Hi everyone,

I've got to make an inlet manifold for my engine because i can't get one to fit under the bonnet. Does anyone know any theory of manifold design, or any resourses on 'tinternet?

I did find this:

"If you are going for top end power then the short manifold is the way to go, the longer manifold gives you a better mid range of power loosing out a bit at the top end. So the choice is limited. If you wanted more top speed you would use a shorter manifold , and a longer manifold for maximum torque. Also the straighter the manifold the better."

Cheers

No its a little bit more invlolved than that, you set the optimum length to the revs you want to gain most power from. then you have to match the cams and exhaust etc to gain the most. I know an excelent website and ill post it here as soon as i find it.

Heres what i was looking for, if you look down for my posts.... the first one gives a poor and simple description of tuned intake lengths and the theory. My next post after that has a link to another site which gives it in much more detail. thats really where you want to look. The maths is involving and if you need a hand then im sure therell be someone on here wholl help, i just about get the maths.

As you can see theres more to it than simply short manifold and long manifold, the F1 guys do it to within mm tolerences to give the greatest boost.

http://forum.locostbuilders.co.uk/xmb/viewthread.php?tid=3394

Total ram length (inches) fron the lip of the ram pipe to the lip of the inlet valve = 228 x Inlet timing in degrees divided by the max power RPM minus 500

Piper tuning manual