GR Yaris POWER STEERING FAILS mid turn on the Nürburgring

Dragos_DreS said:
Mine, are not standard. My tire width is 255.

On the exact same setup with the original wheels and 4S tires, never had a single issue. Even on the Nürburgring GP track where you have to trail brake a lot and hard. I guess the tires lost grip before the steering failed.
Click to expand...

I didn't habe the problem on the GP Track when I was there so maybe its not only steering thats the problem? Wide spacers and other changes to the geometry makes a big impact on the Yaris.

My lap from GP track for reference:


And a slow lap on the real ring for comparison:

On the GP Track it's on 255 Yokohama 052 and on the ring its on regular 245 Conti Sport6.

Driving without front arb on both tracks and its really not dangerous.
 
  • Like
Reactions: Fred and Onehp
I'm pretty sure the driver in this youtube video is talking about the same thing. Time stamp-11:25
Car is stock power with Ohlins and 255 Yokohama AO52.


 
Rather than replying to everyone individually, I will try to do it all in one message. Sorry in advance if I missed anyone!


So, on Wednesday I took the car back on the track and did another 5 laps.
This time I was a little more careful when doing any kind of trail braking and I had zero problems.

Well actually zero is not correct!

I did have the steering get a little harder in certain turns when I was pushing and I could definitely feel the power steering losing power, but it was fine. Pretty much the same as in this last video from Rob (at Time stamp-11:25). The steering gets a bit choppy but nothing that made me feel unsafe at all. Nothing like the last time where I had lost 95% of my steering for 1-1.5 secs.. (like the steering locked up).

Originally, I had the suspension set my 24/7 to one of its softest setting. I thought, since these guys mainly work on BMWs, maybe I know better, and I changed the front coilovers settings to a bit harder.
From what I could tell, the car was a bit sharper, and I had the feeling like it was the right way to go. I was wrong!

This Wednesday, another GR Yaris guy took me for a lap in his car.
He is running KW V4 Clubsport with 255’s (can’t remember which) and this guy claims that he has never had a problem with his steering.
The KW’s were too soft in my opinion but that car did handle the Nordschleife very well.
So, for the last 2 laps, I changed my suspension settings back to softer. I noticed that in some turns the car wasn’t as aggressive; however, in all those bumpy areas, I was able to fly over them with more confidence than before.
The steering choppiness in those hard turn was gone. I would only feel a bit of it in the second carrousel. As you can see from this pic, I wasn’t exactly taking it easy at all anymore.

Please keep in mind that I only have two clean laps so far without any steering issues.
There is a good chance that I will bitch about it again after my next laps on the Nordschleife.



nur_06.webp
 
  • Like
Reactions: GRandemakina, SayonaraLicense, Slarti and 4 others
I contacted both local Toyota product specialist (responsible for GR models) and my Toyota maintenance shop (as Toyota informed to manage these issues via service).
Service answered that there has been no other reported cars for this issue. They had noted that there was discussion on the forums of this issue.
I asked them to report the issue for my car. I would ask others to do the same (report the power steering issue in certain driving conditions) to your service shop so they can gather more data on the cars that have this issue. It's the "official" process and it makes it more likely that Toyota will take some kind of issue for this to fix it. After all, I'd like that power steering can handle whatever driving scenario, especially if I had to avoid collision on the road etc.
 
  • Like
Reactions: DanGR, Dragos_DreS, DobiLux and 4 others
Hello guys, I did the first track with my GRY today and I had intermittent, short, power steering cuts at a right corner entry, on heavy trail braking in a sloping parabolic curve . The car has stock suspension, stock engine, stock brakes. Tires are semi-slick 235/40R18 on WedsSport 18x8.5 ET32. Alignement is still the stock one (car has 3800 km) so has never been touched.

If I brake sooner and I don't take the sloping part of the curve (I stay "down" to avoid putting too much load) then there is no cut. At first I thought the front left wheel wasn't properly tightened. But I finally find this topic and I understand this is power steering going off for some fraction of seconds (so less than 1s, for two or three times each time I took this corner hardly).
 
