Alfa GTV 916 front suspension refresh

[alanm]

Hi all,

Online research into 916 suspension, any suspension, seems to unearth a lot of information and misinformation...
so I thought I would add to it myself 

My car, a 3.0 2001 GTV was suffering from the commonly reported 'crashy' front suspension. Go into even the smallest of potholes and I would get a very nasty BANG from the front. I arrived at a point when I became obsessive about dodging imperfections in the road – far from ideal!

After the cars last service, my specialist Alfa repairer reported that one side of the car was lower than the other, something i'd never noticed. They suspected that one of the front springs had 'collapsed'. This became the catalyst to do something about the problem, I decided to replace the springs because I knew that they are comparatively inexpensive parts and because they are easy to remove. I know, in and ideal world I would replace the struts at the same time, but my budget at this moment in time doesn't stretch that far.

As much as I would like to support local suppliers, the best place to go for the springs and bump stops was the UK.
The Suplex springs (which I understand to be original spec) showed up after only 4 days – unbelievable! I made the decision early on that I wanted standard springs, many of the UK forum users recommended Suplex. For this car I wasn't interested in stiffening the suspension, certainly NOT interested in lowering it! What I wanted was a pleasant ride, the ride that I expect Alfa would have delivered to a new car buyer.

So I pulled the strut/spring assemblies out of the car – a clip and a handful of bolts each side, 4 at the top and 2 at the bottom, less than an hour each side. The wear on the strut shaft went all the way to the top and the bump stops were virtually gone/non existent. My conclusion from this was that the suspension was bottoming out, a product of worn springs and struts.

I then took the strut/spring assemblies to a Pedders suspension around the corner to have the new springs and bump stops fitted (did not want to mess with spring compressors). The guys at Pedders installed the springs and bump stops and handed them back to me adamant that the springs would make NO difference – they reckoned that the struts were the main culprit.

So what is the result?

The springs (and bump stops) have made a HUGE improvement. I feel vindicated, is seemed counter intuitive that the struts were the PRIMARY reason for the problem. What's next, new struts, Koni STR.Ts, because I know that the ones in the car must be worn out and because I know that the strut and the spring work together as a unit.

I will update this thread when the struts go in – I am curious to know whether, in normal driving, they make a discernible difference. I don't think the car is divey or bouncey at all, but maybe its is?

[Citroënbender]

Did you measure the old springs to compare free length vs new?

[alanm]

No, unfortunately I didn't see the old springs when they came out, to see old and new together might have been quite insightful!

The other thing that I neglected to do was measure the distance between the ground and the uppermost part of the wheel arch lip before the spring change. The only vague measure I have prior to spring change is the distance between the top of the tyre and the uppermost point of the wheel arch – one finger on one side and 2 fingers on the other. After the spring change I have 3 fingers space on both sides (50mm give or take).

[Citroënbender]

I'd assumed you asked to have them back - bit of a shame for your sake. Did you note the paint daub colours, or photograph them? For ride height the best measurement is hub centreline to a datum mark on the wheelarch. 

It's my genuine fear you are pummelling your new bump rubbers into polyurethane foam dust - hope you can get new struts in there soon!

[Colin Edwards]

Hi Alan,
I agree with CB.  Fair chance the car is now using functional bump stops on a regular basis.  However, if the ride height on each side is more consistent, then maybe you did have a cracked spring. 

Severely degraded damper high speed compression / bump performance can cause excessive strut compression.  Does the front end "ring" / oscillate when you hit the brakes then get off them quickly?

[alanm]

Hi guys, thanks for the input.

The key statement for me there was:
Severely degraded damper high speed compression / bump performance can cause excessive strut compression.

This was the missing bit of information for me – the strut does not just control speed of compression but also the LENGTH of compression.

I will plan to replace them in a month or so, just spoken to a local supplier, they don't have stock at the moment but say that Koni are doing a production run for the GTV in June. It will be interesting to inspect the bump stops when they come out again, I will be prepared to buy new ones if necessary (they are relatively inexpensive).

Cheers,
Al

[Citroënbender]

A degraded damper (worn internal seals, oil molecules sheared, damping washers fatigue-cracked) will require a longer stroke to dissipate the same amount of input energy as the virginal damper of OE specification.  Hence the bump stops get mashed, and why it feels softer now you have new bump stops in there to mash once more.

[alanm]

Hi all,

Concluding my story about my cars crashy front suspension, I have finally fitted Koni STRT and, yes, the problem has gone away! The new bump stops fitted 6 months or so ago had survived without damage though I am sure they were on borrowed time with the old shock absorbers.

I think the ride with new front springs and the STRTs is good, I wouldn't want the car to be any firmer. Someone from an Australian Koni distributer told me that the STRTs are the same as Koni Sport on the softest setting – this seems about right to me based on experience driving my sons 147 with Koni Sport. From a cost comparison point of view the STRTs were a whisker under $500 delivered vs about $850 for the Sport.

From a handling point of view, cant really say, a test drive in the Yarra Valley yesterday was impaired by too much traffic. The car handled well with the worn out parts, I'm sure that it will be even better now!

BTW, the Yarra Valley drive ended at a fellow Club members house and a ride in a 4C. Bloody hell, what a car!  I want one!

Cheers,
Al.