Multi- Link Rear Suspension

Can you believe there is no manual shifter? Taz, I'm trying to find a source for your question, I think I may have some info early in the week.

 

Terry,

I'm sure you've read the press releases about the suspension, but everything I have read indicates the move to multi-link was purely about handling dynamics and weight savings. I am waiting on another source to report back but you may be correct about the tunnels. The cold engine air (not air intake) are located in front of the rear wheel wells.

Do you think the A/H arm is superior to multi-link for the 458?

 

I have no technical information to support the rumour that I am about to repeat. Apparently the rear control arms on the Scuderia are absolutely superior in terms of suspension geometry and the change in the 458 is to accommodate the bulky twin clutch transmission. The challenge in the next generation will be to reduce the size and weight of the twin clutch transmission to accomodate the rear control arms (A or H).

 

I think this is just a rumor for those who question the movement to Dual Clutch--

The Porsche 911 has been using multilink for years and everyone says it handles much better than before. I think it's just the technology is better-- so why not use it?

Here's a good write up

http://www.carsales.com.au/advice/2009/what-is-multilink-suspension-7533

Here's two paragraphs of what it says as an example:

"Multilink is considered to be the best and most functional independent suspension system that can be used on a production car. A multilink design uses several short links (or arms) to attach the hub carrier to the car's body (or a subframe). The links are configured to ensure that the camber angle of the wheel remains unchanged during suspension movement. 'Toe' and 'caster' dimensions are also controlled by the links depending on their initial design geometry."

"Does multilink suspension have any disadvantages? In short, yes... Such systems are more complex and incorporate more components, making them more expensive to design and produce. For this reason the systems were first introduced by luxury brands. That said, lower vehicle production costs and higher customer expectation have more recently seen the technology filter down to many large and midsized mainstream vehicles."

It also goes on to say that Multi-link systems are LIGHTER and MORE EXPENSIVE to produce. So, those who say it's too heavy or it's an excuse by Ferrari to be cheap are dead wrong.

This car is as fast as the Scud and weighs significantly more. I think whatever they did, it has to be viewed a step in the right direction.

 

my two cents,
all things being equal my opinion is that the performances could be equalized between multilink and double wishbone,

The biggest advantage of the double wishbone is that it is very easy to setup on a race car compared to multi link witch is much more complicated, but if both are setup to give the maximum, and ferrari had 5 years to ensure this, my opinion is there wont be much difference.

What will suffer from the change to multi link is the gt2 race teams witch will have to work way harder to set up race cars, and that might hurt performance since the time for setup is limited to 1-2 hours.

 

Well, the unsprung weight is definitely higher with multilink. Also, all racecars and high-end exotics (e.g. Zonda) have double wishbones. This should tell you something. My guess is that the packaging problems with the double-clutch are the main reason and it is a compromise. Do you think they put double wishbones on Enzo to save money?

 

You lost me at the outset. Completely disagree. There is no question that the first generation dual clutch is large and heavy which poses challenges. I am a huge fan of the dual clutch...

Porsche 911 has its' own design challenges. I have a 993 RS which has it and a 930 Turbo SE which does not and am well aware of the suspension geometry issues. Multilink is better on the Porsche but it is an unfair comparison as "old" technology updated by someone like Elephant can be pretty impressive. In addition the "old" technology was designed for tyres at the time so of course it does not work so well on newer technology tyres

Multilink is completely secondary to the advances in electronics. Scud has how many ECU's? 458 has one

 

Suspension is not a field where I know more than just the basics, but to quote the Professor who's head of the Vehicle Technology Institute at my university: "Multilink suspensions offer more precision and the highest level of control of the wheel movement*, but are more complex and more expensive than the double wishbone setup"

Where exactly did you get the information that multilink setups (which is a very broad term, btw) are inferior to double A-arms?


* the exact word is "Raderhebungskurve", which I can not translate

 

Can you ask your professor why, then, high-end ferraris (e.g. Enzo), Zonda's, you name it, sport double wishbones? Are they trying to save money?

 

In my limited understanding, yes. Double wishbones are very, very good if you have the space to accomodate them. Under these conditions the little bit of extra performance a multilink suspension might offer, depending on its design and the overall setup, does not justify the expensive development and the additional cost to the buyer. Things change however when certain limitations, like the available space, occur.

 

Multi-link rear suspension is a step back. Double wishbones is a superior suspension design (look at supercars and purpose deloveped race cars) The rear suspension in the F430 surpasses the design on the 458 Italia.

However, there is plenty that can be done in the dampers and springs to improve the suspension dynamics over the F430, and I have no doubt that the F458 will out handle the F430, and as soon as Ferrari develops a F458 Stradale/Scuderia, that car will out handle the 430 Scuderia.

