improving roadholding of your Fulvia.

[Fulvia-hf]

Last thread I started was about extracting power from the beautifull V4.
This time I would like to start a discussion on improving roadholding.

My HF again has some period mods and some next century ones.

Period Mods fitted when I bought the car in 1993:

Shortened upper A-arms. (creating 1deg negative camber)
Flavia steering arms (period mod to reduce steering ratio from 4.25 to 3.75 revolutions from lock to lock)
18mm Front anti sway bar (as taken from the Flavia 2000)
Roller articulation between the front leafspring and the A-arms. (HF part)(Rideheight adjustable with shims.)
Berlina 1C rear disks (flat steel centre mixed with cast disk) shaved to 10mm. (Period mod to reduce unsprung weight)
Front disks skimmed to 12mm. (again reduction of unsprung mass.)
Ferodo 300 pads.

next century uprades:

Adjustable Spax shocks allround.
16mm rear anti sway bar (custom made)
Composite leafsprings (save 15kgs)

All in all a lot of parts deviating from the design of the original Fulvia Coupe which was allready so good to drive

With al these mods the HF is fun to drive and compaired to other period classics the steering is very good but compaired to a modern hot hatch it is still slightly mushy and bumpy at the same time. The springing is firm but the 80 section tires lack precision when compaired to modern low section tires. Unfortunately there is not much choice for high performance tires in the narrower 13" sizes and I do not want to sacrifice the beautifull Campagnolos for larger and wider rims.

I wonder what others have done to their chassis.

William

[KeppelmanJ]

I'm not sure how many of your mods are effective or desirable on a street car. Personally, I'd ditch the heavier anti-sway bars because they will make the ride choppier. Also I'd go back to the rubber block between spring and upper A-arm. The rollers may be useful on a track where bumps are not an issue, but on the street you will feel bumps more and likely keep the tires on the road less. Having shortened the upper a-arms (rather than lengthening the lowers) you may have clearance problems doing it, but I'd trade your Campys for 14's (X 5.5) in a lower section and somewhat wider tires. Not familiar with the shocks. Are they tuned to the spring rates? For FWD the Fulvia is awfully good on the street as it is in original guise, and it is, after all historic. Buy a WRX?

[1,6 HF]

I'm with Johnny on the upper A-arm rollers--not for the street. Other than that, I already have a couple of those "improvements" as standard; 1.6HFs already have negative camber (longer lower A-arms) and a quicker steering box. And I do have Ferodo 300 pads, which are excellent. I'd also agree with Johnny about the anti-roll bars; the standard HF bars work well without compromising ride.

Original-size tires (175/80-13) are unobtainable, so I run one size larger (185/80-13) on the standard 6" alloys. And I'm running Michelin XAS, which stick like glue--they grip far better than the 185/70 that were on the car when I bought it, and the gearing is better for the street. Michelin XAS have the added advantage (for those who care) of being the original fitment (optional on non-HF), so they look right on the car, and they're also available in 165/80-13 (but no longer in 175-13).

I'd certainly agree with William on the use of gas pressure shocks. Spax makes good units, and the adjustability would be a plus. But I managed to locate an NOS set of Corte e Cosso gas pressure shocks, as originally fitted (and as used on the works cars). They made a remarkable improvement over the red Konis that had been fitted previously--better ride and the wheels maintain better contact with the road.

I'd love to save 15kg, but for the street, it would be hard to justify composite springs. But I'm in the process of rebuilding the entire front suspension, and I've learned some interesting things. When we pulled my front transverse spring apart, the #3 leaf had both ends sheared, but still held in place by the leaf above. And when we source a replacement, that replacement spring also had a broken leaf (#4, so we were able to replace my #3)--sheared in exactly the same way.

The shearing appears to be due to induced stresses caused when the spring leaves cannot slide freely enough relative to one another. This seems to be due to added friction from even minor corrosion, and embrittlement of the plastic interleaves. I would be willing to bet that half the Fulvias on the road have at least one broken spring leaf in the front transverse spring, for the same reasons we found in mine.

So I'd strongly recommend stripping down the spring, replacing any broken leaves, blasting and repainting all leaves, and replacing the plastic interleaving with PTFE (Teflon) strips before reassembling with white lithium grease between all surfaces. As mine's just going back together now, I can't report on the results, but I expect a significant improvement in ride, plus better spring response.

[KeppelmanJ]

I have not had a broken spring, but I did find springs to be consumables in racing. Even with the car lowered and the bump stops cut, springs sagged to the stops within a year or so of use. I swapped in used ones with similar spring rates, tested by using a hydraulic press and pressure gage. But best of all was having a new spring made up, stock number of leaves and rate by an outfit in Seattle called Gitts. That one held up w/o further sagging. Swapping front springs in and out of a Fulvia on a regular basis is a real chore!

[Fulvia-hf]

All in all plenty of reasons to swap your cumbersome front springs for a single leaf composite spring! It doesn't sag or rust and can be changed a lot easier as the free arc of the spring is just over 4 inches. No internal friction due dirt accumulating between the leafs and no breakage risks. And light at just 2 kilos.

For the purists among us, including myself, I can say that it takes a keen eye to spot it in situ. the rears can be spotted though but on the other hand can be replaced by the OEM springs when desired. Nothing changes on the car.

William

PS At the moment they are not for sale and as far as I know my HF is the only Fulvia in the world sporting composite springs.
When there is a demand I will investigate if these one-off springs can be made available to you.

