Engine diff: '03 Expy and '03 Navigator
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Engine diff: '03 Expy and '03 Navigator
Why does the 5.4L in the '03 Lincoln Navigator make more power than the same engine in the '03 Expedition, and can I make those changes to my Expedition?
I notice that the Navigator is spec'ed to run on 91 octane, vs. 87 for the Expedition? Is it just a matter of software?
Sorry if this is a FAQ.
I notice that the Navigator is spec'ed to run on 91 octane, vs. 87 for the Expedition? Is it just a matter of software?
Sorry if this is a FAQ.
New User
Joined: Apr 2003
Posts: 2
Likes: 0
From: Oklahoma
Engine diff: '03 Expy and '03 Navigator
Actually it's not as much to do with the 4 valve head as it is with compression ratio. If you'll notice the 5.4 Nav has a comp ratio of 9.5:1...thus the 91 octane requirements. The 5.4 Expy has a comp ratio of 9:1. There in lies the bulk of the difference.
However if you read the specs on the Nav it rates the 300 HP engine at 4750 rpm or maybe 5000 rpms. The 260 HP Expy is rated at 4500 rpms. This would also cause some discrepany in calculation of HP.
I would be willing to venture a guess that if one could "tweek" the PCM to advance the timing (Hypertech upgrade) this could effectively raise the comp ratio and thus HP. Hopefully within the next year or so we'll see a PCM upgrade for the '03 Expy.
Cg
However if you read the specs on the Nav it rates the 300 HP engine at 4750 rpm or maybe 5000 rpms. The 260 HP Expy is rated at 4500 rpms. This would also cause some discrepany in calculation of HP.
I would be willing to venture a guess that if one could "tweek" the PCM to advance the timing (Hypertech upgrade) this could effectively raise the comp ratio and thus HP. Hopefully within the next year or so we'll see a PCM upgrade for the '03 Expy.
Cg
