Mileage Monster Build

[red2003xlt]

And cruise control uses up gas unless you're driving on 100% flat ground. Otherwise, you should haul down hills and carry momnetum up the other side while going progressively slower to the top.... like truckers.

I've actually tested this while on long trips.

Unless I'm driving thru the App or Rocky Mountians I use cruise. I get a consistly 25 mph.

I don't think my Ranger has enough weight to affect momentem enough.

 

[Just_Randy]

And cruise control uses up gas unless you're driving on 100% flat ground. Otherwise, you should haul down hills and carry momnetum up the other side while going progressively slower to the top.... like truckers.

I've actually tested this while on long trips.

Unless I'm driving thru the App or Rocky Mountians I use cruise. I get a consistly 25 mph.

I don't think my Ranger has enough weight to affect momentem enough.

I-75 between Michigan and Florida is where I'm talking about. In KY and TN you're either going up or you're going down. In OH I just hit the cruise and cruise. Its all flat once you pass Dayton heading north.

Maybe Rangers are different, but in my Intrepid that has the real time MPG and Avg MPG displayed overhead I was using up more gas than needed by using cruise in hilly areas. I noticed the cruise would slow me down going down hills when my instinct was to let gravity speed me up and it was sometimes downshifting from overdrive to go up the hill. Even if it wasn't downshifting, it was clearly straining to keep the speed constant and nearly always unlocking the torque convertor. All that gravity fighting can't be good for gas mileage. When I'm driving without cruise I never have to unlock the convertor or downshift. I just drive a little slower until I crest the hill.

It could be worth investigating to see if the mileage varies with cruise. Maybe the newer cadillacs have better cruise controls, but an old 95 Intrepid and 2005 Subaru Baja suck the gas on cruise in the hills. My Ranger doesn't have cruise control.

Btw, AWD will suck your gas down too. A 2.5L Subaru gets the same mileage as a 3.5L Dodge.... 26mpg. The dodge weighs a good 1000lb more and has bigger tires.

 

[Psychopete]

I-75 between Michigan and Florida is where I'm talking about.

LOL, I've actually made that trip in my Ranger with no cruise (well, from 30 in Ohio). I did 65 most of the way (speed limit then), then probably 80 the way home. Went to South Daytona Beach for bike week. It was a very long drive strait through (21-22 hours?). The beach was closed the whole week due to the water not being clean enough. I got jipped, but still had fun.

Pete

 

[Just_Randy]

The beach was closed the whole week due to the water not being clean enough.

Man,,, that sucks! I went from Toledo to Miami in one shot. By the time I got to the turnpike in Florida I pulled off for a nap, but couldn't sleep for the heat (about 3 pm, lol). So, I went back at it. Florida is LOOOOOONG! I think the whole trip took 22hrs though. I was hauling! By the time I got to a bed, I could still see the road when I'd close my eyes. I'll never do THAT again.

 

[mountaineergreen]

The cruise was largely ineffective in the terrain I was driving on. I believe the gearing is a bit too high- On 60-65 MPH highways, the engine is racing in 4th and lugging in 5th. If I could run 70+ all the time, it would be fine, but I rarely can do that. 4th is just right at 55 and a tad too low at 60. I think I need an 8.8 with 3.73's to get it right. I may loose a little top end, but where I drive most of the time I'll benefit from lower gears.

 

[Just_Randy]

I know exactly how you feel about the gearing! Mine is the same way and I have 3.73 with 31 inch tires. Thinking of going to 4.56.

Did you ever see that show called Mythbusters? They did a thing about gas mileage on trucks with tailgate up, down, off, hard cover over bed, and tailgate net. I think the net was the best, followed by tailgate up which tied with the bed cover. I think tailgate off was the worst. So, save gas by installing a net!

Btw, I installed a vacuum gauge the other day. I tell ya what, it sure is a challenege to keep that thing above 5! My driving style has been modified to the point were I'm lugging up hills (giving less n less gas pedal as I go up) and racing down the other side in an effort to keep the vacuum high. Its the exact opposite of what cruise control would do. Cruise gives more n more pedal going up the hill and less n less going down.

 

[thegoat4]

"Performance" mechanics operate under the same physics as the rest of us. They simply cater to a customer base that's more tolerant of throwing away money.

I have a 3.0 supercab 2wd, stock. 65-75mph on the highway usually nets just below 27mpg, occasionally getting as high as 29, depending on the wind. Bone stock unless you count the trailer hitch.

 

[red2003xlt]

I-75 between Michigan and Florida is where I'm talking about. In KY and TN you're either going up or you're going down. In OH I just hit the cruise and cruise.

I drive from TLH, FL to Huntington WV. Between Thomasville Ga and North of Atlanta I'll get 25 mph. Once I start climbing hills in Tenn, KY, and VA, my mileage takes a crap.


FWIW: I once owned a 96 Taurus with the same drive train 3.0 automatic. On the same stretch of highway the Taurus got 33 mph. The rpms were less but the curb weight was within 300 lbs(I think).

 

[Just_Randy]

Boy, I'd sure like to know how all you guys are getting 25-30 mpg.... I'm lucky if I get this much: http://www.fueleconomy.gov/feg/2008car1tablef.jsp?id=13787

Of course, I haven't calculated it since I replaced the cam sensor, EGR thingy, plugs, and wires. And I also had 31 inch tires with a bad ball joint on one side. Nevermind, I think I answered my own question.

 

[red2003xlt]

Did you ever see that show called Mythbusters? They did a thing about gas mileage on trucks with tailgate up, down, off, hard cover over bed, and tailgate net. I think the net was the best, followed by tailgate up which tied with the bed cover. I think tailgate off was the worst. So, save gas by installing a net!

