Top speed, suggested long term RPM...

[Ronnie]

M speed rating on mine and that is 81mph.

[EastCoastCB]

Originally Posted by Ronnie

I am curious to look on my tires now and see what the speed rating is. I do have all new tires, and no retreads.

Here are my comments on speed in general, if on an interstate I expect to be able to do the speed limit, and feel it is rather rude to be going slower and forcing everyone to scramble around you. With the bus I get in with the trucks and stay with them.

When I want to go slower I take the back roads. Besides there is more to see on the back roads, so why clog up the interstates poking along.

Interstate lane changes are why I demand interstate speed capability with buses I own.

[EastCoastCB]

Originally Posted by Ronnie

M speed rating on mine and that is 81mph.

Yep, that's a very common rating for these tires.

[Mekanic]

Originally Posted by Necro

Is it not bad on these engines to sit at 2600 rpm for 5 hours straight over and over?

Not in the slightest. it is much better to run it like that than to lug it at high loads at 1700 RPM.

@2500 The water pump, oil pump and Fan are turning faster and working better than the same power out put at lower rpms.

The engine oil IS The coolant for the Crank and it bearings. as well as the pistons.

[EastCoastCB]

Originally Posted by Mekanic

Not in the slightest. it is much better to run it like that than to lug it at high loads at 1700 RPM.

@2500 The water pump, oil pump and Fan are turning faster and working better than the same power out put at lower rpms.

The engine oil IS The coolant for the Crank and it bearings. as well as the pistons.

1700 isn't lugging it in my bus.
What RPM do commercial trucks and RV's usually run? Do they ride the redline?

[Mekanic]

Originally Posted by EastCoastCB

1700 isn't lugging it in my bus.
What RPM do commercial trucks and RV's usually run? Do they ride the redline?

They have a lower redline usually because they are much bigger engines

They will hit the Governed speed as low as 1600 RPM. You will also see gear ratios like 3.42 for a OTR truck.

Yes they will run them at foot to the floor at redline for hours.

[Sehnsucht]

Governed speed isn't necessarily redline, it just means the company doesn't want the driver to abuse the equipment.

Semis are purpose built for either long-haul or short haul, and then for specific vocational work as required. I've driven trucks that were capable of doing 90 all day long but that's not necessarily where they are their most fuel efficient so unless someone is paying extra for that much hustle I wasn't going to waste the money to get there early just to wait around. Likewise, these buses were spec'd for a purpose and wasn't always for highway speed. Beyond just the tires, the engine has a peak efficiency speed and even if it can operate beyond that all you're really doing is draining your own wallet and for what purpose? If you want a go-faster bus then by all means shop around for one but I don't think there are too many to find in the school bus world because its simply not what they are designed for.

[EastCoastCB]

Originally Posted by Mekanic

They have a lower redline usually because they are much bigger engines

They will hit the Governed speed as low as 1600 RPM. You will also see gear ratios like 3.42 for a OTR truck.

Yes they will run them at foot to the floor at redline for hours.

My bus redlines at 2400. Has 3.42 in the rear.
Anyone who wants to travel the country redlining a medium duty diesel can feel free to do so, but that doesn't mean its the most efficient.
My old bus was redlining at 60. Got like 6-7 mpg. Now I get 10+.

[cadillackid]

ECCB you arent lugging your engine at 1700. because of the AT545.. it protects you from lugging it.. the stall speed of the TC-290 converter is above the average lugging point of that engine..



your 1700 RPM isnt at full throttle.. its at part throttle and light-medium load...



lugging is much easier on a Lockup transmission and very easy on a standard shift..


most ECMs will unlock the converter or downshift if you run the engine up to 100% load factor at lower RPM's..



an engine's sweet spot is where you are at the lowest RPM you can run and still be at 50-60% load factor or less.. you are not lugging even at low RPMs at that point..



there are different definitions of lugging but moist generally people seem to agree that lugging is running at 100% load factor at below rated RPM...


meaning if your engine is rated at 2300 RPM dont run it at 100% load factor at 2000 RPM...



Running above rated speed allows you to run in lower gears longer and effectively "multiply" torque to the wheels over running in higher gears and lower RPMs . cruising above rated speed(rpm) is really only recommended if you need that multiplied torque to avoid lugging the engine.... too high RPM and light load factor you tend to just waste energy pumping air too low RPM and high load factor you lug the engine.. making a lot of heat in the cylinders..



run it in the middle someplace// I like 50-70% load factor.. and I built the program for my 6 speed automatic to watch the load factor and throttle input and act on both to give me the best possible mix of the 2.. its not perfect but seems to work well..


