5.0 3.55 rpms
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KKeys (03-05-2019)
03-05-2019, 01:05 PM
#12
Senior Member
A standard V6 or V8 without turbos or superchargers is made for spinning up to create peak power. In general, they are oversquare engines as opposed to undersquare engines. The oversquare makes for a bigger bore, shorter stroke, requires lower compression, the pistons move slower and the internals are usually lighter weight. Diesels and turbo gas engines are opposite of that. Their internals move faster, are heavier but require less RPM to create peak power. Which one is better...Both.
Having towed the same 7500lbs trailer with both the 3.5L Ecoboost and 6.2L, they were both good towing engines. The trucks were not apples to apples as the F150 had the 3.55 (reduced to 3.43 with 33" tires) rear end and the F250 has the 3.73 and the 6 speed transmissions were geared slightly different.
My observations:
6.2L - Keep it spinning in the 3k+ range and it's happy. Anticipate hills or long grades by downshifting and there's always plenty of power to keep at speed.
3.5L - Let it do it's thing in tow/haul mode and the turbos will spool. It will hold a gear (5th & 6th) for a long time before it needs to downshift; however, when it does downshift to keep speed on a grade, it will wind up to 3500 as well. My concern was always how much pressure that small engine was under to maintain moving 14000 pounds of truck and trailer.
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KKeys (03-05-2019)
03-05-2019, 03:10 PM
#13
Senior Member
Stop locking out 5th and 6th, put it in tow/haul and let it do it's thing. If it needs to downshift and rev, it will. If it can maintain speed in 5th or 6th, it will. The advice to lock out overdrive is a carryover from when trucks made 220hp and could not maintain highway speeds in overdrive.
03-05-2019, 11:15 PM
#15
Yep the 5.0 loves to rev, let her spin. The 5.4L Triton by contrast is undersquare (more stroke than bore) and reaches peak torque at 3,500 rpm (365 ft lbs). Even with the same 6R80 trans two different animals. The 5.4L has more pull in the 2,000-3,000 rpm range and can chug along at lower rpm. Let the 5.0 rev a little and it will pull good as it’s oversquare (more bore than stroke). Once you are up to speed and flat grade they will upshift and stay in lower RPMs anyway regardless of engine.
This is why the 5.4 & 6.8 Tritons are touted for their towing ability, it’s the long stroke and lower peak torque (thus less rpm). They however lack in top end power and peak fun as a trade off, something the 5.0 excels at.
This is why the 5.4 & 6.8 Tritons are touted for their towing ability, it’s the long stroke and lower peak torque (thus less rpm). They however lack in top end power and peak fun as a trade off, something the 5.0 excels at.
Last edited by ModularFord; 03-05-2019 at 11:34 PM.
03-06-2019, 01:06 AM
#16
Senior Member
I always forget about those '09 & '10 model years. Those 5.4's mated to the 6r80 were good towing machines.
03-06-2019, 01:43 PM
#17
Indeed they are, they used the 5.4/6R setup in the Expeditions from 07-14’ they make a good pair. Wish the F-150 had more years with that setup like the expy, good combo for towing.
03-06-2019, 04:20 PM
#18
Senior Member
When I tow I don't lock out any gears, if the truck is able to get into a higher gear I let it do its thing. If it cant get into a higher gear then well its going to stay in a lower gear so put tow haul on and let it do its thing. Now if you have plenty hills or what not and you cant maintain speed then lock them out, if not just roll with it.
Wayne
03-14-2019, 10:38 PM
#20
Senior Member
Stop locking out 5th and 6th, put it in tow/haul and let it do it's thing. If it needs to downshift and rev, it will. If it can maintain speed in 5th or 6th, it will. The advice to lock out overdrive is a carryover from when trucks made 220hp and could not maintain highway speeds in overdrive.