Markus, Johns Tipo had a ported head, 3 angle seats, high comp pistons forged rods etc, all it did was detonate, I know I have his head I know what was done. But if you read my reply I said 'but with the same stuff around it it would have produced the same output? ' i.e. no change in cams etc, just without the head prep - the answer would be no, i'm not sure what you're trying to get at??

And in regards to you second comment
'Surely though you should have considered forged pistons and Forged rods Why go to all that effort and use standard fiat internals?? doesnt make sense to me '
It doesnt make sense to you because you are only looking from a road point of view, but if you go to the LMA Eurosaloons website, download the rules for Production Modified Class C you will see Forged rods and Pistons are NOT allowed in my class, thats why I dont have them. If you want to quiz me on choices please PM and I'll tell you what you need to know (to stop me from hijacking any more ), I have an answer for pretty much every choice I made, trust me the car wasnt thrown together .
Thanks
Rich

Well that would make sense to me - the car is only going to be as good as it's weakest link, so any 'restrictive' element is going to reduce flow at the top end and the peak power figure that goes with it. Perhaps someone with a bit more in depth technical knowledge could comment on this?

Apologies for reviving such an old thread, but reading the discussions between Flea and sediciRich it seems that some questions about VE were rasied but left unresolved, so I thought I would give my view on the situation, as whether spending money on head improvements represents good value is a question that may people might like the answer to.

The engine in question is the four cylinder Tipo engine with a 16 valve head, which is essentially the same as the 16 valve Coupe head.

I got some figures from the Carfolio website about the basic engine output:

Max Torque 135 ft/lb @ 4500 rpm
Max Power 143 HP @ 6000 rpm

sedichiRich had his engine remapped by GG and the figures were:

Max Torque 178 ft/lb @ 5122 rpm
Max Power 184.5 BHP @ 6042 rpm

sediciRich also has the flow figues for the head, which were 126cfm before modification and 148cfm after modification - flow figures taken at 10" depression of water with the same cam and lift. For reference, bare port flow improved from 136cfm to 158cfm.

The modifications improved the bare port flow by about 16% and the improvement with the valve in and at full cam lift as about 17.5%. However it is interesting to note that on a fully developed engine (i.e. optimum compresion ratio, cam, inlet tuning, exhaust tuning and fuel/ignition mapping) a four cylinder engine with 126cfm per port should be capable of 216 BHP and with 148 cfm 254 BHP. The calculations for this I have checked across multiple sources in the UK, USA and Australia.

Now, looking at the peak power output, there has been an increase from 143 BHP to 184.5 BHP which is 29%. The increase in peak torque is from 135 to 178 ft/lb which is nearly 32%. That, simply, is a 29% improvement in VE at peak power and a 32% improvement in VE at peak torque.

The standard 3-door Tipo cam has a lift of 9.57mm and the C&B cam a lift of 10.2mm. The C&B cam also has longer duration, though I'm not sure of the exact figures for both cams to compare them. Either way, I would expect the longer duration and higher lift C&B cam to improve breathing, so improving torque, and raise the engine rpm for both peak torque and power.

The other modifications include improving flow in the inlet manifold, to match the flow capability of the head, and of course careful mapping of the fueling and ignition.

And so to my conclusion - which others are welcome to challenge!

In my experience, on a normally aspirated car, modifying the fuelling and ignition to match 97 RON in a road going car mapped for a lower grade of fuel does show an improvement, but nothing like 32% - in fact the best I have ever seen was going to 99 RON Tesco and the gain was about 7%. Changing a cam will also improve power output, but usually with a cost to low down torque. Again, I have never seen a 32% gain in power from a cam change.

So the head work has to have contributed to the increase in output from this engine, but as the flow improvement (best) is 17.5% at peak cam lift, I cannot see how the headwork can have contributed any more than that figure to the overall power output. However, the headwork seems to have made the largest single contribution to engine output.


post scipt

I believe that something is holding this engine back from making more power beyond 6042 RPM. The engine is still making 180BHP at 6800 rpm, but the torque is dying away pretty fast once it has peaked at 5122 rpm. I would expect a flatter torque curve than the one produced.

At peak power, assuming 12.5:1 fuel ratio, the injectors are past 82% duty cycle with batch firing. At peak torque the injectors are at about 78% duty cycle. I would certainly want to try larger injectors, though the turbo injectors were apparently too large. (n.b. neither of the duty cycles above allow any time for injector opening latency - they are calculated assume peak flow for the full duration of opening)

I have read nothing about the exhaust manifold, and that could be the problem. I guess it could even as simple as the standard exhaust cam holding things back through lack of scavenge lift/duration. It may be the runner lengths on the plenum are too long. I'm not sure what it is, but with the peak torque shifted from 4500 to 5100 rpm I would expect the cam to shift the peak power up by a similar number of revs, from 6000 to 6600 rpm or higher, as cams usually grab the whole torque curve and shift it towards higher rpm. As that's not happening, something else is preventing it in my opinion.

Can someone be more specific how much mm can i grind from the head intake ports?
By far i grinded about 1 mm intake-towards-valve, and i don't know where the limit is......can't risk damaging my head.
Great topic, as GC said - All the power is in the cylinder head.....

A well considered post g5l. Yes something was holding it back, in tuning terms the std ex manifold although the new engine was over 200bhp on std manifold but fitted with throttle bodies and race colombo's. The engine you are referring to suffered serious detonation at the hands of some moron dyno operator who I will not mention so in the remap the engine was already damaged with top rings clamped in the grooves and significant blow by (catch tank was testament to that). In the newer engine there is no doubt that the exhaust is the biggest restriction not only in pure flow but with pressure wave mismatch to the inlet tract. Money was the limiting factor, and as I no longer have 2 beans to rub together it will sadly stay that way .

a pic for you G5l http://img.photobucket.com/albums/v74/sediciRich/tipoeng005.jpg