Cube Van MPG

[greg334]

Greg my 12' box truck runs well with 3:73 although it is a duramax. Avg. 17.8 mpg

Whole different thing, the 3.73 puts the max in a different speed and works a bit to the sweet spot of the engine.

The 6.0 has a different sweet spot speed and on top of that, may have a different profile on the ecm so it fuels the engine for that dually.

 

[60MPH]

Whole different thing, the 3.73 puts the max in a different speed and works a bit to the sweet spot of the engine.

The 6.0 has a different sweet spot speed and on top of that, may have a different profile on the ecm so it fuels the engine for that dually.

Good thinking I did not think of the ecm perimeters. The efficiency of the 6.0 is probably at a higher rpm than the max. 1800rpm I think is the sweet spot for the max, at least it is with my lly. Maybe deflectors may be a better option.

I know with a diesel peak efficiency is about 150-200 rpm's above the max torque output. I do not know about a gasser, any ideas on this Greg?? What do they call it something like volumetric efficiency it has something to do with vacuum and some other factors.

 

[Mrnewbie]

Ok now I am really confused. Are you saying swapping the gears might not give me a mpg increase? So it might just be better to not spend the extra money and keep it the way it is?

 

[Moot]

The problem with a DRW cube van, at least from a fuel economy perspective is, not only do you have two more tires adding rolling resistance, the box is 6 to 8 inches wider than a SRW cube which greatly increases drag. I would add a cab roof fairing first while further investigating the rear axle gear change.
Call a company like Chevy/GMC Spartan Cargo Van - Supreme's Delivery Van | Van Bodies | Supreme Corporation, Baybridge or Rockport about a cab roof fairing. They all use a similar looking fairing, probably from the same vendor.

 

[d_b1486]

If u have a pesnke truck with duals, must be atleast 14' feet. So there'd the weight. Penske duallies are 14' or bigger, as far as I know. Plus supreme (box manufacturer) says the front of the box is curved in, and not straight box, so that is supposably a wind deflector. My brother in law has the 12 foot single wheel box and gets low 14s mid 14s. That's a 12' single wheel. 4.8l. If urs is bigger then 12 feet than ur box is the high top, and wider so getting 12s is normal I would presume. The extra weight n wind resistance Is not good.


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[chefdennis]

I mentioned reflashing the ecm because f what greg said...the engine efficency is set with the ecm and changing the axle ratio allone while letting the rear axle run slower, the engine will nit be running at in its best range as set by the ecm...

I the company that i mentioned that reprograms the ecm will ask the engine size what model of trans, the rear axle ration and the TIRE size...and even if you have speed / cruse control...and the vin # of the truck...they will then sset up an new ecm for that your needs are, more power or mpg...

This isn't like the 60's when you could "adjust" the "settings" that will optimize mileage anymore...its all computer controlled...once you change the axle ratio, even the shift points of the trans will be off, they are controlled by the ecm also....in some cases (not all, so i am not saying yours will need to be), the anti lock brakes need attention with a axle ratio change also as you are changing the "wheel speed" and the sensors will not work as they are set to...again, controled by a computer....

Its like the old advertising statement, "this ain't your dads old van" (or Oldsmobile"....)

As for the van itself...those penske vans are heavy...have you removed that big heavy rear bumper and ramp and brackets and replaced it with a lighter bumper?? Weight reduction on those is something i'd do asap if you haven't...

 

[purgoose10]

First of all if you have a cube van then your dragging a 4.10 axle. Wind drag and low gear makes for terrible fuel mileage. The 6.0's best RPM for economy is 1500 rpm. If your running about 65 with a 4.10 your rpms are running above 2300 making for terrible mileage.
Along with the extra tires and probably a 4spd your not going to get good mileage. It will probably take more money than the truck is worth to get it to a liveable spot.

 

[Jefferson3000]

As far as dealing with wind drag, you will have to think of this vehicle as a small box truck and NOT a tricked out van. As far as axle ratio and ecm, yes you will deal with it at manufacturer level, as a van.

Unfortunately, many vanners on this site only understand your truck as a van getting bad fuel efficiency, and fail to see the benefits of a cube's higher capacity and subsequent reward.

 

[60MPH]

As far as dealing with wind drag, you will have to think of this vehicle as a small box truck and NOT a tricked out van. As far as axle ratio and ecm, yes you will deal with it at manufacturer level, as a van.

Unfortunately, many vanners on this site only understand your truck as a van getting bad fuel efficiency, and fail to see the benefits of a cube's higher capacity and subsequent reward.

Your right Jefferson, anyone with a unit like this should be making C rate at minimum and be able to get D rate on some loads with a little ingenuity. A used 15' or 17' cube will be my next vehicle purchase. I see a a whole lot of freight for these size units, you just need to know how to get it on-board

Trying to operate this type of unit at van rates is very difficult. I would only take a exclusive use van load for relocation purpose's.

 

[paullud]

As far as dealing with wind drag, you will have to think of this vehicle as a small box truck and NOT a tricked out van. As far as axle ratio and ecm, yes you will deal with it at manufacturer level, as a van.

Unfortunately, many vanners on this site only understand your truck as a van getting bad fuel efficiency, and fail to see the benefits of a cube's higher capacity and subsequent reward.

I think everyone sees the benefits of the cube van but would also like to see him get better mpg. I think that is why the recommendation was made for 3:73 instead if 3:55.

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[scottm4211]

Cut The Cube!

 

[Jefferson3000]

Cut The Cube!

Along with hate the straight and ban the van, I prefer "curb the cube."

 

[purgoose10]

You talked of a 3.55 the problem is there is only 3.73 or 4.10 available for the size truck. You might get an after market but I don't think so. Besides thats to high and you will be fighting wind problems against horsepower and transmission gearing then if your going to put the money in go 3.73. Best all around gear for a 12,000 and under GVW GM. I've had several GMs and thats the best all around gear ratio for a 6.0 or a 6.6 Dura.

Let me also ad if you do get a 3.55 your computer won't flash to that gear ratio causing more problems down the road.

 

[Mrnewbie]

Thanks for the advice everyone. Chef I have not removed the bumper and ramp yet but am planning on it this weekend. I know that both are extremely heavy and arent helping my cause any. I guess I will do the roof fairing first and continue to look into switching to 3:73 gears.

 

[purgoose10]

Thanks for the advice everyone. Chef I have not removed the bumper and ramp yet but am planning on it this weekend. I know that both are extremely heavy and arent helping my cause any. I guess I will do the roof fairing first and continue to look into switching to 3:73 gears.

That sounds like sound advice. Good luck.