Torque peak/rpm range

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Apr 5, 2006 | 05:11 PM

forddaddy

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Torque peak/rpm range

Anyone know where at what rpm a 2003 5.4 makes it's peak torque? I'm looking at changing rear gears on a supercrew for towing a 7000 travel trailer but I'm already turning 2500 rpm @ 62 mph with overdrive locked out. If I change to a 3.73 or 4.10 gear with a 2wd and 16" wheels, where would my rpm's be @ 60-65 mph?

Apr 6, 2006 | 12:15 PM

kspilkinton

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From: South Kitsap County, WA

What's the tire height on the 16's? There are many online calculators to find this information out.

I went ahead and used my stock tire height of 29" to give me the following results -

3.73 - at 65 mph with od locked out ~2900 rpm, with od on ~1900 rpm
4.10 - at 65 mph with od locked out ~3200 rpm, with od on ~2200 rpm

Best fuel mileage is around 1800 rpm

The torque peak is at 2,500rpm, however the engine makes 75% of the 350ft-lbs at 1000 rpm. The torque curve is pretty flat for this engine.

-Kerry

Apr 7, 2006 | 09:58 AM

forddaddy

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Thanks kspilkinton, that's exactly what I was looking for. Great information.

Apr 7, 2006 | 01:38 PM

kspilkinton

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Joined: Jul 2001

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From: South Kitsap County, WA

Glad to help, I have the 2002 engine curves in a gallery. You may not be able to read them very well. They are the same for the 2003 engine.
https://www.ford-trucks.com/user_gal...&albumid=21045
Ignore the gallery header.

-Kerry

Apr 9, 2006 | 01:02 PM

2000BLK54

Tuned

Joined: Sep 2003

Posts: 311

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From: Arkansas

From most of the dyno graphs I've seen the torque peak is quite a bit later than 2500 rpms. Closer to 3200 rpms actually. Even with a supercharger my peak torque only shifted to about 3800 rpms.