Power Programmers...

[spacemule]

They rate the Durango with the 4.7L V8 at 14 city and 18 highway and the 5.7L V8 (Hemi) at 14 city and 19 highway.

As I pointed out, it is mainly because of three things; driving conditions, driving style, engine design. Let me repeat that last one; engine design. Just because an engine is small does not mean it will get poor fuel mileage, as my 4.3 ably demonstrates. If your argument were true, no one would want rice burners because they would get really sucky mileage, since their engines are so small.

 

[NYH1]

As I pointed out, it is mainly because of three things; driving conditions, driving style, engine design. Let me repeat that last one; engine design.

I've driven both my wife's 05 Hemi Durango and my parents 06 Durango with the 4.7L engine (different engine disign) with the same driving conditions and driving style and as Chrysler and the EPA states, the Hemi Durango gets better mileage. Which is the same results I get when I've driven them both.

The EPA rates the Durango with the 4.7L V8 at 14 city and 18 highway and the 5.7L V8 (Hemi) at 14 city and 19 highway. In this case the bigger engine gets better mileage then the smaller engine. They also rate a Dodge Ram 1500 Quad Cab 4x4 with the 4.7L V8 and the 5.7L V8 (Hemi) both at 14 MPG city and 18 MPG highway?

Apparently it might be the same with the Ford 4.6L and 5.4L (same engine design) according to Peacock who worked on them! I believe it is. My 87 Bronco with a 5.0L got the same mileage as my friends 89 Bronco with the 5.8L. In that case it was the smaller engine working harder. Both Bronco's were basically the same except they had different size engines, which were of the same design. Both were 4x4, auto tranny's w/ overdrive, 3.55 open diffs., same size tires ect. When we towed our snowmobile trailers which weighed the same he got better mileage. It could be bunk thought.

 

[Haywire Haywood]

When I was truck shopping the Dodge Dakota was rated for 18mph with their 6 cyl, and 19 with their 8 cyl. At the time I thought it was weird, but now it makes sense.

But since I bought my truck used, I got what it had, not what I wanted.

Ian

 

[NYH1]

When I was truck shopping the Dodge Dakota was rated for 18mph with their 6 cyl, and 19 with their 8 cyl. At the time I thought it was weird, but now it makes sense.

But since I bought my truck used, I got what it had, not what I wanted.

Ian

It's pretty much the same way now.

2007 Dodge Dakota Quad Cab 4x4 SLT with auto tranny, 3.55 gears-
3.7L V6 15 MPG city and 19 MPG highway.
4.7L V8 15 MPG city and 20 MPG highway.

These are EPA ratings. Larger engines aren't always going to get better mileage, but they do a lot more then people think, especially when towing or hauling heavy loads.

 

[ShoerFast]

My .02 cents worth.....

My service van is a de-rated 17,000 GVW truck, with a 5L engine*, I drive 16% grade roads here at 11,000' above sea level, I keep up with all traffic , but have a little trouble with on ramps in rush hour driving, not to bad, I can live with it. On a 'baby-da-h311' out of it test, I can pull 14MPG on a flat drive at 5280' MSl @ 55 MPH (I will admit that the conditions need to be near perfect, I settle for 10MPG the rest of the week)

Every engine needs to develop good vacuum down the road, and get to speed with out dumping in a lot of extra fuel or dumping it in to course.

Before I touched the program, exhaust or intake manifold , I would get the 'cam-card' specs or degree the cam. and go from there.

Degreeing the cam is over some peoples heads, granted, but getting a vacuum reading down the road is perhaps a good place to start. Installing a vacuum gauge to the interment cluster , along with if you like them an air : fuel ratio gauge that drives off of the O2 sensor(s) cant also Tailor your driving.

Comp Cams , is about my first place 'cam shop' anymore, there are a lot of other companies, but Comp has a lot of grinds for a lot more engines in most cases.

From the hip, I would be looking at an 'Extreme Energy' or 'RV" grind , A better then stock cam** in most cases will correct for any gearing or engine : wight problems that cost you money at the pump. At near $3.00 dollor a gallon gas, it don't take long to pay for a cam.

I would not blink thinking about swapping the cam out of most stock engines. You will gain TQ and mileage, period.

* I did a lot of work to the 5L engine and transmission to make the power I needed.

** The biggest most often mistake is going to far with a cam grind, just a couple 'grinds' from stock can make a world of differance, going 1 grind to far can make a world of hurt to some engines/drives.

 

[Treeman587]

I had a Hemi, with 4.56 gears. It got 12 mpg normal driving. Towing 5000 lbs, it got 8.5mpg. The programmer will help you some, maybe 1 0r 2 mpg. If you change gears to help it get up to speed you will hurt the mpg. Because when you are cruising the motor will be turning a higher RPM. You spend more time cruising than accelerating. Air filter and exhaust mods will help you better.

Or you can get a diesel. I traded my hemi for a Power Stroke. Now towing 5000lbs I get 14 mpg under the same conditions. Hwy mileage is about 17 without my programmer and 19.5 with it. When I put the 35's on there I should be over 20 mpg hwy. Because its diesel the larger tires will slow the motor down on the hwy, which is also where the torque happens to be. Not to mention diesel is cheaper right now anyways. All I have done is intake and 4 inch turbo back exhaust(got rid of the kitty too), And an Edge Programmer


Also, I lost 3000 trading in my hemi, but over the next five years, roughly 100,000 miles, the truck is financed for I will save 10,000 in fuel costs.

Diesel Power did a gas vs diesel test, towing, mpg, etc. in last months issue

 

[SmokinDodge]

I had a Hemi, with 4.56 gears. It got 12 mpg normal driving. Towing 5000 lbs, it got 8.5mpg. The programmer will help you some, maybe 1 0r 2 mpg. If you change gears to help it get up to speed you will hurt the mpg. Because when you are cruising the motor will be turning a higher RPM. You spend more time cruising than accelerating. Air filter and exhaust mods will help you better.

Or you can get a diesel. I traded my hemi for a Power Stroke. Now towing 5000lbs I get 14 mpg under the same conditions. Hwy mileage is about 17 without my programmer and 19.5 with it. When I put the 35's on there I should be over 20 mpg hwy. Because its diesel the larger tires will slow the motor down on the hwy, which is also where the torque happens to be. Not to mention diesel is cheaper right now anyways. All I have done is intake and 4 inch turbo back exhaust(got rid of the kitty too), And an Edge Programmer


Also, I lost 3000 trading in my hemi, but over the next five years, roughly 100,000 miles, the truck is financed for I will save 10,000 in fuel costs.

Diesel Power did a gas vs diesel test, towing, mpg, etc. in last months issue

Treeman please come back a month or two after the larger tires and tell us your mileage. I had 33" Kumho's on the Dodge and I was always getting 16 mpg. After a year or two the mileage starting creeping up, 16.5, 16.9 etc........
The only change had been the mileage on the tires. When it came time to replace the Kumho's (which held up for about 30,000 miles btw) I went to a 245r 75 (one size over stock 235, it's a 31" tire) and we are now getting 17.5 regularly.

My only theory is that the weight of the tires was affecting the mileage. While I still prefer the "look" of the 33's I like the economy from the 245's. Each truck is different though, mine is buzzing 2,250 rpm @ 65mph with the 6 spd and 4.10's

 

[Haywire Haywood]

....rated for 18mph with their 6 cyl....

I did it AGAIN... :angry2: