Tune for MPG

[dcmdon]

Other than being easy on the pedal, I believe the biggest change you can make to get better MPG is to reduce your driving speed when on the freeway/interstate.

I have made it a point that there is no need for me to be in a hurry, no matter where I go.
It's a mindset change, as I've always had some sort of sports car in the past and was heavy on the pedal. It is fun to drive fast and pass other vehicles.
Now, I just putt along, never taking my speed over 70. I pass a few semis along the way, but usually remain in the right lane and get to watch all of the anxious, impatient drivers trying to get ahead.
My MPG is among the highest I've seen using the fuelly app.

The mindset thing is real and its HUGE.

If I didn't get the Gladiator, I was probably going to get a BMW M2. I've always enjoyed fast cars. I sold my 04 STi when I had kids (lightly modded with 400 hp at the wheels)

My plan was to get another fast car. But I realized that as it is in my Volvo sedan, I drive too fast. So I went the opposite way with the gladiator.

Its all about having a vehicle that supports the putt along mindset. After about 2 hours of test drives, I realized the Gladiator did that for me.

I know I can do it. I have an old Chevy convertible that I am content to just cruise in. To that end, I think the Jeep's vague "old timey" steering actually helps.

A buddy of mine after driving my '66 Chevy said "You don't really drive it. you kind of just aim it". The gladiator is a bit like that also.

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[USMC-SSGT]

@poole34 / others

This is great stuff and along with what I was thinking as well.

For someone who asked- im on 3.73 so looking forward to the better performance of 4.88.

100% what killed my MPG was the boat anchor 35” Baja boss tires and lift. Those both are what bring a much larger smile to my face than the fuel gauge brings a frown however. I then lost maybe another mpg when I put on a stubby bumper fully exposing the entirety of 35x12.50 rubber.

I feel like I’m very efficient on the pedal, but do tend to drive 75 on the highway on cruise control. That’s a solid idea of bringing that back a bit. Heck, even 70 will bring me a real world increase.

Where it stands now-gears are happening late January. Exhaust is happening early January.

CAI- I have it sitting in a box. I don’t plan to install it.

Throttle body- if I go that route (undecided) I will also add the CAI. I may do the TB because like a CAI, it’s relatively inexpensive and harmless. Won’t hurt the truck or cause any down line issues.

Tune- if I do all 3, I will likely do the pulsar or buy a second ECU and do the Livernois. I only have 8k miles however so do need to keep the warranty in mind.

 

[steveorama]

@poole34 / others

For someone who asked- im on 3.73 so looking forward to the better performance of 4.88.

100% what killed my MPG was the boat anchor 35” Baja boss tires and lift.

This right here is likely your culprit. You went from 32's to 35s, but didn't regear. Your Jeep is working harder to get it rolling. This is simple physics. A taller gear will make it move with less effort. The downside is your highway miles are most likely better with the shorter gears now if you travel flat highways. If you do more city driving or highways with elevations you really need to regear soon. By regearing to an appropriate gear size to match your tires, will get you what you are looking for with MPG without the further modifications you are discussing. I would regear first. The problem for a lot of Jeepers is regearing isn't cheap and you can't show it off when it's done so no one, but you knows it's done. Not a lot of bang for your buck in peoples minds, but it's probably the most important mod you can do if you put larger tires on your Jeep.

 

[USMC-SSGT]

This right here is likely your culprit. You went from 32's to 35s, but didn't regear. Your Jeep is working harder to get it rolling. This is simple physics. A taller gear will make it move with less effort. The downside is your highway miles are most likely better with the shorter gears now if you travel flat highways. If you do more city driving or highways with elevations you really need to regear soon. By regearing to an appropriate gear size to match your tires, will get you what you are looking for with MPG without the further modifications you are discussing. I would regear first. The problem for a lot of Jeepers is regearing isn't cheap and you can't show it off when it's done so no one, but you knows it's done. Not a lot of bang for your buck in peoples minds, but it's probably the most important mod you can do if you put larger tires on your Jeep.

Very much agree. Also agree that its a tough buy since it’s one of the priciest “mods” you can do that no one can see or hear.

