Gas vs Diesel Shootout in the Dunes & Sand

[nickw]

I do a fair amount of driving in the sand....fair amount of dune driving also. The majority of my time has been spent in gas rigs with the rights setup, and have had good luck with all my rigs; FJ40's, Tacomas, 19' Ranger, 22' Ram 2500. One thing I did notice the other day when I was out wheeling was the diesel rigs do struggle a bit more with some of the softer areas where *wheel speed* is required....like coming up to a soft dune or a section of soft wind-blown sand, being able to rev from 2k to 5k+ in a gasser can get you out of trouble, the diesels seem to suffer a bit in these conditions since the RPM range is closer to say 1k to 3k....a gas rig has close to 2x the potential wheel speed.

Another area I've noticed in run-ins to steeper dunes from a stop, gas engines 'seem' (to me) to be better able to use that RPM advantage without having to shift...which in many cases, is not possible,

Thoughts / experiences?

 

[Mike McMullen]

I agree, that's why my Ram 2500 is a gaser. They are also lighter and I think it floats better on the fine stuff. The other reason is I don't tow and parts and mechanics in Baja are easier to find.

 

[Todd780]

I agree, that's why my Ram 2500 is a gaser. They are also lighter and I think it floats better on the fine stuff. The other reason is I don't tow and parts and mechanics in Baja are easier to find.

Beat me to it. I was going to say I think the diesel engine being heavier would have a negative affect in anything soft.

 

[Peter_n_Margaret]

If you need revs, you have too much air in my view. If you can't crawl up you cause track damage.
No wheel spin, no screaming engines.

The scolloping of this track is caused by too much air and wheel spin.

Cheers,
Peter
OKA196 motorhome

 

[nickw]

If you need revs, you have too much air in my view. If you can't crawl up you cause track damage.
No wheel spin, no screaming engines.

The scolloping of this track is caused by too much air and wheel spin.

Cheers,
Peter
OKA196 motorhome

In normal rigs, aka not heavy OKA's and Unimogs, I've never crawled up a dune in my neck of the woods, you needs some speed and rev's as you slowly lose momentum on way up unless it's super shallow....fully realizing we have differing conditions and sand types. That last pic is super dense and wet, very rare, even on wet days here, guessing that is due to the shade treeds along the track. Cavitation, IME, is generally due to tire pressure as you point out, seems to be the worst at a middle RPM, higher RPM can smooth it out or make it worse.

 

[billiebob]

In normal rigs, aka not heavy OKA's and Unimogs, I've never crawled up a dune in my neck of the woods, you needs some speed and rev's as you slowly lose momentum on way up unless it's super shallow....fully realizing we have differing conditions and sand types. That last pic is super dense and wet, very rare, even on wet days here, guessing that is due to the shade treeds along the track. Cavitation, IME, is generally due to tire pressure as you point out, seems to be the worst at a middle RPM, higher RPM can smooth it out or make it worse.

yep, 100%..... different reasons on different continents.... absolutely on dunes in North America....
speed, wheel speed, the ability to rev quickly is HOW WE DRIVE....
I don't think Nick is talking about overlanding across the Sahara.

The other advantage of gas rigs is they are lighter weight. A diesel adds a massive amount of weight and no diesel trucks are built to drive fast, they are built to haul heavy loads up mountain grades with ease.

Some guys overland in Unimogs, others overland in Raptors......
Some overland with tents and sleeping bags, others have microwaves and dishwashers.

 

[Peter_n_Margaret]

That last pic is super dense and wet, very rare,

Rare there too. Usually dry and soft.
Cheers,
Peter
OKA196 motorhome

 

[billiebob]

I don't think Nick is talking about excessive wheel spin destroying the trail. He is talking about travel across sand dunes which change shape with every wind storm. One of the few places where "tread lightly" has little significance. But more on topic he is commenting on the difference of gas vs diesel performance in the average pickup.

There is no doubt that if you make a mistake and NEED to nail the throttle..... there are times that is the reality...... a gas engine is the better choice in a stock North American pickup. PERIOD....... I can relate that to stream crossings, mud, and as he noted, loose sand, be it in the dunes or on the beach.

Agreed, TREAD LIGHTLY is the way to go always. Guys on ATVs and MotoCross bikes deliberately destroying watersheds ripping up side slopes should be shot but there are times a heavy right foot will save the day and the gas engine does that better, quicker than a diesel engine.

Heck on the tread lightly thing the diesel, being heavier with a heavier everything should be banned. Overlanding should be only for the ultralights like.. the Trabant


or Summari.



There are places no one should ever go regardless of the speed or vehicle. This is why governments gate roads.

 

[Betarocker]

If you can't get the wheel speed up on the diesel with 1200 ft-pounds, you need to learn how to press the go pedal harder and shift up manually to a taller gear.

 

[Metcalf]

Diesel engines don't seem to slow down the T4 truck class in the Dakar Rally

 

[billiebob]

Diesel engines don't seem to slow down the T4 truck class in the Dakar Rally

View attachment 721107

On that note even Porsches do well..... hardly stock tho.



Then there was the 1954 9th place Pan America Lincoln.... 1900 miles of gravel..... in 20 hours. Thats averaging just under 100mph for a day.

 

[nickw]

If you can't get the wheel speed up on the diesel with 1200 ft-pounds, you need to learn how to press the go pedal harder and shift up manually to a taller gear.

Wheels speed is more closely associated with HP than Torque, practially, since gas motors in the same platform generally have the same HP as diesels but get the HP from lower torque at higher RPM and have a wider RPM range.

To your point, in theory, shifting can offset lack of wheel speed...but practically speaking shifting kills momentum.'

 

[nickw]

Diesel engines don't seem to slow down the T4 truck class in the Dakar Rally

View attachment 721107

Fair enough - those things are impressive, but I think the rigs in the other classes would run circles around those things in the bigger dunes and softer sand.

 

[Metcalf]

Fair enough - those things are impressive, but I think the rigs in the other classes would run circles around those things in the bigger dunes and softer sand.

Diesel engines are not uncommon in the other classes, even the fastest T1 stuff. I think it has to do with fuel consumption on the long stages.

 

[nickw]

Diesel engines are not uncommon in the other classes, even the fastest T1 stuff. I think it has to do with fuel consumption on the long stages.

Probably does - I know Toyota used them in their Hiluxes too in the past but they were factory supported highly tuned engines, Audi races/raced a diesel at Lemans and did well too but I know my old TDI revved to 5k, which is 2k over what most full size diesels rev, so I'd draw a line at 'performance/race' diesels and what we can get our hands on....I think that Kamaz falls into that same category