I have a soft cover on my truck. The mileage is unchanged.

However the handling is much, much better especially on the highway.

 

[fixizin]

Did they really say a net is better than NO tailgate...? Due to...??

Anyway, I have the sleekest, lowest profile decklid available, and how I get 25.5 MPG (in the flatlands) is by using the "constant throttle position" method, i.e. I just wedge my right foot against the tranny hump, and keep it there, pegged 71mph in 5th gear... let the speed bleed off as it climbs small rises and overpasses, let the speed build on the downslope... I think this is where cruise control wastes fuel, always jinking around to keep the speed pegged. I don't have cruise anyway, lol.

Obviously you must have manual tranny, balanced and properly inflated (and sized) tires, dead-on front-end alignment, tight steering gear and ball joints and tie-rod ends, and "slow-mo" non-fidgety, (i.e. not over-correcting) manner of steering correction on straight roads.

If you have excessive and/or uneven tire wear, that's going to correspond to impaired MPG, 'cause you always be pushin' things sideways, so to speak.

 

[Just_Randy]

Did they really say a net is better than NO tailgate...? Due to...??

Anyway, I have the sleekest, lowest profile decklid available, and how I get 25.5 MPG (in the flatlands) is by using the "constant throttle position" method, i.e. I just wedge my right foot against the tranny hump, and keep it there, pegged 71mph in 5th gear... let the speed bleed off as it climbs small rises and overpasses, let the speed build on the downslope... I think this is where cruise control wastes fuel, always jinking around to keep the speed pegged. I don't have cruise anyway, lol.

Obviously you must have manual tranny, balanced and properly inflated (and sized) tires, dead-on front-end alignment, tight steering gear and ball joints and tie-rod ends, and "slow-mo" non-fidgety, (i.e. not over-correcting) manner of steering correction on straight roads.

If you have excessive and/or uneven tire wear, that's going to correspond to impaired MPG, 'cause you always be pushin' things sideways, so to speak.

I agree with all that 100%. That's what I've been trying to say, only taking it a step further. On downhills, maybe give it a bit more gas pedal and then progressively less pedal going back up.

On mythbusters, they did 2 shows about gas mileage. I didn't see the first one. The second was a "revisited" show. The fans write in with enough complaints about the first one that they have to come back and do it again and address all the complaints. The first show they explained why the truck got better mileage with the tailgate up rather than off or down. Since I didn't see that show, I don't know for sure what they said, but from reading online I think I have a pretty good idea.

The tailgate makes the air swirl around in the bed. I remember as a kid riding in the back of a truck and throwing trash towards the gate. The trash would come right back to me. I could spend a good amount of time being entertained playing ball with beer cans. Anyway, this swirling pocket of air disrupts the drag that would otherwise be right behind the cab. The net takes this a step further. Not only does the net disrupt the drag behind the cab, but it also wipes out the drag that used to be behind the tailgate.

Why the tailgate off is worse than tailgate down, I can't figure out. The 2nd show didn't offer any reasons, just the results.

 

[red2003xlt]

The cruise was largely ineffective in the terrain I was driving on. I believe the gearing is a bit too high- On 60-65 MPH highways, the engine is racing in 4th and lugging in 5th. If I could run 70+ all the time, it would be fine, but I rarely can do that. 4th is just right at 55 and a tad too low at 60. I think I need an 8.8 with 3.73's to get it right. I may loose a little top end, but where I drive most of the time I'll benefit from lower gears.

What RPMS are you turning at 70mph?

I've got 3.73 and stock tires, I'm spinning at 2700 rpms.

I'm guessing the sweet spot for stock 3.0 is around 2200 rpms.

 

[Big Jim M]

What RPMS are you turning at 70mph?

I've got 3.73 and stock tires, I'm spinning at 2700 rpms.

I'm guessing the sweet spot for stock 3.0 is around 2200 rpms.

And I'm guessing that the 3.0 won't run that vehicle at 70mph without full wide open throttle...which would give you even LESS milage.

The "sweet spot" as you call it is an rpm that will maintain FULL vaccum at the speed chosen.. Using LOWER rpm for that same speed will result in LOWER vacuum numbers...which in turn will cause a RICHER mixture and-or retarded timing.. the result of which is WORSE fuel milage.

Remember our sticker milage estimates are for 55mph! 70 mph hasn't been given consideration for milage estimates.
Big JIm

 

[Just_Randy]

The theory of why UDP's see gains is a pretty simple concept. I am baffled why some people cannot understand that.

I just had a revelation that may be of help with the UDP debate.

A couple of years ago I started wondering if the weight of a chain really mattered on a motorcycle. Would a lighter chain let you go faster? I asked around and nobody knew for sure. I even asked on math and physics forums before getting frustrated and doing some experiments of my own.

What I found is, yes, of course chain weight matters (maybe minuscule, maybe not), but it matters more if the drive sprocket is large. Basically what I'm saying is a 12/36 sprocket combo will outrun a 13/39 combo even though they are the same 1/3 ratio. 1) there is less chain and sprocket weight. 2) the 12 sprocket is affected less by the weight and chain friction than the 13 tooth sprocket. So the same should be true with belts on an engine. Even if you keep all the ratios the same, if you can make the drive pulley smaller, you will be able to accelerate the belt faster and make more power.

I set up an exaggerated test to compare:

Its much harder to accelerate the chain when its on the larger sprocket. On a 20hp motorcycle this is definitely something I can feel. On a 150hp truck? Who knows, but it may translate into better mileage.