Setting the Koni rear dampers

This evening I took the dampers back off the car to set them up properly now that someone on the Fiat Forum has kindly pointed me in the direction of some more helpful instructions. They are set by compressing them completely until they engage an adjustment cam inside the bottom of the unit. The manual states that there are ‘approximately 2.5 turns’. These units have 2.25 turns. I found that the one on the driver’s side had half a turn from zero and the passenger side was on zero. Turned fully counter-clockwise the rebound is softest, turned fully clockwise it is at its hardest.

The PDF describing the settings is available here:

koni_settings

Given that there is not much to go on to determine what setting to use, I decided to time how long the damper took to return from fully compressed to fully extended under gravity for every 0.25 turns from zero to 2.25. The chart below shows the results.

Although not the most scientific experiment ever conducted, I was interested to note that the result is not linear, and the time to rebound became longer at a faster rate the further clockwise I turned.

I timed the standard damper at 25 seconds to de-compress, but I’m not sure if that is a valid comparison as it is much ligher than the Koni unit so I would expect it to be slower like for like. In the end I settled for 1.875 turns (really!) which took 45 seconds to de-compress, so I am assuming will provide a fair bit more rebound damping than the zero to half-turn that I had initially.

Test drive to follow…

A cure?

My Koni rear shock absorbers arrived today, along with great hopes of banishing the bouncing. They were very easy to fit, although so far I haven’t figured out how to adjust them.

The instructions were less than helpful, so I’m still trying to work out how on earth to determine what the minimum damping setting is and how to increase or decrease the effect. As a result I’ve just fitted them as they came and will take them off to adjust when I can find some more information on what I’m supposed to do.

Fitting was a doddle…the most difficult part was getting the wheels off! Instructions follow for anyone who is interested:

Jack the car up on one side at the marked jacking point and pop an axle stand under the rear beam. Remove the wheel which will expose the shock absorber.

The bolt in the picture above can be removed with a 15mm socket. It was torqued to less than 80nm so should be easy to remove.

Ta-da!

The bottom one is just as easy…

This time the 19mm socket is your friend. Again, torqued to less than 80nm.

Then simply remove the original shock absorber. I told you this was easy!

Old…and shiny new. The Koni certainly looks beefier.

Something that I found a bit odd about the Koni is that the metal bush from the original shock has the same outer diameter (pictured propped on the Koni below), but a smaller inner diameter…

Original inner bush with top bolt:

…this means that the top bolt is loose in the bush on the Koni:

I tried to remove the metal bush in the Koni but it was firmly in place, so I decided to just go with it. Doesn’t seem to cause an issue, it just doesn’t look quite right to me.

To install the new shock, start at the top. This will allow you to push the bottom into place…it will take a bit of a shove to compress the damper. I tightened both top and bottom bolts back up to 80nm.

Repeat the other side (don’t forget to put the wheels back on :o)

I’ll make a new post about the results.

The dreaded 100hp ride

My feeling is that the 100hp’s greatest flaw is its ‘ride’. Almost all the magazine reviews either describe very ‘stiff’ suspension or a very ‘bouncy’ ride. What I didn’t notice on my (very short) test drive, but have since been very aware of during all drives, is a constant front to back pitching motion. Although the car’s springs are relatively stiff, they are by no means the worst I have experienced in a road car, and no other stiffly sprung car that I’ve owned has felt so unsettled.

The day after collecting the car, I went for a couple of days of driving in North Wales to put the car through it’s paces. By the end of the first day I was starting to worry that I’d made a big mistake as I was basically feeling sea sick from the constant pitching! On the second day I actually had some enjoyable drives on some of my favourite roads, but I still couldn’t escape the feeling that there was something strange about the ride. For example, over some quite badly broken road surfaces, the car behaved just fine but then on an apparently perfectly smooth road severe pitching would hit it out of the blue.

The more I thought about it, the more it seemed like the car’s dampers were unable to contain the rebound of the springs. This is especially noticeable at the back of the car, which is regularly sent pogo’ing up and down with particular road undulations. The effect is noticeable at the front of the car too, but the weight of the engine seems to add a bit of rebound damping.

Having searched and posted on the Fiat Forum Panda section, several possible solutions came to light. One owner had fitted Koni Sport Dampers and Eibach springs to his 100hp and claimed that the poor ride was entirely resolved. There was also at least one owner who had fitted KW Variant 1 coil-overs, albeit at a higher price than the Koni/Eibach combination.

In order to keep costs down, and for the sake of experimentation, I’ve decided to gradually up-rate my suspension. Tonight I have ordered the Koni Sport dampers for the back of the car, at a cost of £202 from Larkspeed in Leeds. The Koni part code for these is 8040-1347Sport. They are adjustable for rebound on the car and hopefully should not be too much of a pain to fit myself (famous last words!).

If these are a success on the rear but I still feel that the front needs to be sorted out, I will order the front units as well (part codes 8741-1486LSport and 8741-1486RSport). These are around £130 each.

Finally, if I feel that I’m not getting exactly what I want from this set up, I will add the Eibach spring kit as well. If none of it works…well, I’m not sure what I will do! I will post my fitting experiences and results once they arrive.