NA first drive days for BRZ? This week?

[Frost]

Originally Posted by timurrrr

Is swapping sway bars between same-platform cars allowed in OTA?

Are front camber bolts allowed?
My intuition is that BRZ will be pretty neutral with some front camber, whereas the GR 86 will become too tail happy.

By "alignment to reduce oversteer", I presume you primarily mean toe?

Toe and camber depending on what I can get to figure out the car dynamics.

Given the bars between the GR86 and BRZ are physically different, I'm going to say that the rules will probably make me take a penalty for going between 'platforms' as a safety factor.

Front camber bolts are allowed if I take the non-factory alignment penalty. Hardware to go beyond factory alignment is part of that penalty (except if it changes roll center).

I currently drive a 2004 S2000 with square setup and OEM FSB... everyone said I'd be in oversteer city, I'm fine. Am I most competitive in it? Likely not due to the oversteer but its where I put myself to for personal development for the time being. Until I deem myself ready, I want to remain tail happy.

[CincyJohn]

Originally Posted by DarkSunrise

Probably that iron is a harder metal than aluminum.

What do you mean by "harder?" Without actually looking it up, I thought the big difference between iron and aluminum, other than weight and related thermodynamic properties, was plasticity characteristics. Specifically, aluminum would be less prone to bending or deformation, but when it does it's a catastrophic breakage rather than mere bending. Not sure how that effects the dynamics in this situation, though.

[AnalogMan]

Originally Posted by bcj

Yes. They seemed abnormally proud of it for some reason or other.

That is a very, very strange thing for the designers of a supposedly 'driver's' sports car to be proud of.

I can only imagine the surrealistic meetings that must have taken place in Japan where it was decided to do this.

[ayau]

The fact that Toyota and/or Subaru haven't come out with a good reason for choosing iron or aluminum knuckle makes me believe it's purely for cost cutting reasons.

It's possible the BRZ is the more 'developed' platform, and Toyota used 'carry over' parts to try to differentiate itself from the BRZ. The difference in spring/damper/roll bar differences are enough to make the GR86 more tail happy than the BRZ.

Regardless what the differences are, the only thing that matters is how it drives in the real world. Most buyers will just choose the bumper they like more.

[RZNT4R]

Young's modulus, E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied lengthwise. It quantifies the relationship between tensile/compressive stress sigma (force per unit area) and axial strain varepsilon (proportional deformation) in the linear elastic region of a material

Cast iron is stiffer

[DarkSunrise]

Originally Posted by CincyJohn

What do you mean by "harder?" Without actually looking it up, I thought the big difference between iron and aluminum, other than weight and related thermodynamic properties, was plasticity characteristics. Specifically, aluminum would be less prone to bending or deformation, but when it does it's a catastrophic breakage rather than mere bending. Not sure how that effects the dynamics in this situation, though.

Sorry that should have been “stronger” not “harder”. I think it’s generally accepted that iron (and its alloys) are stronger and denser than aluminum (and its alloys). I’m not a metallurgist, but here is a comparison of 6061 aluminum vs ductile cast iron:

https://www.makeitfrom.com/compare/6...idal-Cast-Iron

[timurrrr]

Originally Posted by Frost

Toe and camber depending on what I can get to figure out the car dynamics.

But do you take penalty for changing RCLA?
Or how are you going to change rear camber, if at all?

[Brz-123]

Originally Posted by ayau

The fact that Toyota and/or Subaru haven't come out with a good reason for choosing iron or aluminum knuckle makes me believe it's purely for cost cutting reasons.

It's possible the BRZ is the more 'developed' platform, and Toyota used 'carry over' parts to try to differentiate itself from the BRZ. The difference in spring/damper/roll bar differences are enough to make the GR86 more tail happy than the BRZ.

Regardless what the differences are, the only thing that matters is how it drives in the real world. Most buyers will just choose the bumper they like more.

Highly likely its the cost reason. Toyota would've been told by Subaru that they either use their newly developed aluminium stuff or go back to the old one. They cannot manage too many variations in what should be a fixed assembly line.. dampers , spring rates etc different is already a headache. I am sure with the next minor update, they will consolidate to one like they did in the past. But that will all be quiet and no media fanfare.

