| Re: Intake Plenum for a 260Z
Made some air boxes and manifolds for MGB s with single webber.
The trumpets came within about 25mm of the lid.
The top end was fine with or without lid.
Bottom end lost about 5HP with the lid on until about the mid range then it was ok again.
The solution was put 60mm holes directly over the trumpets in the lid,covered the holes with K&N filter.
What appeared to be happening was the wave from the intake at low rpm was traveling out and hitting the air box lid and sending it back early.
The holes allowed it to pass and solved the problem.
So Ron what I am suggesting is if you do have a room issue the box ends up flatish in shape,check it with and without the lid on at the dyno to check if you get the same problem.
Any one that has made air boxs would say that $375 is not that bad as it can be very time consuming.
all the best
Jim |