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Gas mileage

HSKR R/T

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Does any one have Dyno numbers to prove or disprove 87 vrs 91, that add or takeaway performance. I'm more likely to believe the Dyno, but it doesn't prove or disprove the cleaning quality of high octane. So the old practice I have of burning a tank premium, with a high quality injector cleaner, on long trips that require a minimum of two tanks or more.
That's because premium doesn't clean any different than 87 of the same brand. They all share the same additive package. Stick to top tier fuel and stop wasting money on premium.

And there won't be enough of a difference between octane to have any definitive proof on the dyno. Any difference would be within the standard variance between runs, with zero changes ..
 

CalvinC

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No engine has a sensor to "know" what octane it is running.
Right on, which is why I clarified my language to be they "infer" octane, though it must be said FFV vehicles go a step further and actually do have ethanol content sensors in line. Which can also be purchased aftermarket. Stuff you already know probably, just clarifying.

As for Dyno numbers... hard to come by because any difference in a NA stock motor would be so small it would be difficult to attribute to that vs. other variances. Also not all vehicles react the same so generalizations cannot be made. And if its not same motor on same dyno in same conditions, any comparisons are worthless.

The best I've seen on this where they tried to control the variables as much as possible (e.g. same exact vehicles on same exact dynos under same exact conditions) was a Car and Driver article years ago:

Among the engines tested were the 5.7 Hemi in a Charger and a 3.5 EcoBoost in an F150.

The results were essentially that while the dyno may detect a few more ponies on SOME engines, they dont translate into any real-world difference in performance. Except on the turbo F150, which I can tell you only becomes more apparent with custom tuning.

Curiously there is a single-sentence anecdote in this article about the old Honda 3.0 V6 making less power on premium than regular in a 2001 version of this test, so... idk.
Here's the 2001 article, which does an even better job explaining the fundamentals:
 

HSKR R/T

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Right on, which is why I clarified my language to be they "infer" octane, though it must be said FFV vehicles go a step further and actually do have ethanol content sensors in line. Which can also be purchased aftermarket. Stuff you already know probably, just clarifying.

As for Dyno numbers... hard to come by because any difference in a NA stock motor would be so small it would be difficult to attribute to that vs. other variances. Also not all vehicles react the same so generalizations cannot be made. And if its not same motor on same dyno in same conditions, any comparisons are worthless.

The best I've seen on this where they tried to control the variables as much as possible (e.g. same exact vehicles on same exact dynos under same exact conditions) was a Car and Driver article years ago:

Among the engines tested were the 5.7 Hemi in a Charger and a 3.5 EcoBoost in an F150.

The results were essentially that while the dyno may detect a few more ponies on SOME engines, they dont translate into any real-world difference in performance. Except on the turbo F150, which I can tell you only becomes more apparent with custom tuning.

Curiously there is a single-sentence anecdote in this article about the old Honda 3.0 V6 making less power on premium than regular in a 2001 version of this test, so... idk.
Here's the 2001 article, which does an even better job explaining the fundamentals:
The problem with dyno testing for differences in octane is it's almost too controlled of an environment. Octane levels are all about preventing detonation. So with all things equal, other than octane, unless there is detonstion, there should be no discernable difference in power output. We all know in the real world driving, there are lots of variables that can effect performance that you don't encounter on the dyno


If you car has a knock sensor, it will pull timing to prevent detonation, on lower octane fuels, which would result in reduced performance. A lot of times, that detonation isnt enough to be audible. You also have the potential for false knock detection from other sources reducing engine performance.
 

GMetal

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The problem with dyno testing for differences in octane is it's almost too controlled of an environment. Octane levels are all about preventing detonation. So with all things equal, other than octane, unless there is detonstion, there should be no discernable difference in power output. We all know in the real world driving, there are lots of variables that can effect performance that you don't encounter on the dyno


If you car has a knock sensor, it will pull timing to prevent detonation, on lower octane fuels, which would result in reduced performance. A lot of times, that detonation isnt enough to be audible. You also have the potential for false knock detection from other sources reducing engine performance.
True, thats why I think people" feel" a performance gain when running higher octane. They are actually not "feeling" the engine timing being reduced by knock. Also density altitude can play a factor in the butt dyno.
 

RVTRKN

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That's because premium doesn't clean any different than 87 of the same brand. They all share the same additive package. Stick to top tier fuel and stop wasting money on premium.

And there won't be enough of a difference between octane to have any definitive proof on the dyno. Any difference would be within the standard variance between runs, with zero changes ..
So I can't prove Premium helps clean the fuel system and related areas of the engine, like you can't prove it doesn't, its a matter of opinion. The best part is, it won't hurt my engine if I do use premium and is relatively cheap, adding MMO or injection cleaner helps a lot. I like MMO to help lubricate and hone related parts, especially the long trip that I just completed at 4800 highway miles droning along at 70 MPH getting 21 MPG, only the first and last tank was premium.
 

