RPMs question
Thread Starter
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Senior User
Joined: Jun 2009
Posts: 140
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From: Solon, Iowa
RPMs question
New to diesels. Just got an 03 F350 Dually with the 7.3, no mods yet. I did my first long pull (about 100 miles) with my horse trailer--trailer is about 15,000 lbs with 3 horses in it. I went into a kinda hilly area to see how the trailer would do...pulled really strong and steady...not great acceleration, though. Anyway, I have the 4:10s rear end, and I pulled not using OD because I was in the hills. To run at around 60 to 65, the RPMs were at about 2800. Is it okay to run these 7.3s at 2500 to 2800 RPMs for extended miles? Just don't want to overwork the engine, and don't know if that's okay or not.
One other question. Trailer squatted the bed about 3.5 inches total. Is that too much...do I need air bags? The front end stayed firm on the ground, and no steering problems...just don't know if 3.5 inches is too much of a rear end squat. Drove great and looks pretty level, though. Thanks for any thoughts.
One other question. Trailer squatted the bed about 3.5 inches total. Is that too much...do I need air bags? The front end stayed firm on the ground, and no steering problems...just don't know if 3.5 inches is too much of a rear end squat. Drove great and looks pretty level, though. Thanks for any thoughts.
Postmaster
Joined: Jul 2006
Posts: 3,754
Likes: 1
From: Indianapolis
While 2800 rpms may not be good for fuel economy, these trucks can definitely take it. You can even run in OD if the tranny doesn't shift back and forth due to hills. Mercury marine actually used to used the 7.3 for a boat engine, and it was redlined at I believe 3600 rpm!! And they run hi rpms all day in a boat. And they rear end squat is ok, just make sure you're not resting on the bump stops and you'll be fine.
BTW- welcome to FTE! When you get a chance, you can do some improvements to your new rig, like starting with a 4" (or bigger) exhaust, new intake (NO K&N!!!) and then if you want gauges (first) and then a chip, recommend a DP Tuner (NO BANKS). You can gain about 40 hp just from intake and exhaust alone- try that in a gas truck! Stick around and get to know the awesome folks here, and you'll learn like I did, how to save $$$$ on repairs.
BTW- welcome to FTE! When you get a chance, you can do some improvements to your new rig, like starting with a 4" (or bigger) exhaust, new intake (NO K&N!!!) and then if you want gauges (first) and then a chip, recommend a DP Tuner (NO BANKS). You can gain about 40 hp just from intake and exhaust alone- try that in a gas truck! Stick around and get to know the awesome folks here, and you'll learn like I did, how to save $$$$ on repairs.
Thread Starter
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Senior User
Joined: Jun 2009
Posts: 140
Likes: 0
From: Solon, Iowa
Thanks Mongo...that makes me feel a little more comfortable. I go horse camping all the time, and pull a 15,000 lb. trailer in some fairly hilly areas...most trips are about 3 to 4 hours, and I was just worried that running the motor at 2500 to 2800 rpms in 3rd gear would put too much stress on the engine...but in the hills, I can't use overdrive, which drops the rmps to around 2100. Thanks for the input. When I hook the trailer up, I've got plenty of room left before I hit the bumper pads...so I think I'm okay with the 3.5" squat.
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
If you really want to perk it up, get that intake & exhaust opened up like Danny said, and since you're pulling fairly heavy, get the trans cooler upgraded, and I also highly recommend the TransGo Tugger in your situation. Those two things REALLY helps the trans live a lot longer! Also get gauges somewhere along the way, sooner rather than later. The stock trans gauge is a POS. It's no help.
After that, look at tuning. I like my TW tunes personally.
After that, look at tuning. I like my TW tunes personally.
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
...or Bill from PHP (Power Hungry Performance) or DI (Diesel Innovations) or Cale at BTS (Brians Truck Shop). There are several good tuners out there. No reason to settle for off-the-shelf crap.
