You don't say how many miles (or km) your car has done... but when it comes to tuning there are a few things to bear in mind;
1) The car makes its rated power when it's got new "everything", is in good condition, in a lab and with controlled/optimum temperature and sea-level air pressure, with 95-octane, fresh benzina.
If it's too hot or you have low pressure weather, or your car has some worn/dirty components (particularly sensors) and you're running cheap 91-octane and/or old petrol then it won't make the manufacturer's rated figure.
2) Different dyno's can give different readings. Also, if you test the same Dyno on a warm day, and then again on a cold day (etc) then even the same dyno can give different readings. 80-85kW sounds not bad, if Fiat says it should be 90kW when new, at the wheels.
3) If you remove the airbox you are removing a carefully designed component that creates a positive pressure of still air on the atmosphere side of the inlet manifold. You replace it with "moving" air at atmospheric pressure. The gauze/cone filter lets more air through... but at lower pressure.. which is like less air. Nothing ever produces more power than a standard airbox until the standard airbox limits are reached. It doesn't sound like your engine is such a monster yet, so standard airbox might be a better solution for you. Fit a panel filter inside it, if you like the gauze thing.
3b) Gauze/cone filter *oil* gets sucked onto the MAF sensor electrode and makes it less efficient. "Less efficient" doesn't make the car produce more horsepower.
4) Stainless exhaust behind the cat... If you made the bore of the exhaust MUCH bigger than standard then you're increasing the volume of the pipe.... which (unless your car starts producing a whole load more exhaust gas .. i.e. when the engine tuning allows you a lot more revs) then all you're doing is slowing down the gas flow out of the exhaust (imagine blowing through a straw, compared to blowing through a drain pipe).
Slow exhaust means the exhaust gas backs up, and backed up exhaust gas stops the new exhaust gas coming out by itself... it has to be pushed out by the pistons, which is less good than if the new gas can get "sucked" out by a high exhaust gas speed.
As with the airbox, you want the skinniest pipe that doesn't start to restrict flow... which would mean experimenting with different pipes until you find the "best" one (not too big, not too narrow). I know you'll be shocked that the best size for power will be about the same size as the standard one.
5) Kappa manifold .. I don't know it.. but I presume has a bigger bore. See above.
Also if the manifold is a very different length then it can affect the exhaust scavenging.
Harmonising the length of the manifold with the engine causes a low pressure point at the top of the manifold, which helps to draw gas out and makes it move faster. If you mess this up AND your manifold has a bigger bore (see above) AND you fit a wider bore exhaust after the cat then your exhaust gas will move as quick as cold treacle... whereas you want it moving like a rabbit with a rocket up it's arrise.
6) Sport cat and C&B cams I can't find any issues with, other than the cams affect the valve timing, which you know about. If it gives you extra revs, then that suits a bigger exhaust (slightly)... but if your car has the standard rev limiter, a bigger bore exhaust isn't doing anything for you.
It might seem that you put a few "pieces" on your car but it's essentially standard.. some pluses in there.. and some minuses, so you end up with roughly equal power to a standard car. That's fairly normal for bolt-on parts.
You could probably find a few more kW with a standard airbox and standard size exhaust.. but also don't forget the plugs, coils, HT and fuel pressure and flow. These all have to be running optimally. And then stick some 98 octane in (although I think your car is too old to use more than that, so don't waste money with octane boosters or 99-octane fuel). There's probably another 5kW in there somewhere..
Ralf S.
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