Way back when the Coupe was first introduced in 16v format, it was widely acknowledged as one of the best FWD chassis of its time. The relatively lightweight Lampredi lump meant the car was pretty well balanced, although it still suffered the perennial FWD handling issue of the weight being strongly front-biased with the usual tendency to understeer near the limit.
When the 20v variants were launched in late '96, the handling was improved slightly by virtue of a faster steering rack, but this was partly blunted by the extra weight of the five-pot lump.
Let’s deal with the elephant in the room first – regardless of the model, the Coupe’s suspension design is flawed. It uses MacPherson struts at the front and a trailing arm with separate spring and damper at the rear. This is fine for a small hatchback (ie the Fiat Tipo on which the Coupe is based), but it’s not a good platform for a neat handling sports car. “Proper” sports cars normally use double-wishbone suspension at all four corners.
Over the years, time has not been kind to the Coupe and many cars are still running round on original suspension leading to claims of poor handling. If your Coupe has suspension that’s more than about 5 years old, it won’t be at its best and you may be looking to do something about it.
Before we start, let me make it absolutely clear that in my opinion, the best handling Coupe for everyday road use is one on standard suspension, standard ride height, standard wheels and standard geometry. The key is that all components need to be in good condition, which few standard cars will be by now. So - before you start reading the handling modification section below, think very carefully about what you want from the car, and consider refreshing your car back to as-new standard spec - you'll be completely amazed how good it is.
On the basis that you're still reading, you're probably interested in modifying the handling characteristics of your Coupe, so let’s break this down into some basic categories.
1) Springs & dampers
2) Chassis bracing
5) Anti-roll bars
Firstly, if you have a Coupe that you feel isn't handling correctly, consider #6 before spending any money on modifications. Many weird handling traits can be traced to poor geometry, caused by one or more of the following:-
• Worn wishbone bushes
• Incorrect tracking
• Excessive negative camber
• Worn rear trailing arm bushes
Assuming that everything is as it should be, let’s now consider modifications, but with one big caveat – it’s just as easy to make things worse as it is to make them better – be very careful because it’s quite easy to spend a lot of cash and end up with a Coupe that handles worse than it did before your credit card hit its limit.
1) Springs & Dampers (not shock absorbers)
Changing springs normally changes two things – ride height and spring rate (ie they make the car lower and more stiffly-sprung). This will help on two counts – the centre of gravity will be slightly lower and thus it will be more resistant to body-roll. Additionally, the spring rate will be higher, which further reduces body-roll. A third aspect is that the car will feel more solid on the road, which can sometimes give the impression of handling better, even though the only change is that it’s become more jiggly to drive.
The purpose of dampers is to prevent the car from oscillating up and down for ages after something causes suspension movement. Dampers are generally “tuned” to match the springs that they are associated with, so it’s very easy to screw up the handling by having mis-matched springs and dampers. For example, fitting uprated dampers with standard springs can cause ride-height to reduce over a series of short, sharp bumps, as the damper doesn’t allow the spring to return to full length in time for the next bump. Conversely, fitting uprated springs with standard dampers may cause “wheel- chatter” over sharp bumps, as the damper struggles to control the stiffly sprung wheel.
I’ll save the difference between compression damping and rebound damping for another day, but suffice to say that the vast majority of aftermarket dampers have either fixed damping, or one-way adjustability (ie the adjustment device adjusts both compression and rebound damping at the same time).
Something worthy of mention is that when a MacPherson strut is compressed, the hub follows an arc as transcribed by the lower wishbone. It is desirable that the wishbones is angled downwards to the wheel when the car is at rest, so that as the wishbone moves upwards, the arc is taking the wheel very slightly away from the centreline of the car – this increases the negative camber on that wheel, which is generally a good thing. Once the wishbone passes the horizontal, any further movement is reducing negative camber. On a Coupe, the wishbone is close to horizontal as standard, so reducing the ride height by fitting lowering springs means that suspension movement is always reducing negative camber at the same time, which is unavoidable, but undesirable. The key here is not to overdo the lowering – Coupes don’t like to be “slammed” as todays yoofs call it. They also look bleedin’ awful when they’re scraping the floor, but that may just be the old git in me…
• Road car – stay standard, but renew with good-quality components
• Fast road car – lower by 25mm max, uprated dampers
• Occasional track car – as above, but possibly with adjustable damping
• Track car – good quality coilovers, with adjustable damping (preferably two way)
2) Chassis bracing
Later Coupes (LEs and Pluses) came as standard with a strut brace, which shows that Fiat recognised what we all knew from the start – the Coupe is not a stiff bodyshell (just try parking with one wheel on a kerb and then open a door – now try closing it again and you’ll notice it makes a different clunking noise – that’s the door hitting the striker plate differently because the shell has twisted once the door was opened).
Handling improvements can be made by stiffening the bodyshell. The ultimate is to fit a full weld-in cage (check out some of Begbie’s threads about this). However, this is not cheap or easy and isn’t particularly practical for an everyday car. So, we’re looking at bracing.
