How to get 20mpg+ on 37’s/ECU basics 5/5 up @ 60-70mph with V6 3.6L

[cgflyer]

Update: v4 shit the bed and went back to pulsar. Superchips has been great to work with, but that platform just cant get right. It seems really hit or miss. My v3 was fine aside from occasionally dropping ess memory. No other issues. My v4 started strong and the other beta test units are running fine. Mine just randomly started throwing a start stop battery fault when id drop the pedal to WOT after weeks of all weather use on and off road with zero problems. Like how on earth is that related?

Its just too hit or miss to recommend wholesale. You might get ine thats fine, you might not. Surprise!

I think flashing these things is the only way to go right now. Superchips has some flashing options and boxes that provide other good tools. Livernois probably has the best ecu flash from a mapping point of view and they can also tune the transmission, which is great for a gladiator.

Im wondering if one of the issues with pulsar is due to the different OS formats randomly in different ecu. Like not all trucks have the same OS, so the tunes need to be built for the correct one. Only thing i can think of is that v3 was based on my os and v4 wasnt, but i have zero insight.

Superchips was good about it, apologized for the inconvenience, and offered either a refund or a flash tool format. I dont have a bad thing to say about them, just a bummer the pulsar cant be consistent.

Interestingly i did my normal route without the pulsar yesterday and came in 2mpg short of usual.

On to bigger and better things....Magnuson.

My V3 went weird after I programmed for my gears. Lost ESS entirely, lost the tunes and my backup camera didn’t come on in reverse. I removed it for a week and plugged it back in and all is right again. Superchips told me a while ago that connection has to be TIGHT. I actually am missing one bolt and only have it secured with two right now so that might have been my issue recently.

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[cecaa850]

So ... a fuse replacement and all is running correctly. At least to this point I haven't found any other issues..

Makes perfect sense. Like I said, I don't believe in coincidence.

Normally when the bus is out the headlights and wipers go on. Sometimes the defroster activates as well.

 

[Jtschnel]

Makes perfect sense. Like I said, I don't believe in coincidence.

Normally when the bus is out the headlights and wipers go on. Sometimes the defroster activates as well.

You nailed the diagnosis right of the bat, bus issue. I fully understand the use of main busses sharing information across multiple units/computers in the system, I used to work on avionics busses. Certainly makes a lot of sense from multiple perspectives as these machines becomes more computerized. That said, diagnosis of anomalies can certainly be, shall we say, interesting!

 

[cecaa850]

You nailed the diagnosis right of the bat, bus issue. I fully understand the use of main busses sharing information across multiple units/computers in the system, I used to work on avionics busses. Certainly makes a lot of sense from multiple perspectives as these machines becomes more computerized. That said, diagnosis of anomalies can certainly be, shall we say, interesting!

A dead bus isn't too hard to diag but the intermittent ones that go down then back up will make you say bad words.

 

[Imbuere]

So, probably a dumb question, but from what I’ve gathered in this thread, I figured I’d ask.

Here in Denver, we’re at 5k-6k. I use the cheapest 85 octane gas. I take it that’s why I’m gettin 16-17 mpg consistently?

 

[spectre6000]

Also in Denver. 1-2K' above it actually.

Air density decreases at a rate of 3%/1k' above sea level. So your air is 15-18% less by volume than at sea level. As a result, the heat generated by compression is less. In a naturally aspirated vehicle, that translates to less propensity to knock (detonate, preignition, whatever you want to call it) and thus a lower octane requirement. Our 85 regular is functionally the same as the 87 regular at lower altitudes from the perspective of knock resistance (which is what it's for). So on paper, that's not causing you any issues.

That said, from a warranty perspective, Jeep could conceivably deny a claim stemming from a knock related issue if they wanted to get real jerky about it. The manual specifies an octane rating rather than a named grade. Additionally, some manufacturers have the ability to increase timing when they detect the use of higher octane fuel for better performance and efficiency. I've not heard of Jeep doing this though, and unless you can figure out a controlled way to test such a difference, I would write down any delta to unintentional bias.

You'll probably get your best fuel economy gains by just driving more economically. The altitude gives you a boost to begin with In naturally aspirated vehicles (less oxygen per volume of air results in less fuel injected to achieve the ECU's target numbers). I tend to get a few mpg better than the EPA's hwy rating in my combined driving. I used to DD a '62 VW bus, and I drive like I still do. Combined with altitude, I get 23 mpg on summer gas (22 mpg winter) in my wife's JKUR as the closest comparison I have to hand (it's a very direct analog based on a reasonably large sample of real world economy; long story that's not worth getting into here, just trust me on that one). That's with all the steep up and down mountain grades going to/from the flats for various things.

 

[RobertRinAustin]

Also in Denver. 1-2K' above it actually.

Air density decreases at a rate of 3%/1k' above sea level. So your air is 15-18% less by volume than at sea level. As a result, the heat generated by compression is less. In a naturally aspirated vehicle, that translates to less propensity to knock (detonate, preignition, whatever you want to call it) and thus a lower octane requirement. Our 85 regular is functionally the same as the 87 regular at lower altitudes from the perspective of knock resistance (which is what it's for). So on paper, that's not causing you any issues.

That said, from a warranty perspective, Jeep could conceivably deny a claim stemming from a knock related issue if they wanted to get real jerky about it. The manual specifies an octane rating rather than a named grade. Additionally, some manufacturers have the ability to increase timing when they detect the use of higher octane fuel for better performance and efficiency. I've not heard of Jeep doing this though, and unless you can figure out a controlled way to test such a difference, I would write down any delta to unintentional bias.

