Tuning Stance+ coilovers constantly on bump stops

[koalar]

100HP front springs are the same wire diameter and coil pitch as 1.2 Dynamic with air con. But 100HP are cut shorter. That automatically stiffens the springs.
Fiat probably did the same at the rest but mine were too rusty to measure accurately.

The 100 springs are unique , they are not cut down 1.2 dynamic with aircon, I have no idea where this information came from

I always felt the tests were too stiff so fitted 500 springs (allegedly 30% lighter rate). The back end was much better controlled as springs were not over powering the dampers. I fitted the rubber seats to top and bottom to correct the ride height. I also used Fiat coupe bump stops. There’s a little more body roll beg the better ride was worth it.

The bumpstops are part of the suspension on these cars, the 100hp uses a unique, part. They are both shorter and harder

Fiat test under all conditions, fully loaded, just driver, fast flat roads, bumpy slow corners and so on,

Putting 30% softer spring at the rear, along with softer shorter bumpstops, will mean the rear will sit lower when full loaded, braking will be affected, insurance will be invalidated unless declared and premium payed


Proper uprated suspension (not lowered), that are specifically designed for the car is unlikely to effect insurance premiums much if at all

I much prefer the diesel’s ride. It has the 195-50-R15 tyres and steel wheels I had on the 100 HP. The taller ride height and slightly less precise handling means it doesn’t skip over the washboard roads we have down here.

IMO lowered suspension is a complete waste of money and it will ruin if not damage the car. That said, updated rear dampers would be well worth having. But if they exist at all, they won’t be cheap.

Replacing worn out dampers, for OEM will see the biggest bang for buck


@cooperman fitted uprated B6 to the rear and wasn't overly impressed with the results

 

[DaveMcT]

I cant agree that 100HP springs are anything special.
The 100HP front springs had the same coil pitch as the 1.2 petrol - I compared them.
The 100HP front springs had the same coil wire diameter as the 1.2 petrol - I measured them.
100 HP springs were shorter but were otherwise nothing special. No rising rate or any such niceties.

Diesel springs had thicker wire with the same coil pitch as 1.2 same overall free length.

I can't confirm anything about the struts as mine from 100HP were not original. But I do suspect 100HP has different struts. Just as 4x4 is different again and probably diesel is yet another.

Swapping the rock hard 100HP rear springs for softer 500 springs had no visible difference except ride height. That was sorted by using a rubber cushion on both ends. It had the added value of removing bare metal on metal at the spring pans. In my book, that's a win, because the car was much less likely to find a ditch going backwards. The solid rear was downright scary on intermittently roads. New shocks hardly helped.

 

[koalar]

100HP front springs are the same wire diameter and coil pitch as 1.2 Dynamic with air con. But 100HP are cut shorter. That automatically stiffens the springs.
Fiat probably did the same at the rest but mine were too rusty to measure accurately.

I cant agree that 100HP springs are anything special.
The 100HP front springs had the same coil pitch as the 1.2 petrol - I compared them.
The 100HP front springs had the same coil wire diameter as the 1.2 petrol - I measured them.
100 HP springs were shorter but were otherwise nothing special. No rising rate or any such niceties.

I have no idea how you are measuring them

The front springs on the 100HP are unique

Changing things randomly, is rarely a good idea

 

[DaveMcT]

I stand corrected but I stated what I found. Mine kept the original fronts. The rears were tried with softer springs and found to be considerably better handling.

 

[irc]

When I rebuilt a 100hp for someone else (they wanted it COMPLETELY original and were willing to foot the bill), it had the wrong dampers, springs, top mounts and bottom arms in the front - yes, they are all different.
The parts that were on it weren't old, just wrong, and the ride was awful.
The dampers had to he ordered (took 3 weeks, and this was before BREXIT) although the springs were available off the shelf from Shop4parts.
The ones that were on it were the correct length but otherwise looked completely different.
Almost all of the UK-stocked parts I found at the time supposedly for the 100hp were wrong, and were actually correct for the 1.4 Natural Power (which didn't get sold here as far as I know), which is an 8v 1.4 with more in common with the 1.2 than the 100hp.

