Ford Fiesta ST Beats Toyota GT86 on the Track in EVO Test

[rice_classic]

Originally Posted by wparsons

Who says macpherson struts can't have a camber curve similar to double wishbones? It's geometrically possible to have more camber gain from a strut than double wishbones. It's just easier to adjust the camber curve with wishbones.

Sure, theoretically, you could change the geometry of a DW setup to remove dynamic camber change so that it's similar to the lack of dynamic camber change of a Mac setup but please illustrate to me how you would change the Mac geometry to give "lots" of dynamic camber like you could achieve on a DW setup.


Look at this video (yes it's legos, but good illustration of Macs) Make sure you start at the 2:00 minute mark and you'll see him push down on the car and show what little-to-no camber change happens. At the 2:34 mark he shows an example of how it works when only one side is compressed.
[ame]http://youtu.be/Eexxbtbh8fM?t=2m1s[/ame]

He even makes my point of how it aids in "simpleness" and "compactness".

More illustration: See how the strut is tilted inward and one would thing that under compression the wheel would camber in, but it doesn't.
[ame="http://www.youtube.com/watch?v=oul5FTwstsE"]Automation - Suspension Animation Test - Front Macpherson Strut - YouTube[/ame]




And I'm tired of typing.. I'll have this guy explain Mac struts and Double A-Arm to the crowd.

[ame="http://www.youtube.com/watch?v=1fvJMxErfms"]MacPherson Strut - Explained - YouTube[/ame]

[ame="http://www.youtube.com/watch?v=DsEmK1M87VQ"]Double Wishbone Suspension - Explained - YouTube[/ame]

[Luis_GT]

Sheesh... can't we all just be happy we don't have a POS live rear axle???

[wparsons]

Originally Posted by rice_classic

Sure, theoretically, you could change the geometry of a DW setup to remove dynamic camber change so that it's similar to the lack of dynamic camber change of a Mac setup but please illustrate to me how you would change the Mac geometry to give "lots" of dynamic camber like you could achieve on a DW setup.

Those videos don't show a strut setup to gain camber unfortunately. If you start with the LCA well below horizontal at rest and have it compress to horizontal then you will absolutely gain camber as the suspension is compressed. The camber is gained by the LCA effectively lengthening as the suspension compresses, increasing camber.

I'm not saying it's as easy to do as with double wishbones, but it is definitely doable. Another thing to keep in mind is caster, which adds camber as the wheels are turned.

[rice_classic]

Originally Posted by wparsons

If you start with the LCA well below horizontal at rest and have it compress to horizontal then you will absolutely gain camber as the suspension is compressed. The camber is gained by the LCA effectively lengthening as the suspension compresses, increasing camber.

I'm not saying it's as easy to do as with double wishbones, but it is definitely doable.

That makes sense. I think one of those videos does show what you describe when the wheel passes below the horizontal line.

Do you have any real world examples of how what you describe has been implemented? How about on a lowered track car with very little suspension travel?

You say it's "definitely doable" but is there a readily available OEM application of this?

[autobrz]

u can also increase camber gain of macpherson strut by leaning in the strut top a lot then fix the static camber at the hub. is 1/2 a degree of camber gain per degree of body roll considered good? some guys at mr2oc have setup their cars to do that

[autobrz]

if there is too much camber gain doesnt that hurt straight line traction when the car squats?

[wparsons]

Originally Posted by rice_classic

That makes sense. I think one of those videos does show what you describe when the wheel passes below the horizontal line.

Do you have any real world examples of how what you describe has been implemented? How about on a lowered track car with very little suspension travel?

You say it's "definitely doable" but is there a readily available OEM application of this?

Most cars are already like this... what hurts them is when they're lowered so the LCA's are parallel with the ground at rest, so any suspension compression gives either no camber gain, or adds positive camber. If you run roll center adjusters to bring the control arms back below parallel with the ground then you'll get good (negative) camber gain as the suspension compresses again.

