The 3 basic types of shock absorber are:

- Hydraulic twintube.
Invented by Newton in 1912.

- Hydraulic low-pressure twintube.
Invented in 1920.

- High pressure gas monotube.
Patented by Christian Bourcier de Carbon in 1953.

Christian Bourcier de Carbon founded the De Carbon company in the same year 1953 when he invented the monotube high pressure gas shock absorber. Soon after a license was sold to Bilstein in Germany. Now that the patent has expired also other companies such as Koni use the monotube technology for their top range.

Lancia engineers were among the first to recognize the superior performance of the De Carbon shock absorbers and fitted them to the Flavia and Fulvia. Today the De Carbon technology is preferred by car makers such as Ferrari, Lamborgini, Maserati and Lotus.

High pressure gas shocks can be mounted under any angle. This is important for the rear shocks of the Flavia / Fulvia. Hydraulic shocks have to be mounted within 45 degrees of upright.

There is a lot of literature on the internet about shock absorbers. A few links are below. If you are interested to know more about shocks an suspensions, please, follow the links and use Google to find more. Several points to keep in minde are:

A stiff suspension does not necessarily mean good handling. Often the contrary.

If you still want a stiff suspension, it should come from the springs. The function of the shock absorber is to dampen oscillations of the spring by converting energy to heat. Do not use shock absorbers to obtain a stiff suspension. Shock absorbers and springs each have their own function. Respect those functions as car designers and suspension tuners have been doing for a 100 years.

Do not use new shocks to compensate for old and tired springs. The shocks will soon fail when the springs are bad.

Worn shocks do not only reduce safety and handling, they also increase the risk of having a broken spring as the spring is allowed to oscillate.

Shocks have different damping characteristics for the expansion and the compression stroke. Changing these characteristics changes the rate at which weight is transferred from right to left and vice versa in corners and from front to rear and vice versa on braking and accelerating and thus affects over / understeer. The Fulvia is a well balanced piece of precision engineering. The designers did a better than excellent job on the ride, handling and cornering of the Fulvia in spite of the awkward weight distribution between front and rear. It is a difficult and complex job to improve on it. These De Carbon shocks have the characteristics that the designers of the Fulvia figured on.

Some hydraulic shocks are "adjustable". Note that only the damping on the expansion stroke is adjustable on these shocks. Your Fulvia does not like too much damping on the expansion stroke. First, the subtle way of fast cornering using the throttle is affected and second, the wheels are not allowed to go fully down on a bumpy road. The car will end up riding on its bump stops. The De Carbon shock absorbers avoid these problems as they are exactly right for the job.

Links

Shocks FAQ.

Technique automobile - amortisseurs. Note that other words for high pressure gas monotube shock absorbers are: "amortisseurs oléopneumatiques" or "hydropneumatiques".

Amortisseurs.

Price:

• € 80 each for the front shocks
• € 80 each for the rear shocks.

Shipping and handling:

To order and / or for more information contact
huib@viva-lancia.com

Only the best for your Fulvia:
 
high performance De Carbon mono tube high pressure gas shock absorbers.

All three types of shock absorbers use hydraulic fluid to convert the energy of the spring to heat.

The twin tube hydraulic shocks have the shock absorber mechanism in the inner tube. The outer tube functions as a fluid reservoir.

The low pressure gas twin tube shock absorbers use low pressure nitrogen. Whenever a piston moves through a fluid, there is a vacuum behind the piston, which generates bubbles (aeration, foaming). The idea of the low pressure gas is to eliminate the foaming.

The high pressure gas shock goes a step further. There is only one tube which holds the shock absorber mechanism and the fluid. At the end of the tube there is a chamber filled with high pressure nitrogen. This chamber is seperated from the main body by a floating piston. The high pressure from the gas makes sure there is no vacuum behind the moving piston (thus no foaming) and eliminates the fluid reservoir. There is no outer tube.

Advantages of the De Carbon shockabsorbers are:

Instantaneous response

• Because the high pressure gas eliminates aeration (foaming), action is always immediate.
• The low mass of gas and the single tube further improves response time

Better fade resistance

• Since there is no outer tube, cooling is much better which gives a drastic reduction in fade. Thus more consistent handling and control.

Better durability

• Single-tube construction also allows for a larger internal working area, reducing stress and fatigue for better durability.
• De Carbon's monodisc valving system features a single moving part that drastically reduces inertia and friction, to improve durability and performance.
• Better cooling of the mono tube design results in lower operating temperatures and thus longer life.

No need for re-adjustment

• The viscosity of hydraulic fluid changes as temperature changes. This may be because of climate, season (summer / winter) or heavy duty (rallying) or light duty (motorway cruising). The high pressure gas compensates immediately and automatically for changes in viscosity.

Testimonials

La mia Fulvia adesso è tutta una altra macchina! Ho fatto circa 20 km su strade di campagna (solo sull'asfalto, per ora) giusto per provarla nelle curve strette... il feeling è quello di un perfetto compromesso tra guida sportiva e comfort, proprio come si addice ad una Lancia!

