Any useful MPG mods on 4.0L?

Maybe try removing your tailgate for less drag.....

 

You can still be full throttle and not exceed 3000. I'm usually 3/4 throttle and keep it under 2000.

 

Got a tonneau cover on the bed haha so no tailgate drag for me!

 

Well from that stand point, the throttle never reaches over 20% engaged

Regardless I drive like an old granny, which is fine because it makes you sit back relax and enjoy your ride from point A to B, and not be rushing around

 

Less, you just think you went 100 miles (because it is reading fast)... You also think you got 20 mpg instead of 19... etc.

I would like to hear from a tech how the speedometer can show 60 mph, but the odometer will only move 57 miles in the same hour?

 

This is done on purpose by all car manufacturers. The speedo always reads slighter higher than actual speed because (by law) the speedometer must never read slower than the actual speed of the vehicle*, so manufacturers err on the side of it reading slightly fast. In most modern cars, the car knows what it's actual speed is*, so it will track mileage with that value, but it will show a slightly higher value on the speedometer.

* - assuming stock tires, of course

 

I just installed the ScanGauge the other day and I suspect I need to mod myself and get rid of my "spirited driving" habits.

 

This is part of it, but the rest changes as your tires wear.

The vehicle drives the speedometer and odometer via computer and software. Speed sensor tells it the number of tire rotations, and it calculates from there. As your tires wear (mine lost a little over an inch in diameter from new to well worn. Smaller tire from wear means you go less distance per tire rotation. System does not know or have a way to calculate tire wear, so accuracy will change. Until speedometer/odometer are driven by GPS, or possibly ground radar, the change in error will occur.

 

Mythbusters showed that tonneau covers may not do anything for mileage. Actually, in there limited set of tests they found tonneau covers cost a truck a few mpg's, which makes sense considering the car companies design there pickups with an open box and utilize the currents it creates to enhance mileage.

 

That makes no sense that the air flow would be better with an open bed, you have a flat surface right where the air flows around the truck and from the top of the truck, and hits a wall that impedes flow, which would not help it but regardless I get better MPG with it on than off. But it probably depends on the weight of some of the covers, some weigh over 100lbs, adding that much weight will change the MPG but mine is super light

And I just did a quick research and they increase MPG, and some companies have proven and guaranteed it so im gonna take their word haha

 

First off, you don't need to defend your purchase. Mythbusters doesn't make anymore money by testing tonneau covers whether they work or don't work. Your internet research probably does make money off you buying the tonneau cover especially if it's in house research or company funded research.

As for why trucks get better mileage without there tonneau covers, I'll let a video show you the concept of why this works before you get pissy with me for trying to help you :

https://www.youtube.com/watch?v=r3aqHbD-O9E

Check out the water flow at around the 1 minute mark of the video. It's visually clear that while without a tail gate, or in a similar situation when your cover is on, you disturb the natural high pressure area that forms in the bed and force it to far up or down into or out of the air current around the car. In either case, you either get excess buffeting or an area of low pressure behind the truck. Both cases result in higher drag which of course causes lower fuel economy.

I'm not going to say all those fancy smancy aftermarket manufacturers are always liars but they sure don't tell you how there product can fail to achieve better mileage. Some products do work but I think if you roll the cover off and drive a few hundred miles, then do the same stretch with the cover on, you'd be surprised. No major company that uses trucks over long distances in Agriculture (Bayer, Dow, Agrium, etc.) has tonneau covers installed at the dealer unless the truck will be carrying valuable goods. Those companies have realized the value of a cover is mostly in it's security, not it's fuel efficiency.

At least I'm using more logic than a warm air intake in a desert . That's going to rob you of power big time for very minor mpg's gained, IMHO.

Also throttle vs RPM is not usually a linear relationship (a line). If you've taken some mathematics, which I assume you have, then think of throttle vs RPM as an exponential function (a curve). 100% throttle is 100% RPM, but 50% throttle will not usually give you 50% RPM under load conditions. Just food for thought.

 

You're probably 100% correct that the companies market and have third parties make "research claims" and guarantees to help sell their product. It's business, no matter what you buy there's always a business motive behind it, and that's to be the "best and most popular" on the market, because it means more sales. So I'll definitely do some fluid research and see if I can find anything, if not, school starts in a few weeks, I'll propose the idea to my fluids professor and see if I model something if he will let me use the wind tunnel we have.
Cause I'm genuinely curious about this stuff. And I'm taking CFD (computational fluid dynamics), and this kind of fluid flow will definitely be somethingn we touch on. So I'll do some real research

A warm air intake in the desert would be kinda funny haha but even living in Arizona, flagstaff reaches a high of 80's and a altitude of 7000, which is why I was curious if a warm air intake would help

And yeah, that makes complete sense, which is why throttle engagement (what a is a part of the coding for a scan gauge I'm guessing?) is not the same as RPM, cause you can be WOT, and only be at 3,000... Or you can barely be touching the gas and be over 3500

 

So i look into the SAE research logs on truck aerodynamics and test done at the chevy wind tunnel explains and proves that driving with the tailgate up vs down greatly decreases because of the void it creates within in the bed, allowing air to flow over the bed without as much drag and be more efficient. And then i found that ford tested between a tonneau cover and no cover, and it showed a drag reduction of 2 to 7 percent, which in turn is 0.1 to 0.3 MPG better, so not much at all. But ford goes on to explain the scale of how to decrease the drag on a truck. the most drag is with a netted tailgate, then the tailgate down, then the tail gate up, then a tonneau cover, then a custom design bed cover that basically is a camper shell, but instead of it being the same height from the cab to the end of the bed, the height is the same as the cab, then decreases as it goes toward the end of the bed, then the most efficient is like you see on some semi trucks, the little cone like things on the butt, so a decreasing sized camper shell connected to a cone on the end of the bed of the truck, which significantly decreases drag.

so all in all, do tonneau covers help? yes but your driving habits can negate the positive effects. Same as a muffler