Hey ga16freak, have you already been able to find custom intake to your GA? Or have you made it by yourself? I'm also trying to find some info about intake manifolds for GA but seems that there is quite like nothing available. I have alo been trying to calculate/simulate some working intake but it seems to be a lot harder task than exhaust manifold design..
So every bit of an information you have been able to dig out would be very much appreciated!
oh, and ofcourse I will also share my research&development data.
When I pulled my stock intake manifold off, you would have to have alot of attachments for the air regulator, the small coolant hoses for the throttlebody, the EGR valve and BPT valve is located on there. By the way, the EGR is built into the runners of the intake, so you would have to design that into the manifold. Also, you have the radiator hose under the intake manifold and alot of smaller 5/8" hoses to consider that hook into the lower manifold.
I have pics of when I pulled the entire manifold apart. I think that doing this makes no difference and if you polish the runners, you get 3 HP max. not worth the silly putty 300+ dollars to run the putty through from Extrude hone.
I think you can design this with Autocad and make one, but you have alot of things to re-locate like the EGR and BPT and hoses and such. I think this is a big reason why aftermarket did not attempt this. you need to make alot of extra brackets and maybe re-locate hoses and design new bends in hoses, a really big deal.
o2 induction makes them for the sr's so try them. if you have a b14 you do not have to worry about the air regulator and if you are in a non emissions state, you would not have to worry about the egr either.