Premium fuel with the 2.7?

A link to MTBE info. EPA says bad stuff...

https://archive.epa.gov/mtbe/web/html/gas.html

 

Just fueled up with 91 non ethanol and see what mpg I get. Last fill up with low grade 87 was 18 mpg city driving. Also removed the secondary air filter that had 150k miles on it.... truck seems to have a Lil more pep between the better gas and better air flow

 

Personally never saw an improvement removing the secondary charcoal filter. Mine tore so I removed it. No changes for me in performance or MPG.

 

Throttle response seems a little crisper. Only issue I'm having is a slight low idle/hesitation. I'm on my second tank of 91 non ethanol and still does it a little bit.

 

I've been running 87 octane Deathanol free all winter. Mileage stayed about the same. I'll switch to 91 Deathanol free soon when it gets warmer. I just got skinnier tires so that will probably help the mileage. I have always noticed that, for whatever reason, my Taco with the 2.7 just "seemed" to run better with 91 octane and the mileage "seemed" to be a little better. It was really hard to put a finger on it. I live at over 6000 ft so it would seem that 91 octane would make no difference at this elevation but it does while at the same time being almost in-discernible. I idle my truck so much that it's hard to tell what the real mpg is from week to week.

Personally I don't care because I need gas to go where I want to go and the cost really means nothing when it comes right down to it. It's a necessity.

 

I got 40,000 miles on my 2.7L 2015.. I have been using premium 93 since I took it out of the dealership.. That 87 Octane is not touching my truck lol.. A mechanic explained to me in details.. Putting cheaper gas makes the motor run a little more because It's asking for more when you hit the gas.. Using premium.. The motor runs more freely if it makes any sense.. Meaning once you tap the gas the vehicle just goes with ease.. Depending how you drive and what size tires you got on your truck is another story ..Fuel treatment I go with Mystery oil or (Automatic Transmission fluid) yup. Old school.. (NONE Synthetic) Any regular transmission fluid no matter what type as long as It's NOT synthetic It's good.. I have been doing it since my truck had 10,000 miles.. Remember .. Automatic transmission fluid lubricates the system also.. So if you put a little too much, nothing happens..

 

Then you are throwing away money.

Apparently, not a good one, who knows very little.

Truly no disrespect, but that is utter hogwash. I have a degree in chemical engineering, and worked in the refinement field in the '80s. People have many misconceptions about the Research Octane Number (RON) in petroleum.

First, the naming nomenclature. Calling fuel "regular" and "premium" is misleading. It make one sound superior to the other, and it is not. Regular fuel is just as clean and pure as premium is. The refinement process is the same, with the exception of octane level which is a hydrocarbon and an alkane mix, with the chemical formula C₈H₁₈, and the condensed structural formula CH₃(CH₂)₆CH₃.

This is added to premium fuel to slow the burning process down (thats correct, "SLOW") to prevent detonation. The higher the RON in fuel, an engine manufacturer can safely make higher compression engines, and add more timing, in an effort to make more power. (better performance).

Putting premium fuel in an engine designed for regular is not only a waste of money, but potentially can reduce performance because of the slower burn (incomplete) rate.

Now, there are engine tunes you can program in many ECMs, and these tunes will adjust your timing based on the planed RON you intend to use. In fact, many of these tunes are named for the octane they are deigned for like "92" or "93".

So, in a nut shell, unless modified, use the fuel recommended my the manufacturer. You are NOT getting ANY benefits for doing so, and are wasting money, pure and simple.

Our stock 2.7s are designed to run on 87 octane, use it.

 

Literally none of this is accurate.

Higher octane fuel is more stable under pressure and during combustion. Higher performance engines require this in order to have stable fuel in a high compression motor. The 4L is a high compression motor (not a turbo of course but high compression none the less)

 

Good post, but just to clarify, combustion ratio and boost are 2 different things. In fact, it is common engine building practice to LOWER the combustion ratio when applying forced induction verses normally aspirated engines, however, many after market forced induction "kits", do not "include" requiring lowering that ratio, and are able to work well with good EMC programming, and can still offer good/great performance gains.

Im not trying to pat myself on my own back here, but me and my father have built many high performance engines over the years (mostly for boats). Mostly American big blocks, with forced induction of various types, including roots style (6-71/8-71), centrifugal units, and of course turbos, and know a little bit about race gas and octane.

Just trying share some long earned experience/knowledge, thats all.

Peace!

 

I see the distinction you're making, yeah you're square on.

 

Good read. Thanks!
Porsche, who have a long history of forced induction, have a recent patent on a variable compression ratio engine (higher compression before the turbo spools up). Be interesting to see if it hits production.
I'm unsure of where this myth that higher octane (unless it is non ethanol) is a "better" gasline came from. I file it between "My car runs better after changing the oil" and " The problem seems to have gone away/fixed itself" in my filing cabinet of WTF?
Of course there is truth to the fact that a vacuumed and washed truck runs better...right?
Edit: obviously use whatever octane the manufacturer asks for in the literature provided.

 

91 is the required minimum in my 2.7

 

Edited my post to reflect manufacturers recommendation. 94 octane in my wr250x FTW

 

i run 89, as i get a slight bit of knocking or "kick" when i run 87 at lower rpms under load.

 

Always ran 93 in my truck, even before I turbo'd it. Every so often (~6mo.) I'll Seafoam it, and use Amsoil P.I additive every 2-3 months.
Never had an issue with hesitation, pinging, or knock...even with the turbo.

 

no difference i use none ethanole

 

i get about 20 mpg with 87 and 24.5-25.5 with 93. reset all the learned values between switching octanes so I wouldn't have to go through 5 tanks before noticing a difference.

 

Recently switched to 91 octane/no ethanol. Engine seems to idle much smoother and has more "umph" going up and down the hills here in the Ozarks/NW Arkansas. Haven't calculated MPG yet, waiting a few more weeks after running multiple tank fill ups.

 

I use the alcohol free in my tractor and small engines. I paid $4.87/gallon last week. Regular gas (Shell) here was $3.19/gallon. What is yours costing you?

 

Premium 91 with no ethanol about $3.99 gal (Phillips 66/NW Arkansas). Regular 87 runs around $3.04 (Walmart).