  • Like
Reactions: GottGry and Michael Knight
DanGR said:
Hello guys, I did the first track with my GRY today and I had intermittent, short, power steering cuts at a right corner entry, on heavy trail braking in a sloping parabolic curve . The car has stock suspension, stock engine, stock brakes. Tires are semi-slick 235/40R18 on WedsSport 18x8.5 ET32. Alignement is still the stock one (car has 3800 km) so has never been touched.

If I brake sooner and I don't take the sloping part of the curve (I stay "down" to avoid putting too much load) then there is no cut. At first I thought the front left wheel wasn't properly tightened. But I finally find this topic and I understand this is power steering going off for some fraction of seconds (so less than 1s, for two or three times each time I took this corner hardly).
Click to expand...
ET32 might make the EPAS work harder than the stock ET45 offset since it isn't optimal geometry wise - I might be wrong though
 
  • Like
Reactions: Onehp
DanGR said:
Hello guys, I did the first track with my GRY today and I had intermittent, short, power steering cuts at a right corner entry, on heavy trail braking in a sloping parabolic curve . The car has stock suspension, stock engine, stock brakes. Tires are semi-slick 235/40R18 on WedsSport 18x8.5 ET32. Alignement is still the stock one (car has 3800 km) so has never been touched.

If I brake sooner and I don't take the sloping part of the curve (I stay "down" to avoid putting too much load) then there is no cut. At first I thought the front left wheel wasn't properly tightened. But I finally find this topic and I understand this is power steering going off for some fraction of seconds (so less than 1s, for two or three times each time I took this corner hardly).
Click to expand...
That was a great explanation of the short power steering cuts. Now I know what you guys mean with power steering cuts, as I've had the exact same behaviour on the ring for example in Metzgefeld on the last corner before Kallenhard.
I thought it had something to do with "brake-lock" steering affecting the behaviour, so I just stopped braking a tiny bit earlier and the problem was gone and I was even a tad faster. I had wide sticky tyres and sturdy coilovers w/hard springs and full track geo.
I've never seen this as a problem, but more kind of another thing you have to adopt to. It wasn't there until my lap times dropped to well under 9 minutes.
 
I don't track but I can already feel a change from et45 to et40 as a (minor) locking effect on the steering under acceleration on rutted roads as the traction pulls unevenly the wheel loads up (torque steer). The same affect should happen when braking hard (brake steer) and any uneven load is on the wheels when starting turning but I don't track on my et40 winters so haven't noticed. But it is true on all previous cars I drove with lowered et, and a friends fwd high hp track car became totally undriveable with an et change of 20. On braking it is the same effect for all cars.

Just to say I see a lot of people changing the et sometimes a lot and it makes me scratch my head wondering if they don't notice that... (double knuckle as some BMW steering geometry excepted)
 
Last edited:
  • Like
Reactions: GottGry
Onehp said:
I don't track but I can already feel a change from et45 to et40 as a (minor) locking effect on the steering under acceleration on rutted roads as the traction pulls unevenly the wheel loads up (torque steer). The same affect should happen when braking hard (brake steer) and any uneven load is on the wheels when starting turning but I don't track on my et40 winters so haven't noticed. But it is true on all previous cars I drove with lowered et, and a friends fwd high hp track car became totally undriveable with an et change of 20. On braking it is the same effect for all cars.

Just to say I see a lot of people changing the et sometimes a lot and it makes me scratch my head wondering if they don't notice that... (double knuckle as some BMW steering geometry excepted)
Click to expand...
it does the same with stock ET, with stock wheels. so issue is there, front just need to be loaded sufficiently.. but I agree smaller ET likely make it even worse.
My small ET wheels are ment for low grip & narrow tyres so not likely causing issues there.

