16 valve turbo?

[porschepatron]

I had always been under the impression that all the turbo 4 bangers were 8 valves. But earlier I was flippen through Original 924/944/968 and to my surprise, the later 944 turbo conv was apparently a 16 valve turbo. Here is the quote " The new model used the running gear developed from the racing turbo cup 944s and the proven 2.5 litre 250bhp 16-valve turbocharged motor from the coupe. Maximum torque remained at a stunning 350 Nm (258 ft lb) at 4000rpm, yet fuel consumption could be 25-30 mpg (Imperial) thanks to the Bosch motronic engine management." Did I misinterpret this. Is this a misprint? Not even the 968 turbo has a 16 valve turbo motor! It goes on to say that only 625 cars were released. Isnt it strange that the conv kept almost identical specs maybe it was a weight difference? Just curious.

[Dave951]

Misprint

[porschepatron]

No not 944 S, it's 944's as in more than one 944. The article is talkin about the 944 turbo cabriolet limited edition that was released in 91.

[Porsche 951 Fanatic]

could you somehow put a 16 valve head on a turbo engine?

[Euro Spec944]

[This message has been edited by Euro Spec944 (edited 04-29-2001).]

[1.2gees]

The 16 head will NOT bolt to a 2.5liter block as far as I know. If you start with a 3.0 block, should be no problem.
Ahmet

[topss]

The 16V head will defnitelty bolt on to a 2.5 litre motor. All 87 and 88 944S's are 16V's and 2.5 litres. Many racing guys have been putting 16V heads on 951 motors for a long time. There is slight modifications on the exhaust manifold (the port spacing is exact, just the flanges are different, you just cut the flange plate off the 944S/S2 exhaust manifold and tac it on to the 951 exhaust manifold), and you must use the 951 intake manifold which also needs modification, but, definitely can be done. Supposedly it is a big difference, but the turbo engine can only really benefit from it if producing 400+ horsepower.

[1.2gees]

tops, the 16v head out of a 944S is not a common replacement for the 8v, for a 944 turbo. The 'racing guys' you talk about prefer the 16v head from the S2 instead for a couple of reasons, first being the not so great improvement of the mod, and secondly it's getting harder to find an early 16v head.

However the head from the S2, or the 968 will NOT bolt onto a 2.5 liter (or early 2.7liter, originally with 8v) block. The water passages will not line up between the block and the head.
Ahmet

[topss]

What I just wrote about the 16V head not being beneficial unless making 400hp+, I don't know at what point it actually is a plus, the pros that have done this (Huntley, Powerhaus, etc...) say that unless you are making "big" numbers in hp, (usually 350+ at rr wheels), you won't notice much, but, once you get the big numbers, that it makes a hell of a difference. I have a 16V 2.5 liter S, and was considering swaping a complete 951 engine, but keeping my 16V head, I have talked to Huntley and Powerhause on this, that is what they said.

[topss]

Ahmet, I hadn't read your prior post before I submited my last one, you may very well be right (in fact, I am sure you are), I do know that the earlier 16V head fits (as you said) because I have looked into it with Huntley and Powerhause, and they stated that they are always looking for the 16V head for that type of modification to the 951's, however, I was not aware that the S, and S2 heads were different in passages, (learn something everyday).

[AMCPorsche924Powerhaus!]

Who has done a 16 valve turbo project?
err...is that what 968 rare turbo ones have?



[This message has been edited by AMCPorsche924Powerhaus! (edited 04-30-2001).]

[todd951]

Interestingly enough, the 968 Turbos use the 8V heads.

[Pilot_951S]

Okay lets play legos!

2.5 blocks can take the 8 valve heads, or the 16 valve head from the 87-88 944 S (with some machine work)

2.7, and 3.0 blocks can take S2 16V heads, or 2.7 heads. (with some machine work)

If you have a 2.7 block or a 3.0 block then you can take the 2.7 head, and all the 2.5 turbo plumbing anD make a 3 liter plus 8 valve 944 Turbo with a lot of stock parts. (with some machine work) This is essentially what a 968 turbo is.