Inlet manifold

[number1]

I was just wondering how good the original inlet manifold is, ive heard about changing the inlet runner lengths on an engine to change "wave dynamics"
However im slightly confused about it, Anyone shed any light on this? the article i read about it was kind of confusing lol

Dave

[Laine_16v]

Cant say ive seen that done to an F7 inlet manifold before.

[number1]

Ive only ever seen one F7P/R with a custom inlet, just wondered weather it was worth looking into making one but if the standard one is good enough

Dave

[Laine_16v]

Well the standard one is fine upto 200bhp, then you need to look at alternative inlet methods.

[stan]

The standard on is cack by all means.

pulse wave effect is used to optimise performance at certain engine speeds. This is achieved by changing the length of the intake runner. basically as the inlet valve opens the pressure differential created by the moving piston creates a "wave" which travels from the back of the valve to the end of the runner, where it then returns. the aim is create a returning wave as the inlet opens again on its next cycle. this will boostcylinder filling. as said, the length of the runner determines the time taken for the wave to travel its length, as does the engine speed. its therefore possible to "tune" the length to optimise cylinder filling for a given rpm. this is typically easier on inlet set-ups where each cyl has a throttle plate, but on a plenum set-up it isnt so easy. You will also tend to encounter idle issues with high duration cams due to the same effect.
Also with a plenum set-up, torque is affected by volume and chamber shape. as with most associated tuning paths, theres plenty of theory on it, but for real gains it takes alot of real test time on the dyno to find an optimum for your set-up.

[number1]

Would be better off on bodies then, i read that when using an inlet manifold with a throttle body on one end it causes the end cylinder to recieve more air than the closest one to the tb? or is it the other way around? surely this would cause certain cylinders to run lean/richer than others or is the injector pulse corrected?