944 S2 (3.0L) Intake Swap on 944 S (2.5L)

[j1nx3d]

I have an S2 airbox in my '86 944. it is indeed noticeably tight. I will change to a large pod filter in time. I do wonder about airflow into there, whether I do get enough compared to an S2 or Turbo. I have a 924 turbo vent panel but I am put off on using it because of potential water ingress from rain.

[walfreyydo]

Just wanted to bump this thread with some of my own personal experience of swapping a 968 intake on my S2. I did this swap prior to swapping over the 968 head and to be honest I did not feel much of a difference, but I did not dyno it either. This was on an otherwise stock 89 S2 (with AFM removal already done previously).

In order to do this mod you will need the following (in addition to the 968 intake of course):

1) 968 throttle body and throttle cable: the S2 throttle body will bolt up, but the throttle bracket/cable mount is different on the 968 intake requiring the 968 throttle body and throttle cable in order for the linkage to work.

2) S2 dampener relocation -OR - 968 fuel rail: the 968 does not run a fuel dampener, and therefore does not have the bracket mount on the 968 intake manifold for the S2 dampener to bolt to. I ended up having to zip tie the dampener to existing hardware so it didnt flop around (not ideal). The other option is to run a 968 fuel rail and ditch the dampener.

3) S/S2 head port matching (optional) - the intake runner ports on the 968 intake manifold are larger than those on the S/S2. This is because the intake ports on the 968 head are larger than those on the S/S2. This essentially means you can not take advantage of the larger runners on the 968 manifold unless you port match the intake ports on the S/S2 head.

I believe the HP differences between the S2 and 968 really primarily come from a) the larger intake valves/intake ports on the head and b) variocam. The 968 also has a 0.1 higher compression, but I dont think this makes a huge difference. I do not believe the intake, despite the dual resonance design, really has that big of effect on HP on its own, and is really meant to supplement variocam and the larger intake ports/valves, which is where the real gains are being made.

[stitch2k1]

The 968 also has a 0.1 higher compression, but I dont think this makes a huge difference.

I have been told this was because the head was shaved, and pistons are identical. Dying to get my hands on a 968 head next to this S2 head I have so I can compare. Lol