Next Gen BRZ/86!

[Tcoat]

Originally Posted by rvoll

Actually, it is restricted to 4 wheel drive according to the Subaru specification. You should read more carefully. In addition, they have pictures of the basic platform and you'll see that it is "hard coded" into a 4WD format. Take a look at the frame structure and mounting points.

That said, the BRZ is a joint project with Toyota and I doubt if Toyota would approve of the inherent weaknesses of the global platform for a sports car. The proportions of the global platform are all wrong for a car as low as the BRZ. If you don't have any engineering experience, have an engineer look at the picture and then tell me how they could possibly get a RWD only low car out of that platform.

What picture do you keep refering to? Where is it written that they will all be AWD (they are NOT 4 WD)?
There have been and currently are 100s of vehicles that come in AWD, 4WD, or 2WD that use the same platform there is no design criteria that excludes any setup from a platform.

[rvoll]

Originally Posted by Tcoat

This is not a 1966 Chevy frame that they bolted different bodies on. The pictures shown are the basis of each not the end all and be all "platform" for all the models. You are still fixated on the thought that the "platform" means a single chassis. That is not what it means.

Not fixated at all. The supporting text from Subaru lists 4WD as required on this platform. You can see the platform here:

https://www.subaru-global.com/ourstory/ourfuture.html

http://www.subaru.asia/mig/en/subaru...l-platform.php

http://drive.subaru.com/spr16-global-platform

Google is your friend.... You'll see that the basis IS a frame!!!!!

[Tcoat]

Originally Posted by rvoll

Not fixated at all. The supporting text from Subaru lists 4WD as required on this platform. You can see the platform here:

https://www.subaru-global.com/ourstory/ourfuture.html

http://www.subaru.asia/mig/en/subaru...l-platform.php

http://drive.subaru.com/spr16-global-platform

Google is your friend.... You'll see that the basis IS a frame!!!!!

There is nothing there that says the platform must be AWD (it still isn't 4wd) it simply says that when coupled with their other tech they will have a great vehicle. There is also nothing that says it is strictly built for AWD. They do say that it is flexible enough for hybrid and electric use so doing 2WD would be a piece of cake.

Use your Google mastery to show us the platform for each model that they will be using it on not just one generic shot that they use to show the basic layout.

If you want to play the sarcasm game I am up and ready to go so in all your ancient wisdom tell me what these radically different cars have in common.
2006 Toyota RAV4
2007 Toyota Corolla (2009- in US market)
2005 Toyota Avalon
2007 Toyota Camry
2007 Toyota Aurion
2007 Lexus ES
2007 Toyota Mark X Zio
2008 Toyota Auris/Blade
2008 Toyota Highlander
2008 Toyota Corolla Rumion/Scion xB
2009 Toyota Matrix
2009 Toyota Venza
2009 Toyota Avensis
2010 Lexus HS
2010 Lexus RX
2010 Toyota Prius
2011 Toyota Sienna
2011 Scion tC
2011 Lexus CT

How about these?
2005 Mitsubishi Outlander
2007 Mitsubishi Lancer
2007 Mitsubishi Delica
2008Mitsubishi Racing Lancer
2010 Mitsubishi RVR
2007 Dodge Caliber
2007 Jeep Compass
2007 Jeep Patriot
2008 Dodge Avenger
2009 Dodge Journey / Fiat Freemont
2007 Chrysler Sebring
2011 Chrysler 200
2007 Citroën C-Crosser/Peugeot 4007
2012 Citroën C4 Aircross/Peugeot 4008
2010 Proton Inspira

[rvoll]

Originally Posted by Tcoat

There is nothing there that says the platform must be AWD (it still isn't 4wd) it simply says that when coupled with their other tech they will have a great vehicle. There is also nothing that says it is strictly built for AWD. They do say that it is flexible enough for hybrid and electric use so doing 2WD would be a piece of cake.

We're going back and forth on this, but here is the direct quote:

"The Subaru Global Platform is part of the six initiatives to enhance the Subaru brand described in the company’s midterm management vision, “Prominence 2020,” announced in 2014. Together with the horizontally-opposed engines, Symmetrical All-Wheel Drive (AWD), and EyeSight that represent Subaru core technologies, the new platform will constitute the basic foundation of the next generation of Subaru vehicles."

The global platform INCLUDES "Symmetrical All-Wheel Drive". And it is part of the "Basic Foundation". You are just making absolutely no sense. Did you even read this? What part of "Basic Foundation" do you not understand?

And did you even analyze the platform in the picture? You cannot form a sports car from that platform. Like I said, talk to someone who understands engineering and technology who can look at that platform and explain it to you. Jeeeeezzzz....

