I'm Questioning Power/Torque of Gas vs Diesel

Hello again topless,

I forgot to add another comment on something you wrote.

"Since the Sprinter was designed as a delivery van for use around the globe, it handles difficult terrain with ease, uphill, downhill, tight turns, narrow roads, and those in combination."

The question is why was a specific diesel engine used rather than a gas engine? Along with why there are so few in the Us vs Europe and elsewhere?

Well, it has nothing to do with a tight turn as that is about the size, wheel base of the vehicle. It has to do with the price of fuel. The Sprinter diesel engine costs noticeably more than a gas engine, but eventually there is a payback in terms of fuel costs. In the US the price of fuel is much lower than Europe, so the payback much lower. This changed a little when gas went to $4+, only a little as diesel fuel increased also and more.

Folks that want to sell their used Sprinters are better off than the dealers with new Sprinters. If the used Sprinter sells for half the new price for example, the payback will take half the mileage - noticeable difference, but still a Lot of miles required.

This forum has discussed at length that there is not a cost savings with a new Sprinter (in the US) for a very low time and an unrealistic number of miles. Again which is why there are few commercial Sprinters in the US vs Europe, etc.

Bud

Hi topless,

You write:

"Ask yourself, why are all 18 wheelers powered by turbo diesels? Also why are most trucks used for heavy hauling turbo diesels?"


Are you kidding? There are many features of an engine. You choose the engine based on the application, about that simple.


"Hp is a method of rating the work a motor will do, but torque is what moves things. It's not hp that loosens nor tightens a bolt, it torque."

Huh? Right, no engine has zero torque as there would not be any hp. Again, an Express Van will leave a Sprinter in the dust Unless it has to do it with a lot of hp over a long enough period of time. But it has Nothing to do with Torque. Rather the cooling capacity of the engine.


"Having said that, for general,use, a gasoline engine is fine. There are more advantages to a Sprinter than just the turbo diesel."

It is more than general use but agree. There are Sprinter advantage other than how it makes hp, and downsides too. In life there is often not best, just advantages and disadvantages. We choose the best solution for our application which can also include emotion and feelings.


"When driving in mountains, you can use the manual shift mode in the transmission to engine brake and save over heating you brakes."


I've never had a gas vehicle including a B that can't do the same.


"Since the Sprinter was designed as a delivery van for use around the globe, it handles difficult terrain with ease, uphill, downhill, tight turns, narrow roads, and those in combination. We drove the road between Montrose and Durango Colorado and after that 107 miles of hairpin turns, 3 - 12,000 ft passes I learned to really appreciate the Sprinter. There are hairpin turns on the side of a mountain that are 15 mph. I don trembler a single level part of that road, Longest straight might have been 1/4 mile."


I've driven that road in my gas B and experienced about the same, would have worded it a little different is all.


"The next day we drove down Hiway 50 through Monarch Pass . Speed limit is 45 mph, by using the lower gears, never touched the brakes all the way down the mountain. Was following a Suburban that was riding its brakes all the way."


Maybe if the Suburban driver had pulled over at the end, you could have assisted the drive with a little diplomatic education about using the gears.


"There is more to a truck than just the motor, I was one of the first on this forum with a Sprinter. Got all kinds of static about how my 154 hp motor wouldn't do work. It does."


You would not have received any static from me. I would have supported the fact that 154 hp, that can use that 154 hp over time will get the job done. Some might not be satisfied with the acceleration though. Me, I would not have a problem with the acceleration, but would have also appreciated more.

Bud

Bud has it right IMO. Physics is physics, and it doesn't change with personal preference. There has been, and always will be the diesel vs gas argument, but all you really need to do is look at the numbers to see what is happening. Look at the toque and hp curves and you see it very plainly.

If you compare the slightly older Chevy 6.0 300hp/360tq, it actually has within a couple of foot-lbs of torque at the rpm rated max of the Sprinter V6, and it gains on it from there to it's torque peak at around 4K rpm, over double, near triple the rpm peak of the diesel. By the time you gear them both appropriately, the Chevy will put something over double the toque to the drive wheels at the same vehicle speed.

Also as Bud said, folks sometimes miss how it all works. Yes, torque gets the van moving, but it doesn't keep it moving. If it did, you would not be speed limited at a given torque output. Horsepower moves the van at speed with the 5252 conversion Bud quoted. Since you use the ratio of the engine rpm to 5252, the lower the rpm your torque peak is at, the lower your hp for that torque output. That is why diesels usually have quite low hp compared to gas, as they work at much lower rpm levels. That characteristic also limits their total load moving capacity, as you need hp to do that. That directly translates to slower acceleration and hill climbing speed.

Cooling is definitely the issue with the Chevies, probably not so much with the Fords, especially the V10. The V10 is used in huge RVs compared to a B, and could easily drag an Excel up a mountain pulling just about anything. It is a real full design truck engine and a real workhorse. It will outpull any Sprinter diesel by an absolutely huge amount. They are a bit thirsty, though.

