Regular vs Premium Gasoline

[Samson16]

She named it Koala Bear

Sponsored

 

[FaaWrenchBndr]

She named it Koala Bear

As long as She is happy, everyone is happy

congrats

 

[Samson16]

As long as She is happy, everyone is happy

congrats

Now I get my boat!

 

[DadBald]

So I put in a tank of 93 just to see, and, well, look at my mileage!

I pulled from the pump to a parking spot to go inside for something and the engine never kicked on.

In all seriousness, Ive got about 1000 miles on premium now and I *feel* like I'm getting about 1mpg better. It's still anywhere from 15 to 25+ with the hybrid system. The engine also seems to idle smoother. Could 100% be in my head though. One thing that's for sure is my boost gauge only went to about 10psi on 87 no matter what I did. But in 93 if I punch it, it'll go up to 18ish now. I've never observed this with 87 gas.

 

[Samson16]

So I put in a tank of 93 just to see, and, well, look at my mileage!

I pulled from the pump to a parking spot to go inside for something and the engine never kicked on.

In all seriousness, Ive got about 1000 miles on premium now and I *feel* like I'm getting about 1mpg better. It's still anywhere from 15 to 25+ with the hybrid system. The engine also seems to idle smoother. Could 100% be in my head though. One thing that's for sure is my boost gauge only went to about 10psi on 87 no matter what I did. But in 93 if I punch it, it'll go up to 18ish now. I've never observed this with 87 gas.

It should behave something like this:

 

[Suns_PSD]

The factory calibration on my 2021 3.5EB starts out with an inferred octane rating of 89.2 at 0.0 OAR after a KAM reset. When the knock sensors are very happy and the OAR adjusts to -1.0 the inferred octane rating is 98. I'm not sure what the low end of the spectrum for inferred octane is when the OAR reads 1.0.

Thanks for this info.

My question is, what's the cheapest way to get my truck to have 98 Octane fuel in it?

I see that adding about 40% E-85 shows to get my 93 octane pump fuel up to about 98 Octane, but these engines can't run unmodified on that much e-85 because they can't adjust the timing correct?

What's a good solution?

Thx.

 

[HammaMan]

Fuel flow is the limiting factor. Given that they've dropped e85 compatibility on the 5.0, they really don't want high ethanol content in the motors which makes sense. Alcohol is brutal on the oil in motors that don't get up to temp.

Curious if anyone's done a dual fuel setup using the PFI for e85 while the DI retains pump gas. Best of both worlds.

 

[Suns_PSD]

I mean, is a $12 bottle of Octane booster per tank worth 40 rwhp, or is that a silly notion?

 

[HammaMan]

I mean, is a $12 bottle of Octane booster per tank worth 40 rwhp, or is that a silly notion?

$12 bottle of octane booster on a 30g tank? Usually it's about $1/g. The issue I run into is if going on a few hundred mile trip not really being conducive to 'performance' mode. Being able to flip a switch and swap the PFI over to e85 would be pretty sweet.

 

[SALEEN961]

Thanks for this info.

My question is, what's the cheapest way to get my truck to have 98 Octane fuel in it?

I see that adding about 40% E-85 shows to get my 93 octane pump fuel up to about 98 Octane, but these engines can't run unmodified on that much e-85 because they can't adjust the timing correct?

What's a good solution?

Thx.

Boostane or a similar octane booster is most likely the cheapest option, but long term use of octane boosters isn't a great idea as they can harm your oxygen sensors and catalytic converters over time.

Getting tuned for E30 and blending your own fuel is a much better long term option, but it's not convenient and you have to make sure you're getting the ethanol concentration very close to what you're tuned for.

Running Sunoco 260 GT is the easiest long term option, but it's going to be expensive. Local gas stations are charging $10-$15/gal for 100oct 260 GT.

In the end higher octane fuel may not gain you anything if your tune isn't set up to take advantage of it. On a stock tune file, higher octane fuel will allow the PCM to command more spark advance in some scenarios, but at WOT you would run up against the cylinder pressure limit with 93oct and 98oct wouldn't gain you any power at WOT.

If your truck is tuned, the OAR/KOM isn't maxed out, and you aren't riding a spark limiter, higher octane fuel has the potential to make a noticeable difference at WOT. Not all tunes will see gains from higher octane fuels, it really depends on how they were set up.

 

[Suns_PSD]

Boostane or a similar octane booster is most likely the cheapest option, but long term use of octane boosters isn't a great idea as they can harm your oxygen sensors and catalytic converters over time.

