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sesto elemento
sesto elemento Dork
3/29/16 7:51 p.m.

Flight Service
Flight Service MegaDork
3/30/16 5:40 a.m.

I love the sway bars on push rod setups

Flight Service
Flight Service MegaDork
3/30/16 8:24 a.m.

Here is a question, what mass produced, readily available vehicle (let's say double challenge money) with the best performance capability suspension?

Opti
Opti HalfDork
3/30/16 9:38 a.m.

4th gen fbodies use a really tall knuckle also

theenico
theenico Reader
3/30/16 4:01 p.m.

The tall knuckles mainly originated on FWD cars to keep SAI/KPI in check to maintain a good scrub radius. Later they figured out that it worked well for a lot of applications.

Back to the OP's original post, I don't like dynamic toe changes. I want my understeer/oversteer happening based on how I've sprung and/or anti-sway barred the front/rear of my vehicle.

I also never put poly/delrin on suspensions that bind as part of their design. Mr2s, FoxBody rear, 240sx rear, and most "multi link" setups fall into this group. If the rubber has to go, rod ends or spherical inserts are the next step.

codrus
codrus Dork
3/30/16 5:20 p.m.
Flight Service wrote: Here is a question, what mass produced, readily available vehicle (let's say double challenge money) with the best performance capability suspension?

For $4K, in running, drivable condition? Is there any possible answer other than The Answer?

Flight Service
Flight Service MegaDork
3/31/16 11:34 a.m.

In reply to codrus:

You think?

codrus
codrus Dork
3/31/16 7:05 p.m.
Flight Service wrote: In reply to codrus: You think?

I can't come up with an obvious counter-example. Can you?

Flight Service
Flight Service MegaDork
3/31/16 7:21 p.m.

944, Boxster, E30, CRX, EG

How do those compare?

codrus
codrus Dork
3/31/16 11:50 p.m.
Flight Service wrote: 944, Boxster, E30, CRX, EG How do those compare?

I am assuming you're asking about the inherent suspension geometries of those cars, rather than the specifics of their handling in stock or lightly-modified form.

The E30, 944, Boxster (can you get a Boxster for $4K?) and first gen CRX (at least) use struts up front. Struts use a lower control arm paired with a structural damper to locate the front upright. This design is cheap and provides for a lot of space in the engine bay, but it is pretty limited in the amount of camber gain available as the suspension compresses. You want to gain camber as the suspension loads up in a corner, because that keeps the tire closer to flat against the ground as the car rolls to the outside.

The E30 has a semi-trailing arm rear suspension, which means that in addition to the camber changing as the suspension compresses, the toe changes as well. Changing toe means that the balance of the car is shifts as the suspension loads up, and if it's not set up just right this can make for an evil-handling car. Semi-trailing arms are pretty much obsolete by this point, nobody builds cars with them any more.

If you look at the suspension on pretty much any purpose-built race car that isn't hampered by rules, you'll find a double wishbone (or A-arm) suspension on all four corners. Double A-arms (with shorter upper arms) give you a suspension that gains camber nicely as it compresses, has no toe or caster change (if you locate the steering rack and tie rods properly) and can be analyzed fairly easily to calculate things like roll centers. The downside to them is that they take a lot of space, which car manufacturers would much rather use for things like transverse-mounted inline engines, driver/passenger foot wells, luggage storage, etc.

The Civics of the 90s have double a-arm fronts, but I think the rears are a beam axle. The Miata has double a-arms at all four corners, which is one of the reasons it handles so nicely. At least the NA and NB do, IIRC the NC and ND have a multi-link rear which is similar but a bit more complicated. Other cars with 4-corner double wishbones include the S2000, Elise, NSX, and lots of Ferraris and other high-end sports cars.

That's not to say that anything with another suspension geometry sucks, obviously the cars that you mentioned handle pretty well. The geometry is the basis for the suspension, but a lot of different geometries can be tuned and set up to work well inside certain ranges. In most of those cases, though, they're compromising a least a little bit of the handling for cost, packaging, or other non-performance reasons.

MCarp22
MCarp22 Dork
4/1/16 12:00 a.m.
codrus wrote: The Civics of the 90s have double a-arm fronts, but I think the rears are a beam axle.

Beam axle confirmed:

Flight Service
Flight Service MegaDork
4/1/16 4:25 a.m.

That's look like a semi trailing arm...

Flight Service
Flight Service MegaDork
4/1/16 4:25 a.m.

So 88 or 89 accord had doubles on front...

JBasham
JBasham New Reader
4/1/16 3:55 p.m.
Flight Service wrote: 944, Boxster, E30, CRX, EG How do those compare?

Okay, not to dispute the amazing qualities of The Answer.

But, the E30 suspension is only suckish on paper. It's not great, but it's not the weak link. A little stiffening, and a little training on lift oversteer, and you're good to go.

Spec E30 used to be faster than Spec Miata but the weight to power ratio on the E30 was a little better, like 16 vs 15.

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