GR Yaris Geo fast road help and track set up

Phil1291 said:
Na. That has nothing to do with the alignment.
I hope i never have to do that, with any car under any circumstances, no matter the alignment.
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And I disagree. Of course you need to consider evasive action on the limit and how geo affects it. If geo makes the car hard to control, critically unstable, with just a quick left-right at 200km/h, it's definitely too lively.

It's like saying I don't consider how getting a (half) cage system affects safety.... Handling is part of the active safety system.
 
Onehp said:
And I disagree. Of course you need to consider evasive action on the limit and how geo affects it. If geo makes the car hard to control, critically unstable, with just a quick left-right at 200km/h, it's definitely too lively.

It's like saying I don't consider how getting a (half) cage system affects safety.... Handling is part of the active safety system.
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We‘re not talking about the same thing.

It has nothing to do with the alignment, that i don‘t wanna do it.
It‘s just stupid to test that on an open road, if it‘s not an emergency.

Am i afraid to do it? Hell yeah. Every sane person should be.
Doing an emergency left-right-left at over 200kph on an open road should scare the shit out of you.
But i‘m not afraid because of my alignment, but because at this speed, every mistake can be your last.

And i wouldn‘t have that setup if i didn‘t think it‘s safe.
If someone thinks it‘s too lively or unsafe for you, than please use another, less aggressive setup.

I highly disagree, that toe out at the rear is „unsafe“.
Does it make the car more lively, Yes.
Does it make the car undriveable or critically unstable, No.

So again, it all comes down to personal preferences.
You‘ll never be able to have that ONE perfect setup who fits everyone.

People have different suspensions, different wheels, different tires (some are new, some have 2.0mm left), different driving abilitys and different preferences.
 
@Phil1291 yes talking about different things. Yet our conclusions are importantly different as we're making recommendations here....

You are talking about an Swiss Öhlins equipped car? How many of those about?

I'm talking about the stock suspension car that is already quite lively at speed, and thus I am wary and slightly concerned about general recommendations of adding 3 neg camber front AND toe out rear AND perhaps less than stock camber rear.

Frankly, it sound like a potentially very dangerous cocktail and that's why I am basically warning others to take a somewhat conservative approach, so to see what actually works for them but also considering less likely scenarios.

I understand your point about testing high speed stability, and that is perhaps my point also. If you're not willing/able to test it safely, and most people will never test this until the emergency presents itself, that is a good reason to take a conservative approach as geo will affect stability on the limit and can make a big difference in succeeding in an evasive action at speed. Even with esp on (you should), aggressive geo can make a slapper uncatchable on the ESP.

Because surely if a emergency situation arises where evasive action is needed, you want a betting chance it ends well?

Ok, I *think* I've made my point :D

Take care all
 
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Ok, to wrap this up, here is my 'recommendation*' for fast road geo and some track use on a otherwise stock car, based on following most threads on geo and being extra sensitive on reports on stability. And my own experience as a chassis engineer/driving enthusiast with my car and fairly provocative driving on balance...

Max 2,5 degree neg camber front and slight toe out front. Stock geo rear (have it checked too!).
Or bit more conservative, one one dot camber bolt maxed out in front, giving 2,2-2,3 deg neg front. For nordic winter tyre use in the mix, change toe front to toe-in.

I have in particular the reports from @Lauren in mind who reported regular oversteer at speed on track. This was with 2,5 neg camber front and (unintended) toe out in the rear. This is for one turn. Make that a quick left-right or even a left-right-left at speed, and I'd say my recommendation is already quite aggressive for safe road use...

*no implied warranties, at your own risk etc
 
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I'm having currently following setup, and it is quite tossable (slides easily). Changed the car's characteristics much more lively and so far happy with it.
Though have only driven with Studdless winters in medium to low traction roads (winter conditions) so summer spec needs to be iterated if necessary.
I like to have my oversteer controlled, so that car does not have understeer but it turns in nicely. Have had few times little bigger oversteer due to lift off mid corner but this was mostly due to very slippery conditions (slush). Both my toe's front and rear were really off the spec so getting the car within the spec already makes it better..

as @Onehp says do small changes and check how it works.

Copied from @DeanoC from the other side
Front toe out 14minutes
rear toe in 14 minutes

front camber with one dot bolt maxxed out.