Getting tuned for E30 and blending your own fuel is a much better long term option, but it's not convenient and you have to make sure you're getting the ethanol concentration very close to what you're tuned for.

Running Sunoco 260 GT is the easiest long term option, but it's going to be expensive. Local gas stations are charging $10-$15/gal for 100oct 260 GT.

In the end higher octane fuel may not gain you anything if your tune isn't set up to take advantage of it. On a stock tune file, higher octane fuel will allow the PCM to command more spark advance in some scenarios, but at WOT you would run up against the cylinder pressure limit with 93oct and 98oct wouldn't gain you any power at WOT.

If your truck is tuned, the OAR/KOM isn't maxed out, and you aren't riding a spark limiter, higher octane fuel has the potential to make a noticeable difference at WOT. Not all tunes will see gains from higher octane fuels, it really depends on how they were set up.

I actually drove about 400 miles today and had some time to experiment.

I do have a Livernois tune actually and always run 93.

I turned on the TQ app and set up the OAR scale. It started off reading .3. When I left my home and got warmed up it jumped around wildly for a moment after I accelerated a few times, at one moment reading -1.8 and another reading .8. Then it went back to .3 and stayed there for another 392 miles. I had half a tank about half way in to the days driving and added a bottle of Lucas Octane booster. OAR still did not change, however (maybe in my head) it felt stronger after about 30 minutes. I did a couple of full throttle runs and it felt very strong, yet OAR never left .3.

To top it off I got unusually good mpg coming back, like a solid 1.5 mpg better than I typically get driving 75 mph. I'll drop in to my normal routine for the rest of the week and know then if there is some economy there.

Not sure what to make of it. If I could verify that I was getting more timing I was prepared to add a bottle of the Lucas with every tank. But I guess if it damages engine parts long term, that's not going to work either.

Bummer.

 

[SALEEN961]

I actually drove about 400 miles today and had some time to experiment.

I do have a Livernois tune actually and always run 93.

I turned on the TQ app and set up the OAR scale. It started off reading .3. When I left my home and got warmed up it jumped around wildly for a moment after I accelerated a few times, at one moment reading -1.8 and another reading .8. Then it went back to .3 and stayed there for another 392 miles. I had half a tank about half way in to the days driving and added a bottle of Lucas Octane booster. OAR still did not change, however (maybe in my head) it felt stronger after about 30 minutes. I did a couple of full throttle runs and it felt very strong, yet OAR never left .3.

To top it off I got unusually good mpg coming back, like a solid 1.5 mpg better than I typically get driving 75 mph. I'll drop in to my normal routine for the rest of the week and know then if there is some economy there.

Not sure what to make of it. If I could verify that I was getting more timing I was prepared to add a bottle of the Lucas with every tank. But I guess if it damages engine parts long term, that's not going to work either.

Bummer.

I've never used the TQ app, but I believe the minimum and maximum values for OAR are -1.0 and +1.0 so I'm not sure how to interpret the -1.8 reading the app gave you. My best guess is that it's displaying something different from the OAR that can be found on SCT and Cobb devices.

 

[Samson16]

Why did you change your avatar to a Jeep???

Back to normal now.

 

[UGADawg96]

Back to normal now.

 

[Suns_PSD]

Well, there is zero doubt that my truck gets better gas mileage with the Octane booster in the tank.

I do the same commute every single morning through the TX Hill Country, takes 40 minutes. It's a favorable commute and I always get my highest trip economy on this trip, at right at 20 mpg and occasionally as high as 21. Doing this commute every morning for 2 years and I've never gotten higher than 21.4 mpg. That was after getting stuck behind a truck (there is a dirt pit on the route and it happens with some regularity) driving well below the speed limit and catching every light just right. Well, this morning, normal commute (average speed of 36 mph due to lights, school zones, traffic, etc.) and yet I averaged 22.9 mpg. This is well outside the margin of error.

Furthermore, my Trip meter that I set yesterday while running 75 mph, is currently reading 20.7 mpg whereas that duty cycle usually has me down close to high 17s low 18s. (this is a lifted Limited with a camper)

I'd also say that I feel the power is notably better.

Spending another $10/ tank is not at all cost effective, but the advantages of better economy and power are worth it to me.

How can I run Octane booster full time in this engine without causing any long-term damage?

PS. OAR in the Torque app has never budged from .3 after over 400 miles of driving, half of that with the Octane Booster.

Sponsored