black98ws6ta

iTrader: (77)

I am thinking of fabricating one for a 03 cobra and was wondering if there are rules of thumb for runner length or plenum volume? In all honesty the only reason I am going this direction with the intake is to showcase some of my fabrication and to have a nice looking manifold. I dont know very much about how the options affect the performance. Here is one I saw on Mod Fords and I dont even really like the look/design.

cracker

iTrader: (1)

This one is for sale. Works forward or rearward facing. Let me know.

Mavmavv

Runner length will move the usable rpm range around of any engine. Longer runners = more tq down low. Shorter runners are for higher RPM applications.

Things that also need to be taken into consideration are the size of the motor. Im not positive, but im pretty sure thats the gist of it.

98Z28CobraKiller

iTrader: (17)

If it's for an FI application, all you need are 2 flanges, 8 4" runners and a plenum box with a flange for a throttle body.

black98ws6ta

iTrader: (77)

I didn't know if something like this would work for the plenum or if it was too small? Most v8's seems to have more plenum volume.

elias_799

iTrader: (8)

i would not mess around with building an intake manifold if it is your first time, especially on an expensive car like that. you can make some of the cylinders run lean and burn your piston rings.

Shawn @ VA Speed

iTrader: (3)

x100000 airflow distribution is the most important part of manifold design.it is also the most overlooked

elias_799

iTrader: (8)

yea and that's why the sheet metal manifolds that are made correctly go for allot of money, not just because they look good.

black98ws6ta

iTrader: (77)

Most of the manifolds look very simple to me...they all have a plenum and equal length runners. It does not appear that the few posted in this thread have anything special for airflow or distribution? I am looking for facts on the subject.

I am confident I can build replica's of all the peices I have came across so far(as far as funtionality goes, maybe not 100% on the workmanship, lol)