International Lancia Forums

Some six months ago I started a thread about shockabsorbers for the Fulvia. The shockabsorbers situation for the Fulvia is fortunately not so grimm as for the Beta series were new shockabsorbers are no longer available off the shelf. For the Fulvia roughly three makes are available (in europe). The Carbon, which is a gas type non-adjustable shock. Koni, available in red and classic versions which are the same safe for the black paint. The Konis are oil type and adjustable. Third is Spax, this English shock is of the gas type and externally adjustable.
At the end of the thread I promissed to report my experiences with the not so familiar Spaxes.
The reason it took soem months to report was the fact that the Spaxes listed for the Fulvia (and Flavia) did not fit straight out of the box. Bushings were the wrong sizes and the shock body for the fronts was simply to long causing the risk to bottom out on bumps. Several 'prototypes' with different lenghts, revised damping settings etc were tested by me on my HF on road and track. A few weeks ago Spax made the agreed spec available with the following order numbers. Fronts G3312 and rear G3318. The shocks are set for both series 1 and 2/3 and damping adjustment is possible from touring to track firmness. These shocks will improve your Fulvia not only in handling but also in comfort and ease of adjustment. (A screwdriver is al you need)

William
How much, as a matter of interest?
I know that Paul Leclercq's specials were very costly and I certainly can't afford them, but the Spaxes sound well tried and tested. I've used early Spax dampers at the front in the past and was pleased with them.
Regards,
Justin

I was surprised at William's problems. I have a pair of Spax at the rear on my car and they fitted without problems.

Nevertheless I sounds as though William has had good service from SPax in this instance, and I am pleased to seee that the results are good.

Paul

There must have developed some kind of error in the drawings as the listed partnumber for the rears really did not fit. I have recieved three sets with the same problems. The bushings were 45mm wide which should be 35. The strokelenght of the fronts was about 1"to long so that the shockabsorber would function as the end of travel stop. Now the lenght is shortened so the shortest measurements are the same as the original lancia design.
see table:
lenght: G3312 koni smora org. G3318 koni smora org.
max: 310mm 330mm 320mm 440mm 425mm 425mm
min: 220mm 220mm 220mm 290mm 275mm 290mm

The thing I found the most amazing was the fact that three clicks more damping changed the rear from saggy and soft, (I have soft rear springs and at that day a boot full of holiday gear) to firm and responsive!
I have tried Spax on cars with tired leafsprings and the gaspressure actually raises the car and increases travel! Especcially welcome at the front were sagged springs makes the car prone to riding the bumpstops. These shocks can make you postphone the replacement of your transverse spring. They are that good!
The ease of adjustment is perfect for cars that are driven both on road and track and al is needed is sitting on your knees with a screwdriver and 2 minutes of your time to change the car from comfortable to track firmness. The comfort is still higher than the konis as the oil which koni uses as damping fluid promotes 'stick slip'. This means in laymensterms that a force is needed to move the pistonrod. The bump is thus always felt. Gas type shocks as De Carbon or Spax are basicly resistance less and move at the slightests provication and make you think the road is better than it was before.
the price is about the same as koni.

I appreciate your enthusiasm for the shocks, William, but I must warn against using shocks to compensate for tired springs. Each component has its function. The spring has to carry the weight and absorb the bumps. A spring is a tuned circuit and will continue to transfer energy in the imaginary plane. In other words it oscillates. The shock absorber is there as a resistor to dissipate the energy by turning it into heat so that the springs stop oscillating.

Basically for each combination of (weight of) a car and springs, there is an optimum shock absorber. If you want to tune the car for competition, you start reducing the weight of the car and stiffening (and possibly lowering) the springs. The new combination requires a different shock absorber. Of course you can fine tune the shock for the exact application and your personal taste but that is all 2nd order.

Look at the differences in strength of the mounting points of springs and shocks. The front spring is in a have metal cross member on each side bolted to a solid alu tower using 4 M10 bolts on each side. The top of the shock goes into two thin rubbers which sit in a ridiculously undersized alu eye (undersized compared to the cross member carrying the spring). The bottom ends of the front spring are attached to a strong part of the upper A arm through a high shore rubber buffer of 65mm diameter. Even then the forces exceed the limits of elasticity so that the rubber buffer is plastically deformed.
The bottom of the shock is a small eye with a tiny rubber bolted with one M8 bolt to steel strips on the lower A arm.

A similar story goes for the mountings of rear spring and rear shock absorbers

The shock absorber is not designed to carry any weight. Its mounting points even less. In fact it is the whole structure of the car which is designed to transfer the weight to the spring mountings and certainly not the shock mountings.

Also the lower suspension ball joint cannot carry any weight. If the front shock absorber would transfer any weight to the lower A arm, that weight would hang on the lower suspension ball joint. It is not designed to do that. It has a small spring inside which would be compressed resulting in excessive play. The lower A arm and its suspension ball joint are there to keep the front wheel up right. The weight of the car is on the top joint, if the lower A arm was not there the wheel would collapse.

One of the advantages of (properly assembled!!) leaf springs is that they already sort of function as a shock absorber because the leaves rub against each other which dissipates energy.

Both the twin tube shocks (like Koni) and the monotube shocks (like De Carbon or Spax) function by pushing fluid through a tiny hole. To have it dissipate energy you need pressure. On the twin tube ones it means the piston inside already has to travel some distance to build up pressure before the shock absorber starts doing its job. On the monotubes gas under high pressure is already added to the liquid. The pressure is thus always there. The shock absorber already does its work from the first tiny movement on.

Because of the high pressure gas in the monotube shocks, the stem is pushed out. The force can be calculated by multiplying the pressure of the gas with the surface area of the cross section of the stem. The pressure is about 30 bar. Or you can test it by pushing it in with your hand and try estimate the force. I estimate it at about 30 to 40 kilo. A much younger guy might estimate it at 20 kilo.

