Engine spec ratings... comparing apples to apples

[Twigg]

Originally Posted by Iceni John

But would its tires, suspension and brakes be up to the task? And don't even think about fuel consumption at that speed - we all know how wonderfully aerodynamic our buses are. (Sort of like the Bugatti Veyron whose entire fuel tank is empty after just 12 minutes at top speed.) I lose 1 MPG doing 67 MPH compared with doing 60 MPH.

John

Right, but top speed is 253 mph ... It gets through a set of tires too.

That's a lot of air to move, even for the Veyron.

[Iceni John]

Originally Posted by Twigg

Then there is always this:



The 109,000-horsepower Wärtsilä-Sulzer RTA96-C, which first set sail in the Emma Mærsk in 2006, weighs in at a rotund 2,300 tons, and it's 44-feet tall and 90-feet long.

I like the idea of cylinders that a grown man can get inside - no child labor needed with an engine like that. And it's a two-stroke (yeah) with a thermal efficiency of 50%, more than any other internal-combustion engine of any design anywhere. Wow! It's clever how it doesn't need any camshaft for its exhaust valves, and how each piston's downstroke helps compress the charge air for the next cylinder's piston intake.

It's also pretty impressive that one Mercedes-Benz haulage tractor can move over 2000 tons. I can't imagine what its transmission is enduring to do that.

John

[EastCoastCB]

Originally Posted by Iceni John

But would its tires, suspension and brakes be up to the task? And don't even think about fuel consumption at that speed - we all know how wonderfully aerodynamic our buses are. (Sort of like the Bugatti Veyron whose entire fuel tank is empty after just 12 minutes at top speed.) I lose 1 MPG doing 67 MPH compared with doing 60 MPH.

John

Sure they would. Just cause it aint one of your old crowns doesn't mean its not safe to drive at highway/interstate speeds. The tires are rated for interstate speeds. No one's talking about sustained 80mph + speeds but you have to understand that passing power is a nice thing to have.

[brokedown]

Originally Posted by Iceni John

It's also pretty impressive that one Mercedes-Benz haulage tractor can move over 2000 tons. I can't imagine what its transmission is enduring to do that.

John

And wolud you believe its pulling it with an AT545 transmission?

No, I didn't think you'd buy that.

[Iceni John]

Originally Posted by EastCoastCB

Sure they would. Just cause it aint one of your old crowns doesn't mean its not safe to drive at highway/interstate speeds. The tires are rated for interstate speeds. No one's talking about sustained 80mph + speeds but you have to understand that passing power is a nice thing to have.

OK, got it! I thought you could be driving in those states with 80 MPH limits. Texas State Highway 130 even has an 85 MPH limit. Incidentally, the speed record for a Crown is a shade over 100 MPH, set by an old Hall-Scott gasoline engined one some decades ago on a race track.

John

[EastCoastCB]

Originally Posted by Iceni John

OK, got it! I thought you could be driving in those states with 80 MPH limits. Texas State Highway 130 even has an 85 MPH limit. Incidentally, the speed record for a Crown is a shade over 100 MPH, set by an old Hall-Scott gasoline engined one some decades ago on a race track.

John

Thomas buses have been shown going 80+ down the interstate. In service, even.

[Robin97396]

That is exactly correct. Buses going 85 with kids.

It must have been a very hot day.

[Rusty]

Originally Posted by Robin97396

That is exactly correct. Buses going 85 with kids.

For real? I'd be a shade past pissed if they drove with my kids that fast in one of these POS.

I see a ton of HP increase threads, not one single one on brakes or disc upgrades. Or lining thickness. Cam adjuster?

We should see how fast these suckers power-stop from 85-0. THAT might be an interesting thread.



...says the guy with the 5.9L

[EastCoastCB]

Originally Posted by Rusty

For real? I'd be a shade past pissed if they drove with my kids that fast in one of these POS.

I see a ton of HP increase threads, not one single one on brakes or disc upgrades. Or lining thickness. Cam adjuster?

We should see how fast these suckers power-stop from 85-0. THAT might be an interesting thread.



...says the guy with the 5.9L

IDk- the cars people drive their own kids around in are bigger POS' than a school bus.

[brokedown]

My Thomas will roll smooth at 85 all day long! 85kph that is!

Sent from my Nexus 6P using Tapatalk

[Twigg]

Originally Posted by Rusty

For real? I'd be a shade past pissed if they drove with my kids that fast in one of these POS.

I see a ton of HP increase threads, not one single one on brakes or disc upgrades. Or lining thickness. Cam adjuster?

We should see how fast these suckers power-stop from 85-0. THAT might be an interesting thread.



...says the guy with the 5.9L

Power increases alone don't increase speed though, just pulling ability and acceleration.

[EastCoastCB]

Originally Posted by Twigg

Power increases alone don't increase speed though, just pulling ability and acceleration.

You're correct. It all depends on the trans, rear, and tires.

https://www.youtube.com/watch?v=RuUYB6CkYck

[Twigg]

It was also reasonable to bring up the point about brakes and suspension.

My view there is that people are generally not trying to extract massive gobs of extra power from their buses.

What is usually being asked about is a few extra hp, for hills and towing, and a few extra mph for highway cruising.

Many buses are restricted either by electronic/mechanical governing, or very low gearing.

The brakes, suspension and tires are all engineered to operate safely throughout their performance envelope. Buses are rarely loaded to their GCVW, nor are they often pushed at maximum speed, both things the brakes are engineered to handle.

So we are not hot-rodding here, and modest power increases and/or better highway speeds are covered.

It's worth bearing in mind, if only to recognize that we don't have a great deal to be concerned about.

Keeping what you have in good condition is, however, important.