It's a fantastic all new car! Did some 20 km of country roads (twisty but on tarmac!) to try the cornering improvements... really feels a great compromise of comfort and sporty feeling!

Alberto Manassero, alberto.manassero@tiscali.it
13 Febbraio/February 2002

I did pop in the rear shocks on the GTE, took me 15-20 minutes to do them both. Easy. I had Megan manning the jack and she would adjust the rear axle to make putting the shocks on even easier. Again, the shocks make a really big difference. The ride of the car is just superb. And the handling did go up a notch, its now getting closer to the Coupe, I can corner much more vigourously than previous.

Jay T Hinton, jhinton@loc.gov
24 Oct 2000

Just letting you know I had enough time to install the DeCarbons on the front of the GTE. There wasn't enough daylight left to do the rears yet, but maybe tonight.

They are good. I don't know if the cornering is improved, but the ride and response to bumps and stuff is very good. You hit a homerun with these shocks.

Jay T Hinton, jhinton@loc.gov
21 Sep 2000

Some mounting tips

The front shock absorbers have silentblocs (rubbers) at the bottom. The rear ones have silentblocs at the top as well as the bottom. When the car is driven over an uneven road, the shock absorbers rotate a little when the wheel goes up or down. This is made possible by the rubber of the silentblocs.
The inner bushes of the silentbloc must not be able to turn. The mounting bolts should be tightened enough to make sure that the inner bush is firmly clamped in the mounting bracket.
The tightening of these mounting bolts MUST be done with the shock absorber in the position that it will be when the car is on its wheels and loaded with a nominal load.
If not, the rubber of the silenblocs is already tensioned when the car is lowered and put on it's wheels. When the wheel goes over a bump, the rubber will be stretched more and may even exceed its limit and tear.
Bad rubbers on shock absorbers are almost always due to wrong mounting.
The rubbers must be without tension, when the car is static on its wheels and with nominal load.

The same mounting rules apply to any silentblocs (e.g. those on the upper and lower wishbones of S2 and S3 Fulvia's and those of the rear leaf springs).

I use pot jacks to jack up the wheel I am working on to the approximate static position. Be very, very careful. Loaded springs can be very dangerous.

The front shock absorbers come without nuts for the top end. If your old shock absorbers are original Lancia or Koni's the old nuts will fit. If the old shock absorbers are Monroe, the old nuts will not fit and you have to get new nuts first.

The mounting brackets for the top of the rear shock absorbers are different for S1 and S2/3 cars. On S1 cars each of these mounting brackets is a complete piece with rubber inserts with metal bushes through which the top mounting bolt goes. The thing will thus easily adapt to the size of the metal bush at the top of the rear shock absorber.
On the S2/3 cars the mounting bracket is no longer a piece of art, but consists of two metal plates with a hole for the mounting bolt. The distance between these plates must be such that the bush of the shock absorber fits exactly between the plates. If not (some old aftermarket shock absorbers have different size bushes) undo the 2 M6 mounting fixing bolts (socket 10) for each plate partially. this allows the mounting brackets to move a bit sideways. Then tighten the mounting bolt for the shock absorber as per above. Then tighten the M6 fixing bolts of the brackets again. We have heard of a case where the shock absorber was taken to a machine shop to machine the bush. This is ridiculous.

The top mounting bolts of the rear shock absorbers should be mounted such that the head is towards the center of the car and the nut towards the side of the car. If not, it will be impossible to remove the mounting bolt without removing the mounting bracket from the car first.

High pressure gas shock absorbers always go to the maximum length position if they are not mounted. The rear shock asborbers have a strap around them to keep them compressed. Cut this strip AFTER the shock absorber has been properly mounted.

If the car is jacked up at the front, the front wheels go down because of the tension of the front transverse leaf spring. The maximum travel for the upright is determined by the maximum extension of the shock absorber. It means thus, that it will be impossible to remove the bottom mounting bolt of the shock absorber because of the tension of the front leaf spring. To avoid this problem I a) undo the top nut first, but then you will probably be unable to put the nut on the new one, or b) put a jack under the bottom wishbone near the bottom ball joint (be very, very careful and select a stable position).

BE VERY VERY CAREFUL WITH LOADED SUSPENSION SPRINGS. THEY CAN KILL YOU OR CUT OFF AN ARM OR A LEG. MAKE SURE THAT JACKS, AXLE STANDS ETC ARE PROPERLY PLACED AND ARE STABLE. IN ADDITION LOOK THE SITUATION OVER WHEN YOU CHANGE POSITION. TRY TO PREDICT WHAT WILL HAPPEN IF THE SPRING IS RELEASED AND STAY OUT OF THE WAY.

NEVER WORK UNDER A CAR WITH THE CAR JUST ON A JACK, EVEN IF THIS IS A PROFESSIONAL HYDRAULIC JACK. ALWAYS PLACE AXLE STANDS BEFORE YOU WORK ON THE CAR. In Holland these axle stands can be bought at a very low price from the Gamma supermarket.