The cooling can be addressed in the Chevies, if needed. They have the oil and trans cooler in the radiator tanks, and it is pretty easy to take them out and into designated coolers with their own fans. This takes a huge load off the radiator and also adds extra cooling capacity of the new coolers. I have heard of folks pulling over 7000 lb trailers with their b's, over the mountains without cooling issues after the changes.

Diesels do have advantages, especially turbo diesels. They get better fuel economy, don't lose as much power at altitude, and many, but not all, are designed as high durability commercial engines. But, they are stinky, noisy, more expensive to maintain, and slower. To say a diesel is the best choice for a class B because over the road trucks are diesel is really not a good comparison. Over the road trucks look for the best economy, reliability, and practicality. They don't care if they have to go up a mountain at 10mph, which they do. They only need to be able to get up the mountain with a huge load, not do it quickly.

The diesel/gas debate will go on forever, but it is not nearly as clear cut as some would make it. Gas, or diesel, may be the right choice for any given application, but neither is inherently better just because they are diesel, or gas. Personally, I like the at home serviceability of the gas engine, as well as the much better power and acceleration under pretty much all conditions, except when heating becomes an issue (ours is better than most because of a trans cooler and auxiliary fan on it and the radiator). Your choice and needs may be different.

To the OP. Don't be scared of either, just because of what they run on.

topless wrote:
Got all kinds of static about how my 154 hp motor wouldn't do work. It does.

It's really quite amazing isn't it. :) We love ours after 118K miles all over the NA continent. But to each his own.

Ask yourself, why are all 18 wheelers powered by turbo diesels? Also why are most trucks used for heavy hauling turbo diesels? Hp is a method of rating the work a motor will do, but torque is what moves things. It's not hp that loosens nor tightens a bolt, it torque.
Having said that, for general,use, a gasoline engine is fine. There are more advantages to a Sprinter than just the turbo diesel. When driving in mountains, you can use the manual shift mode in the transmission to engine brake and save over heating you brakes. Since the Sprinter was designed as a delivery van for use around the globe, it handles difficult terrain with ease, uphill, downhill, tight turns, narrow roads, and those in combination. We drove the road between Montrose and Durango Colorado and after that 107 miles of hairpin turns, 3 - 12,000 ft passes I learned to really appreciate the Sprinter. There are hairpin turns on the side of a mountain that are 15 mph. I don trembler a single level part of that road, Longest straight might have been 1/4 mile. The next day we drove down Hiway 50 through Monarch Pass . Speed limit is 45 mph, by using the lower gears, never touched the brakes all the way down the mountain. Was following a Suburban that was riding its brakes all the way.
There is more to a truck than just the motor, I was one of the first on this forum with a Sprinter. Got all kinds of static about how my 154 hp motor wouldn't do work. It does.

Our 2005 RT 21OP has the Chevy 300 HP V8. Easily climbs hills(so much fun passing all the Class A's laboring over in the slow lane!) and with the oil cooler the temp needle never moves. Any seldom needed service is available everywhere.

Hi arm,

The 1995 Dodge Roadtrek had about 200-220 hp. The fellow is looking for a 2009 or later B with the Express Van having 325 hp! Heck of a difference.

"Gas engines get their Max torque at 4000 - 4500 RPM"

Your engine max torque is 3500, but I don't have any idea what difference it makes. The cooling system is there or not, but where you go up grades at 55-60 the Express Van with 325 hp will............... There are few highways where the Express Van slows with long grades.

Bud

The V-10 does have power but WHINES to beat the band while climbing, where as a diesel just purrrrrrrs as they climb.

I'm not going to talk torque, ft, pound rpms , fuel economy etc, just the difference in the sound of the two engines. Diesels are so much smoother that gas.

I remember the first time i ever drove a Diesel and I started to climb a hill- the engine never got any louder it just swallowed the hill and never bogged down of the rpm never increased. THAT is the day I understood why people buy diesels. Since then I only buy diesels.

My experience supports what Stan909 says. Right now I have a low power 1996 Dodge roadtrek 190 and I live in the mountains. I might max out at about 9000# full of water etc. No problems maintaining speed up steep grades at 55-60 MPH. However if I was towing again with a GCVW 12,000# - 15,000# or over, Diesel would be the way to go. Gas engines get their Max torque at 4000 - 4500 RPM and thus tend to overheat if run for prolonged periods at that speed. Diesels get Max torque at about 1800 - 2200RPM and can go at that speed forever. So in a prolonged climb they win out hands down. They also excel when fighting a 30 - 40 MPH head wind when travelling across the prairies. But how often do you get those conditions???

They both have their Pros & Cons. You have to decide which works for you and how thick your wallet is.

Also if you travel off the main roads gas can be worked on in any little town or by you if you have tools, and experience. Finding diesel mechanics in out of the way places is difficult and even if you find diesel fuel it may be a little stale etc.
I have worked on diesels for may years, but don't own one unless I have to have it for the operating conditions presented.

The Triton V-10 that was an option in the now-discontinued PW Excel was pretty nice.