I am however in team “lockers before lights” and have already purchased them and scheduled the install. To prove to others that I did something however I did go ahead and have my body shop paint match my custom differential covers. Helps street cred.

 

[steveorama]

Very much agree. Also agree that its a tough buy since it’s one of the priciest “mods” you can do that no one can see or hear.

I am however in team “lockers before lights” and have already purchased them and scheduled the install. To prove to others that I did something however I did go ahead and have my body shop paint match my custom differential covers. Helps street cred.

You're on the right track then. I imagine once you get the gears done and recalibrate for them and the tires, your search for better MPG will resolve itself. You won't be getting 20 MPG, but I would expect a mile or two just from that. So what you were looking for.

 

[dcmdon]

One other thought. I think you need to approach this the same way you approach building a light car, boat, or airplane.

grams make ounces, ounces make pounds, etc.

you aren't going to get anything that is going to. help a lot. Many changes may not even be easily measurable. But if they are real, they will begin to add up and make a difference.

If you make 5 changes and each impacts economy by .5 mpg, then its 2.5 mpg total.

Though I still am skeptical that its worth it.

Lets say that in all, your changes help you go from 17 mpg to 20 mpg.

If you assume 12,000 miles per year and 3.25 per gallon you are at.

(12,000/17) x 3.25 = $2294/yr at 17 mpg
(12,000/20) x 3.25 = $1950/yr at 20 mpg

So you are looking at $345/yr in savings. This suggests that its not worth spending thousands to get better fuel economy. Unless you can really knock it out of the park.

I used to have a VW Passat that I generally got about 28 mpg. While I owned it I sold my boat to a good friend of mine who lived about 120 miles away. I was going to show him how to run it at his marina, so I followed him back home in my VW. He was nervous driving with a trailer and averaged under 60 mph.

I normally drive 75 mph or more.

When I refueled I figured my mileage and was astonished to see something like 36 mpg.
So again, I think that adjusting your driving will have the most impact. And it doesn't cost anything other than your time. (which might make it a deal breaker for some)

 

[USMC-SSGT]

One other thought. I think you need to approach this the same way you approach building a light car, boat, or airplane.

grams make ounces, ounces make pounds, etc.

you aren't going to get anything that is going to. help a lot. Many changes may not even be easily measurable. But if they are real, they will begin to add up and make a difference.

If you make 5 changes and each impacts economy by .5 mpg, then its 2.5 mpg total.

Though I still am skeptical that its worth it.

Lets say that in all, your changes help you go from 17 mpg to 20 mpg.

If you assume 12,000 miles per year and 3.25 per gallon you are at.

(12,000/17) x 3.25 = $2294/yr at 17 mpg
(12,000/20) x 3.25 = $1950/yr at 20 mpg

So you are looking at $345/yr in savings. This suggests that its not worth spending thousands to get better fuel economy. Unless you can really knock it out of the park.

I used to have a VW Passat that I generally got about 28 mpg. While I owned it I sold my boat to a good friend of mine who lived about 120 miles away. I was going to show him how to run it at his marina, so I followed him back home in my VW. He was nervous driving with a trailer and averaged under 60 mph.

I normally drive 75 mph or more.

When I refueled I figured my mileage and was astonished to see something like 36 mpg.
So again, I think that adjusting your driving will have the most impact. And it doesn't cost anything other than your time. (which might make it a deal breaker for some)

This is a great read and something I haven’t missed. Things like the exhaust I simply want because of the sound at startup/idle and the no drone during cruise.

But a CAI ($349) Throttle body ($299) and a pulsar ($630) without a second ECU adds up to $1278. That’s 3-3/4 years to break even. That’s IF you get 3 mpg improvements. As we all know, with those mods it would be a pretty optimistic and lofty goal.

Hence most of this being the reason for the thread, the “is it possible?” Have people done it and seen these results. I like a project and would consider the costs as a fun project. Where the data is hard to find is the variables. There are people who have done all of the above for the pure sake of performance to get on it off the line or to tow better in the mountains. MPG isn’t their goal and wouldn’t have been on their radar. Just a nice added bonus.

 

[dcmdon]

This is a great read and something I haven’t missed. Things like the exhaust I simply want because of the sound at startup/idle and the no drone during cruise.