You'll probably get your best fuel economy gains by just driving more economically. The altitude gives you a boost to begin with In naturally aspirated vehicles (less oxygen per volume of air results in less fuel injected to achieve the ECU's target numbers). I tend to get a few mpg better than the EPA's hwy rating in my combined driving. I used to DD a '62 VW bus, and I drive like I still do. Combined with altitude, I get 23 mpg on summer gas (22 mpg winter) in my wife's JKUR as the closest comparison I have to hand (it's a very direct analog based on a reasonably large sample of real world economy; long story that's not worth getting into here, just trust me on that one). That's with all the steep up and down mountain grades going to/from the flats for various things.

Another way to look at it is you lose 3% of your engine's horsepower or torque if you prefer, per 1k feet of elevation due to the less dense air. At a mile high plus, you're down 20%.

What I notice is worse mpg on 85 because the transmission spends less time in 8th gear when I'm in the mountains going up and down. Need to run 91 to really see a difference and it's more noticeable in winter. Don't really notice much difference in the flat

 

[ShadowsPapa]

So, probably a dumb question, but from what I’ve gathered in this thread, I figured I’d ask.

Here in Denver, we’re at 5k-6k. I use the cheapest 85 octane gas. I take it that’s why I’m gettin 16-17 mpg consistently?

Octane is the fuel's resistance to self-ignition. Nothing more or less. It does not have more energy, it does not have less energy. It doesn't burn slower, it doesn't burn faster.
So no, all things being equal, 85 or 87 or 90, you should get the same MPG unless you change something else like elevation or driving style or air temperature, etc.
Your 85 at that elevation is roughly like me using 87 at my elevation (800-920 feet, depending on what part of the road I'm on near home)

 

[spectre6000]

Another way to look at it is you lose 3% of your engine's horsepower or torque if you prefer, per 1k feet of elevation due to the less dense air. At a mile high plus, you're down 20%.

What I notice is worse mpg on 85 because the transmission spends less time in 8th gear when I'm in the mountains going up and down. Need to run 91 to really see a difference and it's more noticeable in winter. Don't really notice much difference in the flat

Depends on how you drive. Most modern engines make far more power than is really necessary. I used to daily several different cars over the years that only made double digit horsepower, and a few that were low double digit. Every day. Only running vehicle at any given time. Even in an area where people notoriously drive aggressively. 0-60 times under 5 seconds look great on paper, but under 15 seconds is good enough for driving sanely.

The point is, don't try to make up for that lost power with more throttle. Chill, and allow the mpg gains to be made, and they're free for the taking. There are more benefits to living up here than just the scenery.

 

[Spur]

https://www.mechanic.com.au/news/understanding-short-term-and-long-term-fuel-trims1

This is what makes the difference. Including knock sensors.

 

[ShadowsPapa]

Modern engines' electronic controls account for long term engine wear.
As things wear, the needs change and these track that. It used to be that when someone asked about tuning/timing, air/fuel, etc. first thing to ask was how was it physically, how's the compression, that sort of thing, and you would account for some of that.
Now if you make a change that impacts the air going in - it learns and adjusts in the long term numbers.
Don't make a change and expect instant results.
I remember testing "knock sensors" years ago. Large screwdriver with a large handle, or a small ball-peen hammer and a timing light. If you tapped the block and the timing didn't change, you needed to figure out why. If you could watch the timing jump back when you tapped the block, it was working.

 

[cecaa850]

So no, all things being equal, 85 or 87 or 90, you should get the same MPG unless you change something else like elevation or driving style or air temperature, etc.

The Chevy Cruze I had got much better mileage running supreme than it did on regular. The computer would bump timing when it didn't detect knock.

 

[ShadowsPapa]

The Chevy Cruze I had got much better mileage running supreme than it did on regular. The computer would bump timing when it didn't detect knock.

But that violates the "all things being equal" because it changed timing. So there wasn't more energy or BTUs in the more expensive fuel, the engine wasn't doing well on the regular.

That's going to depend on the engine. Some vehicles it won't matter because they are already running ideal timing and advancing timing further will decrease HP and/or mpg (and possibly cause damage). If the engine design is such that they get knock too easily, it can't or won't change timing. If it's already at the ideal max, it won't change it because there's no knock. Peak combustion pressures before roughly 14-16 ATDC (on legacy engines, based on rod length, cylinder size, etc.) will decrease power.

Apparently that Chevy had room to bump timing to get the peak where desired for that engine. So we could assume it wasn't running peak timing efficiency otherwise.

IF all things remain equal, since there is no more energy in premium than regular.........

 

[DbMojave21]

Hey guys. Been watching this thread for some time. Anyone bought any of the tuners and is getting decent gas mileage? I'm running 35s and most times 60 or under and i struggle getting anything close to 17. Typically 14-15. Just curious since this discussion has happened, if anyone has anymore real time data? Thinking about buying one but thought I'd check. Thanks

 

[WAOverlandJT]

Hey guys. Been watching this thread for some time. Anyone bought any of the tuners and is getting decent gas mileage? I'm running 35s and most times 60 or under and i struggle getting anything close to 17. Typically 14-15. Just curious since this discussion has happened, if anyone has anymore real time data? Thinking about buying one but thought I'd check. Thanks

im with you lol. curious if after 20 pages where the best bang for the buck is to increase efficiency. Seemed like the pulsar was at the start of the thread but folks also seem to be having issues there.

I’m on hybrid AT 35’s with a big roof top tent and sit about 13 and it just sucks. Not just the expense but the range is the frustrating part. Not being able to trust going 300 miles without a fill up can be tough. I drive this thing like a baby also. Without the rtt I bet I’m still only 15 at best And it seems to be getting worse as the fuel tables go on (per the videoed at the start).

so curious what the update would be on advice for folks. Is it still the same 3 upgrades?

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