1999-2004 4.0 Intake Manifold Question.

[streetxj]

Nobody has put the '99+ intake on a flow bench and seen what it really does. From the design of the '99+ intake, the inner 2 runners, 3+4, Are a little shorter and straighter than the outer 2 runners, 1+6, and probably flow just a little bit better than 1+6. They probably added the extra material to the injector bosses of the inner 2 runners, 3+4, to slightly restrict their flow so to equalize the flow of all the runners. Having unequal air flow between the different runners is bad. Having the inner runners flow more air will make those cylinders run leaner. Tuning will be a compromise at best with each runner flowing different amounts of air.

Somebody please put this '99+ intake on a flow bench.

The inner runner injector bosses are still a bit larger than the other injector bosses. The size is actually much closer to the runner #2 and #5 injector bosses. Still a bit larger though and even though I grinded down the side bumps in the #3 and #4 runners a bit, they are still there. So, the "equality" factor is still there. If it was a problem, I think my jeep won't run good. It runs much better now, compared to how it ran with the stock log intake manifold.