Idahoktm

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I'm not sure on how everyone drives their trucks but I'm getting 18 to 19mpg in the city and 25 to 27 mpg on long trips. I have the 3.92 gears and the eco mode that kicks in when needed. I don't do more then 70mph on the long trips and I also have a bed cover. I don't get into it hard driving around town at all and I'm not hauling anything that would affect fuel mileage. Pulling my 37 foot travel trailer I can get 11mpg but its usually at 10.5mpg. This is all hand calculated not on the dash. My dash readings are close thought. It is completely stock also.

I didn't buy my truck for the MPG except this thing called a Window sticker, it has words and statements that are provided as fact
I am lucky if I get 17 mpg on the highway when my truck was bone stock with EXACTLY what is listed on this document.
I just filled up and got mostly city miles this tank and I got 12.5mpg (I only care what highway miles show as there should be no variation on highway miles as there are no stoplights and I don't drive in traffic)

It's funny that you basically called @Triple6 a liar after he posted up his MPG's. He claimed to get 0/1 MPG better than sticker in the city and +3/5 MPG better than sticker on the highway. You on the other hand claim that you get 5.5 MPG less than sticker in the city and 5 MPG less than sticker on the highway. Overall, your numbers are more exaggerated than his, so who are we to believe? Based on the MPG's I got with my Laramie and now that I have 1000 miles on my TRX and I'm getting 11.8 MPG in the city, Triple6's numbers are more believable.
 

GMetal

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That is wrong. They have sensors for flex fuel vehicles to know what alcohol percentage is in the vehicle. Which is how they can be tuned for anything from 87 octane non-ethsnol to E85 pump gas. And we all know, once you get passed E10 blends the octane starts going up. Which is why E15 is 88 octane and not 87 octane.
My statement is correct. Im well aware of flexfuel sensors. They detect alcohol yes. Not octane.
 

GMetal

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Does any one have Dyno numbers to prove or disprove 87 vrs 91, that add or takeaway performance. I'm more likely to believe the Dyno, but it doesn't prove or disprove the cleaning quality of high octane. So the old practice I have of burning a tank premium, with a high quality injector cleaner, on long trips that require a minimum of two tanks or more.
Not really. Dynos apply loads using water or friction but its not exactly like driving up hills. Your engine controller has tables it follows and adjusts according to existing sensors like MAP, IAT, RPM, O2 And an estimated fuel flow based on fuel pump flow, fuel injector flow rate which then calculates the Volumetric Efficiency and makes adjustments accordingly. There is no sensor telling the engine you put in high octane fuel. It just applies the timing the computer commands for the VE and if the knock sensor sees knock it will retard timing.
Buy good gas from busy stations.
 

Darksteel165

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It's funny that you basically called @Triple6 a liar after he posted up his MPG's. He claimed to get 0/1 MPG better than sticker in the city and +3/5 MPG better than sticker on the highway. You on the other hand claim that you get 5.5 MPG less than sticker in the city and 5 MPG less than sticker on the highway. Overall, your numbers are more exaggerated than his, so who are we to believe? Based on the MPG's I got with my Laramie and now that I have 1000 miles on my TRX and I'm getting 11.8 MPG in the city, Triple6's numbers are more believable.
I don't have an Laramie, and I have already shown tons of pictures with fuel level, mpg, and average speed along with engine running time.
My numbers are fact, what would I have to gain lying and giving fake lower numbers?

27 mpg is not possible with the 5.7 in an Ram 1500. Going downhill and not hitting the gas peddle does not count as mpg.
 

vincentw56

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I don't have an Laramie, and I have already shown tons of pictures with fuel level, mpg, and average speed along with engine running time.
My numbers are fact, what would I have to gain lying and giving fake lower numbers?

27 mpg is not possible with the 5.7 in an Ram 1500. Going downhill and not hitting the gas peddle does not count as mpg.
Yeah, I seriously doubt those numbers in the high 20s too. I've never heard another person with a 5.7 in a Ram give numbers like that.
 

silver billet

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This is a 3 hour 100% freeway trip with an avg of 63mph under optimal conditions (great temp, low humidity, low/no wind, fully inflated tires, 91 octane and a very steady right foot). 8.4 l/100km = 27 mpg.

Hand calced is probably 24 to 25 mpg.

Gotta love the 3.21! It just idles its way through life.
 

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spyder

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Yeah, I seriously doubt those numbers in the high 20s too. I've never heard another person with a 5.7 in a Ram give numbers like that.
I live kinda in the middle of nowhere, and if I keep the speed in the high 40s/low 50s for an extended length, the readout will say mid to high 20s. I've played around with it out of curiosity and kept it that high for 50+ miles, but it's an unrealistic speed to stay at in almost any conditions except for a 4am Sunday drive.
 

silver billet

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63mph on the freeway? Were you drafting a Prius? :ROFLMAO: That's not freeway!

