Raceboy

It's the exaust cam that interests me, can I use 944 S ex. cam on S2 head?

Chris White

they are physically interchangeable and it will work but they do have different lobe patterns.

Raceboy

Thank you, Chris White.
I'm sure you know the characteristics of each cam, could you tell it to me also?
Did a search on this, and came up that S exaust cam has less duration but no numbers.

951and944S

Exhaust cam on 87-88 944S 16V -

Opens at 36 deg. before BDC
Closes at 4 deg. before TDC

Exhaust cam on 89+ 944S2 16V -

Opens at 39 deg. before BDC
Closes at 7 deg. before TDC

944S and S2 cams are interchangeable, 968 cams have different sprocket tooth count that would require mods to use the 968 chain tensioner.

TS

smarlow2

I just had the engine in my 87 S rebuilt and the builder (a retired Porsche factory mechanic with over 40 years of experience) put an S2 cam in it and the car runs better than it ever has. It definitely picked up some torque and has better throttle response. This was a $6700 top to bottom rebuild on a track car.

V2Rocket

sorry to revive an ancient thread but if these numbers are accurate...basically Porsche took an "S" cam and advanced it 3 degrees to run in the S2?

I know S2 guys put "S" cams into their cars for some easy power as it is hotter...is it because the 3 degrees of relative cam retard makes the top end a little nicer? I think the S/S2 intake cams are the same?

Which exhaust cam would be better for boost purposes...S or S2? I would think S2, to blow less incoming boost out the exhaust port.

H.F.B.

A short look into the technical specifications reveals, these numbers are indeed accurate. But notice the difference regarding the identification on the camshaft.

V2Rocket

so the S2 intake cam has 8 degrees more duration?
and it looks like the S2 exhaust is in fact the S exhaust, advanced 3 degrees.

at first glance i'd think the "S" intake cam would be better for boost, because it has 7 less crank degrees to push the charge air backwards out the valve. is that wrong analysis?

exhaust cams seem about the same since by the time those are opening, all the useful work has been taken from the combustion. the S2 is nice because it might give you a hair more valve clearance as the piston comes back up...

Jay Wellwood

Holy Old Thread Revival Batman.

It's been several years since this thread was last updated/posted to.

Has there been any real world experience since then?

The 16V turbo projects becoming more popular over the last few years would lead me to believe that there is new info out there regarding S vs S2 cams, and which combination yields the best results.

V2Rocket

since this thread was active more aftermarket camshafts for the 16v engines have become available.
stock 944 cams are tiny and you're really giving up a lot using them still.

due to age too, aftermarket cams aren't all that much more expensive than finding a good stock set anymore...
https://webcamshafts.com/pages_vehic...rsche/204.html
https://dbilas-shop.com/en/engine-va...8-2-5-3-0-16v/
there's a third vendor i can't recall as well.

Jay Wellwood

Cat Cams?

http://www.catcams.com/engines/engin...anufacturer=19