Power steering issue with slicks?

[ROADRACER]

Originally Posted by churchx

If it happened on first lap and possibly is not temperature triggered .. then i guess it might be rather from what strength/torque from EPS is asked to turn a wheel. Not sure it's that simple of a fix, it might be also some programmed firmware logic. I'd rather explore possibility of retrofit of EPS from MY2017.

I think you are correct. I think the power being ask of the EPS motor is beyond the design limit. I wish there was a way to just reduce the assist level to a point it didn't exceed the limit, or raise the limit with a firmware modification.
I would bet there is a Japanese guy sitting at a desk at the Subaru factory in japan that made the system that could fix the problem...unfortunately I don't have his email address.

[churchx]

As with car stock, with less grippy tires, with stock alignment, it's unlikely for problem to occur, i somewhat doubt for there to be official fix. Unfortunately twins with at least stock alignment, are not of optimal setup to track often. Even more so, if updated EPS is among new features of restyle model, and even though if not among major, but extra incentive/selling point. And actual engineers in most big companies are almost never possible to reach directly by customer according common practices. So i guess, that any possible fixes for older twins EPS will probably be unofficial and may probably come from own experiments or will from community.

[RedReplicant]

Is there a fix / hack for this yet? I ran my SC'd car yesterday for the first time and this was happening all over the place, I thought it was wheel on hard part at first until I found no evidence and I did a bit of reading online.

I run a Koyo unit in my Miata that looks very, very similar to the BRZ one and have never had an issue, so I'm pretty surprised to find out the cause here.

[Pat]

Originally Posted by RedReplicant

Is there a fix / hack for this yet?

Yes, stop letting your front tires rub inside your wheel wells. Increase the ride height, get stiffer springs, etc.

[RedReplicant]

Originally Posted by Pat

Yes, stop letting your front tires rub inside your wheel wells. Increase the ride height, get stiffer springs, etc.

Tires are not rubbing anywhere, 600lb / 700lb springs, ~130mm to pinch weld, etc. Only driven the car one event so far, pace was TT4 record pace in what will be a TT3 car so a few seconds off TT3.

[PulsarBeeerz]

Someone makes an upgraded motor for the EPS. I just can't remember the manufacturer.

[DocWalt]

Originally Posted by RedReplicant

Tires are not rubbing anywhere, 600lb / 700lb springs, ~130mm to pinch weld, etc. Only driven the car one event so far, pace was TT4 record pace in what will be a TT3 car so a few seconds off TT3.

Check that end links aren't binding too.

I had this issue plenty on my 2013 even with no bind or rubbing. Annoying.

[RedReplicant]

Originally Posted by DocWalt

Check that end links aren't binding too.

I had this issue plenty on my 2013 even with no bind or rubbing. Annoying.

Okay, they are the stock ones up front that I'm replacing with RacerX as I type this.

Originally Posted by PulsarBeeerz

Someone makes an upgraded motor for the EPS. I just can't remember the manufacturer.

I saw the one company that was mentioned before, not sure what the price point is but it looks like the same unit (Koyo) I run in my Miata and am really happy with.

I wonder if the revised units will plug and play in older cars

[rice_classic]

Originally Posted by RedReplicant

Okay, they are the stock ones up front that I'm replacing with RacerX as I type this.

These are the ones I use without any issue. Make sure your sway bar can clear your lower control arm. You can check this by removing a strut and end links and rotate the sway bar up and down while the LCA is in an upward position as it if was under cornering compression.



I have scuffs on my LCA where my massive Eibach sway bar occasionally just skimmed it when I had the length of my end links set wrong.

[RedReplicant]

Originally Posted by rice_classic

These are the ones I use without any issue. Make sure your sway bar can clear your lower control arm. You can check this by removing a strut and end links and rotate the sway bar up and down while the LCA is in an upward position as it if was under cornering compression.



I have skuffs on my LCA where my massive Eibach sway bar occasionally just skimmed it when I had the length of my end links set wrong.

I went through everything more closely after reading your comment and found this hiding behind the struts. Not sure if it was there from before I bought the car, but I think I'll need to pull a tiny bit of camber out or see if the OEM -> RacerX links bought me enough clearance. I didn't really find any evidence on the original endlinks that I'd expect for contact, but better safe than sorry.

[strat61caster]

Slap some painters tape on the spot to see if it happens again.

[Icecreamtruk]

Im with most people here on that its probably rubbing somewhere. If its happening everywhere (or very often) its not the EPS cutting out, that only happens under very heavy load, so usually cambered turns or big elevation changes at turn in points. Since you didnt post any pictures of it, look UP inside your wheel wells. The tire usually rubs on the black plastic (fender liners) right above the tire at max compression if you are too low, and 130mm is very low.

[ROADRACER]

Originally Posted by PulsarBeeerz

Someone makes an upgraded motor for the EPS. I just can't remember the manufacturer.

Does anybody have a link or information on this (upgraded) motor? Its kind of a big deal if one was actually available.

[RedReplicant]

Originally Posted by Icecreamtruk

Im with most people here on that its probably rubbing somewhere. If its happening everywhere (or very often) its not the EPS cutting out, that only happens under very heavy load, so usually cambered turns or big elevation changes at turn in points. Since you didnt post any pictures of it, look UP inside your wheel wells. The tire usually rubs on the black plastic (fender liners) right above the tire at max compression if you are too low, and 130mm is very low.

No rubbing up top, fender liners are intact and untouched.

I found the marks previously shown from the bar endlinks and I also found that close to lock at full droop the remote reservoir lines were being stretched, so I cleaned that up. It only happened under heavy trail braking or mid corner where load was highest.

I have another test day next weekend, so we will see if it has cleared up.

Originally Posted by ROADRACER

Does anybody have a link or information on this (upgraded) motor? Its kind of a big deal if one was actually available.

This is what has been discussed elsewhere https://www.dcemotorsport.com/Home/EPAS

The units look very similar to what I ran in my Miata, which is a Koyo from a Saturn Vue (and other cars). The Pro Street ECU looks the same as my control unit and also has the same harness w/ rheostat to control assist.

I would be kind of curious to see what failsafe mode is like on the units we have. Normal assist or turns off completely?