Early 99 Intake covers upgrade.

Tail_Gunner

CRJ & ERJ A&P Mech.
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I'm a little delinquent with this, but I recently completed a modification where I replaced the 2" hole early 99 intakes with 3" hole intakes for a 99.5 and later 7.3.

Because the later intake covers have a slightly higher profile than the early ones, I had some clearance problems between the driver's side intake cover and the bottom of the turbo. After some work with a "clearancing tool" (i.e. hammer), and after a couple of test-fits of the turbo, I finally obtained about 1/16" of clearance between the two.

Since the intake hole diameter went from 2" to 3", I needed to get different connector boots. The factory connector boots adapted the 2 3/8" intake plenums down to 2" for the intake covers. So I got some transition hoses to adapt the 2 3/8" intake plenum to the new 3" intake covers. Aside from the clearance issues and the adapter connector boots, the only other issue was shimming & adjusting the fuel lines for clearance between them and the taller intake covers. Everything else was pretty straight forward.

As far as performance improvements, there does seem to be less smoke (i.e. more air) and possibly a bit more grunt at higher boost/ mid rpms . Boost wise, I think my high-end boost numbers have dropped just a bit, but I think I sort of expected that. If there is less restricted airflow between the turbo and the intakes, I would think the boost would drop slightly with the better airflow. I can't say EGT wise if there is any improvement. At the same time I did this mod, I also ditched my post turbo Banks EGT gauge for a new one with the probe mounted in the exhaust manifold. So I don't have a constant point of reference to compare before and readings. But if anything, the intake cover portion will be pre-completed when the day comes for upgrading the turbo.
 
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