The difference in ride from random c**p that was on it to the all-new correct parts was immense - you could feel why people loved the 100hp when it was new.

 

[The Panda Nut]

Reason the 100 rides like a brick going down concrete stairs is that the rear bump stops are much longer than the standard car and reduce suspension travel to arounf 2" at which point the car hits the stops, and it does this over every single bump. With pasengers in the back it rides on the stops. The stops are cheaply made and they last but arounf 5 to 10, 000 miles at best. The result is they fall off, one at a time and the car can become dangerous as a result, as it pitches diagonally when only one side is restricted. On a flat road its all fine, and one up its all fine. On UK B roads this was not a good thing. The bump stops are a Fiat only spare as far as I could tell, and silly prices. Springs are around 10% firmer by manufacture and are unique to this car. Dampers are also different to cope with the springs. Restricting the suspension travel makes the ride hard to accept. Fiat coupe bump stops still restrict sring travel but allow about 4" of travel. Febi Bilstein parts are top quality and 1/6th the price. I fitted them and there was no effect on handling other than all 4 wheels staying in contact with the road for longer, and no rear wheel lifting on sharp corners at speed. The car was hugely more stable and the ride much more acceptable. Bilstein B4 dampers to OEM spec work exceptionally well but rattle as they have incorrect bush sizes for the car. Monro were the OEM damper suppliers and their standard parts for the 100HP are excellent. I removed the rattling Bilsteins after just 1000 miles and fitted Monro these were also very good and bog standard for the car. I sold my 100 on at 108000 miles it was still riding and handling well. Normally I like standard spec, but in this case I preferred a little more spring travel. Standard springs and OEM spec dampers retained the cars amazing poise. and ride height. Its a change I would do again and recommend

 

[The Panda Nut]

I cant agree that 100HP springs are anything special.
The 100HP front springs had the same coil pitch as the 1.2 petrol - I compared them.
The 100HP front springs had the same coil wire diameter as the 1.2 petrol - I measured them.
100 HP springs were shorter but were otherwise nothing special. No rising rate or any such niceties.

Diesel springs had thicker wire with the same coil pitch as 1.2 same overall free length.

I can't confirm anything about the struts as mine from 100HP were not original. But I do suspect 100HP has different struts. Just as 4x4 is different again and probably diesel is yet another.

Swapping the rock hard 100HP rear springs for softer 500 springs had no visible difference except ride height. That was sorted by using a rubber cushion on both ends. It had the added value of removing bare metal on metal at the spring pans. In my book, that's a win, because the car was much less likely to find a ditch going backwards. The solid rear was downright scary on intermittently roads. New shocks hardly helped.

I entirely agree with your sentiments on the ride for normal UK roads. My changes achieved the same or similar ends but staying with standard parts apart from bump stops. 2" of suspension travel was a daft idea, and not reallt worth the side effects. Crude restrction of this type is not my idea of great engineering. It worked but was as unreliable as it was silly

 

[koalar]

Reason the 100 rides like a brick going down concrete stairs is that the rear bump stops are much longer than the standard car and reduce suspension travel to arounf 2" at which point the car hits the stops, and it does this over every single bump. With pasengers in the back it rides on the stops. The stops are cheaply made and they last but arounf 5 to 10, 000 miles at best. The result is they fall off, one at a time and the car can become dangerous as a result, as it pitches diagonally when only one side is restricted. On a flat road its all fine, and one up its all fine. On UK B roads this was not a good thing. The bump stops are a Fiat only spare as far as I could tell, and silly prices. Springs are around 10% firmer by manufacture and are unique to this car. Dampers are also different to cope with the springs. Restricting the suspension travel makes the ride hard to accept. Fiat coupe bump stops still restrict sring travel but allow about 4" of travel. Febi Bilstein parts are top quality and 1/6th the price. I fitted them and there was no effect on handling other than all 4 wheels staying in contact with the road for longer, and no rear wheel lifting on sharp corners at speed. The car was hugely more stable and the ride much more acceptable. Bilstein B4 dampers to OEM spec work exceptionally well but rattle as they have incorrect bush sizes for the car. Monro were the OEM damper suppliers and their standard parts for the 100HP are excellent. I removed the rattling Bilsteins after just 1000 miles and fitted Monro these were also very good and bog standard for the car. I sold my 100 on at 108000 miles it was still riding and handling well. Normally I like standard spec, but in this case I preferred a little more spring travel. Standard springs and OEM spec dampers retained the cars amazing poise. and ride height. Its a change I would do again and recommend