[Yoshoobaroo]

Engineer here (mechanical product development), failing to see how you can't make a RWD sports car out of this:



Basic structure looks very similar, biggest difference is the more pronounced triangulation in way the firewall sides tie into the fender and side rail, likely to increase torsional stiffness:



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[nikitopo]

Originally Posted by rvoll

If you don't have any engineering experience, have an engineer look at the picture and then tell me how they could possibly get a RWD only low car out of that platform.

I don't think he has an engineering background. He is constantly trying to ridiculate weight reduction, even in the range of 200lbs, and that removing weight from rotational parts has zero effect. I am sure he'll ridiculate even the fact that Porsche offers as option a single mass flywheel.

[Yoshoobaroo]

Originally Posted by nikitopo

I don't think he has an engineering background. He is constantly trying to ridiculate weight reduction, even in the range of 200lbs, and that removing weight from rotational parts has zero effect. I am sure he'll ridiculate even the fact that Porsche offers as option a single mass flywheel.

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[rvoll]

Originally Posted by Yoshoobaroo

Engineer here (mechanical product development), failing to see how you can't make a RWD sports car out of this:



Basic structure looks very similar, biggest difference is the more pronounced triangulation in way the firewall sides tie into the fender and side rail, likely to increase torsional stiffness:

Really? I can make a "sports car" out of a truck frame, but it won't be a really good sports car. That's the issue. The front is designed to hold AWD differentials and thus the proportions are not amenable to a good, light, RWD sports car design. In addition, the ratios of width to height, which are a part of the platform, would not be good for a low car. Rather than looking at what is there, look at what components of that design would be good for a sports car. The assumption you obviously make that the platform could be "cut down" with a reworked front end degrades the idea that this is THE platform for all of the cars. If the assumption you make is true, then there is no real platform at all, just a bottom frame.

This is the difference between an automotive engineer and a mechanical engineer. My background was in product development and design in a number of industries. So I'd like you look again at the design, taking into account that the platform will be designed for AWD (and not RWD) and tell me how you could make a good sports car from it. If you have a CAD program, take the ratios of width and height and place a car body on it and you'll see it will be far too tall to be a low sports car. What you'll get, at a minimum, are the proportions of an Impreza or WRX which are about 58" tall. Our BRZ's are about 51" tall. Think about it....

[rvoll]

Originally Posted by nikitopo

I don't think he has an engineering background. He is constantly trying to ridiculate weight reduction, even in the range of 200lbs, and that removing weight from rotational parts has zero effect. I am sure he'll ridiculate even the fact that Porsche offers as option a single mass flywheel.

I never said that. If I were tracking a car, I'd remove as much weight as possible in all parts -- and I've done that in the past. Why would you assume otherwise? However, as a daily driver, I'd easily add 200 pounds for things like air conditioning, a better ride, comfortable seats, a good infotainment/audio setup, electric windows, etc. You wouldn't? In terms of saving a few pounds for custom wheels for a daily driver, I do think it is a waste of money. You don't? I also said that buying extra wide wheels and tires for this kind of street car ADDS POUNDS to the car you don't need and is a waste of money will most likely reduce performance and MPG.

And I've owned Porsche's for 27 years, by the way. I sold my last one about 2 years ago.

[nikitopo]

Originally Posted by rvoll

I never said that. If I were tracking a car, I'd remove as much weight as possible in all parts -- and I've done that in the past. Why would you assume otherwise? However, as a daily driver, I'd easily add 200 pounds for things like air conditioning, a better ride, comfortable seats, a good infotainment/audio setup, electric windows, etc. You wouldn't? In terms of saving a few pounds for custom wheels for a daily driver, I do think it is a waste of money. You don't? I also said that buying extra wide wheels and tires for this kind of street car ADDS POUNDS to the car you don't need and is a waste of money will most likely reduce performance and MPG.

And I've owned Porsche's for 27 years, by the way. I sold my last one about 2 years ago.

Yes, you didn't say that. I totally agree with you. I was referring about @Tcoat

[Yoshoobaroo]

Originally Posted by rvoll

Really? I can make a "sports car" out of a truck frame, but it won't be a really good sports car. That's the issue. The front is designed to hold AWD differentials

Wrong. Subaru 101: the front diff is in the transmission, also referred to as a transaxle, a term you've surely come across in your background in product development and design in a number of industries. This makes it ridiculously easy to convert a Subaru to RWD. Just take the front halfshafts out and replace the front diff with a spool. Subaru did a bit more of a thorough job by getting a new transmission for the BRZ.

Subaru AWD tranny:


BRZ tranny:

Originally Posted by rvoll

and thus the proportions are not amenable to a good, light, RWD sports car design.

Wrong again. The BRZ is already based off the Impreza, like all modern Subarus are. Just like 20 years ago they were all based on the Legacy. You think it's coincidence that the front wheels are so far back for a RWD car? Or that it's quite front heavy with 55% over the front axle? Why didn't they increase the rear overhang to get it to 50-50? That's a trick BMW loves. Why is the engine so far forward? Why do we have a random 'overpipe' where the uppipe/downpipe on a wrx go? The chassis and engine design was supposed to be clean slate right? Guess what? There's still an Impreza under all that metal.

