Cheers Jim,
Bit nervous about responding, this forum is blessed to have some of the worlds best and most experienced sohc people contributing, if i'm not on the money I,m I hope they put their two bobs worth in for all to share.
Re cam and carb selection from flow figures:
I think its about knowing what you want to achieve. If you have a goal you can use a combination of resources to achieve that goal. This forum, component suppliers, experienced technicians or mechanics, technology like engine design software, exhaust design software and flow bench, dyno tests this forum, racing on track or street. Some people have confidence in the local hotshot and buy or choose based on that, others can never be satisfied unless they are continually experimenting for a better combination. Flow figures are another tool or rescource used to form part of a matrix. The matrix forms a big picture, your goal hopefully.
So if hyperthetically the matrix consisted of bore , stroke, compression, air in, air out, valve sizes, fuel mixing device, exhaust, cam specs and your goal is x hp or torque , life is easy you just use the above tools and it wont take long to find out what you need.
Where I'm going with all this is in the old days the person who changed the most cams, carbies, exhausts, pistons, hogged out the most heads etc was generally the wisest and fastest. Whats changed for most older , wiser , experienced , racers is the number one modern tool, COMPUTER, COMPUTERS and COMPUTERS.
Its a cheap way ( $50 to $1,500) to get a lot of experience quickly, modern computers & engine design software only give back what you put in. SO.... they need information like whats in the matrix to give you the ponies.
You dont need flow rates for these software packages but if you use them, they make the final figures very very accurate and reliable results encouraging you to buy or make what is in the matrix.
Porting and cam selection was traditionally a black art, arty farty stuff really veiled in secrecy but these days with internet there are a lot of publications and info around and more people have a basic understanding of porting. Flow cfm information is a reliable way to compare, air speed through the port can contribute to carb selection, cam selection can be fine tuned using those matrix parts in a software. In my humble opinion the one thing that hasnt changed is you need an artist to make it happen. Physically shaping is a real art, it takes special tools the same skill and mindset as an artist who paints a nice canvas painting. Over the last few months I have read every thread on this forum and the the most exciting thing for me is looking at the port pics, there is so much good sh#t on this forum if you look. My artistic days are over but I enjoy the rush of seeing nice port work, its the artistic side of engine building.
Jim Ive been out of the scene for a long time but the call of the sohc and reading threads has rekindled the spirit and I am having a real rush fooling around with a speed project. This solidworks CAD is un Fcukin beliveable, the port pics above are just snap shots, on the PC screen those mass of dots are a mass of moving colour and everything is just so easy to interpret, I used to spend hours mapping a port and writing the numbers on a bit of paper but it was difficult to get a clear picture in your head on how the port looked as a whole. This sh#t is not cheap, I paid about $14 grand for the licence and I made sure it had a flow test function , now I,m getting serious and starting to understand how things work I find out its not that accurate, say 5% either way, I queried with the dealer and he says mate you need the specialised flow testing upgrade for your software, another bloody $14,000. hmmm I'm thinking something within 5% will be a good indicator, once I get the port close to where I want it I might try the ol one off free trial on the good sh#t programme.
Jim a thread this long is probably not good thread etequette, but sh#t mate I live in the middle of a desert an feeling lonely, oh by the way, in answer to your question , yes.
