FWD MacPherson/Torsion Beam Suspension Setup

So I have been planning on buying a Fiat 500 Abarth whenever they finally hit showrooms. So today I decided to see what type of suspension they are going to be using. To my dismay this is what I read:

Front: MacPherson suspension, coil spring with twin-tube shock absorbers and stabilizer bar — included with 500 Pop and 500 Lounge Sport-tuned shock absorbers and springs — included with 500 Sport

Rear: Rear twist-beam axle with coil springs and twin-tube shock absorbers — included with 500 Pop and 500 Lounge Sport-tuned shock absorbers and springs — included with 500 Sport

From everything I have heard and read FWD MacStrut cars are a pain to set up. To make matters worse the rear is a torsion beam, which wikipedia makes sound like a terrible idea.

Here is the list of disadvantages according to my friend wiki:

Basic toe vs lateral force characteristic is oversteer
Since toe characteristics may be unsuitable, adding toe-control bushings may be expensive.
Camber characteristics are very limited.
Not very easy to adjust roll stiffness
Welds see a lot of fatigue, may need a lot of development
Not much recession compliance - can be poor for impact harshness, and will cause unwelcome toe changes (steer effects)
Wheel moves forward as it rises, can also be poor for impact harshness (this can be negated by designing the beam with the mounts higher than the stub axles, which impacts on the floorpan height, and causes more roll oversteer)
Need to package room for exhaust and so on past the cross beam
Camber compliance may be high

Am I right to be annoyed by this setup? Will the car be a PITA to dial in for autocross and track days? What type of things can be done to combat the aforementioned list?

Okay, you know what else has that kind of suspension?

Rabbits and A2 Golfs, basically the awesomest front drive cars made.

So don't worry.

Since a lot of the more modern cars use a MacStrut front suspension and a lot of those are Auto-Xing and racing it seems like a lot of people have figured it out.

How about the rear suspension?

Also early Chrysler FWD and GM FWD and many, many others.

Increase the negative camber up front, drop the sway bar, put uber stiff shocks on it with R-comps and go win some stock trophy's with it.

Drive it with two feet, one on the brake, the other on the throttle.

Rinse, repeat, etc.

Joshua wrote: How about the rear suspension?

For stock-class there's nothing you can do.

For other classes or just driving around on the street, put a huge sway bar in the rear and increase the negative camber.

Ideally you wouldn't go too far with the bar, but increase roll stiffness with springs and shocks, but big bars are usually cheaper and easier to do.

My 2011 Fiesta has that set up. Stock, it handles great. There are a couple of sway bars,that stiffen the beam, available. The twist beam has been given a bad rap and how is it any worse than a multil link suspension with a really stiff sway bar ? Adding camber and caster to the front and reducing roll makes for a darn good handling car. Hey, Porsche and BMW both have strut front suspension. They seem to handle pretty well.

Hmmm I guess things are looking up...

not sure, but I think that next yr there will be a rule change that allows front or rear bar change / add ( either / or ... but not both )

just remember this... what you read in specs does not always equal to what you feel on the street.

If you went by specs alone.. the 911 and every BMW would feel terrible on the road.. understeering everywhere due to the camber issues with the front struts.. and porsches would be spinning off into the bushes everytime you pulled out of the driveway due to the engine being at the wrong end.

Joshua wrote: Am I right to be annoyed by this setup? Will the car be a PITA to dial in for autocross and track days? What type of things can be done to combat the aforementioned list?

The problem/solution is running lots of static negative camber on the struts. Also a lot of toe-out which will do bad things to tires combined with the former.

A twist beam is efficient in that it is itself a sway bar. And to add more "bar" rate you can just attach more metal to one. Shims on the axles can generally be used to change the static camber. A multi-link rear with a big bar is just a lot more stable--especially multilinks with long lateral arms.

first thing i thought of was the cobalt SS which uses the McTwist setup. lets not forget the lightning laps that thing put down in stock form in the last C/D comparo. that's a legitimately good handling FWD car using a "crappy" suspension.

as others have mentioned its all in the contact patch in the front and getting the rear to rotate. i have no doubt there'll be a significant aftermarket for the car, so i wouldn't be too concerned. there are plenty of cars that handle far better than they sum of their parts

My tercel is Mac+torsion rear beam, I love it, very toss-able, I have a 20mm rear bar on it and a 22mm front, add some front camber plates with 2-3* neg and it feels good.