what is your engine's highway speed happy place?

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Oct 20, 2005
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I'll be digging through the 250,000 mi transmission soon and it will be an opportunity to consider any gearing change "while I'm in there"
I am running 35's (which are actually 34.3"OD) and while a bit under powered off the line or trying to pass - which I don't really care, and which could very well be from the 250,000 mi engine - at indicated 70 mph which is probably more like 74mph, I'm showing about 2300 rpm and the engine seems satisfied there

Is there a rpm number for highway cruise that this engine works best at?

thanks
 

COYS

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37s 4.88s, 1mph off gps verified here. 80-5mph is the sweet spot all day.

227F9C83-0CEF-4476-AF62-7474D6BF4714.jpeg
 
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I'll be digging through the 250,000 mi transmission soon and it will be an opportunity to consider any gearing change "while I'm in there"
I am running 35's (which are actually 34.3"OD) and while a bit under powered off the line or trying to pass - which I don't really care, and which could very well be from the 250,000 mi engine - at indicated 70 mph which is probably more like 74mph, I'm showing about 2300 rpm and the engine seems satisfied there

Is there a rpm number for highway cruise that this engine works best at?

thanks

Dang, are you running stock diff gears? At 75 mph with 315/75-16's I am pushing a hair over 3,000 rpm.
 
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I am about 8 mo into this new to me truck. I do not know whether the gears are stock or no.

I was just mesmerized by Coys’ gas gauge at 87 mph and 3000 rpm and guessing the all day ends in about 20 minutes - 😜
 
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Although at 2300rpm I am not regularly seeing 205 miles since fill up with a quarter tank left.
Like, ever.
 
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Over geared initially with 5.29s and 315s and was running 3k at 70. Had the t-case rebuilt and put in a high range over drive gear. 2650ish at 70, 2800 at 75, 3k at 80. Cruise at 80.
 
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Just to throw it in the mix - stock gears, 315s, sea level, unloaded, right around 2k @ 65 on flat... around 1900 at 60, which I usually cruise at. No freeways here; highest speed limit is 55. All my gauges are calibrated dead on via yellr box, confirmed w/ 2 GPS units. Had it up to 75-80 a couple times to see how she felt (smooth!) but forget the Rs.. I think 70 is about 2200?

Seems like mine has a happy place around 60 or so where it likes to hold. Either that or ~50 before OD kicks in, similar Rs.

With an average overnight camping load including us & 3 dogs, I feel it a little more on a slope, but easy to drop a gear or toggle OD off. Not a fan of lugging. That + my 18ft skiff (additional ~1klb) is comfortably slower-ish, but again... sea level and mostly flat, relatively short distances.

I can easily see regearing for elevation, load, or frequent grades. For me locally, I bet the t-case 10% underdrive kit would be neat.
 
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Best for what, mpg? I would think it'd be under 2500 but really don't know. Like Spenser, I keep it at 60 so as not to exceed the 55 mph speed limit much.
That would be the question
Best could be fuel efficiency; or power; or engine longevity. There does however seem to be a certain harmonic per engine design that balances all 3.

On my Cummins it’s 1700 rpm. That’s 18.5 mpg. If I go to 1900 I’m a little faster but now 15

Looking for the sweet spot
 
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Just to throw it in the mix - stock gears, 315s, sea level, unloaded, 2000k around 65 I think... just under at 60, which I usually cruise at. No freeways here; highest speed limit is 55. Speedo/computer/scangauge are calibrated dead on via yellr box, confirmed w/ 2 GPS units. Had it up to 75-80 a couple times to see how she felt (smooth!) but forget the Rs. Seems like mine has a happy place around 60 where it likes to hold. Either that or ~50 before OD kicks in, similar Rs.
Mine is all stock also, running with 265 tires...no heavy load anywhere...sweet spot seems to be around 70 mph and that's around 2500 rpms (I think)...I tend to drive her around 65 mph down the freeway. As long as I'm not running the AC (Don't really need it now in Portland), I see about 17.3 mpg (mixed), per the Torque Pro app tattle-tale ;)
 
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Best for what, mpg? I would think it'd be under 2500 but really don't know. Like Spenser, I keep it at 60 so as not to exceed the 55 mph speed limit much.
I read a long time ago (can't find the post) that the "sweet spot" for performance and MPG per Toyota engineers was 64 mph...as long as you're still wholly stock.

I'll try to find the post/article...
 
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35's, 4.88's, armor all over, tires at 38psi = 72mph cruise (*groundspeed). Any faster and the gear whine gets intolerable. At this speed, I wear ear plugs for legs longer than 30min. Two roll-up ear plugs fit perfectly in the A/C vent...

Gas mileage is abput 13-14mpg over flat ground. Any faster just makes it worse,
 

80t0ylc

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1FZ’s rpm peaks: (got this info from Tools-R-Us yrs ago)
Torque = 3200
HP = 4600
This may be helpful for finding “your engine’s highway happy place”. All things being equal, where you drive affects what kind of performance you‘ll get, both mpg and muscle, as well as how you drive. The thing with the 1FZ is that on the highway, there’s not much power to spare, or so it seems. Speaking of stock non-turbo engines.
 
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My 1hz n/a diesel likes to be around the 2400 rpm at 90 to 95 kph area in 5th gear. I might go up to 2500 rpm to do 100 kph or slightly more but never go further when highway driving.

I run 285/75r16 AT tyres. I think that's equiv to 33 inch. 1hz is stock n/a with no turbo.

There's no way I could 140 kph with my 80! I'd never push the motor more than about 3000 rpm due to it's age and I'm not really skilled enough to assess the behaviour just by listening, etc.
 
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