Fiat 1108 fire cam change remap?

[tpv]

I was looking at various performance camshafts for the fire engine.
Mine uses the magneti marelli multi point injection.
£30 a year road tax due to low emissions.
I hear these systems are self learning but was wondering if I was to put a 260 degree cam , up from 224 standard I believe would the ECU need remapping and would it still pass the mot emissions test.

I also read that a remap alone could gain 9bhp..... but I suspect that to be marketing twoddle/ plather/ nonsense?!

The gains from the cam change are around 9bhp supposedly.

This is interesting as the fiat 1108 engines in formula 750 make 85-95bhp with single bore intake, control race cam and head work.....they balance bottom end too but that won't really gain power.
The single inlet is one Venturi on a 40/45 dcoe but I'm not sure of the choke size, the standard inlet throttle body is 36mm so would obviously flow as well as a 40dcoe etc with a 36mm Venturi, in fact it looks like a single 55 with a 36mm Venturi!
I wonder what the control cam is duration and lift wise?
Anyone know?
300 degrees 2500-7500/8000rpm?
The 260 is 1500-6000rpm.

 

[bugsymike]

It sounds like you have looked into it quite a lot.
As I understand it to get the sort of Hp those Formula 750 achieve, their modifications mean that the power is much higher up the rev range which is why balancing the bottom end is critical for any sort engine life. This is great if you only use it for racing but for a car used for everyday use it would be a pain with no bottom end grunt, having to slip the clutch to pull away etc.
In the past it used to be possible to buy what was known as a "fast road cam" this gave a good compromise, along with a free flowing exhaust, so maybe going that way and possibly with larger injectors and later remapping?
The Fire 1108 was always a nice free revving engine and a pleasure to wind up on suitable roads even in standard form.
Remapping seems to benefit turbo intercooled diesels much more than petrol engines, but it is more through increased torque and not higher revs, so can actually achieve good fuel economy at the same time if used "sensibly" .
As a youngster where possible a similar but larger capacity engine proved more practical and reliable.

 

[tpv]

Yes I was just thinking about only running at 8000rpm and changing the engine every 3 days! Lol
I saw an old bloke who raced Austin 7 who reckoned matching piston weights is most crucial part of balancing said he was told this by one of the founders of cosworth but I think that's nonsense as the rods also reciprocate, rather the top 2/3 is considered reciprocating so even weighing rods and matching them means where the weight is has to be a factor!

Still get fast road cams from Newman and Piper.
Oh I that Italian company whose name I forget but the price is £100 more than Newman.
I was wondering what the lobe centre angle of the standard valve timing is as the Newman 260 catalogue gives a number.....that I've forgotten!
If it was same as standard it would save £150 on Vernier wheel.

Then there's valve clearance shims.

The 260 was a fast road and standard springs could be used.

They do seem free revving, I wonder if the longer stroke/ bigger engines are?

Tbh I think standard cam and itb's would give 75bhp+
I think I read about a 600 that used 34 or 36mm...
AHH armchair tuning!

 

[bugsymike]

Balancing pistons, rods etc. is all part of it and attention to any rough edges etc. which cause loadings.
I agree re the larger engines possibly slower to rev out, more so if increased capacity by stroke rather than bore.
Fords generally were "oversquare" so revved better than BMC that benefited from more torque in my days.
I had a Ford Anglia 997cc with a 1500cc engine , but put the 997cc flywheel on it as much lighter so it picked up faster, I don't know how accurate it was but the brand new Smiths rev counter used to show around 7000rpm, the car had negative camber , 5.5 J Dunlop steel wheels four branch manifold etc. Great cheap fun on apprentice wages until the rear axle tramp on hard acceleration broke the rear springs, it still had the 997cc back axle.

 

[tpv]

Balancing pistons, rods etc. is all part of it and attention to any rough edges etc. which cause loadings.
I agree re the larger engines possibly slower to rev out, more so if increased capacity by stroke rather than bore.
Fords generally were "oversquare" so revved better than BMC that benefited from more torque in my days.
I had a Ford Anglia 997cc with a 1500cc engine , but put the 997cc flywheel on it as much lighter so it picked up faster, I don't know how accurate it was but the brand new Smiths rev counter used to show around 7000rpm, the car had negative camber , 5.5 J Dunlop steel wheels four branch manifold etc. Great cheap fun on apprentice wages until the rear axle tramp on hard acceleration broke the rear springs, it still had the 997cc back axle.

Did you know that the 997 Anglia had the same bore as the 1500?!! Formula junior used them with a downdraft cylinder head and single carb.
They just used different cranks bit like fiat fire 1.1 and 1.2 that's why I find the 1.1 of more interest.
It actually feels fast on country lanes and mine only has intake and exhaust changes.
I fitted 175-50-13 tyres to lower final drive ratio and so bring gears closer together by 10%
It's got a hornet exhaust.

 

[bugsymike]

Did you know that the 997 Anglia had the same bore as the 1500?!! Formula junior used them with a downdraft cylinder head and single carb.
They just used different cranks bit like fiat fire 1.1 and 1.2 that's why I find the 1.1 of more interest.
It actually feels fast on country lanes and mine only has intake and exhaust changes.
I fitted 175-50-13 tyres to lower final drive ratio and so bring gears closer together by 10%
It's got a hornet exhaust.

I know on a 997cc 105E I took one out to 1340cc by fitting the crankshaft and conrods from a Ford Classic 109E 1340 as they were both three main bearing cranks. It didn't last long as I simply left the 997cc head on it, so even with 5 star petrol still available at the time compression ratio was way up, so it pinked a lot and driven by a young idiot
The 1500 was a five main bearing crank so much stronger.
It was always fun in those days and "tuning" could be done on a shoe string budget.

 

[LeonL]

The ecu should work fine with a 260 degree cam. Emissions won't be a problem. A remap for these engine's mostly add some ignition timing and run a bit leaner. Try if you could find anouther ecu and have that one chipped. Biggest restriction on the mpi engine's are the manicat.

I had a stock 1108 bottom end with spi make 80 with head work and the punto 75 cam and throttle body. Most power came from the exhaust manifold and 2 inch exhaust