Javelin
Javelin UltimaDork
6/28/12 11:12 a.m.

These pics are from the Edmund's Long Term test blog's new FR-S's suspension walkaround. I thought they would help Bryce (Nashco) with his hypothetical AWD BRZ build.

^ That one is the most interesting picture. The cars are rear steer because there's no room for the rack. The white arrow is pointing to the cylinder head. (Notice the exhaust pipe below and to the right of that). However, it does look like the engine is sitting pretty high compared to the axle centerline. It might take a bulged hood, revised intake, etc, but there may be a way to jack the engine up more and do the through-the-pan CV axles. I have no idea where the heck the diff would go though.

Interestingly, the rack is a full manual unit and the EPS is column-mounted under the dash. I wonder how hard it would be to take out the EPS for race cars?

Rear suspension, too, just in case you were curious (note that Subaru/Toyota/Scion were very liberal with their use of "double wishbone" as the description...):

The green arrow is showing no rear camber adjustment from the factory. For cereal people?

92CelicaHalfTrac
92CelicaHalfTrac MegaDork
6/28/12 12:02 p.m.

Curious question: Are there many cars that have rear camber adjustment from factory? I've never had one that i know of...

It seems to me that most people who would care about it would either be parking lot racers in "stock" class or someone who has damaged their suspension and needs to bring it back into spec.

But i've been known to miss the point before.

ReverendDexter
ReverendDexter UltraDork
6/28/12 12:06 p.m.

I still completely fail to understand why people think an AWD FT86 is in any way desirable.

peter
peter HalfDork
6/28/12 12:36 p.m.
Javelin wrote: The green arrow is showing no rear camber adjustment from the factory. For cereal people?

Interesting. I can't quite picture in my head how this multi-link rear could have (easily) adjustable camber. I think the adjuster would have to be in the top bolt of the upright, and even then the compliance of the bushings and such in other links would be a factor.

Yuck.

  • edit, no, I got that wrong, that top link isn't bolt-through-the-upright, it looks like a ball joint. OK then..
peter
peter HalfDork
6/28/12 12:37 p.m.
ReverendDexter wrote: I still completely fail to understand why people think an AWD FT86 is in any way desirable.

Same people who were dismayed that the FFR 818 wasn't going to be AWD...

NOHOME
NOHOME HalfDork
6/28/12 12:40 p.m.

Not very elegant from a visualy pleasing point of view, but I will attest that it is fun to drive.

With a few miles under my FRS tires, I am not convinced that this car has any real claims to superperformance in any category.For example, until you turn the traction control nanny off, it shuts down mid corner in what I consider normal driving. A grocery cart is going to pass you on the inside. So since most people will never turn the thing off, it is a pretty neuterd steed.

But that might not be the point unless you bought it as a racecar. What is pertinet is that , for reasons that you will need to do a test drive to understand, I continue to be intrigued everytime I drive the car.

I am curious to see how this chassis comports itself on the cone courses of North America.

Javelin
Javelin UltimaDork
6/28/12 1:06 p.m.
92CelicaHalfTrac wrote: Curious question: Are there many cars that have rear camber adjustment from factory? I've never had one that i know of...

If they have it, it's usually an eccentric bolt for minor changes (+/- 1 degree for example). The "real" adjustable ones are where you can actually change the pick-up points/arms, but yeah, those are very uncommon. All that said, most IRS RWD cars will have the first type of adjustment, usually to make up for production tolerance variances (usually a side-to-side difference, so they can get both wheels equal), not necessarily as a tuning element. So yes, it's a little odd that there's nothing there at all, but supposedly the aftermarket has already "fixed" it. It's not an uncommon thing, though.

92CelicaHalfTrac
92CelicaHalfTrac MegaDork
6/28/12 1:11 p.m.

Ahhh... learn something new every day. I've always had to buy those eccentric bolts.

Javelin
Javelin UltimaDork
6/28/12 1:18 p.m.
92CelicaHalfTrac wrote: Ahhh... learn something new every day. I've always had to buy those eccentric bolts.

A lot of the factory ones are done as replacement "crash bolts". So you buy a car and it has a 0 on each side, then eventually one side is out of whack (usually due to a crash, hence the name), so they order a -1 bolt and drop it in to equalize the sides. If you know the part numbers you can "cheat" and install what you're looking for, or if you're lucky get an actual eccentric so it's somewhat adjustable.

Ian F
Ian F UberDork
6/28/12 1:40 p.m.

