GR Yaris Issues when driving on slippery surface

Now actual slippery driving issue noted. posted also to old forum..

Wonder if others have noticed this but did some couple hundred km of driving on snowy roads with lots of little slides and noticed that occasionally it is a bit vague how front end hooks up if driven with track mode.
Sometimes it feels like 50:50 (usually in mid corner) which is ok, it can be managed with weight transfer etc.
When driving longer corners with less steering input (or on straight), have noticed that power output is more front biased. this has caused some not wanted understeer in few occasions. Due to this I don't trust driving with track mode - sport seems to give more stabile power output between front and rear axle and car is thus more predictive to be driven on throttle.

Might mention my mach of this if they have a clue, but I feel it could me something of an software issue how driveline is directed to transfer power between front and rear on track mode, depending on throttle and steering angle etc.
 
I think maybe you would like some more camber in front, power understeer is definitely there otherwise.
Or just drive in Sport all the time.

When driving with 3 neg camber in front (2 dot camber bolt maxed out), even in track I could do power oversteer on slippery surfaces at will, bit rwd feeling even beyond initial rear kick (= sport). However at high speed I found it to be too lively at the rear (with Nordic winter tyres), so I settled with 2,3 deg neg camber in front (1 dot camber bolt maxed out) and haven't looked back since.

Note: this is on winter/all season tyres and low friction surfaces, on a dry track with track rubber, completely different experiences are plausible.
 
Otherwise to test/diagnose the front drive theory is leaving the handbrake up a bit without actually engaging the drum brakes, then you're driving a fwd car and you'll feel the difference.

Warning: possibly esp is not working then so try at own risk and in safe surroundings!
 
Onehp said:
I think maybe you would like some more camber in front, power understeer is definitely there otherwise.
Or just drive in Sport all the time.

When driving with 3 neg camber in front (2 dot camber bolt maxed out), even in track I could do power oversteer on slippery surfaces at will, bit rwd feeling even beyond initial rear kick (= sport). However at high speed I found it to be too lively at the rear (with Nordic winter tyres), so I settled with 2,3 deg neg camber in front (1 dot camber bolt maxed out) and haven't looked back since.

Note: this is on winter/all season tyres and low friction surfaces, on a dry track with track rubber, completely different experiences are plausible.
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Cheers I believe this is something driveline power transmission related, not camber related as such (of course it has its effect).
Could also be that I'm not that familiar using the track mode on slippery surfaces so its tendency to understeer is higher than what in sport mode where rear almost always goes first.

Would be fun to analyze more if there was individual wheel speeds available for OBD logging, could do test runs on ice track with both track and sport mode on and see how they react (combining with steering angle and throttle input).

Or then just go sideways and enjoy life. ;)
 
Maybe not entirely the same thing but good to have 'grips' with.

When under a four wheel slide, the car can get unsettled when both letting of the throttle or pressing the clutch as it regains grip, and also to a degree when going on the throttle and the drivetrain engages and the car becomes 'locked in' into whatever attitude the car has. Going straight meaning understeer.

This is down to that when under throttle, the Torsen diffs and the whole drivetrain are under tension/torque and have all the four wheels 'connected' together, stabilising the car. So when going off the throttle, ideally you want the car to be in a situation where it would be settled off throttle (not sliding) as all wheels now turn individually (no torque in drivetrain = torsen diffs act as open diffs). And the other way around, when engaging power for a slide in slippery conditions, you want ideally for the car already set in the slide.

For small bends/corrections with slowing down a little, one answer is left foot braking. Like lifting it slows you down but it keeps the tension on the drivetrain and all four wheels in sync, and is therefore much smoother/progressive. Added advantage is no lag as when going back on the throttle, so all in all much better control.
 
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Today fresh snow again and still amazed how great this driveline is! For the road use / occasional track days, I cannot think anything that how it could be improved.
The way car goes into slide and is manageable with the throttle is just pure joy. Its just crazy what Toyota has done, or maybe the other way around why other Manufacturers haven't been doing this. So glad I got one!

With the tire selection I have car is bit picky on the perfect conditions - give us fresh snow and maybe -1 to -5'C is the best weather for magic as tire is the grippiest. On too slippery roads the car becomes tad difficult to play around in proper speed.
 
Tested the weight transition of GR Yaris on more open area and its noticeable how fast the car changes its direction when weight is on front axle and there is traction. This is definitely cars strength but then also a big challenge for a driver - car reacts so fast that it is very easy to be too slow in the corrections. No wonder there is numerous incidents..

