my iPhone using Tapatalk

The only other 'normal' shuddering I feel is when the diff locks up in a slow, tight corner like a three point turn. With that and VSC ruled out, I'm ready to agree that something isn't kosher.

Not particularly helpful outside of getting past the "it's normal" replies.

Yeah fair enough, it’s definitely not normal, I’ve driven the car 130k and this only started happening in the last 3-4k I’m gonna try out my snowtires this weekend see what happens. I’ll give an update here once I’ve done that. If that doesn’t solve it then maybe shocks [emoji2371] car has 220k on it so it’s anybodys guess at this point


Sent from my iPhone using Tapatalk

I totally missed this post last time around, thats interesting though, this could very much be what I’m experiencing being that it is a high mileage car. I kinda hope not [emoji23] would be much nicer to have a simpler fix. But worth considering anyway.

I’ve definitely not had it as bad as what you’ve explained, the car has acted normal other than the wheel hop, it’s more apparent around slower speed corners but i’ve felt it a bit in mid-high speed corners, just takes a bit more confidence to get it to that point lol


Sent from my iPhone using Tapatalk

So I tried swapping tires on the weekend with no luck. I tried my snowtires on the back and putting front tires onto the back. Both ways it still shuttered.

One other interesting thing I just kind of connected the dots about, is that ever since this problem came about I’ve been struggling more than usual for rear end traction, especially in high speed corners, get on the gas and it gives you a flick of oversteer. I thought this was just my tires wearing out but honestly having a closer look at them, they’re not down to the wear bars yet so they should still have good traction in dry weather.

I’m really starting to think this has got to be shocks, what do you all think? It kinda just makes sense to me, might give that a try


Sent from my iPhone using Tapatalk

Is it equal in both directions? Dampers are tough for me because of their gradual decline. Any leaks?

I think all of the lower speed corners where I get the shuttering on my daily drive are left hand corners. All the right hand corners are higher speed but, I did step out sideways on the right high speed which was unusual. I’ll have to see if I can find a slow right hand corner.

I’m gonna take a look for leaks this weekend seei if I find anything. Any other way to tell if I’ve got a bad shock while I got the wheel off?


Sent from my iPhone using Tapatalk

i feel like if your shocks were that worn out you would notice in other ways.
just throwing it out there, is it possible that this is in your head and you're so focused on it that you're noticing things that either have always been that way? or making it out to be worse than it is? you wouldn't be the first to do it and im not saying that the case but have you considered it?


Sounds like you need to get under the car and start checking some boxes to see what still works so you can eliminate it off the possibilities list

As far as the traction goes, that could be in my head. But the shuttering is definitely a real issue it can be rather aggressive, if it were like that from new I probably would have gotten rid of the car cause it’s not at all pleasant.

Yeah I think this weekend I definitely need to see what I can find. Probably just start shaking things around see if I can feel anything loose, looks for shock leak, and see if I notice anything that seems abnormal


Sent from my iPhone using Tapatalk

So I took a look under the car, nothing really feels loose, all the bushings feel good. Shocks don’t look like they’re leaking. Only spot I wasn’t sure of was upper control arm bushings I couldn’t really move without the pry bar. I suspect that they just have pressure on them with the car up in the air.

I’m a bit lost on what to do next


Sent from my iPhone using Tapatalk

Have you even had the alignment checked?

I haven’t, but thats a good idea, I’ll get that checked


Sent from my iPhone using Tapatalk

Ok it's been a while, I've gotten a bit distracted and put this issue on the backburner, had other things to focus on. But I do have some updates to hopefully help narrow down the issue.

So I put a new clutch in the car, got brand new tires, and a 4 wheel alignment. Alignment shop told me I had play in the rear pillow ball bushing so had that replaced as well.

The issue still persists. I can definitely say it only happens around left hand corners, right hand corners are smooth as butter. The traction problem I mentioned earlier where the rear end would step out around higher speed corners is completely gone, likely fixed from new tires or the pillow ball bushing.

So it's got to be either the rear right shock or the diff I would think? I can't imagine it's driveline play cause I would think if it were that I would have a problem around both right and left corners.

reason I think it could be the diff is maybe just the way it locks up is only effected around left hand corners. Not an expert on these diffs maybe some one could shed some light on that.