Andrew Cooke
16-04-2010, 19:58
I thought I'd start a thread where owners of the various F4R engines could post dimensions they've measured. I've got a couple of bits measured so far, so I'll start the ball rolling. Note that there is a fair spread port to port, so at best these numbers will be +/-0.25mm.
PH1 172 and PH2 172 upper inlets at the face where they join the lower inlets, they're much the same at:
25mm x 46mm
note that the upper manifolds are tapered down to this size, and easily opened out to match the RS lower.
PH2 and RS lower inlets, they are not the same as each other. Note that where the manifold bolts to the head the mounting face is not true to the port direction, I've tried to measure the size of the port rather than the 'gasket' size. (it'll make sense when you look at yours, honest...)
PH2 lower inlet manifold 25mm x 46mm (1050 sq mm)
RS lower inlet manifold 27.2mm x 47.9mm (1144 sq mm)
note that the cross section of the lower manifolds are approximately parallel.
PH2 172 cylinder head inlet port is 29.6mm x 49.8mm (1286 sq mm) at the manifold face, but soon closes down to 2x 25.6mm (1030 sq mm) round ports.
Even though the inlet ports are CNC'd they look a bit crappy on my engine, and not especially consistent port to port. I might be wrong, but I imagine a good cylinder head would bring more power to a standard inlet/ECU engine than a pair of cams.
Over to you lot, plenty of variants to measure, as well as exhaust ports :)
PH1 172 and PH2 172 upper inlets at the face where they join the lower inlets, they're much the same at:
25mm x 46mm
note that the upper manifolds are tapered down to this size, and easily opened out to match the RS lower.
PH2 and RS lower inlets, they are not the same as each other. Note that where the manifold bolts to the head the mounting face is not true to the port direction, I've tried to measure the size of the port rather than the 'gasket' size. (it'll make sense when you look at yours, honest...)
PH2 lower inlet manifold 25mm x 46mm (1050 sq mm)
RS lower inlet manifold 27.2mm x 47.9mm (1144 sq mm)
note that the cross section of the lower manifolds are approximately parallel.
PH2 172 cylinder head inlet port is 29.6mm x 49.8mm (1286 sq mm) at the manifold face, but soon closes down to 2x 25.6mm (1030 sq mm) round ports.
Even though the inlet ports are CNC'd they look a bit crappy on my engine, and not especially consistent port to port. I might be wrong, but I imagine a good cylinder head would bring more power to a standard inlet/ECU engine than a pair of cams.
Over to you lot, plenty of variants to measure, as well as exhaust ports :)