Tripl7

As the evolution of the cylinder head has come along way from what it started as, being 2 valves per cylinder to 3 to 4 even 5 used by Audi, much improvement has been made. As a mechanic working on domestics Im having a hard time thinking of a modern engine not having 4 valve heads, turbo or not. Even newish diesels run multivalved heads. Whatever the reason may be for variable cam timing, emissions, efficiency, or power it seems to be a better approach than a 2 valve head IMO. I don't think enough 16v engines have been toyed with as far as R&D goes. As cost vs efficiency and reliability is concerned I think there is a fine line on deciding if 16v is a right path to take or not. The limit of these engines is getting pushed higher and higher with better technology, but 16v heads seem to be a dark tunnel for most because of lack of availability/trial and error.
Duke, you seem to have good success with your seasons running a 16v head. I'm willing to bet the 16v head will open a new source of power to these older engines as they get better understood. Am I saying 8v heads are getting obsolete? Not really since they still work so well for most the crowd. My 2 cents for now.

Voith

Maybe I am just too paranoid since I had a valve failure ruin my bmw block before. I got complete S2 head offer cheap and I already have 2.7 with brand new factory sodium valves. Ill have to sleep on it.

Tripl7: Yamaha used and braged with 5 valve tech and they silently switched back to 4. So is audi, but audi probably did it because of direct injection. Maserati made 6 valve head, but it never went in to production.

Dutch944

If you dont take that S2 head for cheap.. I'll take it..

Raceboy

I went to 16v head simply because it is modern, has very good flow characteristics compared to ANY head (not only Porsche ones) and it just looks cool. Also 1981 924 GTP had 2.5 16v turbo motor that spent the least time in pits in 24H Le Mans race.

I knew already back in 2008 when I decided to do an engine swap that it will be 2.5 16v and not plain jane 951 engine

Penguinracer

There are many highly skilled people on these boards & some of you have apllied that skill & considerable time, money & patience to building incredible 16V motors.

I'd love a 16V motor - but I lack the skills, time, facilities & patience to do it myself - so I have to turn to reasonably affordable vendor-supplied solutions - which really mandates a high-spec 8V build.

I hope I'll be happy with the cost-benefit of my build - but I'd never let "16 Valve Envy" detract from the fact that this is the ultimate performance solution for these cars & I applaud those who have applied their skills to making it work.

I also hope that one day a few vendors offer affordable 16V conversion kits - but I think that day will be a long way off - if ever!

Tim

pole position

Ferrari= 5 valve head

Voith

Not any more. They are back to 4.

URG8RB8

We are going to see just how good an 8V head can be very soon! I now have to state an 8V head with the stock valve location since Slate Blue has Over the Topped me! Anyway, pretty much given an open check book to Sid and Dave. Very curious to see what happens. This will be a state of the art 30 year old head. Full Titanium valves and retainers, NASCAR beehive springs, BeCu seats, and anything else they can come up with to reduce weight. Custom Cam and cam tower as well to be tied in with this huge project. Yes, I should have went 16V, but I like the path not only less taken, but never taken! Many animals on that trail that can eat you!

blade7

No I bought it privately from It's first owner back in 1990.

nick_968

Does anyone offer bolt on parts to go with the 16v head yet? The main reason for me to not use the 968 head I have in my loft is simply the issue with the fabrication to make it all work. Other than that I would love to be using a 16v head.

Raceboy

You can use stock exhaust manifold and just make custom crossover pipe to suit your needs. Fabricating a custom intake is essential as the stock one is so bulky. What other bolt on parts do you need?

Swapping in 16v head on 944 is no different than on other cars and some custom work is expected...

333pg333

In my opinion it would make no economic sense for any vendor to build a 16v conversion kit. Not enough buyers for what wouldn't be a cheap purchase. Only LR could afford to think of doing this I would guess. What % of 944 owners would come up with many thousands of dollars to buy such a kit?

It would also depend on what you want to use the car for but even for a nice streeter you will still need pistons, rods, intake, exhaust, turbo, ecu, (MAF?). Add to this any modifications you want for the intercooler. So it's a decent job even in most basic form. Of course having the skillset to carry off much/all of this work rather than pay for it would make a big difference. Same with 8v too of course.

I am still of the opinion that even 350 true hp to the wheels is quite a lot for a street car so the 8v is fine in most cases. Having 500+ like Shawn, Sid and others must be somewhat mind bending at times! I can't imagine how fast our car would feel on the street. Must be a blast but you can get into serious problems seriously fast with that sort of power. Not sure that I'd trust myself with it. Look forward to seeing what Eric comes up with in his Uber Monster!

However this thread isn't about 8v vs 16v. It's merely to point out that 16v's are quite do able and nobody should be scared off persuing one as a project. I'd surely advise going this way on a track car even though our new engine is still 'only' 8v. I believe the benefits outweigh any perceived negatives.

Jay Wellwood

A lot has changed in the decade or so when I started the path to converting a 3 liter to Turbocharged status.

In the beginning days, not much was known. To run a 16V 3 liter turbo, stand alone engine management, custom fabricated intake were the entry points for those with a 944 base. For those with a 968 base, a little more work was involved.

For those in the 968 crowd, using the 8V approach provided probably at the time an easier path to success. Swap a few parts and it was 'mostly' a plug and play approach. Still some work involved, but again (recall this is a decade ago) - not many were conversions were 16V heads.

Does one outlast another - I don't know that there is a direct correlation. Seems it is a combination of factors (driving habits/environment and build condition to name a few) rather than specifically 8V vs 16V.

From strictly a flow perspective, simple math tells me that more surface area for gasses to flow in/out of the combustion chamber = more efficient power production.

Yeah, this is all coming from someone WITHOUT a running 968 Turbo. However, I will add that while I started this process well over a decade ago - a lot has changed. In some ways, this has been a stroke of good luck for me - but I digress.

In the end, from where I stand, it seems it really boils down to a couple of things on which way you want to go (i.e. 8V vs 16V). Which model will host the power plant and what your intended use is.

No doubt either approach will produce endless smiles.

Dave W.

all I can add is that Honda made an engine with 8 valves per cylinder at one time.

Dutch944

THIS!

Still worried about my driverslicense..