[Anaxilus]

Originally Posted by WolfpackS2k

the "renderings" I've seen recently look way better than that (i'll look around for them shortly). However I'm still not fond of Mazda's current design language being applied to the Miata.

Originally Posted by ansibe

What rampage said! EXACTLY what he said!

I was stunned when the fiesta beat the ft86! On equal power i was sure the rwd car would walk all over it. Aren't our cars the best handling cars you can buy (for less than $80k)?

It didn't. Watch the other video and mark the track times, you'll see the drivers lost to the Fiesta, not the 86.

Originally Posted by Suberman

The real puzzle is why Subaru bothered to fit double wishbones at the back.

No puzzle, they didn't fit double wishbones. It's multi-link.

Originally Posted by Rampage

Under 300HP RWD does not > FWD. Look no further than Continental Sports Car challenge ST, Pirelli World Challenge Touring Car, British Touring Car Championship and FIA World Touring Car Championships where FWD regularly dominates RWD. Believe it or not FWD does have some advantages over RWD such as less parasitic loss through the drivetrain. Today's performance tires are not overtaxed by sub 300HP engines even when they have to do the steering too.

Except in JGTC GT300 where cars are restricted to 300hp and there are ZERO FWD cars. Looking at the BTCC, there appear to be severe regulations on costs which limits what cars you can run and what you can do to them. Hell, being able to run w/ Honda aftermarket support versus Vauxhall and MG seems to be a tremendous advantage from the get go. All the vehicles in BTCC seem to have very weak aero and a rear spoiler as an afterthought. I'd say the success of the FWD cars in that series is as much a function of better overall physical packaging and aero due to using hatchbacks rather than larger, longer 4 door sedans w/ small, primitive rear wings that can't operate as efficiently by comparison. Hatches have always had better polar moment in the rear as well compared to sedans which is why the Audi Avant has usually beaten its sedan counterpart in the slalom. Same for the excellent performance of the CTS-V Wagon. More weight on the rear and better rotation. Look at how hard the Evo and STI sedans struggled against smaller hatches in WRC. Yes, FWD has distinct positives but that's not the only or primary reason the hatches do well. I know Tanner Foust runs a Fiesta but it's AWD.

Under ideal circumstances with no holds barred, it never pays to put braking, acceleration and lateral grip over the front wheels biased 60-65%. Now if you want to caveat and start restricting hp, downforce and top speed, sure, I'll buy into FWD. I'm sure I could make enough rules to have a Prius C come out on top too.

I'll make an offer to all the rabid FWD fanbois out there. I'll give $200,000 to anyone that can make a FWD F1 car that can make it to the second round of qualifying next year. If you fail, I'll only take half of that.

[rice_classic]

Originally Posted by Anaxilus

I'll make an offer to all the rabid FWD fanbois out there. I'll give $200,000 to anyone that can make a FWD F1 car that can make it to the second round of qualifying next year. If you fail, I'll only take half of that.

You need to add 2 or 3 more zeros onto the end of that offer.

Deal of my own...

I'll give you $200,000 today to find me a production car on sale today that can generate 2000lbs of downforce at 150mph, makes 300hp/liter, doesn't have a starter, costs a half-billion dollars to operate annually but still gets 30mpg, can haul around groceries and cost under $25k brand new.

If you fail, I'll need it all back plus interest.


p.s. you can never bring F1 into a car argument. It's like dropping the name "hitler" into a political argument... it kills it dead instantly. Why? Because F1 has no bearing on anything else automotive that the proletariat is familiar with. Also the rules are so god awfully restrictive that if they were allowed to do whatever they wanted the cars would look radically different and operate radically different. Remember the 6 wheel Tyrells?

[rice_classic]

Originally Posted by wparsons

If you run roll center adjusters to bring the control arms back below parallel with the ground then you'll get good (negative) camber gain as the suspension compresses again.

