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Alfa Dedion vs four link live axle

Posted: Tue Mar 06, 2007 2:00 pm
by zambon
Please help me with a debate I keep having.

I am currently languishing in the third world here in Mexico. I am not refering to the economy or politics. I am refering to the automotive culture.
I am from the old USA where people never stop saying things like "No replacement for displacement." Which is true, but they use it to criticize my car for only having 3 liters, which I consider to be plenty of displacement. Then those same guys get red in the face when their Mustangs cant outrun 2 liter stock Mitsu LanEvos.
Here in Mexico they subscribe to the same philosophy. The difference is that there are no LanEvos or STIs here to keep them honest. In fact there are no hot sport compacts here. I spend time with a group of mechanics who are all about v8 dinosaurs and they love to complain about my machine.
That is all fine, because I dont have any interest in Corvettes or Rustangs. One thing has been bothering me though:

I got stumped the other day when one of my friends was making fun of the dedion triangle in my car. He was saying that I should dump it and run a live axle with at four link. He doesnt understand the Dedion and I dont know the four link. What advantages deos each suspension type have?
I know that we supposedly have less unsprung weight due to the diff not being connected to the axle. That said, our dedion weighs quite a lot. Maybe even as much as a mustangĀ“s axle/diff. Our Dedion sends the force from the wheels to the center of the car at all times, but I am not sure how much that really matters.

What does our dedion do better? Worse?

Posted: Tue Mar 06, 2007 2:06 pm
by DaveH
The Watts part of the Alfa rear suspension provides superior transverse location than '4-link'.

In fact, didn't Ford just update the Crown Vic with a Watts linkage?

Weight-wise, I doubt the Mustang diff and axle gets near the DeDion setup.

Posted: Tue Mar 06, 2007 3:20 pm
by Murray
Zambon another "advantage" of the Dedion is the rear wheels maintain pretty constant camber in a corner.Follow one around a racetrack and you will see that the rubber is always pretty flat to the surface.The rear-end is always composed and reacts in a very predictable linear fashion.In theory a solid rear axle is similar but all hell breaks loose as soon as you run over a rough surface.The Dedion almosts acts like independant rear suspension on bumps but with a much simpler design.All that said my son's Honda civic handles just as well but who cares :twisted: I have more fun !

Posted: Tue Mar 06, 2007 6:42 pm
by Daniel
Any live axle setup has the problem of torque reaction - the torque reaction is taken into the suspension and one side squats while the other lifts. With the Dedion setup the torque reaction is taken from the transaxle mounts straight into the chasis.

Posted: Tue Mar 06, 2007 8:39 pm
by Barry
Four link`s are for going straight,a quarter at a time................... 8)

Posted: Tue Mar 06, 2007 9:06 pm
by Greg Gordon
The DeDion tube is far superior to a 4 link setup. With a 4 link, everytime the car leans in a turn the rear wheel alignment changes. This is especially true with the short arms on the Fox Mustangs. With the DeDion, they are pointing straight ahead no matter what.

Posted: Wed Mar 07, 2007 1:01 am
by zambon
Four link`s are for going straight,a quarter at a time...................
That was what I was thinking.

These turkeys dont even know about corners. I have been looking for some time for a corner to drive my car around. The search continues. Around here the roads are straight and flat. The only reason to have good handling is so that you can quickly move to avoid the giant potholes.
My friends have run cars on the local circuit, but most likely only Mustangs and Camaros. One of them used to drive a C4 Corvette targa, which he thinks is the end all be all. It was an Automatic and he wasnt even embarrassed. I called it a ladies Corvette. I have driven those Corvettes and I was shocked by how bad they are.
Anyway, based on that I am guessing that they just approach the circuit as a series of accleration runs interupted by corners. 1/4 mile racing is big here and circuit is not. I just dont get 1/4 mile guys.

Thanks for the answers,
James

Posted: Wed Mar 07, 2007 8:48 pm
by Barry
James,Got myself a new toy...1977 model,running a Cummins 6l diesel turbo..
Some tweaks by Cummins themselves,1200 Nm torque!!
Could make for a nice tow truck...

Posted: Wed Mar 07, 2007 10:41 pm
by zambon
Damn!
That thing would get you some serious respect where I am from... Or where I currently live, for that matter. Diesels are rare here and all the guys want one.

I sold my F350 last summer :(

For the record, I am the skinny guy with the clown outfit in the photo, not the Mexican pansone with the big gut. He brought the tow truck to give the Alfa a jump... (In Spanish the word for gut is pansa, and the word to describe a guy with a gut is pansone. I came here to learn such things).

Posted: Thu Mar 08, 2007 1:42 pm
by zambon
I just remembered that my father used to have a Ford f250 heavy duty in yellow that was about the same vintage. That was back when I had training wheels on my bicycle. I used to ride in the truck while my father plowed snow.
(I like your truck and am jealous).

Not only will it be good for towing, it will be a good tool if SA gets crazier and you need to go Mad Max...