ATOM_X ATOM X said: alanoo said: winstar said: While I'm here I'm intreaged how you intend to use the Z20net pistons and rods with a z22se crank to get such a high compression ration I actually don't see any reason why it shouldn't work, rod big ends are the same, + at stock there's a lot of clearance at TDC so it could be a very easy and smart solution; not sure how it would cope with aftermarket cams. Only issue I can see is that these pistons are not designed for such a low rod ratio / angle and the pin/rings position may not be ideal for a long stroke engine; may lead to heavy slap, friction and skirt wear if this is the case the rods are longer than SE's sorry that should read rod & piston assembly is longer
OAKMERE alanoo said: exmantaa said: Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...) ;-) The port design is indeed not ideal for high RPM power but... 7000 is not "high" rpm, the ports are not that small too. Even not ideal does not mean that it will not work at all 🙂 On the .org too I read someone saying the Honda K20 were ports hugely bigger, this is not true, they are only very slightly bigger. the BTCC ports are actually not a lot bigger than stock too, The exhaust ports are a much much bigger issue than the inlets Alanoo It was me that thought the k20 inlet ports were much bigger than the z22se but I could well be wrong I will take another look when I am at Phoenix next month.
ATOM_X OAKMERE said: alanoo said: exmantaa said: Very curious to these NA results, bearing in mind some comments I read about the Z22SE's port design not very good for high gas speeds... (Read: high NA power...) ;-) The port design is indeed not ideal for high RPM power but... 7000 is not "high" rpm, the ports are not that small too. Even not ideal does not mean that it will not work at all 🙂 On the .org too I read someone saying the Honda K20 were ports hugely bigger, this is not true, they are only very slightly bigger. the BTCC ports are actually not a lot bigger than stock too, The exhaust ports are a much much bigger issue than the inlets Alanoo It was me that thought the k20 inlet ports were much bigger than the z22se but I could well be wrong I will take another look when I am at Phoenix next month. the more important ccnsideration is that the exhaust throat can equal the sum of the valves my calcs are 25.5mm x 45.5mm that means NO back pressure All my SAAB heads have this size throat but I am reticent on the VX so I just open up to the gasket
alanoo Illustrating a bit, all showed on an all new untouched z20net head BTCC 2001 Z22SE exhaust ports (264 bhp spec) Fully opened right into the SAI ports BTCC 2004 inlet manifold ports (285 spec) Almost not ported at all as you can see...
exmantaa Interesting exh manifold flange... :thumbup: Any pic of the exhaust ports on that BTCC head?? Edit: read the "standard Saab head" part now, but curious now how they utilized the SAI ports in these heads.
