Recently read a review of the 1.4 16v stilo engine. It says the Compression Ratio is 11.1. Seems very high for a "standard" car ( Most fiats seem to have quite high CR's tbh ). Anyone have experience in just how high you can take this ? :tempt:

I think my 2.4 has something like 10.5? ...... I want it higher though

Crazy Horses said:

Recently read a review of the 1.4 16v stilo engine. It says the Compression Ratio is 11.1. Seems very high for a "standard" car ( Most fiats seem to have quite high CR's tbh ). Anyone have experience in just how high you can take this ? :tempt:

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Yep the 1.4's compression ratio is 11:1, www.carfolio.com is my web destination of choice for things like that

You probably can't take it much higher as it's an interference type engine, skimming the head will bring valve clearances dangerously close. Why not just get the head ported and polished and fit a tuned decat manifold? www.jaex.co.uk did one for my 1.2 Stilo (same engine as 1.4 essentially) which was originally made for the mk2 Punto 1.2 16v, it's really has proved to be a worthwhile investment

That's right. I'd leave the CR well alone.

They're difficult to port (read expensive) but some reports say that simply knife edging the inlet side will improve top end. Tubular manifolds and Polish cams are out there.

Remaps are possible, but they're said to throw rods at 140bhp or so, so don't go nuts.

1.4 16v engines in Centos, untouched internals, tubular mani, bigger TB, aftermarket ECU, generally put out 110bhp or so.

fingers99 what larger TBs can be used with the 1.2/1.4's in the Stilos with Bosch ME7.3 ecu? I'm fitting a 1.4 in mine in place of the 1.2, going to be swapping the manifold over but not sure what, if any, larger TBs can be used with it? If not I'll just remap and be content

I'd guess any modern FIAT one. Needs to have the same general type of
throttle stepper motor and IAC -- and you'll need a remap. Marea,
maybe?

If going aftermarket ECU, you can literally fit anything, so cheapo
48mm Dell'Orto TBs off K Series Rovers are a popular choice.

Had read the K series throttle body could be used or even a Punto one. Also read the porting side of things can be a bit of a hole in the wallet as too smooth a surface is actually negative and the Exhaust ports should NOT be touched. Could try and look for the articles if anyones intrested. But I'm sure I'll just be preaching to the choir.
Skimming was an idea harboured back in the grey matter, but depends on the safety margin, surely there is some give..? Perhaps High CR could be compensated with higher octane fuel ?
No point changing the Final Drive ?

MarkThompson4 said:

You probably can't take it much higher as it's an interference type engine. www.jaex.co.uk did one for my 1.2 Stilo (same engine as 1.4 essentially) which was originally made for the mk2 Punto 1.2 16v, it's really has proved to be a worthwhile investment

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Excuse my ignorance but whats an interference engine ? I have experience ( by ownership ) with A and K series engines but thats about it. What was the cost involved ? If you don't mind me asking.

Crazy Horses said:

Excuse my ignorance but whats an interference engine ? I have experience ( by ownership ) with A and K series engines but thats about it. What was the cost involved ? If you don't mind me asking.

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An interference engine is where the valves (when shut) overlap the piston crown, you can tell an interference engine from a non-interference type engine by the pattern on top of the piston crowns - there are four grooves on top of the pistons where the valves sit when the piston reaches TDC - this is what the "interfering" is. So if the valve timing was slightly out then the valve stands a good chance of not closing in time to fit in the groove causing it to touch the piston and bending the valve stem. Also lowering compression ratio by skimming the head brings the valves slightly closer to the top of the piston, increasing the risk the valve has of touching the piston and causing the problems mentioned above. A non interference engine is the opposite - where the valves don't overlap the piston so valve damage is unlikely if the timing is out.

The manifold cost me £215 back in February 2012, don't know if he still makes them but I'm sure he could make one to the same spec if requested. It requires an extra section of pipe off the down pipe onto the flexi join as the flanges on the flexi and the back of the manifold don't meet (I'm guessing this is because it was made for the shorter Punto model). It improved gas flow no end, bottom end torque is still there and the high end is good, it's a steady build up of power and there are no flat spots, though I've noticed the exhaust note changes and the power kicks in when your foot is on the floor and you cross 2000rpm, it's not a lot faster but sounds great and is a lot of fun

Thanks for the reply, it's all a learning curve. First Fiat I've owned.