alright guys im doing a fwd head swap on this new engine,this requires me to use a fwd manifold,but since im not using dis the fwd manifold wont clear the distributor.
so my plans are to build a sheetmetal manifold.im having a hard time finding good info on design though.everything i read for a forced induction engine calls for a short runner,and a mid sized plenum.now i know a short runner is really good for high rpm hp.But i cant find anything that gives me a clear answer on runner lenght vs rpm range.and the fact that this is for a fi engine makes it even harder .

now since this is a 60* engine and the heads are so close together already limits my runner lenght.

now on a fi engine is runner lenght as critical as plenum volume.i just dont want to do this head swap and build a manifold that is gonna make power way outside my rpm range(idle to 6,500 maybe 7k)

but on the other hand since this is a fi motor does it even really matter at all?

heres 2 examples of what i figured i could do something like,if runner lenght is important i would have to do something like the first one to get a longer runner,though i think it would be better suited to a twin turbo setup.

(the first manifold is actually for a 60* engine,the second is used on the 3.8 tta/gn engines)

 

Do you have Engine Analyzer Pro? It lets you enter the runner length and diameter and calculate power based on that. Inlet Runner and Peak Torque Calculator
this is for peak tq but may help.

 

thnx man

 

Is this for boost/turbo? Skip the runners/any harmonic tuning all together and you’ll get a flatter overall powerband that will be easier to tune.