The original 100hp does uses shorter bumpstops

They are very hard to come by, none in the UK last time I looked

They get replaced with standard panda/500 which are too long

Fitting the wrong rear softer springs, which they often are, if if advertised as 100HP makes the problem worse, by hitting the bumpstops even more often

 

[The Panda Nut]

The original 100hp does uses shorter bumpstops

They are very hard to come by, none in the UK last time I looked

They get replaced with standard panda/500 which are too long

Fitting the wrong rear softer springs, which they often are, if if advertised as 100HP makes the problem worse, by hitting the bumpstops even more often

That makes sense. The bump stops on my 2009 car were like a 500 bumpstop with a rigid plastic tube around the outside so no give at all. I did buy it at a year old so it may have had already been replaced. I would not ever change the manufacturer parts for something totally different. I think it was you who advised a specialist kit specifically designed for the car and I agree. The 100HP is an amazing tool and Im not sure why anyone would want to risk ruining it with off the shelf universal parts. Even the likes of Top Gear and Wheeler dealers have clearly shown that its easy to make a car much worse by sticking aftermarket universal stiuff on it. I remeber the Renault Espace they tried to soup up being vastly worse after more or less everything they did to it. Even allowing for the TV antics I think this says it all. Back to the OP's original question. To make it better take it all off and chuck it away and go back to stock.

 

[irc]

To make it better take it all off and chuck it away and go back to stock.

...but do make sure they're selling you the right bits for a 100hp.

If you're serious about it:
Find the correct original part numbers from a trustable source (like EPER).
Don't completely trust the website look-up facilities, they are handy, but not always right.
Check if the offered part "also fits" other models... if it says it's the same as a 1.1, 1.2 or a 1.3 (or even a 1.4 Natural Power) then be suspicious.

 

[koalar]

Monro were the OEM damper suppliers and their standard parts for the 100HP are excellent.

Originals are stamp FCA
Part number 1857280 / 50708433

About £70 each

bumpstops are unique

OEM. not cheap or easy to come by


Unfortunately at 15 years old it likely to have some cheaper alternative parts fitted

 

[A3jeroen]

I recall reading about Bravo bumpstops or Barchetta bumpstops.

gr J

 

[The Panda Nut]

I recall reading about Bravo bumpstops or Barchetta bumpstops.

gr J

Almost certainly the same as the coupe. As long ascthe springs are protected from over compression to a heathy extent equally on bothvsides things should ok

 

[DaveMcT]

Almost certainly the same as the coupe. As long ascthe springs are protected from over compression to a heathy extent equally on bothvsides things should ok

This was my attitude. Coupe bump stops did cause a little more body roll but the improvement in grip over rough surfaces more than made up for it. The old stops and hard springs skipped all over the place.

 

[koalar]

No rising rate or any such niceties.

The springs are designed to work in tandem with the secondary springs of the bumpstops

Heres my dynamic on old OEM springs and damper

This car has driven over some of the roughest roads in the UK with climbing gear on the back seat, I hit the front down pipe several times a year and have even turned the clamp upsidedown for an extra few mm, but on roads where I can do 30+mph I have never noticed hitting the rear bumpstops, without weight in the back



Here my car with me a small person in the back, already on the bump stop

This is when the secondary springs comes into play, it now raises the spring rate, it's now part of the suspension, it is properly designed to maintain the correct correct geometry, for both handling, stability and braking when loaded

So instead of an expensive rising rate spring

fiat incorporate the rising rate into the bump stop which they have to fit anyhow,