There are no formulas to predict the performance or optimise the performance of the design of a header. This is because the exhaust gases are moving at, or have portions moving at transonic speeds....
I wouldn't be using an Apexi Neo for ITB tuning. Firstly, find someone who is comfortable with tuning ITB's. Then buy an EMS they are comfortable tuning with. It is very difficult to tune ITB's and...
Which timing belt did you use? Are you using a stock cam gear? I would check mechanical timing. Is the oil pressure sensor plugged in? Are you using the stock throttle body?
No, I’m actually glad that you’ve stuck with a SOHC. I actually encourage more people to build them instead of swapping to a B or K because they’re so fun and cheap to play with not to mention they...