Proof that 87 Octane fuel is limiting your 3.6

[Rusty PW]

Yes. Several things.

For starters, on the engine side, a hard ceiling of 279 LB FT torque demand is set on stock tuning, but there is a flywheel torque table that is used as a multiplier and reduces this down even further.

Also, the throttle blade won’t open fully even at wide open throttle until RPM range is around 3500-4000 on stock tune. Tuning it correctly will get it to fully open right off idle if torque demand warrants it.

Most of the torque limitations outside of that are within the factory cam scheduling, mostly just the intake variable cam scheduling. Depending on fuel/octane/knick resistance, the intake cam timing can be advanced anywhere from 5-70 degrees from its resting place at any time.

The tricky part is Stellantis ECUs don’t like these parameters simply maxed out, unlike some GM stuff I’ve done. There are several tables that have to align with one another to make everything work well together. There are other tables that have to be inverse of each other or they can throw a limp mode condition. It’s pretty advanced and took awhile to get everything ironed out the way I wanted.

I can feel torque management in the first 3 gears on my diesel. Wondered if the gassers was the same. I get about half way through 3rd before it wakes up when lead footing it.

I had a Hemifever tune on my Power Wagon that cut torque management back. I could light the 37's up in 2 gears.

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[bmpcamry09]

I can feel torque management in the first 3 gears on my diesel. Wondered if the gassers was the same. I get about half way through 3rd before it wakes up when lead footing it.

I haven’t been inside of the diesels, but in the gassers, torque demand ramps up gradually in the driver demand/pedal tables as vehicle rolling resistance and speed increases. Basically as your vehicle speeds increases, it takes less pedal to make the same amount of torque demand. That is likely what you’re experiencing. This is also why people are often okay with how throttle tip in feels on the highway but they hate how it feels in the city.

 

[Rusty PW]

I haven’t been inside of the diesels, but in the gassers, torque demand ramps up gradually in the driver demand/pedal tables as vehicle rolling resistance and speed increases. Basically as your vehicle speeds increases, it takes less pedal to make the same amount of torque demand. That is likely what you’re experiencing. This is also why people are often okay with how throttle tip in feels on the highway but they hate how it feels in the city.

When you are trying to merge into traffic from an on ramp from a stop. It's terrible.

 

[NC_Overland]

I run premium in mine, but only to keep it running smooth with no pre-ignition. I only have 63k on my 2020, but I barely drive it anymore and around 60k miles it started needing 93 octane to run good. It’s probably carboned up, but I fill like once a month, and it runs great on 93, so I don’t care.

 

[g8tor2020]

Have several questions...

How much for a tune?

Will you be providing a cable and be doing this remotely?

Would customers be able to disable the tune and go back to stock themselves?

Also after watching couple of your youtube videos I noticed the test(s)you are running are on stock jl. I'm wondering how much of a difference it would feel with bigger tires and suspension. I'd imagine for the average jeeper they would notice a small difference?

 

[g8tor2020]

@davey yes higher octane will certainly help.
For example, I have a 2020 Rubicon, stock. I average 19.8 mpg on a trip running 87 octane, if I use 91 octane on the same trip I get 21.3.
In the heat of the summer when pulling my 16’ camper which is single axle and weights 2,480 dry, I am down to 10.0 mpg running 87 octane at 63 mph. When I jump up to 93 octane, not only do I get close to 12 mpg but my sweet spot jumps up to 71 mph.
This non scientific study of mine is based on over 100k miles with the Gladiator. Trips all over the east coast and throughout the south. Camper towing had been from Pa. to Fl. Several times, Ohio and parts of New England.
Around me, there is about an $0.80/gal difference between 87 and 93 octane. So for daily driving without a load etc., it does not make financial sense to me to run anything over 87. When I am towing, not only does it nearly pay for itself in mpg, the fact that the sweet spot jumps up 8 mph and I can go further between fill ups is well worth it.
I confess that I have not done any real world comparisons using 89 octane. That might be more economical and be enough. I don’t suspect so. Maybe hot weather and not loaded, it would suffice.

I've ran 91 octane on my 2020 gladiator ever since I bought it. I've probably ran 87 maybe a hand full of times. For whatever reason I have noticed that I do get slight better mpg on 91. And I guess it also helps with carbon buildup . I live in cali so your 93 is far superior than the 91 crap we get here.

 

[bmpcamry09]

Have several questions...

How much for a tune?

Will you be providing a cable and be doing this remotely?

Would customers be able to disable the tune and go back to stock themselves?

Also after watching couple of your youtube videos I noticed the test(s)you are running are on stock jl. I'm wondering how much of a difference it would feel with bigger tires and suspension. I'd imagine for the average jeeper they would notice a small difference?

I have a tuning guide that walks through everything needed as far as purchases and what not. I’ll attach it here for you as well. You would have your own device and use your own laptop to flash my product.

Big Jeep builds are a majority of my customer base and they report dramatic improvements.

yes, you can go back to stock anytime.