Stock suspension, mostly driven fast gravel road.
Lithium battery so car's rear is 16kg lighter than stock (making it more tail happy).

Screenshot 2022-02-01 at 9.34.45.png
 
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Onehp said:
Max 2,5 degree neg camber front and slight toe out front. Stock geo rear (have it checked too!).
Or bit more conservative, one one dot camber bolt maxed out in front, giving 2,2-2,3 deg neg front. For nordic winter tyre use in the mix, change toe front to toe-in.

I have in particular the reports from @Lauren in mind who reported regular oversteer at speed on track. This was with 2,5 neg camber front and (unintended) toe out in the rear. This is for one turn. Make that a quick left-right or even a left-right-left at speed, and I'd say my recommendation is already quite aggressive for safe road use...

*no implied warranties, at your own risk etc
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I have since had the rear set to a very small amount of toe in. In all honesty I still expect it still to oversteer when you come out of the power into high speed corners, but we shall see. A track day before the sprint is going to be a few months off yet. It does seem on approaching higher speed corners >80mph that any lift or braking causes the rear to rotate, mostly likely due to weight transfer.

I know that Adrian at Fensport had this issue too and his car is a long way from stock. I know he calmed his down a little though his setup is far more complex with a standalone ECU as it would seem that the proportion of drive front to rear varies a lot more than we first thought. Having said all of that, it's easy to catch it and balance on the throttle, which is for me at least a lot of fun.
 
The rear stepping out off throttle is a combo of loaded suspension, weight transfer to the front and the rear clutch decoupling instantly which upsets the rear wheels as they try and slow down because they are over geared
 
Onehp said:
1,5 difference in neg camber front and rear is actually quite a lot. It's the difference front to rear that dictates the limit behaviour, ie if the front or rear let's go first, and I would think of greater influence than 1mm toe in or out rear. I would suggest to go for 2 neg in the rear if you have the choice (rear camber bolts).

I also want to remind of a discussion on the other place of a guy that lost control of his GRY over a crest and totalled it. Luckily no uncoming traffic or bystanders or he could have easily been guilty of killing innocent road users.
He had done geo changes and I speculate that it could have contributed to losing it over the crest making a correction, the geo contributed with on the limit unbalance. This was never confirmed afaik (quite hard) but I do know for sure such a scenario is heavily influenced by geo in a similar way as evasive action. Geo is very much a matter of balance - literally and between properties, and I personally am always cautious to making big changes without considering the impact on all handling aspects. ISO 3888-2 being one of them, but also, or perhaps especially, even higher speed considerations.

Take care all
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That's just supposition, nowhere have i read/seen the guy state that he had his alignment changed. I don't have rear camber bolts so i'll see what the standard set up is and work with that. Also should have mentioned that i'll be dropping the car slightly on eibach springs 👍
 
DeanoC said:
The rear stepping out off throttle is a combo of loaded suspension, weight transfer to the front and the rear clutch decoupling instantly which upsets the rear wheels as they try and slow down because they are over geared
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Yup. It's a lovely trait making the car quite 'rally' and adjustable in its handling. But lairy if not prepared for it. On track, mastering trail braking, or at least not doing it unintentionally, is key.

To break it down some more with additional neg camber front

Corner entry with Trail braking - braking with weight tranfer and turning in, this will kill understeer and thus front neg camber doesn't play in. Toe out in the rear however will aid the rear rotating.

Mid corner more front camber will aid front end grip and its here that too much of it in quick left right left can upset the balance and stability. But it can also be used on purpose, i.e. Scandinavian flick...

Out of the corner the neg front camber helps killing power understeer as the awd 'locks' up and seeks to stabilise the car.

Something like that
 
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DeanoC said:
The rear stepping out off throttle is a combo of loaded suspension, weight transfer to the front and the rear clutch decoupling instantly which upsets the rear wheels as they try and slow down because they are over geared
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Lift off oversteer uphill into an off camber corner approaching a brow at speed is really not pleasant, especially when you have no idea its going to do it :eek::eek::oops:

IIRC I said "goodness me" or some such, but at least there were no :cry::cry::cry:
 
Thanks for the replies

Just to confirm totally stock car

Would lowering springs and spacers be recommended to improve the handling ??

If so what size etc… the hillclimb isn’t until the end of April do lots of time

Thanks again
 
What is the max rear camber you can get with stock adjustment and what is needed to go beyond that?
 
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