1hdt cruising rmp (1 Viewer)

[toyota guy]

What is the rpm limit while cruising for extended periods of time on the highway? Here in Montana the speed limit is 80mph on many highways but going 70mph I’m about 2200rpm and I feels good, going faster seems like it may be pushing the rpm’s a little. How high is too high?

 

[Loober]

I run my 1HDFT usually around 120km/hr cruising, roughly 75mph and its right around 2800 for long periods with no issues, I am running an H55 which has shorter gears then your auto. It seems to be the sweet spot for it. I usually never rev past 3000, mainly because the power curve drastically drops off after that thus no benefit in doing it, but I think it would be fine reving that high.

 

[Dork]

I also sit at 120kph for hours on end, but I've got 35s and the auto so it's close to 2300rpm or so.

I've also pulled trailers for hours on end spinning at 3000rpm with o/d off with no ill effects.

 

[toyota guy]

Thanks for the reply guys, I guess I’m good to go.

 

[IanB]

If you're an auto, you can go pretty fast compared to a manual trans truck and keep your rpm's down, everything else being the same, and once you add bigger tires it gives you even more room. Fuel economy will suffer at higher speeds though.

Mine seemed to like 90-100km/h rolling hills best for fuel economy, which I have none of where I live.

 

[Indestructible 47]

1HD-FTE hdj79 I'm at 2900rpm gps speed at 120km/h. Uses about 14L/100kms whereas i can get as good as 10.5L/100km at 90 - 100km/h. I'm running 305x70r16. I really wanna do a 5th gear kit though, dropping it back to 2100, 2200rpms at 115km/h would be nice. Will most likely need gears or bigger shoes for that though.

 

[ZCissner]

im at 2250 in 5th gear going 60mph with 8psi boost and get 19mpg in full-time 4wd

 

[roscoFJ73]

How high is too high?

I think they would be ok to run at 3000rpm all day lightly loaded but no more. Pulling a trailer or heading into a strong headwind might be overloading it, but the steering ,brakes and suspension is not really designed for much over 120kph.

 

[AussieHJCruza]

I used to tow long distance with my Gturboed 1HDT - 3000+ rpm for the best part of 10 hours with occasional slow down/stop. No problems at all doing that pushing 20+ psi of boost whilst cruising.

The 6LP Yanmar marine engine (Which is a 1HD-#) seems to be rated at 3800 rpm so I don't think they mind revs greatly.