[Dave Simons]

How about some photos, specially the springs?

[ncundy]

My father looked at composite material for the propshaft on his Aurelia a few year a ago. It was very expensive as there is really no "after-market" industry in this area in the UK. The ball park figure was £2000 ish. Similarly cart springs haven't been used on cars in Europe since the mid '70s so again no after-market industry.

However in the 'states cart springs have been used very successfully to date, particularly on Corvettes (which have composite springs fitted OEM). Consequently there is a thriving after market industry in this area in the USA. Whilst a special will always be more expensive than a production item if you were interested I would suggest a first port of call should by the USA.

A set of composite corvette springs is about $300.

Although very interested in the technical details, I am not interested in modifying my car to this extent my self, I don't see the point unless competition is intended. Also I suspect the quickest route to reducing weight on my car is me going on a diet :)

William - I had a good look at your car at Goodwood (I assume it was yours ?). Very rare and very nice, and no I didn't spot the springs :D

[Fulvia-hf]

Hi Neal,
Reducing UNSPRUNG weight by going on a diet is very hard;-)
And yes it was probably my car you saw on the pre'66 carpark. Is was rather dusty as we just came back from a 10 day camping holiday in Cornwall and Devon.
There were rather a lot of Lancias there at goodwood. Especcially Aurelias were abundent. And the Lancia Ferrari D50 on the track had the best sound of them all!

William

PS can anybody help me with how to upload the pictures Dave requested from my harddrive? I´m not so digital as I want to be I´m afraid..

[Fulvia-hf]

Hi, I'm back on the thread this time with pictures! Fortunately the webmaster was able to tell me to scroll down the message posting window to see the box "manage attachments"
Hopefully it works.
Let me know what you think.
William

[1,6 HF]

Interesting. You really need to be looking for it to spot the composite spring.

[Fulvia-hf]

What struck me most when I first lowered the car off the ramp was the fact that when I pushed the front end of the car down it just came back within a milimetre from its previous stance. There is no stick slip at all!
The steel spring stays at least one inch compressed and you need to lift the car to get it back to the original height.
This feeling is compairable to coilsprings which obviousely also don't have internal friction. The shockabsorbers need a different damping setting though as this lack of friction needs to be compensated, at least on the way up, by firmer rebound. The adjustable shockabsorbers for the Fulvia being Koni and SPAX claim independent rebound adjustment but do really also firm up the compression at the same time the rebound is stiffened up.

You really want shocks adjustable for rebound and compression with two separate adjusters. Koni can produce them and I'm having this theory checked by them coming spring.
Cheers
William

[ncundy]

Hi Neal,
Reducing UNSPRUNG weight by going on a diet is very hard;-)


Yes......I know; it was self-depreciating joke ;)

With your roller bearing on the front - did you use a straight roller bar or a series of sealed ball races on an bar ? I've seen it done both ways over the years, whats your opinion? Do you use it to adjust ride height ?

[Fulvia-hf]

As you can see on the picture I replaced the roller for the stock rubber when installing the composite spring. the reason being that I need to think of an anti wear strip under the leaf as the material is quite soft and the roller would therefor eat its way trough it in a couple of months. The roller I used is an original HF item as is cast in the casting. With spacers under the casting the ride hight can be changed. I replaced the original bush with bronze insert for a row of 5 sealed bal bearings as the roller would catch to much road dirt to keep it 'roling'.
William
PS and like many responses to this thread claim the rollers aren't really suitable for road use. This due to the sticky response of the leafspring. This will make the front end even more crashy. I have confident in the composite spring in this regard as there is no internal friction. I will start to work on the anti wear strip. I'm thinking about 0.5mm titanium glued to the leaf extremity.

[fulviafiend]

Love the idea and appreciate all the hard work done, but is it me or are we talking some serious technical modifications here… once we get into these sort of changes we are beyond road use and into proper competition territory?

FF

[Fulvia-hf]

That depends. I use the car mainly on the road and just have visited the 2006 Lancia centenario and more recently the 2009 Goodwood revival with it. Including full camping equipent for two weeks without problems. It's just that I'm an aircraft ground engineer by trade and love to think out technical solutions. I do not have the proper degree however to be able to calculate all these ideas but use the trail and error method when there is no data available. It works well most of the time and if not I revert to the original set-up as I always keep in mind that this is a special and rare Fulvia and therefor keep my modifications allways fully reversible without drilling holes or welding brackets.
William

[ncundy]

William,
Thanks for those. That is similar to the ones I have seen over here - bearings rather than bar.

[ecoangel]

An alternative to the Rollers is period mod that was used on Flavia Sport race cars - the front spring is attached to a lower silent block BUT not on A arms. This would work on CF spring without wear issues.

[Fulvia-hf]

I don't quite understand. You mean the rubber block is attached with the two studs to the leaf but not bolted to the A-arm? Is that side deprived of the suds sliding over the A-arm then?
William

[ecoangel]

YES!

Just put a little lubricant under the rubber to A arm joint - it is free to slide.

[Dave Simons]

YES!

Just put a little lubricant under the rubber to A arm joint - it is free to slide.

Does that mean that the lower plate (of the vertical rubber column) and the 2 studs are removed?

Getting the corner weights right usually means shimming the spring/arm blocks, or selecting the right ones. Having the rubber moving relative (if it doesnt buckle) to the arm sounds like a recipe for variable handling, depending on the wear rate of the rubber!