But a CAI ($349) Throttle body ($299) and a pulsar ($630) without a second ECU adds up to $1278. That’s 3-3/4 years to break even. That’s IF you get 3 mpg improvements. As we all know, with those mods it would be a pretty optimistic and lofty goal.

Hence most of this being the reason for the thread, the “is it possible?” Have people done it and seen these results. I like a project and would consider the costs as a fun project. Where the data is hard to find is the variables. There are people who have done all of the above for the pure sake of performance to get on it off the line or to tow better in the mountains. MPG isn’t their goal and wouldn’t have been on their radar. Just a nice added bonus.

A cold air intake will net you exactly zero.

If we assume a CAI actually flows better and provides the engine with cooler air, which is somewhat in doubt, then it will even then only matter when you are at wide open throttle (WOT)

At all settings other than WOT there is a large throttle butterfly blocking most of your Jeeps intake manifold. That's how your engine is controlled. If you are requesting a certain amount of torque from the ECU it will adjust the throttle until a certain manifold pressure is achieved. If your intake is perfectly unrestrictive, it will take less throttle opening. But the target manifold pressure will be the same as will the power provided.

Modern fuel injection systems meter fuel based on the MASS (not volume) of air that your engine is taking in not the volume. So the fact that it may be a bit cooler is also irrelevant. Mostly. If the air is appreciably cooler, your FI system may be able to run a bit more ignition advance if its tuned to take advantage of it.

**Edit**. And as I think of it. At low throttle settings, ignition advance will be set without much regard for detonation because at low manifold pressures detonation isn't a risk. **

But this is an edge case that will give very marginal improvements if any at all.

I hope this makes sense. Feel free to challenge me if anything doesn't sound right.

 

[Mac Attack]

One other thought. I think you need to approach this the same way you approach building a light car, boat, or airplane.

grams make ounces, ounces make pounds, etc.

you aren't going to get anything that is going to. help a lot. Many changes may not even be easily measurable. But if they are real, they will begin to add up and make a difference.

If you make 5 changes and each impacts economy by .5 mpg, then its 2.5 mpg total.

Though I still am skeptical that its worth it.

Lets say that in all, your changes help you go from 17 mpg to 20 mpg.

If you assume 12,000 miles per year and 3.25 per gallon you are at.

(12,000/17) x 3.25 = $2294/yr at 17 mpg
(12,000/20) x 3.25 = $1950/yr at 20 mpg

So you are looking at $345/yr in savings. This suggests that its not worth spending thousands to get better fuel economy. Unless you can really knock it out of the park.

I used to have a VW Passat that I generally got about 28 mpg. While I owned it I sold my boat to a good friend of mine who lived about 120 miles away. I was going to show him how to run it at his marina, so I followed him back home in my VW. He was nervous driving with a trailer and averaged under 60 mph.

I normally drive 75 mph or more.

When I refueled I figured my mileage and was astonished to see something like 36 mpg.
So again, I think that adjusting your driving will have the most impact. And it doesn't cost anything other than your time. (which might make it a deal breaker for some)

You are correct! Not bragging, but I make over $80. per hour....when I'm working...not when I'm not working I make ZERO, zilch, nada...the best way for me to make money while having fun is to avoid costs...cost avoidance...and driving slower...is, as you state, is probably the best, easiest, least expensive option. But, other alternatives...are so much more fun!

 

[ShadowsPapa]

Only thing I have seen so far that really makes any difference is bring it back to stock, tires, etc and you will get your MPG back. I have tried to add/change very little on it since its my DD along with Kayak/trail transport. Seems to me the biggest hit came with the tire change. Moving from stock to Rubi Take off tires/rims put most of the hit on me. If gas keeps going up I might have to find some sort of change

Tires made at least a 2 mpg hit for me. Going from the stock H/T tires to A/T tires did EXACTLY what the dealer shop said it would do - drop mpg. And that makes sense - Jeep sells the Overland for highway driving, mpg, etc. They knew what they were doing with the narrow highway tires and the gear ratio involved.