In my opinion, there are only two braces that make any difference. The strut brace and the front subframe brace. Anything else is purely cosmetic.
The strut brace bolts to the two suspension turrets under the bonnet and prevents them flexing in and out towards the centreline of the car when the suspension is loaded. I cannot remember a single Coupe owner that said they couldn’t feel an improvement after it was fitted. There’s some discussion about the merits of the Sparco “bendy” brace versus others such as OMP, but that’s for another time.
Think of the front subframe as a squared-off ‘U’ shape, with the legs of the ‘U’ pointing forward. The lower suspension arms are bolted to these legs, so under longitudinal forces (ie accelerating or braking), the legs have a tendency to flex in or out, which in turn changes the steering geometry. This unwelcome effect can be reduced by closing off the open end of the ‘U’ shape by bolting a brace across the gap, turning it into a square.
The other braces I’ve seen are rear braces, which mount across the two rear upper seatbelt mounts. This is at least a foot from the nearest suspension component, so cannot have any discernible effect on handling. The other brace, which is farcical in the extreme, is a floor brace that bolts between the two B-pillars down by the lower seatbelt anchor. Work out for yourselves why this may not have much of an effect.
The only other modification I’ll throw into this section is poly-bushing. I’m utterly convinced that poly-bushed front wishbones make a huge improvement. I’m less convinced that rear subframe bushes are in improvement against NEW standard bushes. However, this article is about mods and improvements, so I would say that poly-bushed rear subframe is a notable improvement on the 15-20 year old standard bushes that you’re probably using right now!
• Road car – upper strut brace
• Fast road car – as above, plus poly-bushed front wishbones
• Occasional track car – upper and lower braces, plus poly-bushes front and rear
• Track car – rollcage plus all of the above
Let’s be truthful, most people change their wheels for purely aesthetic reasons. It’s difficult to deny that in the age of 18” wheels as standard on a lowly Corsa, the Coupe looks a little “under-wheeled”. However, the Coupe was designed to work best on 15” or 16” wheels, so think carefully before you whack on a set of 18s.
There are four aspects (other than aesthetics) that should be considered when deciding what wheels to buy.
Personally, I would argue that #4 has the greatest effect on handling (although getting #3 wrong can have a huge negative effect)
Wheel diameter is a compromise as soon as you move away from the standard wheel size. In order keep the rolling circumference the same, you’ll need to reduce the aspect ratio of the tyres, which will lead to a firmer ride (as well as more expensive tyres…). The firmer ride might actually be a benefit though, as there’s less tyrewall deflection when cornering, which can give greater steering precision. One benefit of increasing diameter is that there’s potentially more airflow into the inner wheel area, which is better for cooling the brakes (which is pretty poor on the 20VT)
Wheel width is a compromise as soon as you move away from the standard wheel size. As well as probable issues with offset (see below), you might run into problems with clearance against bodywork or suspension components.
Whatever you do, don’t fit wider wheels so that you can fit wider tyres, thinking they will give you more grip – they won’t (see the tyres section below)
Offset is a huge issue on Coupes, especially the 20VT variants (due to the Brembo calipers). Get this wrong at your peril, as a wheel with the wrong offset will completely mess up your handling (as well as giving you loads of torque-steer, which the Coupe is famously pretty devoid of)
Weight is one of the biggest aspects of wheel design that most people don’t pay much attention to (the aesthetics are usually at the top of the list). The issue with wheels is that it is un-sprung weight, which has a huge effect on the efficiency of suspension. It’s also rotational inertia, which changes the ability to change the direction of the wheel (remember your secondary school physics?).
• Road car – standard wheels
• Fast road car – Standard, or maybe 17” wheels – no heavier than standard
• Occasional track car – 17” lightweight alloys – standard width, or maybe 0.5” to 1” wider
• Track car – as above, but make sure they are tough, as road alloys can crack when repeatedly used on saw-tooth kerbs
This subject could fill dozens of pages on its own and is highly subjective, so I’ll express my own opinion and you can take from it what you want.
Nigel’s Golden Rules
• Buy the best tyres you can afford, (but don’t waste money on better tyres than you need)
• Never buy part-worns unless you are 100% confident of the history (ie you know and trust the previous owner).
• Never mis-match tyres across the same axle – asking for trouble
• Try to match all four tyres – front-rear balance is just as important as left-right
• Wider tyres don’t give any more grip. Yes, it sounds counter-intuitive, but it’s correct, I assure you. Wider tyres give different grip, but probably not enough that you would notice on a road-going Coupe. So – stick with something close to standard width (ie for a 20VT, go for something between 205 and 225 width)
• Pay attention to the aspect ratio – putting 205/55 on because they are cheaper than 205/50 may seem like you’re saving money, but you’ve just increased the sidewall height by 10%, which will cause all sorts of side-effects, ranging from incorrect speedo, rubbing against wheelarch liners, and more tyre deflection leading to a less precise feel for the car.