Mac Struts do not have a dynamic camber curve. The geometry doesn't lie. This camber gain you're thinking of is extremely small and doesn't take into account body roll and is negligible (comparatively) in any lowered/stiffened vehicle. Also it's not a dynamic curve "per se" as it's only the result of the lca pivot from below the horizontal to the horizontal but after it passes above horizontal (most Mac setups have the LCA at or above the horizontal) there is relatively no further camber gain (gain in negative camber in relation to body). That's the important part... in relation to body roll.

To quote from another thread: (bold is mine)

MacPherson struts do have some camber change in compression, as do most independent suspensions other than pure trailing arms, but the amount is very small because the effective swing-arm length is quite long. What they don't provide is camber gain with body roll, the way a double-wishbone suspension or swing-arm suspension does. As the body leans and the outside spring compresses, the arc of the lower control arm does push the lower edge of the spindle outward (which would tend to create negative camber), but the magnitude of that force is much less than that exerted by the strut as body lean pushes it outward (which tends to create positive camber). The result is always a net camber loss.

[Anaxilus]

Originally Posted by rice_classic

You need to add 2 or 3 more zeros onto the end of that offer.

Deal of my own...

I'll give you $200,000 today to find me a production car on sale today that can generate 2000lbs of downforce at 150mph, makes 300hp/liter, doesn't have a starter, costs a half-billion dollars to operate annually but still gets 30mpg, can haul around groceries and cost under $25k brand new.

If you fail, I'll need it all back plus interest.


p.s. you can never bring F1 into a car argument. It's like dropping the name "hitler" into a political argument... it kills it dead instantly. Why? Because F1 has no bearing on anything else automotive that the proletariat is familiar with. Also the rules are so god awfully restrictive that if they were allowed to do whatever they wanted the cars would look radically different and operate radically different. Remember the 6 wheel Tyrells?

Of course, that was the point. Besides, even w/ $100,000,000, not one F1 team would ever go FWD and there are no rules preventing it. The rules are there to prevent the teams from going faster, not slower, lol. FWD is to chassis layout what McPherson Strut is to Suspension. A series of choices based on a set of conditions that can do well enough, but not ideal.

Uh, yes you can, when you talk about WWII, Stalin, Pol Pot, etc. It's a fallacy to think anything w/ F1 or Hitler is a fallacy. Ad Hitlerum is itself a fallacy but a convenient restriction for those not actually well versed in philosophy or logic. /end OT rant.

[DylanFRS]

Originally Posted by Anaxilus

Of course, that was the point. Besides, even w/ $100,000,000, not one F1 team would ever go FWD and there are no rules preventing it. The rules are there to prevent the teams from going faster, not slower, lol. FWD is to chassis layout what McPherson Strut is to Suspension. A series of choices based on a set of conditions that can do well enough, but not ideal.

Uh, yes you can, when you talk about WWII, Stalin, Pol Pot, etc. It's a fallacy to think anything w/ F1 or Hitler is a fallacy. Ad Hitlerum is itself a fallacy but a convenient restriction for those not actually well versed in philosophy or logic. /end OT rant.

Just because I am curious, does this mean you are willing to say that AWD is superior to RWD? If so, I would like to see it written out.

I mean, pure physics, AWD>RWD>FWD. But I personally think that model breaks down below 200hp. I don't think the FRZ would necessarily be faster around a track if it were AWD.

[Anaxilus]

Originally Posted by DylanFRS

Just because I am curious, does this mean you are willing to say that AWD is superior to RWD? If so, I would like to see it written out.

I mean, pure physics, AWD>RWD>FWD. But I personally think that model breaks down below 200hp. I don't think the FRZ would necessarily be faster around a track if it were AWD.

For the same aero, weight and dimensions, in a pure theoretical sense absolutely! I have a Legacy GT, it's just too big and fat to be my DD as are most, if not all AWD cars (atm...).

[Allch Chcar]

You guys are killing me here.

I'm giving some serious thought to the Fiesta ST. I like the Focus, I almost bought a Focus SE. But I'm not interested in the Focus ST. I wanted to like the 1.0L turbo but the driving impressions for it in the Focus were terrible.