forget power, let's talk MPG

[KTMpat]

Don't really care to make my 4000 lb Navajo brick go 0-60 quicker than a Mustang... my SHO does that circa 6 seconds. What I/WE/EVERYONE need is MPG, please. No offense to the street racers, but pouring money into a sports ute to make it act like a race car is re-inventing the wheel... a lot of work. Then some guy with a used Integra puts a total of $300 in an NO2 system and blows you away. But then, it's loads of fun drag racing another soccer mom in her Expedition (lol).

I would like to see some itemized ideas for more miles per gallon, save putting an egg under the gas pedal. For example, changing the thermostat from 180 to 195, or maybe ram air, exhaust mods, air deflectors, etc. Thank you in advance. Pat

 

[Alec]

Well, I haven't taken a road trip since putting the headers on, but before the headers (with everything else listed below), I did about 25 hwy and 18-20 city (depending on which city). The biggest mpg improvement came with my chip, but I also have to use 93 octane to get that. Mileage drops about 3 mpg if I use 89 octane. It increased some with the K&N and the catback, but dropped slightly with the TB. I have a feeling that the headers really helped, but haven't filled up yet.

 

[V8Pete]

Taller gears. I picked up 3 mpg freeway (17 1/2 to 20 1/2) by changing from 3.73 to 3.08.

Pete

 

[2001ExpSport]

I just bought a set of Bosch +4 spark plugs and went from 12.5 to 14 mpg city. I don't know how you guys are getting 18 mpg city. Either you guys have feather feet or you are full of it.

Just my .02 worth.

 

[mzancz]

I have a 91 Explorer, with barely any mods, just put in Bosch Platnium +4's and Splitfire wires. The best I've gotten so far is 14.5 per gallon, thats ok, but I was hoping for a little more.

 

[mike91]

it's funny but

Actually, 90% of the mods that everyone has performed on their truck on this site, does improve the MPG. Changing your intake and exhaust for more power will effectively help the engine to run more efficiently and at cooler temperatures. An engine that doesn't work under load, burns less fuel in the long run and hence, better MPG. Aftermarket Spark plugs and Wires help burn the fuel more efficiently as well - I have yet to hear from anyone complain about losing MPG from changing the plugs and wires.

As Pete mentioned, one way that goes against the performance theory is gearing. One way(i.e. 4.10's), you accelerate and spin the wheels quicker, but you lose MPG. On the other hand 3.08's will slow things down a bit and MPG will go up.

Finally certain air deflectors such as the one on the hood can and will add drag to the vehicle and more drag decreases the MpGs.

 

[Brett]

I'm getting 19-20 mpg in town and usually around 23-24 on the highway. I usually get around 325-340 miles from a tank. So far all I have done to the motor is Bosch Platinum 4+ plugs, Jacobs plug wires, and K&N drop in air filter. I change the oil every 3000 to 3500 miles with Valvoline 10-30w. I run 87 octane gas.

I've also got 4.10 gears pushing 265/75/16 Goodyear Wrangler AT/S tires.

I guess you can call me a feather foot because I never rev the motor past 4000 rpm, and I usually shift between 2200 to 2500 rpm.

 

[scott]

My best ever was

19.5 average with 80%/20%- highway/city driving. This was after plugs, wires, K&N, Flowmaster, Tornado(this actually gave me a shade over 1 mpg) but then I got power hungry and supercharged it. Now I get about 16 mpg but I have to run 93 octane though due to the SC and also my Superchip. So it's pretty expensive to drive these days. I guess 16 mpg with the cost of premium would be like 13-14 mpg from regular unleaded. Gas is too expensive!!!!! ...sorry...

 

[William Schumacher]

for what it's worth !!!!