I have not found any information on why Ferrari went with multi-link, I suspect it is related to the necessary space to allocate the bulky Getrag DCT, without making the car much wider.

 

Taz,

just spoke with the head Ferrari tech at my dealer, he just returned from a class at FNA for the California. Like the California, he stated that the multi-link in the 458 is being used to provide more room between the chassis for the gearbox. Looks like the feedback on this thread is correct.

Chad

 

Well, not really. You can't look at any one part of the rear end. You have to look at the entire package of the rear end. Each must work together for the overall goal -- make the car work better, handle better, and go faster.

Ferrari's goal was to create something that went better and faster. And the stats show that's what they did.

And now after acheiving the goal, we criticise them? Geez why not criticise them from moving away from solid axles and those new fangled "disc brakes" too.... Darn those engineers! Always doing something new and better.

Every design -- EVERY DESIGN -- has it's compromises. The 458 rear end is no different. But, the goal they set out has been met.

We should be applauding it for how well it works, not whining about days gone by.

Here's the difference between Porsche people and Ferrari people:

Porsche people: The new 911 now uses multilink! Cool! Handling is better and it's good to see some innovation! Go Porsche!

Ferrari people: Damn Ferrari they are changing what worked in the past! Don't these guys know they are damaging their heritage! [grumble, grumble] Damn Ferrari! Damn them.

 

And everything you say is even more so when you consider that Ferrari say the front is sharper as a direct result of the new multi-link rear.

 

What is the true measure of the superiority of one suspension over another?

Is it how much is costs?

Is it how it affects the ride comfort?

Or is it in terms of performance on the track?

If all other things were equal, then a faster lap time would imply that the suspension was superior from a performance standpoint.

I would bet that Ferrari chose the multi-link set-up because it was faster and offered better ride comfort.

 

We are not being nostalgic here. Multi-link is not a new development at all. It has been around for a while on BMW's, MB's, even Nissans. I guess Ferrari could not afford to follow Nissan's example and put multi-link on Enzo. I understand, that's the kind of compromises you have to make with low-budget cars .

On a serious note, it looks like Ferrari chose to compromise the suspension geometry to accomodate the DCT box. No doubt, the car will be faster than 430 and will handle better. They just traded off the suspension set-up for the transmission. However, a trade-off is a trade-off, you do give something up in the process.

 

What you might not know is that the Porsche 911 was using Torsion bars until the 964 hit the market in 1989, the first 911 ditching the torsion bars and going to coil-overs and multi-link suspension. Yes, the new for 1989 C4 (20 years ago) had a great suspension innovation, go Porsche!, it was an amazing improvement over the Torsion bar cars (something close to a live axle in approach). Definitely, the Porsche 911 handles better with the multi-link rear suspension. Porsche is limited to what they can build for the rear suspension in the 911, because the engine is located behind the rear axle (occupying lots of space).

Despite using a multi-link rear suspension, the 911 needs a lot of improvements on the suspension, such as better subframe bushings front and rear, better joints for the upper and lower control arms, tie rod style rear toe links, elimination of rear camber and toe eccentic bolts that don't hold the alignment, stiffening of upper strut mounts (except the front ones for the GT3/GT3RS/GT2). If using race tires, they also need new springs and new shocks.

The Ferrari F430 suspension is so well designed, that mine only got stiffer bushings for the wishbones (straight from the F430 Challenge) and new spring/shocks to match the grip of track tires. Any street car switching to track tires needs stiffer springs, and that requires different shocks. For street tires use, there is zero need to improve the F430 suspension, a Porsche 911 instead has a long list of necessary improvements.

The F430 suspension is among the best suspensions I have seen on a street car. The suspensions better in design are the double wishbones at all corners with push rods, as found in the Enzo and Carrera GT among others. Notice that the Carrera GT uses wishbones not the multi-link inferior design, and it is a Porsche.

Benefits of double wishbones:
- Less flexing, so almost zero camber, toe and caster changes due to flex on the suspension arms.
- Due to the lack of flexing, the static alignment numbers can be set with lower values, giving an advantage on acceleration and braking without sacrificing lateral grip.
- The cars feel more predictable and easier to drive.

 

Necessary improvements? In theory maybe. But out on the road try dropping a well driven 911 in an F430. And then switch to the 911 and see how you keep up with the 430 (just to remove the 'driver' factor). Theory is all very interesting but at the end of the day, in the real world, if it works, it works. Guess we better hope that Porsche don't get round to making all those improvements or the Porkers will be leaving us for dead!

 

you rekon? Why haven't they changed the shape then?

 

What the literature says on the subject:

Quote from "Fahrwerkhandbuch" ("Suspension Handbook"), Vieweg+Teubner 2008, horrible translation by me