sherry66

If that is the case has not the 16v head been shown to be the much more capable flowing head allowing to run lower boost levels for more reliability ?

sherry66

Patrick has mentioned in previous posts that the stock 16v head on the flow bench saw 352 int & 234 ex at.600 lift , quite an improvement over 8v .

ealoken

16v outperforms 8v on all levels, higher VE, lower cylinder pressure on same hp etc etc. What stops many is all the fabrication needed to make it work.
Getting cash to buy parts is only 35% of the build.
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Thom

Are you sure this was for a standard head?

sherry66

The incoming 8v head we have was flowed at 279int & 211ex at .600 lift @28".

On the same flowbench the stock 16v was tested (at 25") to flow 352int & 234ex at .600 lift. Clearly the 4v heads are way superior than the 2v heads.
Good thread and info Ake, thanks for posting.
__________________

That is how I read it , taken from thread "16v CFM Head Numbers "

Thom

It seems this was posted on the 928 board? 928 4V heads are different from 944S/S2 and 968 heads, with smaller, rounder than oval inlet ports and apparently optimised for peak flow through port velocity rather than volume.
It was my understanding that 944 4V heads usually flow around 300 cfm @28" at stock valve lift (which is far less than 0.6"), though I cannot remember where I saw this figure, most likely posted on here a long while ago.

ETA : I just found the thread, where the following data was posted :

968 / Stock / 28" CFM / Intake
.100 96
.200 199
.300 287
.400 326
.500 347

968 inlet cam allows for max valve lift of 0.433" so we are probably around 330 cfm on a standard 968 top end.

blade7

I don't think anyone doubts the S2/968 heads are superior when it comes to design and power potential. Though the 2.5 16V naturally aspirated 944 engine didn't seem to perform substantially better than the 8V version. I'm guessing a 3.0 8V turbo feels stronger up to say 5k revs, and then the 16V version romps away. But I expect the car spends much more time under 5k than above it, so the 3.0 8V turbo isn't dead yet, especially if you like your engine to look original.

ealoken

My 2.5 8v pulls strong all out to 6800 rpm.
Doesn't die at 5k.
A 16v would just enhance top revs even further.

blade7

I didn't say it dies at 5k rpm, but there must come a point well below 6.8k that the 16v takes over.

V2Rocket

928S4-GT-GTS heads are virtually identical to 944S heads but very slightly smaller ports.

i don’t think a 16v head will allow 0.600” lift so that big flow number may not mean much. It’s been a few years since I looked in depth at it. I seem to recall much over 12mm would cause binding in the head itself

Thom

Well yes, thanks.
It seems they were made in the same mould, with 944S heads slightly opened up on the inlet ports and the water passage with the block machined open.

ealoken

Here is Bas 968 turbo Dyno.

Dutch944

Thanks Erik!
We did one more pull in which we managed 494HP and 570NM.
Be aware that this dyno show 15-20% less than most dyno’s.. The car did 550hp/670NM at 1.2 bar previously on the old dyno of my tuner.

New turbo coming soon…..

blade7

Don't think I heard back from Penguin about his spare calipers. I'm thinking about buying a Vauxhall Corsa hatchback for Mrs blade7, only 205 bhp but they come fitted with 330 mm discs and 4 pot Brembo calipers. Kind of makes me wonder if similar discs on a 400+ WHP 951 would be enough?

blade7

Over 6 months and no update....