-Christopher

[Ranchorossa]

What is the serial # on the transmission? That will tell you a lot.

[LeeCDVM]

I hate being a devils advocate ... however ... who in their right mind wants to go faster than 65mph? These are big machines and big machines going fast are very hard to stop, not to mention very hard on the engine, tires, transmission etc, etc, etc.

Slow down, enjoy the view, don't be in a rush ... you'll get there soon enough

Doc

[PNW_Steve]

Originally Posted by LeeCDVM

I hate being a devils advocate ... however ... who in their right mind wants to go faster than 65mph? These are big machines and big machines going fast are very hard to stop, not to mention very hard on the engine, tires, transmission etc, etc, etc.

Slow down, enjoy the view, don't be in a rush ... you'll get there soon enough

Doc

Amen!

Enjoy the journey.

[EastCoastCB]

I'm happy doing 45. Till Atlanta. Then you NEED 80mph.
That's why my bus from the suburbs of Atlanta was equipped to do such speeds.

[PNW_Steve]

Originally Posted by EastCoastCB

I'm happy doing 45. Till Atlanta. Then you NEED 80mph.
That's why my bus from the suburbs of Atlanta was equipped to do such speeds.

A while back a member shared a story about an experience he had during his training for driving a truck. He voiced his concern about backing traffic up because he was driving too slow. The instructor said something to the effect of "Screw them. If they wanted to drive faster, they should have left before we did. "

I am not going to be very popular when I get to Atlanta I rarely exceed 65mph in a bus or towing a heavy load. It's not about my buses ability to go faster it is about how quickly can I stop. And.... I am not in a hurry. I generally enjoy the journey as much as the destination.

[cadillackid]

I run atlanta at 65.. well or 6 POINT 5. depending on the time of day I hit..



ive said it several places in this thread and all over this forum.. buying a bus has taught me to road trip all over again...



we sure had a hell of a good time in our 700 mile, 3-bus caravan to Wisconsin at 62 a couple weeks ago.. we stopped for breaks alot.. talked on our 2 way radios..

-Christopher

[Sehnsucht]

I actually enjoy doing the speed limit in a big vehicle because If the little cars swarm around me they get way out ahead of me in no time so its not really an issue. But I like that trainer's perspective too - because its really true for all of us that if we would just leave earlier we wouldn't feel pressured to always drive so fast. There's a life lesson in there that I think applies aptly and it was just mentioned... Slow down and enjoy the view! That's really the whole point of why most of us are in this thing. Lets face it, if you need to be somewhere fast then the worst possible thing you can choose to get there is an enormous brick on wheels!

[cadillackid]

When I need to get a long distance in a hurry I go to the airport.. when I have the time to enjoy my trip I hop in a bus. Or maybe I take a train..

Funny thing is on a long trip o think my airplane tickets cost less than fuel for my bus..
I still choose to drive my bus most times

[o1marc]

I went through a few states coming home with 80mph speed limits. The bus handles it just fine, brakes with no issues. When you're traveling 3K miles, 10 mph could mean another day of driving. Rarely is traffic in Atl. at 80mph, at 75 I'm usually not passed.

[PNW_Steve]

Originally Posted by cadillackid

buying a bus has taught me to road trip all over again...



-Christopher

Me too.

When I was 25 I was all about the destination and getting there as quickly as possible. Driving a bus cross country taught me to enjoy the journey. No more 18 hour stretches of driving as fast as I thought I could get away with. Now I rarely exceed 65 mph or drive more than six hours a day.

Life in the slow lane

[Sleddgracer]

Originally Posted by PNW_Steve

Me too.

When I was 25 I was all about the destination and getting there as quickly as possible. Driving a bus cross country taught me to enjoy the journey. No more 18 hour stretches of driving as fast as I thought I could get away with. Now I rarely exceed 65 mph or drive more than six hours a day.

Life in the slow lane

maybe when I age out a bit more I'll pay more attention to the journey than the destination, but at 80 years old, when I'm on the road I have a destination, a purpose, and a deadline in mind - I'm very aware of driving within my reaction times, and seldom travel much over the speed limit, but I want my bus to climb hills faster than a Volkswagen van and I want to at least maintain the speed limit without stressing the motor - my bus will be used for getting from here to there, rather than holidaying along the way ( who would want to picnic in -30 weather with a blowing wind anyway? - lol )