In a way its a pity as car should be driven (to my understanding) with some trail braking in order to get the front bite, but its the area where steering has issues. If not turning while braking issue is not that big.
 
  • Like
Reactions: DanGR, Onehp and GRandemakina
Michael Knight said:
it does the same with stock ET, with stock wheels. so issue is there, front just need to be loaded sufficiently.. but I agree smaller ET likely make it even worse.
My small ET wheels are ment for low grip & narrow tyres so not likely causing issues there.

In a way its a pity as car should be driven (to my understanding) with some trail braking in order to get the front bite, but its the area where steering has issues. If not turning while braking issue is not that big.
Click to expand...

That's alarming! Am I missing something?

I'm on stock wheels, tyres grippier than stock (but not semis), agrressive street geo and the car trail-brakes just fine on the road; in fact, beautifully.

Or do you mean that it does it only when driven really hard on the track?
 
Dragos_DreS said:
Hi Everyone,

So today I did my first proper laps on the TE37’s with the Yokohama Ao52 (255).

On my first lap, I set the tire pressure to 2.10 BAR just to get a bit of heat into them and after passing 3 crashes, the Ring temporarily closed or a little while.

As it reopened 30 mins later, I had to do another warmup lap and I got the tire pressure this time to 2.35BAR which I dropped down to 2.05BAR.

Here we GO, the tires are at the right temperature and grip!

I could finally push the car hard and for a little while I was amazed at how well the car drove on the new tires.

When I got to the second left on (Metzgesfeld), boom 95% of my power steering, gone. And by gone, I mean gone right in the middle of the turn.
I fought my wheel to the left as hard as I could but at some point, I thought it was safer to just hop onto the grass just in case the wheel stayed locked and I couldn’t steer to the right afterwards.

Can anyone tell me what happened?

I heard that the wider tires, plus the extra grip from the Ao52’s might have overloaded the electrical steering motor? Can that be?

Pretty scary if the car is able to turn at high speeds but the steering fails mid turn.

Any advice would be greatly appreciated.

View attachment 18491
Click to expand...
I have power steering issue at track some time
When I run 295 tire and super big caster
Since he Yaris is electric power steer
So I upgraded my battery to lion battery
This seen reduce my problem
 
  • Like
  • Wow
Reactions: Orion, GRandemakina, GottGry and 1 other person
Diyman25 said:
I have power steering issue at track some time
When I run 295 tire and super big caster
Since he Yaris is electric power steer
So I upgraded my battery to lion battery
This seen reduce my problem
Click to expand...
Hello, thanks for sharing the info. Could you explain how a better battery could solve this issue, since it occurs when the engine is running, so while the car is powered by the alternator?
Thank you in advance.
 
  • Like
Reactions: Michael Knight
DanGR said:
Hello, thanks for sharing the info. Could you explain how a better battery could solve this issue, since it occurs when the engine is running, so while the car is powered by the alternator?
Thank you in advance.
Click to expand...
In theory lion batteries can release large current in demand compare to acid battery
So this will help when Gr Yaris steering rack need lots current with very wide tire
 
Diyman25 said:
In theory lion batteries can release large current in demand compare to acid battery
So this will help when Gr Yaris steering rack need lots current with very wide tire
Click to expand...
True for specific (per weight), but if that Li-ion is 2kg vs acid 23kg or something, is the Li-ion more then 10x stronger per kilo in practice?
 
Onehp said:
True for specific (per weight), but if that Li-ion is 2kg vs acid 23kg or something, is the Li-ion more then 10x stronger per kilo in practice?
Click to expand...
No they are between three and five times the Wh/kg, depending on which of the four types of battery chemistry used (LTO,LCO,NMC or LFP)
 
Old64er said:
No they are between three and five times the Wh/kg, depending on which of the four types of battery chemistry used (LTO,LCO,NMC or LFP)
Click to expand...
Peak current is different again and depends on quality of the battery, temperature, soc etc
 
You must log in or register to reply here.
Top Bottom
Back