I read on SCCAforums that one new owner already acquired crash-bolts for the front suspension and was able to eek out about -1.3 degrees. I'm curious where they are installed. Strut to spindle mount?

nderwater
nderwater UltraDork
6/28/12 2:12 p.m.

Dan's walk-around is pretty thorough. I thought it was interesting that:
- The car is MacPherson strut/muli-link, not strut/double-whishbone (as advertised)
- Neither is it "front-midengine" as half the cylinder head sits ahead of the front axle
- Weight distribution is 55% front, 45% rear

ReverendDexter
ReverendDexter UltraDork
6/28/12 2:37 p.m.

In reply to nderwater:

Everything I heard prior to the car's release was strut/multi-link.

I thought the "qualification" for front-mid was that the COG of the engine was behind the front axle, not necessarily that the entire engine was behind it. I thought that was how the newer 'vettes qualified as front-mid.

That's a little more forward that I had heard, but everything prior said there was going to be a slight forward weight bias as that was preferable for the type of driving the car was designed for.

Not trying to be arugmentative/contradictory, just thought it was interesting that those things were interesting to you

Javelin
Javelin UltimaDork
6/28/12 2:40 p.m.

In reply to ReverendDexter:

Toyota, Scion, and Subaru's own advertisements all say "double wishbone", not multi-link (as Dan noted).

Front mid-engine means the entire motor (not just the cylinders) are behind the front axle centerline, period. FB RX-7 is front-mid, C6 Corvette is not.

PS - more than half of the FRS/BRZ engine is ahead of the centerline, if not 3/4's.

92CelicaHalfTrac
92CelicaHalfTrac MegaDork
6/28/12 2:53 p.m.

Ugh... nothing is more annoying than "Front mid, rear mid, over mid, in my face mid, etc etc etc"

That E36 M3 is dumb.

Is the motor in the front? Yes? Ok, it's a front engine.

Is it in the back? Yes? Ok, the engine is in the back.

Everything else can be quantified by F/R weight distribution.

As for the rear suspension... i can see how they're advertising wishbones. It's not a traditional multi-link setup, and is fairly similar to Toyota's old "SuperStrut" system which had a lot of wishbone elements to it. At the very least, there IS one wishbone in there, and the one angled arm is anything BUT a multi-link setup.

That said, those pictures are either at annoying angles, or the car is complicated enough that i feel stupid looking at it.

Javelin
Javelin UltimaDork
6/28/12 3:00 p.m.

In reply to 92CelicaHalfTrac:

I'm with you 67%. I think in Front Engine, Mid Engine, and Rear Engine (Beetle, 911, Corvair) only. Front-Mid is marketing scam, it's still a front engine car.

dculberson
dculberson Dork
6/28/12 3:01 p.m.
Javelin wrote: Front mid-engine means the entire motor (not just the cylinders) are behind the front axle centerline, period. FB RX-7 is front-mid, C6 Corvette is not.

That's not a consensus view.. it's not exactly an easy term to find strict definitions of, but many people say it's the "center of gravity of the engine is behind the front axle" and not "entire motor is behind the front axle."

Wikipedia defines it as center of gravity, for what that's worth..

http://en.wikipedia.org/wiki/FMR_layout

Edit: though I do agree with you two that "front mid engine" is silly!!

Slippery
Slippery New Reader
6/28/12 3:18 p.m.
92CelicaHalfTrac wrote: Curious question: Are there many cars that have rear camber adjustment from factory? I've never had one that i know of...

My S2000 has it from the factory, you will get quite a bit of camber out of it ... as in -3 deg or so. I am pretty sure RX-8s have it as well.

J

92CelicaHalfTrac
92CelicaHalfTrac MegaDork
6/28/12 3:38 p.m.

Weird. Motoiq says the rear camber is adjustable.

For some reason, the upper link is a heavy and probably expensive forged steel piece instead of a stamping. The upper link has to snake around some stuff and is an odd shape so maybe a forging is easier to make in an odd geometry as perhaps it is hard to form an elaborate stamping unless an expensive progressive die is used. It has an eccentric so camber can be adjusted to a degree. The upper arm has a forward cant which defines the forward instant center and controls the amount of antisquat in the suspension geometry. Look for an aftermarket part with more camber adjustment and lighter weight here.
Javelin
Javelin UltimaDork
6/28/12 3:43 p.m.

Could be. Dan might have missed it. He does quite a few of these suspension posts, but I don't think he ever takes them apart.

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