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Suspension | Chassis | Brakes -- Sponsored by 949 Racing Relating to suspension, chassis, and brakes. Sponsored by 949 Racing.


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Old 05-03-2017, 10:35 PM   #29
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Originally Posted by churchx View Post
strat61caster: it already IS understeering with even zero camber at all corners of stock alignment (indeed, like most new cars, for safety). Question was - why even more understeer then that is safer? So that it becomes unsafe but other way around then too tail-happy and "you see tree that kills you" (c) R.Hammond ?
Untrained ones shouldn't switch off electronic SC instead of dealing in weird alignment, "because F1".
Stock isn't zero in the rear. Mine was 0F/-1R from the factory. A little is put in the rear for safety reasons.
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Old 05-04-2017, 12:18 AM   #30
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Gforce: your power argument/reasoning to dial in more understeer is about as valid as ill-advise to go for staggered tire setup for these cars if fitted with forced induction. Though i'm somewhat suspecting that you are trolling.
You will need to explain this to be understood.

Staggered tire sizes are a just fashion statement for street cars.

Even F1 has gone back to a less staggered setup for 2016/17, more like 60's formula cars which did run on street tires.

The more drive you try and put through the rear axle the more understeer you need to allow the car yo out the power to the road. This is pretty simple and well understood chassis physics.
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Old 05-04-2017, 12:24 AM   #31
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Stock isn't zero in the rear. Mine was 0F/-1R from the factory. A little is put in the rear for safety reasons.
McPherson strut front suspension usually has around zero camber. If the chassis is fwd then you often see more negative camber at the front.

For example, my 1991 Alfa Romeo 164 has negative 2.4 degrees front camber and negative 0.5 degrees rear camber. My 97 SAAB Aero has zero degrees front camber although up to one degree negative front camber is acceptable. Rear camber is zero because the SAAB uses a beam axle.

The BRZ has steeply angled front struts. There is some negative camber gain at the front as a result. The main reason for the angled struts was styling though.

Front strut camber gain depends a great deal on the angle if the front LCA at static ride height. Lowering the car moves the front strut towards negative camber.

The BRZ has static negative rear camber because the original chassis is awd. The BRZ fits Impreza rear suspension almost unaltered from the little sedan except for stiffer shorter springs.
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Old 05-04-2017, 12:27 AM   #32
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Why exactly was I quoted?

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Old 05-04-2017, 02:47 AM   #33
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You will need to explain this to be understood.
Staggered tire sizes are a just fashion statement for street cars.
Even F1 has gone back to a less staggered setup for 2016/17, more like 60's formula cars which did run on street tires.
The more drive you try and put through the rear axle the more understeer you need to allow the car yo out the power to the road. This is pretty simple and well understood chassis physics.
Car suspension/balance/braking/nannies can be engineered/designed about specific setup. Be it staggered or not. 350Z, MR2 were designed with staggered setup. It's not JUST fashion statement. Ours - around squared setup, like most of cars.
To keep handling/balance right for cases with more power then stock, one proportionally rises grips on both ends. Be it fitting wider tires both front & rear, be it doing aero / suspension changes to increase grip on both ends proportionally. Or doing combination of them to compensate with one another, but keeping balance/bias somewhat close to OE, be it with staggered or of square.
NOT thoughtlessly or for stupid bling reasons or due some upmarket cars engineered with completely different suspension & balance in mind have some some single component done this way, "so it must be better". Everything works as system. Systems often are different, most often then not blind copy component of one into different is mistake that needs to be workarounded with changes/upgrades to other components. Everything is possible, but i don't get why tripling spendings to fix mistake is wiser then not doing it in first place.
There are competent people from suspension shops on this forum providing lot of valuable info/suspension tuning advises for these cars. There are many track day junkies that have tried different setups and reported their experiences. There is lot of good info to read in internet if one searches. But you keep bringing up completely different cars with different suspension & contradicting everything those people say & had experienced.
And i don't get why you need to tune grip balance so that it's close to neutral only under full gas and make it stupidly understeer in all the other cases and then call it ideal and advising it to others not driving wrong. If you are not providing right driver inputs you need to fix your driving, not tune suspension around it and calling it according "well understood chassis physics". Understeer/oversteer balance is not judged under 100% acceleration in turn, so no need to change bias due more power. Upping overall grip? Possibly. Changing bias? No.
You are free to make your car worse for sake of your beliefs/weird driving style and "because F1". But please, don't advise that to others.
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Old 05-04-2017, 07:27 AM   #34
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As for F1- we don't have pushrod suspension, so don't compare.

As for all this talk about "oversteer and "understeer" is useless. There's corner entry oversteer, mid-corner oversteer and track out oversteer and each is caused by something different. Know what you are trying to fix before you make any adjustment.

If you want to understand car balance, pick up Carroll Smith's Engineer To Win and Tune To Win and ignore internet threads. There's so much uninformed opinion here it's kind of frustrating to read. Real professionally written books are good for learning how cars work.
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Old 05-04-2017, 09:16 AM   #35
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Why exactly was I quoted?

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Only because your quoted bit referred back to another quote talking about front camber only. Quotes in quotes in posts are not quoted.

The topic of zero camber at the front struts only was expanded to talk about zero camber at all four wheels.
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Old 05-04-2017, 09:23 AM   #36
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As for F1- we don't have pushrod suspension, so don't compare.

As for all this talk about "oversteer and "understeer" is useless. There's corner entry oversteer, mid-corner oversteer and track out oversteer and each is caused by something different. Know what you are trying to fix before you make any adjustment.

If you want to understand car balance, pick up Carroll Smith's Engineer To Win and Tune To Win and ignore internet threads. There's so much uninformed opinion here it's kind of frustrating to read. Real professionally written books are good for learning how cars work.

Push or pull rod (F1 uses both but mostly pull rods these days, they can be made lighter) makes no difference to geometry.

Any skilled driver not only knows about understeer and oversteer and how it all works but ought to know.

All road cars are sold by manufacturers with understeering chassis. At the most basic level all cars steered by the front wheels must understeer to initiate the turn.

Most expert drivers are referring to the tendency of the chassis in a bend when you apply power, does the chassis oversteer or continue to understeer. Given enough power all rwd chassis will oversteer under power. AWD and fwd will always continue to understeer as more power is applied. An exception to this is provided by part time computer controlled awd which can now end all front drive if the computer is programmed to do so which the system sold by ZF to various makers does. Similar systems are now made by companies such as GKN for fwd systems with part time awd adding drive to the rear wheels only as needed. The Ford Focus RS uses this system in reverse to allow the awd chassis to actually drift, albeit completely controlled by the computer.
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