As this a known feature its important that car is always pointing to right direction or othervise it will shoot itself in the ditch, very rapidly.
 
mattipuh said:
With the tire selection I have car is bit picky on the perfect conditions - give us fresh snow and maybe -1 to -5'C is the best weather for magic as tire is the grippiest. On too slippery roads the car becomes tad difficult to play around in proper speed.
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This seems to me the reality of real world driving. Like Monte Carlo, conditions vary widely and usually only one tyre choice. Studded is great in perfect conditions, but much of the time they are in the way of joy - unless perhaps one is willing to wear them out in half a season, then there is a wider use case.
I have the VC7 on my family car and they are a great nordic winter tyre and allow to have fun in wide range of winter conditions. When conditions get sketchy, even studded can be a bit scary as you automatically expect some more of them yet grip can drop very low. So really it is much about a driver challenge and upping the driver game. Which also includes knowing, in some conditions it is best to hold back, no idea to try and risk too much.
 
Drove back from maintenance via good b-road - it was close to zero but road was covered with rough snow so there was plenty of grip available also for non studded tires. Car was just perfect to toss around with sport mode and TC off. It is delightful to drive in fourth gear and step the rear out to little slide around the bends - just pure joy!

Glad the GR has sufficient torque so you can utilize its power without the need to rev the engine too much.
 
mattipuh said:
Cheers @Chris64 just trying to be funny .. Hope it works occasionally!

@Onehp exactly that - issue in this recce was that I've got studdless winters and it was rather icy road with some water on it so the level of available grip is from medium to nonexistent (depends how much ice there is) so the definition of "slow" varies quite a bit depending on the road condition.

There are times when studs would be nice to have to have more constant grip - icy roads especially if temps are close to zero degree celsius are not that fast for studdless.

Drove yesterday to winter wonderland with kids and noticed that if the corner is very slippery car can power understeer if not driven with determination so watch out with that mode too. (better to use weight transfer and drive with throttle - easier to get car pointing into direction wanted).

Overall the car is just splendid road car in various conditions - we had sleet, ice, snow etc and was able to drive without fuss.
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Regarding power understeer. Assuming a Circuit Pack car, they have Torsen diffs. In slippery conditions under power they will lock readily especially the front when there is weight transfer to the rear - which will cause understeer but they only do this under power, if you come off the throttle, they will unlock and the understeer should reduce/stop...

I experienced this in slippery conditions in my DC2 Integra Type R and I learned to come off the power before turning in and then balance the throttle on exit...
 
corgi said:
Regarding power understeer. Assuming a Circuit Pack car, they have Torsen diffs. In slippery conditions under power they will lock readily especially the front when there is weight transfer to the rear - which will cause understeer but they only do this under power, if you come off the throttle, they will unlock and the understeer should reduce/stop...

I experienced this in slippery conditions in my DC2 Integra Type R and I learned to come off the power before turning in and then balance the throttle on exit...
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Yes this sounds likely. I was kind of modest with throttle when it happened.
 
I'm very impressed by the stability of mine (convenience with Dunlops) in all conditions, including a 50 mile drive on black ice last night - in 50/50 mode.
Not a hint of anything untoward, although I wasn't doing anything more than 70%.
 
Many videos claim that GR Yaris is tad too serious car, compared to other hot hatches. We did a qualitive survey on the topic, here are the results.
It is silly from what angles car is still recoverable.. I confess did 2 spins, but 4 recoveries from full steering lock so 67% propability of succeeding if you're there!
 
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It's most severe traffic warnings in Finland due to "Waltteri" Blizzard. Just went out with GR to pick some fuel and groceries - whas laughing out loud the whole trip.
Just epic fun to toss around, especially when there's enough snow car is sliding everywhere!
 
That said although I'm impressed by the stability of the 4wd system, I'm also super impressed by its ability to recover from when there is a slide.
3 recent events, the first lift off oversteer (my fault) the back end fishtailing and recovering, the second hitting a big gravel spill on a fast-ish corner on a motorway - the car figuring out the rapid change in surface friction, and the 3rd a wiggle going round a sharp corner too fast. All of these in 'normal mode' 60:40 on Dunlops, 4-5 degrees C. I'll stick to 50/50 track.
 
Valtteri storm (same as Malik) is turning out to be a real riot! Hilarious stuff in track-mode.

Also, I made DIY aero wheels, feel free to copy the design.
 

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