GR Yaris GR Yaris at racetrack

Faraday said:
... I got it aligned before the trackday and I’m at -2.5º in the front with more aggressive toe all around...
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For my understanding, what does "aggresive toe all around" translate to for this 4WD car, please?

I assume a bit of toe out at the front should make it more eager at turn-in. So, for the front, more aggresive probably means toe out.

However, which toe setting is considered more aggressive at the rear?

And is there a front-rear combo that's more aggresive as a whole? For example, many go for toe out at the front and toe in at rear.

Thanks
 
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My experience for whatitisworth... I went +1 / +1 front and rear and the rear was quick to step out on the road and more so at sprints, went to +1 / -1 and it is still tailly at the track, moreso now the lsd but tame on the road. Took a couple of highway runs to get used to it because it felt skittish but not dangerously so and not as bad as a solid front axle 4x4, just compared to how planted it was on stock suspenders and settings.

Turn in is much sharper and it rotates immediately.
 
Had another session at Alastaro with GR Yaris. Now with Boes seat console that is a good improvement for faster driving, no moving around cabin anymore and position during cornering was planted. So happy with that.

Managed to shave off almost 2s of previous time, now 1:33.4. Still think there's 1-2s to improve (stock brake pads & street tyres) as drive was far from neat and there was time left in two fast corners still. So good time starting with 1:31 with street tires and maybe 1:27-1:28 with semis?

Fun car with this setup, however too understeery if pushed fast track driving so maybe it is a compromise with this setup. Works 90% still and great on road.
Has initially problems getting heat to rear tires even though in last stint managed to get some heat there aswell.

Managed to overtake one GT3 and couple of race cars so in that sense it was good paced session.
 
Have now driven few days with the spacershop extender and must stay it is really a game changer in terms of driving position.
With the boes console car feels very confident to toss around. So i think it's a good alternative for bucket seat. I get zero lateral movement with the console and car is on its toes with steering wheel closer the driver.
 
Asked from Toyota maintenance regarding coolant temp issue - GR has not got any flect operation after engine shut down so it is worth keeping the engine idling for quite some time after each track stint just to avoid any heat issues..
 
Yaris San said:
do the RPX put grief on the discs or are they reasonable kind ?
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No clue - they state moderate disc wear but need to get a micrometer and follow up how they tolerate..
Really strong braking performance and quite a bit of dust at least on day one..
 
Michael Knight said:
Had another session at Alastaro with GR Yaris. Now with Boes seat console that is a good improvement for faster driving, no moving around cabin anymore and position during cornering was planted. So happy with that.

Managed to shave off almost 2s of previous time, now 1:33.4. Still think there's 1-2s to improve (stock brake pads & street tyres) as drive was far from neat and there was time left in two fast corners still. So good time starting with 1:31 with street tires and maybe 1:27-1:28 with semis?

Fun car with this setup, however too understeery if pushed fast track driving so maybe it is a compromise with this setup. Works 90% still and great on road.
Has initially problems getting heat to rear tires even though in last stint managed to get some heat there aswell.

Managed to overtake one GT3 and couple of race cars so in that sense it was good paced session.
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Far out! That is getting mighty quick for a stock 1.6L car. Wonder what the GT3 driver was thinking:D
 
I managed to do some laps last month. I decided to go with 255/35 GY F1 Supersports to have enough termal capacity for 1 lap without issues and it worked as expected. Still the grip is not quite there compared to semislicks but I wanted to try road tyres first.

Stock brakes with Castrol SRF worked really well, but after a couple of days I installed CSG Spec pads, first guess by CSG going for compounds C2 front and C11 rear was spot on (I am the first to test these). Perfect feel and bite, OEM pads are really good but this is on a whole different league, so I could brake later with more confidence and easier modulation.

Too bad I encountered so many yellow flags (5 days of TF and not a single lap without yellows/traffic) but that's the Nürburgring in August... Can't complain, it was fun! Easy under 8 pace with no semis and stock suspension, what a machine.

