How to milk out MPG's.

[5.0Flareside]

IDK man I'm just tossin turds around and talkin smack......I have no idea how far up the gauge mine will go with these 3.55's in her now but with 3.31's I smoked a Gen1 Lightning on the highway....ya ya 4.10 versus 3.31's......he was just mad I hung with him till his speedo pegged out. (120 BTW)

well the electronic shift kit shuts me off in high gear at a certain RPM. i cant remember to be exact. and last time i did the math it was 110 mph ish. thats after the 4.10 swap. used to i could get it up to like 120ish.

 

[polarbear]

I get 17-19 mpg consistently with the Grand Marquis in town, and it'll turn high 20's on the hwy. Funny thing is, son Nick can get behind the wheel and lop 5 mpg off of those numbers.

Why?

I'm gonna throw a guess out here- I've got a light foot out of the hole, and I'm consistent on the Interstates (although 70-75ish is a typical cruising speed for me). Nick wants to be first away from the light- always. He never uses the cruise control, and generally varies his speed between 65 and "OMG I hope there isn't a Trooper nearby."

To be honest, though, you haven't lived until you ride along with Aaron in the Acura.

 

[LEB Ben]

plus the 70mph mark of gas usage compared to 60-65 well thats just dependent on the vehicle, my truck gets decent gas mileage (13.5 mpg) at 60 mph. but great (15 mpg) at 70-80.

Any clue what your rpm's are at those spots? I'll agree there is a sweet spot...but I've never heard of it being that high.

In the right lane? Dunno how you are getting better economy at a higher speed, kinda defies physics ..

I'm not sure if there is a universal speed...but yeah, impeding traffic is a violation. I know on some of the highways I've traveled on, I've seen the speed limit sign, with a minimum speed posted underneath...typically between 10 and 20 mph.

I'm speaking for my own truck...6mpg at 70 mph, 8 at 55-60.
Which, by my math is roughly a 30% increase.

Same speeds with me...if I'm doing 60, I can pull 14mpg's easy in the Bronco...if I hit that 70mph thresh hold...I drop to 10-11mpg's.

 

[5.0Flareside]

Any clue what your rpm's are at those spots? I'll agree there is a sweet spot...but I've never heard of it being that high.



I'm not sure if there is a universal speed...but yeah, impeding traffic is a violation. I know on some of the highways I've traveled on, I've seen the speed limit sign, with a minimum speed posted underneath...typically between 10 and 20 mph.



Same speeds with me...if I'm doing 60, I can pull 14mpg's easy in the Bronco...if I hit that 70mph thresh hold...I drop to 10-11mpg's.

the rpm's are...

70 mph 2400 RPM's.
80 - like 2800 (i think.)

i'll get her wound out to 3400 rpms in overdrive sometimes.

 

[LEB Ben]

the rpm's are...

70 mph 2400 RPM's.
80 - like 2800 (i think.)

i'll get her wound out to 3400 rpms in overdrive sometimes.

Something about those #'s isn't right (especially in OD)...to be pulling those kinda numbers, you'd need a 38-39" tire with a 4.10 rear. Otherwise, those numbers seem about 6-700rpm too low to me...and if your cruising rpm's are that high...something wrong.


Edit...however, my calculations have been wrong before...and if you really are only pulling 2400r's at 70, I can see the decent mpg #'s...but I still don't get how it's better than at 60. Less rpm's on highway driving=less gas consumption.

 

[5.0Flareside]

http://www.csgnetwork.com/multirpmcalc.html

gear ratio: 4.10
tire height: 29
mph: 70

results:
Auto n/od: 3414
AOD: 2328 <<<<<<<< bout what mine will be....


then the complete ratio calculator:

Ratio: 4.10
tire height: 29
mph: 70
trans final gear ratio: .71


Engine RPMs: 2361


80 mph RPMS= 2698
110 mph: 3710

 

[LEB Ben]

Damn...I like that Calculator. Beyond that, I see now. I was calculating for a 31-32" tire and even though I thought about it...I forgot to account for the final OD ratio...whoops. But damn, those numbers just seem to be screaming for an OD rig.

 

[5.0Flareside]

That 4.10 gear makes a big difference with almost stock tires.

 

[LEB Ben]

Depending on how much highway driving you do, you might consider going with a bigger tire to drop your effective ratio and lower your rpm's. It won't hurt your mpg's that much...and you'll be taking a bunch of unnecessary wear and tear/stress off your rig. But if you mainly do citty driving...no biggie.

 

[5.0Flareside]

i do 50/50 now.

but i wont be going to a bigger tire anytime soon, itll be a few years cause i have a set of 1 year old 255/70s on there right now.

 

[Fordzilla80]

Keep your tires @ the proper PSI, proper tune up regularly, drive like a granny, give yourself enough room to not have to use the brakes; which leads to having to accelerate more, try to leave earlier than you normally do if traffic is an issue... Take all unneeded stuff out of the car as weight and a 2.2 I4 don't get along...

Thanks man.Checked the tires today,they were a bit low,so I aired them up to the proper PSI,and tune up is coming soon.I took a different route today that kept me off the highway until about a mile from the school,and that helped immensely.The route keeps me away from the aforementioned lock em up idiots on the highway,so I think that and the lower speed limit helped it out.