As mentioned wind resistance increases exponentially with speed. There's a reason the 1970s saw 55 mph speed limits. Anything over about 60 really kills these.
Weight - I dropped more mpg with the steel bumper and winch, another mpg or so at least.
Height, weight, exposure of the undercarriage and suspension to the air (air dams like the Overland has actually DO something)
That piece between the bumper and front fender on the sports - that's to help keep air off the front of the tires. Spinning tires in the air are worse than a simply piece of body. I know people hate those things, but they do make a difference in mpg.

 

[USMC-SSGT]

Little experiment today. Almost impossible to be accurate but I did the best I could. Calm wind day on an open freeway 36° outside. It’s sea level here but never flat. It’s usually up or down a 2% grade constantly so flat, but not flat enough for accuracy. Found a couple stretches that stayed flat long enough for it to stabilize. Each was +-1mpg bouncing back and forth. Experiment only shows difference between 65mph and 75.

 

[MyRight]

Little experiment today. Almost impossible to be accurate but I did the best I could. Calm wind day on an open freeway 36° outside. It’s sea level here but never flat. It’s usually up or down a 2% grade constantly so flat, but not flat enough for accuracy. Found a couple stretches that stayed flat long enough for it to stabilize. Each was +-1mpg bouncing back and forth. Experiment only shows difference between 65mph and 75.

My experience shows you'll see a greater difference for the duration of a full tank, so your numbers should improve.

 

[ShadowsPapa]

Little experiment today. Almost impossible to be accurate but I did the best I could. Calm wind day on an open freeway 36° outside. It’s sea level here but never flat. It’s usually up or down a 2% grade constantly so flat, but not flat enough for accuracy. Found a couple stretches that stayed flat long enough for it to stabilize. Each was +-1mpg bouncing back and forth. Experiment only shows difference between 65mph and 75.

Calm? We are expecting 70 mph+ winds later today. IHP, and other entities are warning drivers - stay clear of the big rigs and any other high profile vehicles. And I have an appointment 30 minutes away later today - will be testing my truck once again against record winds.

Anyway, one thing I've noticed and EVERY Wrangler, CJ or JT owner already knows this - wind speed has a huge impact. I can drive a road with the wind at about 10 mph out of the SW and get maybe 19 mpg - and on the way back get over 20. And the only difference - is that bit of wind. And the road I'm talking about is a N-S road so even that SW wind has an impact.

 

[Papa Jawa]

I’ve read hours of stuff here from pedal commanders to pulsars to livernois and everywhere in between. Still need a little help.

I’m a little unique in that I’d like more MPG and couldn’t care less about more HP, Torque, pedal response etc. I know it’s a jeep and I’ve done everything possible to make it worse (lift, tires, stubby etc.) I am just looking for a gain, not a miracle.

I already am great at step 1: being easy on the skinny pedal. I seldom exceed 4K rpm unless required to merge etc.

Here is where it gets confusing for me- pulsar seems obvious that it plugs into the computer and does it’s thing. How are the preferences changed such as “performance” vs “eco” type changes? Does the pulsar realize any changes in MPG at all? This one is honestly bottom of my list. It’s my daily driver and I don’t want to risk no starts or crawl mode. To me, even one occurrence negates any single positive.

Livernois- I gather you remove your “computer” and send it to them. They then do their work and send it back to you. From here you still need to load the different tunes on it? How is this accomplished? How do I go about changing between performance and eco? Or 91 octane and 87 or the other options out there? This one seems to be the best and most reliable option with the exception of warranty (unless you buy a second ECU.)

Next up, all these options. They all seem to run in the not quite a grand column. Is there any real MPG increase in these tunes? Is it negligible at best or are we talking average of 15mpg to average of 17.5?

I will have an intake (I know, useless as a football bat) and a corsa exhaust if those make any difference in the tune recipe.

I feel you. I have thought long about this. I gave up. I decided to love the shit out of my Gladiator, I consider the MPG (15-16) part of the cost of ownership. But it still grinds me that it isn't a little better

I will be an early buyer of the 4xe if it comes in a Mojave, if not then I will have to think a while.

See you on the trail

 

[MyRight]

It sort of makes me wonder what the enviro's that own JT's do to offset the extra carbon they are spewing...
Do they buy carbon credits to make themselves feel better, or do 20 self lashings every night before bed?

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