Lancia 16v turbo head max BHP/lbf ft

[Evodelta]

Hello,
Really like the new forum!
I'm starting to get the bits and pieces together for a big power integrale engine (I'll post up more of my thoughts and what I have done elsewhere) and was wondering what is the maximum power that you could get a head to provide or support? Is 500bhp within reach with the standard valve sizes? I think it should be, but needed to make sure. I've scourced a good head and would like to get it down to GCRE for you to do the work on in the future.
On a similar note, what are yours/anyones thoughts on the excessive cam shaft end float problem that quite a few 16v heads seem to suffer from? Does it really make the head sound tappety or diesely and is there a known cure for it without having to buy new bearing caps and do the associated machining? (i'm thinking of maybe building up the bearing surface here and the carefully machining it back to within the tolerances) I can't see it detracting from performance, it's just an annoying noise, although It's difficult to say on a worn engine whether you are hearing this noise or the other sounds made by worn valve guides or incorrect valve clearances.

Martin.

[Alexis]

Hello Chippy, see you have made your way over here too :)

I'm going to quote what Guy has said about the headwork he did on mine regarding flow figures...

Head is now ready for guides and seat work, fully flowed.

Flow test final spec on in/ex ports 3 (bare port, no guide only):

inlet 160.3 cfm @ 10", (139 standard), now with full spec in manifold 153 cfm
(loss reduced on final port tidy-up by 3 cfm, was 150 on last test).
To put a perpective on that, 152 cfm is easily enough to give 250 bhp 2 liter 16v normally aspirated - so you can imagine that turbocharged even with very low boost - power will be huge.

ex 125.5 cfm @ 10" (116 std)

E/I ratio with inlet man (ignoring guides as they cancel out anyhow) is 125.5/153 = 82% which is fine. (Sierra Cosworth has incredibly restrictive ex ports and gives only 65% tops in full race trim).

The standard inlet man/port ignoring guides again gives about 139 - 12cfm manifold loss = 127 cfm standard port flow, ex std is 116 cfm so std E/I ratio is about 91% which is way too high.

Hope this helps you Martin and if you wish, can click the link in my signature and you can see what im up to?

[Alexis]

now im replying to myself too :roll:

I believe Guy has also mentioned that one of the greek / cyprus integrale dragsters head flows 166CFM but still good enough to flow 800bhp? I'm sure will Guy will be along shortly to comment anyway :)

[Evodelta]

Hello Alexis,

Yes, it's good to be here, I'm chomping at the bit to post up some stuff, but I'm slow when it comes to computers and am supposed to be working, the down sides of being self employed: No work done = No money!

Well, if a Cossie engine can produce 500Bhp+ with the its more restrictive exhaust ports then i guess we can do as well if not better. I'm itching to get the 16v mapped to see what my latest mods have brought me, but a lack of decent intercooler is holding me back, once I've decided what I'm doing in that department and get some results I'll let you know, in fact, I would like to open up a debate on the subject of charge air cooling.....

I already had a look at you progress, things look to be coming along well :D

Martin.

[ACE-GREG]

Hello my friends and especially hello my friend Guy,
This is my first post here and also i would like to thank Guy for the invitation.

Regarding the Integrale cylinder heads, they have great improvement areas and are capable for more than the following image shows at the wheels at Mustang Dynamometers.
This is from my old motor and my old turbo setup.



Greg

[Guy Croft]

Hi Greg,

it's great to see you here in person.

Now you will have to post again so that the poor members will NOT see Guy Croft posted last, they will see you!

Then I shall sit back and enjoy the show.

GC

[1NRO]

Hello Guy and fellow disciples,

First posting but have been following closely, shaping up very nicely. The wealth of knowledge is great.

The standard shown above is incredible and i only hope i might digest enough to make half those figures.

Martin mentions larger valves, is this possible?

Nik

[Guy Croft]

Hi Nik

at first I was going to write, no, that is such a high flow head that it would be a waste of money. Expensive, sure. But I thought, no, let's examine in more detail. Make a half-decent technical appraisal based on what I know.

Let's take Greg Demetriadis' 16v Lancia Integrale head as a benchmark - the typical bhp etc indicated above, running standard 34.4mm inlet valves. Greg had prepped that head when it came to me for overhaul and he had done a good porting job. The problems with it were valve seat/train - not the porting.

That head on test at GCRE after overhaul flowed 160+ cfm at 10" with valve in at full lift (actual lift confidential), losing only 4cfm compared with the bare port flow (no valves) and this loss is marginal and due partly to a bit of shrounding in the 2 o'clock - 5 o'clock region clockwise the right valve in the shots below. Such a close intersection of valve-in flow with bare port flow tells me that there is not a valve shape or shrouding issue - when you have that - you have to lift the valve very high indeed (way beyond cam capability) to get them to intersect a sure sign that the shrouding is very extreme or the valve shape wildly wrong for that port and throat layout.

If you look at the DB 8V Fiat flowtest you can see what I mean - the heavy blue line and purple line are the same port ssetup after and before deshrouding - the port is flowing the same, but with the purple line the valve is heavily shrouded and the valve-in flow nowhere near intersects the test 7 bare port flow.

So - if shrouding is not an issue with standard inlet valves 34.4mm dia, how much of an issue will it be with say 36mm? Slightly more - is my indefinite answer, there will not be much we can do about it but hopefully the high exit flow regions left of the right hand valve 5 o'clock thru 2 o'clock going clockwise - will outweigh the losses. They usually do.

And can we make the port much bigger than Greg's without breaking thru, no, I would not think so. So our peak flow at any valve lift is capped somewhere between 160+ and 170 cfm at 10" test pressure.

So - what will bigger inlet valves so - well, see the SOHC Fiat plot below a huge difference in flow from low to high lift. In the case of the 16v the peak flow figure will bot exceed our current 160 plus limit - but the flow at the lower valve lift points should be substantially higher - more or less in ratio of valve area , say up to 10% more in some of the range - I say most because I don't think the gains will show up linearly.

Does the 16v Fiat/Lancia head thus also need bigger exhaust valves as well? Probably not, Bit of simple maths will help here:

The flow ratio of std valves (E/I ratio - exhaust to inlet) is over 78% with standard valves, with inlet ports flowed out to a high StII spec of 150cfm or so & modestly enlarged ex ports. Whereas - the valve area ratio of 28.5mm ex to 34.4 inlet would tend to suggest it should be lower - around 68%. (Incidentally the fact that the true E/I ratio is higher suggests not that the ex valves are flowing more than they should - but rather the inlets are not flowing as much as they should - in this case probably a function of port size. )

Pro-rata that to a 36/28.5mm combo - 63% valve area ratio - 7% lower, I would expect to see an new E/I flow ratio with 36mm/28.5mm valves of about 7% lower ie: 75% with a mildy enlarged exhaust port and more with a very large one.

So, in summary, although it would be a very expensive undertaking (don't ask, I never talk prices here) - and the E/I bare port flow ratio would have to be checked before the final decision on the ex valve size, the results might be very good indeed. There is also the quesiton of how well the inlet manifold flows, another series of tests will be needed to make sure the gains from bigger valves are not destroyed by an 'underflowing' inlet manifold.

I don't know of anyone who has done the big vavlve conversion on the F/L 16v head. If anyone has - AND - has the flow graphs, I'd like to hear form them here. I am not interested in just power figures.



GC

[1NRO]

Thanks Guy,

The ability to write such information in the clear way you do can only inspire those who read.

Whats you take on the endfloat problems some 16v heads suffer?

Nik :D