Personally, on a stock Coupe, and even on the “base” non-turbo models, I wouldn’t entertain anything less than “mid-range” tyres (Falken, Kumho, Toyo, Avon, Uniroyal, Vredestein, to name a few). Occasionally, a tyre from these manufacturers turns out to be as good as tyres from the premium category (for example, I use Uniroyal Rainsport 3 on my daily drive Alfa GT and they are amazing, especially in very wet conditions).
On a coupe that’s being used for enthusiastic driving, I’d always recommend premium brands (Pirelli, Dunlop, Continental, Michelin, Bridgestone, Goodyear).
• Road car – mid-range brand – NEVER use budget tyres
• Fast road car – top-end of the mid-range (eg Uniroyal Rainsport, Toyo T1-R). but preferably a premium brand.
• Occasional track car – Top-end premium tyres on all four corners
• Track car – spare set of wheels with trackday tyres (eg Toyo R888, Yokohama AO48, Michelin Pilot Sport Cup)
5) Antiroll bars (ARBs)
This is another counter-intuitive area, where what you would expect is the exact opposite of the truth.
Let’s start from the blindingly obvious. The Coupe will understeer as standard. Reducing this understeer is desirable, but only up to a point, Going too far will result in a car that oversteers, even though the “wrong” wheels are being driven. This is fine if your surname is Plato, but it’s not a good idea on a road car.
You should also consider that there is a finely-tuned balance between the front and rear ARBs
Counter-intuitive revelation – to reduce understeer on a FWD car, you need to increase the stiffness of the rear ARB (or by a process of elimination, reduce the thickness of the front ARB, but this isn’t so easy). However, you can only go so far before the reduction in understeer turns into oversteer. At this point, you have two choices – increase the front ARB stiffness as well, or back off a little on the rear.
For the Coupe, the choice is limited. Front ARBs are limited to either a Lancia Dedra or Eibach. For the rear, there’s a bit more choice. There are 22mm, 23mm (very rare – I believe only Novitech made them) or 24mm ARBs.
• Road car – standard ARBs at both ends
• Fast road car – Standard front, 22mm rear
• Occasional track car – 23mm rear
• Track car – either a 24mm rear on its own (which will make the car very “pointy”) or a 24mm rear with an uprated front to balance it out a bit.
Another area that is highly subjective and very much down to the preferences of the individual. Bear in mind that you don’t have a lot of choice with the geometry on a Coupe and even some of the basics below will require mods (eg camber bolts, caster-adjustable top-mounts). However, here are my experiences:-
I have played around with geometry on my Coupes for years and have found that it’s possible to get “ultra-stable” right through to “feels like a rwd car, on ice, with slicks” and almost anywhere in-between.
“Ultra-stable” is great for big, wide-open circuits (think Silverstone GP) or fast A roads. It’s also the only setting I would use on a top speed run at an airfield (you’d be amazed at how vague a Coupe goes at over 175mph if the geometry is set up for cornering performance).
“RWD-mode” is huge fun on tight twisty circuits or B-road blasting, but it’s scary at anything above 120mph in a straight line and downright dangerous in 100+ mph sweepers.
For “Stable” try:
• 2mm toe-in
• Standard camber and caster (or maybe even extra caster if your top-mounts allow it)
For “RWD-mode” try:-
• Parallel toe
• 1.5 to 2.0 degree negative camber
For the best balance between the two, my everyday settings are something like:-
• 1mm toe-in
• 1.0 – 1.25 degrees negative camber
There are two other items that I can think of that might fall into this category (or at least don’t easily fit into any of the above categories. I’m not going to going into any depth for any of them, as again, they are an entire subject in their own right. All should be pretty self-explanatory though.
• Brakes – I’ve seen many Coupe owners spend serious amounts of money making their car go faster and not pay any attention to helping it stop. If you want to cover ground quickly, good, reliable brakes should be on your list (in fact you could take the view that they should be done first before any go-faster bits)
• Limited-slip differential. The Viscodrive on the 20VT is great for handling 220-ish bhp, but it can wear out and it can easily be overwhelmed by a decent increase in power.
• Driver training (either track tuition or IAM for general road driving). Another of Nigel’s Golden Rules! Every pound spent on driver training will result in better / faster / safer driving than a pound spent on modifications. Seriously – don’t under-estimate just how much faster you’ll go when you’ve been taught by someone that REALLY knows what they are doing. I would go as far as to say that a well-trained driver in a standard Coupe will beat an average driver in a well-modded Coupe.
Any one of the modifications in 1) through to 7) above will improve the handling of a Coupe. However, they are very complementary and should be considered as a whole, not as a collection of separate subjects. For example, if you fit a 24mm rear ARB, set the camber to -2 degrees, put good tyres on the front but average tyres on the rear and decent brakes on the front only, you WILL be going backwards at the first corner you try to take quickly. It’s a balancing act and as I mentioned right at the beginning, it’s easy to get it wrong.