 
Had last(?) fun session yesterday at local race track. Cool day, so had a goal to improve PB on the track as on last visit it was so hot engine was totally soaked.
It was tricky to get tires up to temperatures and actually they did not heat up that well, but managed to improve on last session as track dried out.

PS4S is stange tyre. felt like it lost the best grip after one lap even though it didn't get so much into temperatures. Could be placebo as well, but definitely more understeer was there.. All in all, good for maybe one lap but after that it is not longer gripping so proper track tires are recommended if more track fun is in plans.
Friend was using 225 semis - that could be a still usable approach for stock suspension.

Had a short code brown moment in one of the faster corners when car's rear end snapped in mid corner - could be that I was lifting or breaking too much in corner entry (can't recall exactly) but all in all it was sudden and kind of scary experience. Luckily managed to avoid spinning. Should try to replicate the situation again so that would better understand when does it go.

Fun car overall, especially now when there is more confidence to take it to the limit. Being gentle enough with the front end to get the car rotating and then getting the best corner exit seems to be the way for good laps. I think that current car setup (alignment) is good for track too. It's more up to the driver to put the car into its place.
If faster times are required then semis and coilovers would be the path.

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Michael Knight said:
Had last(?) fun session yesterday at local race track. Cool day, so had a goal to improve PB on the track as on last visit it was so hot engine was totally soaked.
It was tricky to get tires up to temperatures and actually they did not heat up that well, but managed to improve on last session as track dried out.

PS4S is stange tyre. felt like it lost the best grip after one lap even though it didn't get so much into temperatures. Could be placebo as well, but definitely more understeer was there.. All in all, good for maybe one lap but after that it is not longer gripping so proper track tires are recommended if more track fun is in plans.
Friend was using 225 semis - that could be a still usable approach for stock suspension.

Had a short code brown moment in one of the faster corners when car's rear end snapped in mid corner - could be that I was lifting or breaking too much in corner entry (can't recall exactly) but all in all it was sudden and kind of scary experience. Luckily managed to avoid spinning. Should try to replicate the situation again so that would better understand when does it go.

Fun car overall, especially now when there is more confidence to take it to the limit. Being gentle enough with the front end to get the car rotating and then getting the best corner exit seems to be the way for good laps. I think that current car setup (alignment) is good for track too. It's more up to the driver to put the car into its place.
If faster times are required then semis and coilovers would be the path.

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Hey man, sounds like a fun day!

I hear you about the PS4S tires. I had the same experience where they felt great after 3/4 of the out lap, but before finishing the first hot lap they were... too hot! I also tested the Michelin PS5 and found them similar, but slightly better - 2 laps. Nankang AR1's also overheated but I got maybe 3 or 4 laps before they were cooked. I also ran higher pressures in the PS5's to see if that helped, I think it did. I hear Mercedes guys running the PS4S at 43psi on track. I went out 36psi cold and ended up in low 40's hot. If you are having trouble getting heat in maybe drop the pressure. What were you running?

Interesting you had a fast corner moment on the rear. I had a professional driver do a few sessions in my car and she found the same problem. In the wet the rear was unstable mid-corner on fast turns. It was less pronounced in the dry sessions but definitely loose under brakes. She said it felt like the car had too much rear brake and also that it was quite light, so not much weight to get the nose to dive under brakes and help initiate the rotation.

Next I will get adjustable rear camber arms and see if a little more neg camber helps. My stock rear is -1.5deg on one side and -2deg on the other.
Front is -3deg and toe is -1.6mm F and +1mm R - which worked great, understeer gone!
 
Rallyboy said:
Front is -3deg and toe is -1.6mm F and +1mm R - which worked great, understeer gone!
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I thought positive toe = toe out. So, reading the relevant bit of your post above as "front toe in & rear toe out" leaves me scratcing my head.

I probably got something wrong. Could you please clarify, for my understanding?

Thanks
 
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Spirited said:
I thought positive toe = toe out. So, reading the relevant bit of your post above as "front toe in & rear toe out" leaves me sceatcing my head.

I probably got something wrong. Could you please clarify, for my understanding?

Thanks
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It's the other way round.
Negative = toe out, positve = toe in. :)
 
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