I had my Jacobs ignition off for 2 months because it was bolted down where my air box was(I had taken the box out for the KKM last year),however,I did not like the hot under hood air and the increased amount of dirt going into my engine and went to the Amsoil drop in box foam filter,and
I just put the Jacobs in 2 weeks ago,(mounted it between the grill and radiator),and WOW,I noticed a big gain in mpg.,I would never be able to go 300 + miles on a tankfull with this truck(4.10 gears sohc auto),and now since putting back on the Jacobs ,and upping the gap of the new Bosch reg. plats
to 0.60 it seems to be dialed in !!,I also just put on a ram-air setup,4" hose routed from the oval slot in the airdam to the side of the airbox that faces the left wheel,I plugged up the other side with plastic and lots of cool tape,also cooltaped everything the air passes through,but the gains came from the jacobs !!

 

[KTMpat]

thanks all, now question about gears

How about an engineering evaluation? I know if you have 3.08 gears with 28 inch tires, you can effectively maintain the final ratio using 3.73 gears with say 30 inch tires... and possibly 4.56 with 33 inch, etc, etc.

One would believe then that rather than going to taller gears for better MPG, one could just go larger tire diameter to get same effect. HOWEVER, I don't think this holds true in real world application. There is something about wheel torque (smaller diameter tire has more torque) that is more efficient than a large wheel diameter and lower gears (higher ratio). Rolling mass, more tire contact to ground, and other resistance comes with larger tires.

Other observation, members here having the SOHC motor seem to get better mileage than the OHV... no matter what the gears. Brett has 4.10 gears with approx 31.7 inch, call 'em 32 inch tires, and gets great mpg. ...sheesh!

Keep the ideas coming and I'll do a roll up, thanks much!

 

[scott]

Bill...

unless something has changed with Jacob's they say don't use Platinum plugs with their systems.

KTMPat- the larger tire instead of taller gears doesn't work well because of the increased "rolling mass" of the larger/heavier tires.

 

[DC]

I get around 15 MPG around town, 18 on the highway. I have an automatic. I am sure automatic vs manual makes a difference in MPG.

 

[William Schumacher]

something has changed !!

Scott:, when I first tried the unit,I tried it with the stock plugs,& gap setup,I told them I had no improvement,and they told me to try another plug non plats,and up the gap a bit,I told them I did and still no improvement even though I never changed out the plugs,(I was not sure if this would increase my gains),they then told me to get a new set of regular plat plugs,and go to 0.60 on the gap,I went to the bosch plats,and started seeing a gain in power and mpg.then I wanted to put my airbox in so I could use an Amsoil filter and a ramair setup, and since the jacobs ignition was mounted where the box was,I had to take out the jacobs untill I could find another place for it,and it's in a great place up behind the grill,as soon as I put it back on I was getting solid results again,
thats it !!

 

[donkey boy]

Re: thanks all, now question about gears

Originally posted by KTMpat
... One would believe then that rather than going to taller gears for better MPG, one could just go larger tire diameter to get same effect. HOWEVER, I don't think this holds true in real world application. ...

KTMpat, you are absolutely correct, also in the real world. This holds true as long as you just go with taller (not wider) road tires and you keep the air pressure rather high, around 35 psi. Unluckily for milage, taller tires are normally also wider, which again will cost gas. Milage also gets negatively affected by low air pressure or Mud-Terrain style tire pattern.

 

[CAC91]

My Explorer averages a tad better than 18mpg and most of my driving is around town. I run 87oct, have a 5spd and 3.55 rear with stock tire size and live at about 5800ft.

 

[Grateful11]

I average 23.6mpg on a 20 something tank average. I'm running 85% Interstate using 87 octane. I have gotten 420 miles on a tank. My wifes Expedition gets 20mpg on the interstate. And yes I know how to figure gas mileage.

 

[kilroy]

2WD don't count! LOL Theres much less drag on a 2WD so I sure hope you get that kind of milage!

Anyway, I seem to get around 14 MPG no matter what I do, I occasionally got an 18, but can't seem to figure out how. I do have the deflectors on th hood, windows and back door, but considering it costs more money to repair rock chips in the hood(lots of gravel pits around here) than I would save in milage, I think they are worth it. I especially like the rear deflector, now my rear door stays clean!

I just wish I had kept my Crown Vic, it got 21 MPG consistant city, 28 Highway. Of course it wasn't quite stock either, had a police processor with a rev limiter instead of the regular one.