midgrade vs premium gas 5.7hemi

[RamNSubie]

This is correct.

I used to use premium in the summer months to lower the operating temps of other vehicles, but it never added horsepower or made any engine rung smoother that wasn't designed for it.

So you always used the minimum required octane rating? Going to a higher rating from minimum will not really have any effects as your engine will be running properly already.

Higher octane gasoline does not burn slower, it has a slight lag in ignition compared to lower octane fuels. This is why you can advance the timing when you run higher octane fuels.

When running a lower then recommended or getting some poor quality gasoline your modern vehicle will pull(retard) timing to prevent knock.

If you haven't actually had to study fuels and how they burn and the conditions they burn under don't state something as "fact."


I wonder if anyone can give me the octane rating of diesel and how important it is.

 

[Kotta390]

I run 87 octane in the winter, when the temp stays below 40degrees (no engine knock, 1.8mpg loss compared to 89). Above that temperature, i run 89octane. I ran 93 for 2 months during last summer, and only saw a hand calculated 1mpg gain.

You are saying no engine knock on 87 octane?? If so, then how do you explain the gain in fuel mileage, as exaggerated as it seems, with 89 octane compared to 87 octane?

 

[Jerry1984]

You are saying no engine knock on 87 octane?? If so, then how do you explain the gain in fuel mileage, as exaggerated as it seems, with 89 octane compared to 87 octane?

I haven't noticed mpg difference between 87 and 89. I have noticed a gain with non ethanol fuel which is pretty rare around here and quite a bit more per gallon.

 

[RamNSubie]

I haven't noticed mpg difference between 87 and 89. I have noticed a gain with non ethanol fuel which is pretty rare around here and quite a bit more per gallon.

Non-ethanol gasoline does result in better fuel economy. I have known this since 08-09 when the gas stations around me made the switch. I would find the stations with straight gasoline until they were gone. I have a 95 Jetta with the 2.0 in it, went from 33-34 mpg to 29-30 mpg.

 

[Kotta390]

I haven't noticed mpg difference between 87 and 89. I have noticed a gain with non ethanol fuel which is pretty rare around here and quite a bit more per gallon.

Well that makes more sense then someone saying they gained 1.8mpg with 89 octane over 87 octane and the lower grade fuel had no knock. If only you guys knew how much false knock are on these trucks lol.

 

[Crescent1101]

What about running 91/93 performance tune with the superchips tuner? Anybody notice a big increase switching the tune from the 89 to higher?

 

[THETANK]

I put diesel in mine and she runs like a champ, weird I know but it's true I swear

 

[JJP71584]

I run 93 with a HF tune and noticed the performance difference immediately, prior to that I ran 87 in the winter (I auto start my truck a lot) and 89 in the summer, not going to change anytime soon...truck really woke up after the tune, I'm sure most of the performance is due to that

Sent from my SPH-L720 using Tapatalk

 

[danmp]

Ultramar doesn't have ethanol in their 91?

I hope they don't since the Shell in my area charge way more for the v-power than any other premium brand.

Also all the stations now only use one nozzle for all their grade... Kind of curious about the quantity in the hose before it clear the 87 from the previous fill up. I try to always put around 100 liters so the amount of 87 is to a minimum.

No Ultramar doesn't have ethanol in their 91. Also they are always the last to rise the price , and the first to get lower , that's one of the main reason why I got there ( at least in my area)

I had a sierra with E85 possibility and even with the fake gm fuel spec, the E85 the mpg was almost 200% worse than gas only; 23 liter/100km 14 l/100km. So I guess that the E10 ( mostly every regular 87 in canada ) will get a higher fuel consuption.

There is a huge difference on how the eco mode stay on with the 91 no ethanol fuel.

 

[Sir John]

lol....I love this topic of gas. I could put the most expensive gas in my truck and it would cost me about $4 more per fill-up from the cheapest gas. I cannot even get a McDonalds value meal for that price anymore.

 

[02Steve15]

Was thinking about trying this out while gas is cheap. I run 87 but I don't think we have 91 up here...either 89 or 93. Would you recommend one over the other?

 

[RamNSubie]

Was thinking about trying this out while gas is cheap. I run 87 but I don't think we have 91 up here...either 89 or 93. Would you recommend one over the other?

89 is all you need.

 

[noupf]

i'm gonna throw a curve ball in here for everyone......


Are you aware that your altitude means a lot when answering this question? The 91 or 93 octane is obviously not needed ( as stated by the owners manual ), but go ahead and look into how much more important or not important it is to use 87/89 based on the altitude of where you live.......

 

[9th]

If I were to only get 18.5 mpg on I-10 and I-75 (I am from Maine but know those interstates from working in the Gulf of Mexico) I would think something is wrong with my truck. I get 18-19+ on Maine highways.

My best MPG in Interstate-10 and Interstate-75
https://i.imgur.com/SEJWbXN.png
Running 65mph~90mph

Probably my foot is too heavy

How you compute your mileage?

 

[RamNSubie]

i'm gonna throw a curve ball in here for everyone......


Are you aware that your altitude means a lot when answering this question? The 91 or 93 octane is obviously not needed ( as stated by the owners manual ), but go ahead and look into how much more important or not important it is to use 87/89 based on the altitude of where you live.......

This is very true. The higher you go the thinner the air is. Thinner air means less in a naturally aspirated engine. What this does is lower the pressure created during compression. Less pressure = less heat, less heat = less chance of knock. It will also cause a rich condition in anything carburated.

 

[RamNSubie]

Probably my foot is too heavy

How you compute your mileage?

The few times I was actually curious and did it by hand I was getting 18-19 on the few longer drives I have done, which was only 1.5 hours each way. I do more 20 minute drives then anything.

As far as the heavy foot, my best comes from up to speed as quick as possible without making myself stand out then cruising at my speed.

 

[9th]

The few times I was actually curious and did it by hand I was getting 18-19 on the few longer drives I have done, which was only 1.5 hours each way. I do more 20 minute drives then anything.

As far as the heavy foot, my best comes from up to speed as quick as possible without making myself stand out then cruising at my speed.

I drive like I don't care what mpg I got

By the way I only have 24 mpg average with my Nissan Pathfinder(4th Gen/R52) during my Florida to California long drive...my problem is not my car but my driving habit

 

[MANual_puller]

I went from 87 to 91 with my old truck('06) and just monitoring the knock sensors and watching the short term spark retard things look tons better. I'm getting lower values for the knock sensors and it is retarding less often. I could tell a difference with the '11 after the first fill up too, same thing, less knock and less retard. It clearly had the cheap crap in it.

 

[Farmer Fran]

I tow a lot so I only use 89.

 

[jmr]

I would stick with midgrade