Trucks in my region are legally governed to about that speed (105 km/h), meaning, they're physically unable to go faster. I generally sit in the right hand lane, I don't draft them or do anything out of the ordinary, but I don't see the need to pass people either. I love that lane, trucks are very moderate in their flow, they don't speed up fast and then hit the brakes etc etc, just a calm steady flow.

Keep in mind that the EPA figures are determined at less than that speed so that's not too shabby for a real world trip.

Most of the time I can get between 22 and 24 mph on the evic with less ideal conditions and with more of a hurry.
 

6of36

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Trucks in my region are legally governed to about that speed (105 km/h), meaning, they're physically unable to go faster. I generally sit in the right hand lane, I don't draft them or do anything out of the ordinary, but I don't see the need to pass people either. I love that lane, trucks are very moderate in their flow, they don't speed up fast and then hit the brakes etc etc, just a calm steady flow.

Keep in mind that the EPA figures are determined at less than that speed so that's not too shabby for a real world trip.

Most of the time I can get between 22 and 24 mph on the evic with less ideal conditions and with more of a hurry.
You have the patience of a saint. lol. I'm glad we don't have Canadian speed limits. If I get on a freeway, it's for a 3 to 12 hour drive. My freeways are 70 or 75 MPH. If I do 78, which cops don't even look twice. That's 15 miles further per hour. On just the 3 hour drive, that's 40 minute shorter time. I'll take the loss in mileage, over the time. It's not worth going more over the limit though, risking a $150 minimum fine, to save a couple more minutes.
 

Idahoktm

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I don't have an Laramie, and I have already shown tons of pictures with fuel level, mpg, and average speed along with engine running time.
My numbers are fact, what would I have to gain lying and giving fake lower numbers?

27 mpg is not possible with the 5.7 in an Ram 1500. Going downhill and not hitting the gas peddle does not count as mpg.

Who said you had a Laramie? Reading comprehension is not your strong suit, so I'll give you a pass on that one.

You have been claiming all along that Ram sticker numbers are unachievable. Reporting 12.5 MPG helps your credibility with that argument.

When I see pics of EVIC's showing 24 MPG over a few hundred miles, I'll give the guy the benefit of the doubt when he claims he can get 25-27 MPG on longer trips. However, you claiming 12.5 MPG average with a stock Limited is laughable.
 

RVTRKN

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Trucks in my region are legally governed to about that speed (105 km/h), meaning, they're physically unable to go faster. I generally sit in the right hand lane, I don't draft them or do anything out of the ordinary, but I don't see the need to pass people either. I love that lane, trucks are very moderate in their flow, they don't speed up fast and then hit the brakes etc etc, just a calm steady flow.

Keep in mind that the EPA figures are determined at less than that speed so that's not too shabby for a real world trip.

Most of the time I can get between 22 and 24 mph on the evic with less ideal conditions and with more of a hurry.
Thats crazy, in Germany (at least 40 years ago) they have billboards on the autobahn pleading for drivers to keep it at 130 KPH, with no speed limit. I can tell you when a Lamborghini, Mercedes or BMW starts flashing their lights you better get over, it can be your fault if rear ended. I could barely go 130 with my little 1975 English Ford Escort and learned to get out of the way fast. Can you clarify the governor demanded by law on your truck, and what region? 65 MPH (105 KPH) is slow, but I guess they could have governed you to 55 MPH (90 KPH), like when the USA had a National speed limit of 55 MPH. There were a few States here that made a lot of money on tickets if you were caught going 57 or more MPH, but most ignored the 55 MPH limit.
 
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silver billet

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You have the patience of a saint. lol. I'm glad we don't have Canadian speed limits. If I get on a freeway, it's for a 3 to 12 hour drive. My freeways are 70 or 75 MPH. If I do 78, which cops don't even look twice. That's 15 miles further per hour. On just the 3 hour drive, that's 40 minute shorter time. I'll take the loss in mileage, over the time. It's not worth going more over the limit though, risking a $150 minimum fine, to save a couple more minutes.

I've never considered myself a patient guy, to me the benefit of driving 63 is that's far more calm and safe. I used to do the 75+ thing, and sure I got there a few mins earlier but I was always moderately ruffled when I arrived because the guy in front of me constantly hit his brakes or didn't move over, or guys jumping in and out in front. It's a horrible way to drive, where I'm at anyway.

I do occasionally hit the higher speeds, mainly at night when traffic is non-existant.

Same thing with stop and go traffic, soon as I hit that I make sure I find a trucker to sit behind in the right-ish lanes, they focus on going a constant (albeit slow) speed instead of the stop-and-go traffic that infuriates me. And nobody jumps in between you and a trucker, little bonus there.

So yeah, not patient, just the only way for me to keep my mood in check.
 

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