Sent from my SM-G781B using Tapatalk

[Stonehorsw]

Originally Posted by CincyJohn

What do you mean by "harder?" Without actually looking it up, I thought the big difference between iron and aluminum, other than weight and related thermodynamic properties, was plasticity characteristics. Specifically, aluminum would be less prone to bending or deformation, but when it does it's a catastrophic breakage rather than mere bending. Not sure how that effects the dynamics in this situation, though.

Aluminum has better specific strength (strength per weight), but some times you cannot package the increased volume. Also, aluminum does not have infinite life to fatigue.

[stilesg57]

Jalopnik review published today. Same person who drove the GR 86 two weeks ago. Takeaway is the diffference isn’t even perceptible unless you quickly drive the two back to back, and even then most people couldn’t tell a difference if you blindfolded them until they were in the car and then had all the interior logos covered.

Frankly, I’m more inclined to believe that take than trying to parse a hodgepodge of non-professional opinions into a definitive observation with a clear and specific alignment fix required for one car and not the other. But I’ll be happy to be wrong


Re: the engine noise speaker, if it’s really in the dash then it’s significantly above the car’s COG and 1) they’re treating us for suckers with that line about moving the license plate frame lower all because they care so much about COG, and 2) I’m pulling that MF’er ASAP — not the wire, the whole speaker — since clearly I care about COG more than Toyobaru does

[Blighty]

Originally Posted by RZNT4R

Highly unlikely that it's the actual sound from the actual engine, the engine bay would need to have microphones.

What I would be more inclined to believe is that they used an anechoic dyno chamber and got samples from many loads and RPMs, created their desired sound profile from that and THAT is what is being generated inside the car.

Engineers like to say things. Remember how they said the supra team split off from the Z4 team after the foundations of the cars had been laid and hand't worked together beyond that? The actual car turned out to be a parts bin job where they didn't even bother changing the BMW door chime.

Anyway, it still sounds like junk and Gran Turismo Sport made a better job of generating a fake engine noise for the GT86 years ago.

All I can tell you is what the engineers have said. They were very specific.

What is the 'foundations' of the supra exactly? No engineer said it was toyota parts? Its was always only toyota tuning.

GT Sport, and other games do not compare. I'm not saying you have to like what they are doing, but games can only ever be an approximate how an engine responds - they miss so many details that may things properly convincing.

[Blighty]

Originally Posted by ayau

The fact that Toyota and/or Subaru haven't come out with a good reason for choosing iron or aluminum knuckle makes me believe it's purely for cost cutting reasons.

It's possible the BRZ is the more 'developed' platform, and Toyota used 'carry over' parts to try to differentiate itself from the BRZ. The difference in spring/damper/roll bar differences are enough to make the GR86 more tail happy than the BRZ.

Regardless what the differences are, the only thing that matters is how it drives in the real world. Most buyers will just choose the bumper they like more.

Toyota at the Japan track days said it was for steering feel.

Lotus say the same.

[Blighty]

Originally Posted by SockMonkey

I've seen this brought up before but never justified beyond "But lotus does it". I'm not saying there isn't a benefit, but I can't think of one. What possible benefit does added, unnecessary un-sprung weight possibly have? People go to great lengths such as lighter rotors, calipers, and forged wheels to lower the un-sprung weight. So that can't possibly be the answer. And aluminum knuckles aren't known to fail. The only logical explanation is they wanted to save some $. I'm not saying that is wrong or bad, but they shouldn't pass it off like that wasn't the intention all along.

Unless I'm wrong and someone can give me a different explanation..

I guess its a little like what kind of glove you might wear on your hand. The knuckle is the primary point of connection between the wheel and the chassis, the elasticity of iron and aluminium is different, and while those forces are small, they are potentially noticeable as the effect is very much a direct line to steering.

[Frost]

Originally Posted by timurrrr

But do you take penalty for changing RCLA?
Or how are you going to change rear camber, if at all?

I've been spoiled by the S2k!

I guess I'm new to the platform and going to see whats available and 'legal' within the rules.

If not, YOLO!