 

[flareside_thunder]

No doubt......

 

[FordF-SuperDuty]

To be honest, though, you haven't lived until you ride along with Aaron in the Acura.

Same with my dad in his G37, He's taken it up 130.

 

[countryboytn]

here its 10 mph.. i know someone thats got a ticket cause of that.

I get 17-19 mpg consistently with the Grand Marquis in town, and it'll turn high 20's on the hwy. Funny thing is, son Nick can get behind the wheel and lop 5 mpg off of those numbers.

Why?

I'm gonna throw a guess out here- I've got a light foot out of the hole, and I'm consistent on the Interstates (although 70-75ish is a typical cruising speed for me). Nick wants to be first away from the light- always. He never uses the cruise control, and generally varies his speed between 65 and "OMG I hope there isn't a Trooper nearby."

To be honest, though, you haven't lived until you ride along with Aaron in the Acura.

Seems to be about the same gas mileage with me and my dads COMPLETLY different driving styles in out Lumina. He takes off extremely slow, drives under the speed limit, doesn't get in any hurry at all... and I drive, well kinda like Nick. I think what kills dads mileage is that he is on the throttle more than I am... where I get up to speed and sorta coast with traffic, he's on it less...but longer. If that makes sense?

I have to drive too many miles to college,and on Mondays and Wednesdays,I have to make the trip twice.

]
Mapquest says it's 7 miles

Sorry, but this makes me laugh. I have to drive roughly 5miles to get to town, thats for anything. I know alot of people who have to drive double that, or more.

 

[5.0Flareside]

i drive 42 miles roundtrip to work and back. now for alot of people thats not alot, but compared to what i used to do, its a chit load.

 

[polarbear]

Depending on how much highway driving you do, you might consider going with a bigger tire to drop your effective ratio and lower your rpm's. It won't hurt your mpg's that much...and you'll be taking a bunch of unnecessary wear and tear/stress off your rig. But if you mainly do citty driving...no biggie.

You'd be amazed at what a negative effect larger tires have on fuel mileage. Yes, they help the overall RPM/mph equation, but it takes an incredible amount of energy to get those bigger meats turning. On newer rigs, the larger tires also fubar a number of calculations the onboard ECM does (air/fuel mixture, transmission shift points, etc).

 

[LEB Ben]

i drive 42 miles roundtrip to work and back. now for alot of people thats not alot, but compared to what i used to do, its a chit load.

Time to sell the truck and buy a matching Corsica?

You'd be amazed at what a negative effect larger tires have on fuel mileage. Yes, they help the overall RPM/mph equation, but it takes an incredible amount of energy to get those bigger meats turning. On newer rigs, the larger tires also fubar a number of calculations the onboard ECM does (air/fuel mixture, transmission shift points, etc).

I hear that Ernie...but on his truck...increasing an inch or two diameter on a street tire might add 4-5lbs per tire tops. The impact of the tires I recommended would have negligible effects. Now if he went from his 29's to something in my sig...or even a 33 for that matter...I'd agree all day with you. I'd I'm not even going as far as saying the rpm difference would necessarily help his mpg's...but I definitely think it would help in higher dollar components, because his truck just seems to be screaming to me at those rpm's. So if he drops them, his engine will be happier, his tranny will be happier and his rear axle will be happier too.

 

[5.0Flareside]

Time to sell the truck and buy a matching Corsica?



I hear that Ernie...but on his truck...increasing an inch or two diameter on a street tire might add 4-5lbs per tire tops. The impact of the tires I recommended would have negligible effects. Now if he went from his 29's to something in my sig...or even a 33 for that matter...I'd agree all day with you. I'd I'm not even going as far as saying the rpm difference would necessarily help his mpg's...but I definitely think it would help in higher dollar components, because his truck just seems to be screaming to me at those rpm's. So if he drops them, his engine will be happier, his tranny will be happier and his rear axle will be happier too.

screw you. one POS in the driveway is enough. im trying to get a Mustang for her.

and really its not screaming at those Rpms, its just floating right along.

 

[LEB Ben]

screw you. one POS in the driveway is enough. im trying to get a Mustang for her.

HAHAHAHAHA

and really its not screaming at those Rpms, its just floating right along.

Dude...for reference sake, Red cruises at 70mph at 2900...with no OD. And the Bronco cruises at 70mph at 2300rpm...with no OD. And Thunder would cruise 70 at 2100rpm with OD.

 

[taxreliever]

You'd be amazed at what a negative effect larger tires have on fuel mileage. Yes, they help the overall RPM/mph equation, but it takes an incredible amount of energy to get those bigger meats turning. On newer rigs, the larger tires also fubar a number of calculations the onboard ECM does (air/fuel mixture, transmission shift points, etc).

I drove my rig 3000 miles cross country on 235/75/15's and got 9 MPG's consistently. When I got to Boston, I had a shop put my 37's Super Swampers on (only a few hundred miles to home so I thought it wouldn't be a big deal) and for the next 250 miles, I got 13 MPG's. I surmised that if there's enough power under your hood, the additional power required to run bigger tires isn't enough to make a difference and I made up the additional MPG's because of the larger diameter tires; more distance with the same RPM's. I think this would be the exception to the rule as bigger tires mean more drag, more energy required, etc.