Max safe sustainable RPM

Rdnck84_03

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Yes. ZF5 and 3.55s are great. That’s my current setup.

A buddy of mine has a 95 F350 CCLB dually with a ZF5 and 4.10s. It’s just fine at 80 mph. But the engine is wound for sound on the interstate… it runs amazing though. But, he has a fully built 7.3 PSD making 380 horse and 770 torque… and gets 9 mpg…
That's how my 97 psd is. I get between 8-10 mpg running 65 empty or loaded. If I keep it on the back roads at 50 or less it will get between 12-14 loaded or empty. It would be an awesome truck with a 2spd rear.

James
 

tbowker

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I'll chime in on this one. Since I've owned my truck it's only gone long distance one time, from Wyoming to Florida. After a 500 mile break in period I've stayed at 65mph for the most part, 70 occasionally when passing. At 65mph it runs at 1900 rpm, I have 3.55 gearing. Anything faster and fuel economy plummets beside it getting obnoxiously loud. I read some guys on here talking about running their engines to redline, by the sound of mine, I think it would detonate before it ever made it that far, beside the fact that it seems to have no appreciable gain in power after 2500 rpm. I've pulled trailers a couple of times, nothing more than maybe 8k pounds, and truth be told, it runs like a Cadillac when it has a load. Mostly I just use it as my daily driver going back and forth to work, about 75 miles per day, I use the back roads to try to avoid traffic as much as possible. The interstates here in Florida have 75mph speed limits so I try to avoid those, I know I'll **** people off by only going 65 and most people anymore drive like complete morons. I know some of you guys out there in the northwest frozen tundra have speed limits of 80 or more on your interstates, I'll take my motorcycles that fast (or more) but not this old truck.
 

Brian VT

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I really don't go anywhere but I need to get on the turnpike some times when I do. The speed limit is 70 mph but most are driving closer to 80 mph. My C6 gives me 68 mph tops. I read here that it's fine to run it on the governor so I run it up to 68 and set the cruise control. I don't know the rpms as my tach. doesn't work. It's annoyingly loud. I just pretend that I'm in a lobster boat trying to get home. They sound about the same. lol
 

Rdnck84_03

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Cruise control.... that's another item on the list of things to fix. :frustrate
It definitely makes long distance driving much nicer.

I accidentally fixed the cruise in my 83 when I installed the brick nose steering wheel.

James
 

IDIBRONCO

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Yes. ZF5 and 3.55s are great.
For sure!
7.3 PSD making 380 horse and 770 torque… and gets 9 mpg…
That seems kind of pointless unless he pulls heavy with it most of the time.
Anything faster and fuel economy plummets beside it getting obnoxiously loud.
I can't help with the fuel mileage, but just turn up the radio.
I use the back roads to try to avoid traffic as much as possible.
Those are both GREAT rules of life! I live by them.
Cruise control.... that's another item on the list of things to fix.
I think he was using the governor as a cruise control. :joker:
 

Rdnck84_03

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Hmm, my steering wheel has issues.... wouldn't that be a convenient fix. ;Really
I'm going to guess that the contact points on the original wheel were corroded or otherwise damaged. I actually swapped it because the plastic that held the horn button in broke and I kept snagging it with my shirt sleeves while turning.

I went for the brick nose wheel because I don't like how thin the bullnose wheel is (for my big hands the brick wheel is much more comfortable). Fixing the cruise was just an added bonus.

James
 

IDIBRONCO

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I went for the brick nose wheel because I don't like how thin the bullnose wheel is (for my big hands the brick wheel is much more comfortable). Fixing the cruise was just an added bonus.
I know that it's a not-so-popular opinion on here, but I like the way that the brick steering wheels look much more than the way that bull steering wheels do. I swapped brick wheels into both my Bronco and my Blue truck because the bull ones were ruined. The improved looks, to me, are a bonus. Neither one fixed the cruise. I've only had two or three vehicles that has working cruise so I really don't miss it. Is it nice? Definitely. I've found out that not having or using it helps to keep me awake when I'm tired. A foot dimmer switch helps too. Just a little bit of extra movement or thinking (in the case of no cruise) makes a big difference to me.
 

KansasIDI

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So the general consensus seems to be, high rpm operations may slightly lower the overall life of the engine, and will decrease fuel economy, and increase noise, but overall, no drastic ill effects, correct?
 

The_Josh_Bear

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...I've only had two or three vehicles that has working cruise so I really don't miss it. Is it nice? Definitely. I've found out that not having or using it helps to keep me awake when I'm tired. A foot dimmer switch helps too. Just a little bit of extra movement or thinking (in the case of no cruise) makes a big difference to me.
Between 3 work trucks and my 3 personal vehicles, my cruise works fine on all 6 of them. But I NEVER use it, same reason as @IDIBRONCO . I honestly cannot remember using it once in 10 years...maybe once, just for funsies.

Being aware of my speed and adjusting it bit by bit here and there keeps me awake, I get sleepy fairly easily when driving so I need every trick I can get. I'm getting better! After 16 years as a professional driver I can now go 4 hours without getting sleepy for the most part. LOL That's funny...but not a joke. I used to have a 2 hour limit, and even that was a stretch. Thankfully I'm short-trip local, no way I could do line haul.

Floor dimmer switch for the win! I LOVE THEM AHHH
 

Cant Write

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I am a huge fan of cruise control. Helps me to combat leg cramps and gradual slowing of pace.

I’ve made 2 RT’s back home in my ‘91 suburban without cruise. 16 hours minimum 1-way. It’s brutal without CC IMHO.

To combat fatigue, I gawk and build day dreams off what I see LOL . And when that fails, I buy Giant Brand Sunflower Seeds. Kettle Cooked specifically as it has a fraction of the salt and keeps the “shag carpet” tongue from setting in.:rotflmao
 

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