 

[bmpcamry09]

A user on the JL forum pointed out his displeasure how in my video, I used two different Jeeps as a comparison. My goal with that video was to show what 87 octane can do to one vehicle and how we can improve it with another. This user used the opportunity to call me a liar and try to discredit my business and what I have done for the Jeep community, so I figured I would post this up here to clear the air.

This is the same Jeep from the original video, on the left is the stock tune datalog taken on 5/6/26 around 5:10 PM. Ambient air temperatures were 81 degrees. On the right is the datalog from our 4th revision, taken on 5/9/26 around 5:58 PM. Ambient air temp on the tuned run was 79 degrees. You can see the VIN numbers up top are the same and the MPH/RPM ranges are the same. I even managed to get the RPM reference point to be identical here at 5129 RPM. Remember, these are numbers generated directly from the OBD2 port, not a dyno. This customer lives in Flordia and is basically at sea level. It is a 2018 JL 3.6 6MT. His name is Jeremy and his username on the JL forum is @hephaestus. He is a mechanic and owns his own custom shop. He basically interviewed me for an hour over the phone before trusting me with his Jeep too by the way.

We are looking at a wide open throttle run in these logs. At 5127 RPM we see the following:

-Knock retard of -7.5 degrees on stock tune, reduced to -4.2 degrees on the custom tune, still not perfect, but WAY better than stock.
-Intake Cam Angle on stock tune at this time is 106 degrees, on the custom tune is is 112 degrees, I am retarding the intake cam on purpose. This is because as RPM rises, retarding the cam further (full retarded on these is 147 degrees btw) reduces pumping losses, improves peak horsepower, and improves high RPM aircharge/VE. As you can see, our cylinder airmass stock at this time was 671 MG and with the tune was 709 MG. This was a desired goal, and it helps remove the heat from the combustion chamber, thus helping reduce knock retard.
-EQ commanded was .67 lambda stock, insanely rich, tuned it was .82, which is still fairly rich for a NA application, but is the sweet spot I found on these.
-HP/TQ figure on stock tune at this time was 210/215, with the custom tune, it was 235/241. Simply by tuning to make the engine better work with the 87 octane fuel, the ECU itself is reporting that is is making 25 more horsepower and 26 more pound feet of torque.

That appears to be data that matches my claims. Sorry if anyone believed otherwise, I am just trying to get this information out there for people who actually care to take a deep dive in to the data.

 

[hephaestus]

Hello, it is my Jeep being discussed in the above post. I own Sand & Salt Garage in Milton, FL. We work on pretty much all your toys. Jeeps, trucks, jet skis, atv's, sxs's, lifts, accessories, etc. While we don't tune vehicles, I do have some background in LS tuning, so when considering a tune for my personal daily driver I did have some fairly strict requirements.

I really had no power gain requirements, although if SAFE power gain was possible, I was happy to get it in what is probably the most under-powered vehicle I've ever owned. My main goal was to increase reliability by disabling high lift cam mode to reduce the the chances of the common wiping of cam lobes. @bmpcamry09 claimed I could gain power while eliminating this pointless feature and proved in another video that it was not used by the ECM for power, but instead, likely for emissions. I don't get time these days to geek out on data like he does, but after discussing my requirements and desires at length with him, and hearing some of what I considered the right tuning strategies from him, I was convinced that we were on the same page.

My Jeep started with 4.10 gears on 35's. 5th and 6th gear were unusable for anything other than interstate speeds and if I towed even a single jet ski, (which is a common load for me) it would bog me down so bad that the trip was miserable. Immediately upon the first iteration of his tune, the power gain, especially low to mid range, was VERY noticeable. It was like a completely new Jeep and I no longer had to fight my clutch nearly as bad as I did before. (I've owned stick shift transmissions as my daily drivers for most of my life and the JL clutch is the worst of all of them.) I used 5th gear a lot more often and 6th was way more useful on the interstate. I could still tell that rpms were not right though, especially on the interstate, and it was always my intent to regear to 4.88. So I put I think about 1500 miles on the new tune to experience it with the stock 4.10 gears and then went to 4.88's.

I've heard people say that regearing is the single best thing they've ever done to their Jeep. For me, it was a huge improvement, and it did fix my rpm's on the interstate. (There's nothing a tune can do to fix the wrong gearing.) 5th and 6th are commonly used even below interstate speeds now. I can climb hills on the interstate in 5th and 6th gear now, whereas shifting down to 4th or 3rd was common before. But in terms of seat off the pants power gain, the gears are a fairly distant 2nd as compared to the tune. The tune was, by far, the single best mod I've done. And I drive with a little more confidence now with almost 110k miles, knowing that I'll likely never wipe out a cam.

I do plan to someday make a comparison video of the stock tune vs 87 octane tune, vs 93 octane tune that I have but haven't tried yet. Things have just been so busy in the shop this summer that I haven't had time. I also just kind of suck at video editing. But it's still something I want to do to promote both BMP Calibrations and Sand & Salt Garage. I'll try to remember to link the video in this thread when I finally do it. I'm also more curious now about if I'll see any improvements by running 89. I'm sure 93 is nice but I just don't want to commit to spending that much on fuel all the time. Both my wife's and my personal jet skis require 93, and we ride often, so I feel that pain at the pump enough with those.

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