Some people believe the monotube shocks work only in one direction because they expand if released. It is not the case. They work in both directions just like the twin tube shocks.

An other word of caution against adjustable shocks. The low cost ones like the Koni’s and the Spax can only be adjusted in one direction. If I remember correctly it is the outward (or expansion or rebound) stroke that can be adjusted. There has to be a certain ratio between the damping on the compression and the expansion stroke. If not it starts to behave as a valve like the inlet valves or exhaust valve or the vacuum valve for the servo or, in electrical terms, like a diode. In other words, it will block motion in one direction and let it pass in the other direction
If the expansion stroke is over damped the car will lower itself on cobble stones and similar surfaces and thereby increase the load on springs, shocks and their mountings and reduce the clearance on roads where you need the clearance most.

My advice is not to mount new shocks on tired springs. The life time of the shocks is seriously reduced because they have to work too hard. And on the other hand, if you replace the springs, also mount new shocks. If not the springs oscillate too much and tire sooner.

Huib wrote:An other word of caution against adjustable shocks. The low cost ones like the Koni’s and the Spax can only be adjusted in one direction. If I remember correctly it is the outward (or expansion or rebound) stroke that can be adjusted.

This is not the case. In 'cheaper' shocks like the konis and the Spax the adjustment affects both bump- (or compression damping) as rebound damping. Both are set harder or softer when adjustments are made. Expensive dampers like Leida have separate adjusters for rebound and bump but cost 5 times as much.
The raising of the car with gas type shocks is due to the mentioned 30 bar pre-pressure and present with both De Carbon as Spax. This force pushing the car up is a static force. The force acting on the shockabsorber mounts during movement of the suspension is much fiercer and I assume the same is with oil type or as you call them twin-tube shocks. The attachments of the shocks through 8mm bolts seems weak but the force needed to sheer them is enormous!

I agree that you cannot 'repair' weak springs with these shocks but the amount of miles most people drive their classic Lancia's is low enough to be able to enjoy their rapidly wearing gas shocks for many years. So they can ride their cars safely while planning the inevitable replacement of their leaf springs.

The difference between the De Carbon and Spax is that while the first are made for comfort only (perfect on berlinas) the later can be tuned for comfort or speed. And in 5 minutes time!!

William

As Justin asked, what is the cost?

It's a case of "How deep are your pockets" as with all tuning options. If you want to spend a couple of grand on each corner, I'm sure Ohlins would make you a fantastic set of modern remote reservoir dampers. The other undoubted "rule" of tuning is "You get what you pay for", so the affordable sports shocks like Koni and Spax will hopefully provide some sort of advantage, while fully tuneable bump and rebound competition gas shocks will perform longer and better in the extremes of full competition.

As Paul says, if William has found an improvement, that's great to hear and it is worth sharing.

Thanks for the info, William

Michael wrote:If you want to spend a couple of grand on each corner, I'm sure Ohlins would make you a fantastic set of modern remote reservoir dampers.

That would be the same as fitting carbon wings on a Ford model-T

We have to keep everything in perspective here,
The suspension of the Fulvia was modern in its day but too crude in design to make it 2006 by just fitting top spec shocks. In my oppinion the 'low cost' adjustables as Koni and Spax are high tech enough to do the Fulvia justice.
And for about 340 euro a set of four you can't do it much more justice!

It is quite all right, William to experiment if that is your thing. It is the best way to learn and gain experience. I have done the same thing. In fact some 8 years ago I also tried to compensate for tired springs by installing high pressure gas shocks. Shortly after the right rear shock seized which also resulted in a bent Panhard rod. I do not know for sure that it was caused by the bad springs, but it is likely. I replaced shocks with Monroe types that I still had lying around and replaced the Panhard rod. A few months later the left rear spring broke.

Right now I am working on a coupe which has a crack next to the top mounting bracket of the right rear shock. Again I am not sure whether it has had too stiff shocks in the past and if yes, that hese were the cause, but it is the most likely.

I appreciate your work that you have done with Spax. I am interested to try a set myself. However, may visitors of this forum are not in experimenting nor racing. They just like to enjoy their Fulvia as it is. Trying to compensate for tired spring with different shocks is tempting. Replacing springs is a difficult and dangerous job requiring special tools to do it safely. I just want to warn less experienced Fulvisti.

If the springs are bad, the springs have to be replaced. If the shocks are bad, the shocks have to be replaced.

It is quite easy to tell when a forum is a success: you get all shades of opinion discussed in a rational and well-argued way.

This thread is a good example.

To prove the point, I am going to offer a third angle on this.

I understand Huib's point exactly; in fact yesterday evening I met a group of Fulvia enthusiasts, who whilst revelling in the characteristics of their cars, really for the most part enjoy them just as they are - more or less standard - albeit with the exception of some Cromodoras here and there.

Now whilst I agree that carbon wings on a "Flivver" would be rather silly, and perhaps a set of Ohlins as described by Mike "un peu de trop" the rather pricey dampers fitted on my car ( and on one or two others) really are better. Not better because the ride is board hard, thus making the car conform to the popular image of a "competition car" but because the ride is better than original - not only in normal use, but yes on the track where the turn-in has been improved and even more so when having to deal with stupid "speed bumps" which the Fulvia rides over perfectly without banging and crashing whilst remaining perfecty controlled. I recall very well the amazing difference between the way that the Thema and the Fulvia coped with those bumps

So to sum up, pick the features that YOU want to change - if any: titanium valves, con-rods and rose joints or leather upholstery and French polishing - after all it's your car!

And yes - I would love to try the Ohlins!

Paul

Paul