Originally Posted by rvoll

In addition, the ratios of width to height, which are a part of the platform, would not be good for a low car. Rather than looking at what is there, look at what components of that design would be good for a sports car. The assumption you obviously make that the platform could be "cut down" with a reworked front end degrades the idea that this is THE platform for all of the cars. If the assumption you make is true, then there is no real platform at all, just a bottom frame.

This is exactly what global platforms are for: Scaling.
The platform has all the basic features a car's chassis needs: Subframe interface points, a floor pan, bulkheads and firewalls, suspension pickup points, etc. The dimensions between them are variable, as the real engineering is figuring out how these subcomponents fit together. Once you figure out a solid way of putting the chassis together, you can change dimensions to suit your applications.

VW uses the MQB platform from the Polo to the Atlas, the latter being pretty much twice the size as the former. It also underpins 3/4 of everything VW/Audi/SEAT/Skoda make, including the low slung TT and massive SUVs. The Nissan FM platform underpins the 350Z/370Z and Skyline, the Infiniti FX SUVs, a bunch of RWD sedans, eventually the R35 GTR, and a GODDAMN FWD MINIVAN Yes, the 370Z shares its platform with a FWD minivan.

Originally Posted by rvoll

This is the difference between an automotive engineer and a mechanical engineer.

Mechanical Engineer can be any industry. It merely denotes an area of expertise, in my case Mechanical design, Static and dynamic analysis, scalable architecture design, and design for manufacturing, among others. Regardless, the governing principles are the same. Stress, strain, CTE, mass, inertia, vibrations and dynamics, it all applies accross industries. A good engineer can hop between them and excel in multiple fields.

Originally Posted by rvoll

My background was in product development and design in a number of industries. So I'd like you look again at the design, taking into account that the platform will be designed for AWD (and not RWD)

Irrelevant, see first paragraph.

Originally Posted by rvoll

and tell me how you could make a good sports car from it.

Idem.
Also Subaru already did:

Originally Posted by rvoll

If you have a CAD program, take the ratios of width and height and place a car body on it and you'll see it will be far too tall to be a low sports car. What you'll get, at a minimum, are the proportions of an Impreza or WRX which are about 58" tall. Our BRZ's are about 51" tall. Think about it....

Again, refer to my previous paragraph about platform sharing. This is nothing new. The whole point of scalable platforms are the fact that they're, what? Scalable? naaaaaaaaaaaaaaaah.

[spikyone]

Originally Posted by Yoshoobaroo

Engineer here (mechanical product development), failing to see how you can't make a RWD sports car out of this:



Basic structure looks very similar, biggest difference is the more pronounced triangulation in way the firewall sides tie into the fender and side rail, likely to increase torsional stiffness:
Sent from my iPhone using Tapatalk

Indeed - and the point about "platform" is not that you use all of the pieces shown in that image either. The new meaning of "platform" is that you have something similar to prefabricated Lego assemblies that you can vary by model with just a few hard fixing points, so you're barely constrained by the structural geometry.

VW's MQB platform is a great example, this:



is based on the same "platform" as this:



For comparison, the sizes/weights of those two are (rounded):

Audi TT: 4.2m x 1.8m x 1.3m (l x w x h), wheelbase = 2.5m, 1200-1400kg
Skoda Kodiaq: 4.7m x 1.9m x 1.7m, wheelbase = 2.8m, 1400-1800kg

They are substantially different in every conceivable way, yet they share a common platform. The upcoming Audi A1 is likely to be smaller than the TT, and that is also based on MQB!

[nikitopo]

Originally Posted by Yoshoobaroo

Wrong again. The BRZ is already based off the Impreza, like all modern Subarus are. Just like 20 years ago they were all based on the Legacy. You think it's coincidence that the front wheels are so far back for a RWD car? Or that it's quite front heavy with 55% over the front axle? Why didn't they increase the rear overhang to get it to 50-50? That's a trick BMW loves. Why is the engine so far forward? Why do we have a random 'overpipe' where the uppipe/downpipe on a wrx go? The chassis and engine design was supposed to be clean slate right? Guess what? There's still an Impreza under all that metal.

It looks that you ignored the pictures I posted one page before. It is totally wrong saying that the BRZ is just a coupe Impreza.

[Yoshoobaroo]

Originally Posted by nikitopo

It looks that you ignored the pictures I posted one page before. It is totally wrong saying that the BRZ is just a coupe Impreza.

You're confused because you need to improve your reading comprehension skills. I said it is BASED ON the Impreza platform,as @nikitopo also mentioned, but since you've been entirely tonedeaf to anyone who tries to explain the way modern car platform sharing works, I doubt you'll get it this time.


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