87 to 88 to 92 octane

[2018_ram]

i have a 2018 ram 3500 with the 6.4 hemi i been running it on 91 octane with no ethenal but its expensive at 3.54 a gallon. thinking about going to lower grade but here in minnesota we have 87, 88, 91 and 91 has no ethenal. 87 has 10% and 88 has 15% ethenal. and i think our trucks run on 89 right? so will 88 be ok?

 

[HEMIMANN]

You're conjoining two separate fuel issues - alchohol and octane rating.

Our 6.4L engine is designed to run on octane rating up to 89. The manual says 89 is "preferred", because the compression ratio and ignition timing algorithm is such that it can burn 89 octane gasoline efficiently. This means the ignition timing can be advanced further without knocking / detonation, resulting in less fuel consumption and more power. So far, so good.

Now we get to the alcohol (ethanol, to be specific) part - adding alcohol to gasoline is a massive taxpayer lobby scam by corn processors and growers. Adding ethanol costs more than resultant energy delivered. Adding ethanol increases fuel consumption. Adding ethanol leans fuel mixtures and raises engine temperatures. Adding ethanol corrodes and degrades fuel storage ability. Adding ethanol does NOTHING to lower engine exhaust emissions - the 3 way catalytic converters produce near zero emissions regardless if fuel has ethanol in it. In fact, adding ethanol has been shown to INCREASE exhaust emissions with a new pollutant - aldehydes. So why is it everywhere?

Easy - we have the best government than money can buy. Archer Daniels Midland bought off congress years ago.

OK - so what to do? You are correct in that using 91 octane pure gasoline is wasting money and octane rating, as our engine is not designed to advance ignition timing far enough to burn all of it. This can also lead to excess unburned fuel deposits.

You are also correct in saying none of the lower octane rating gas in MN is pure gasoline. Do NOT use the 88 octane rating gasoline!!! This has more than 10% ethanol in it. Use the 89 octane gasoline that limits ethanol to 10%. It's the best we can do here.

Finally, use only Top Tier licensed gasoline - these have sufficient detergent additives to keep injector nozzles and intake valves clean. You can look them up online, or I can just tell you that Holiday, Costco, Shell have it. Kwik Trip is pushing the high ethanol 88 octane only - don't use it.

<end rant>

P.S. - the only pure gasoline octanes lower than 91 I've found were at the Cenex in Hayward, WI.

 

[caulk04]

In something that gets driven regularly, there's really no reason to avoid ethanol. Something old or something that sits a lot, think about it. I don't use ethanol free in any of my stuff, even the mix gas that I only have to mix up every 6+ months.

I've been using E15 88octane from all my local Sheetz stations for years in two different Hemi's and my wife's 11 Explorer. It's cheaper than regular 87 and with just a tick higher octane. Going to 89 is a significant increase in price. E15 is fine, even if the vehicle isn't flex fuel rated.

 

[2018_ram]

You're conjoining two separate fuel issues - alchohol and octane rating.

Our 6.4L engine is designed to run on octane rating up to 89. The manual says 89 is "preferred", because the compression ratio and ignition timing algorithm is such that it can burn 89 octane gasoline efficiently. This means the ignition timing can be advanced further without knocking / detonation, resulting in less fuel consumption and more power. So far, so good.

Now we get to the alcohol (ethanol, to be specific) part - adding alcohol to gasoline is a massive taxpayer lobby scam by corn processors and growers. Adding ethanol costs more than resultant energy delivered. Adding ethanol increases fuel consumption. Adding ethanol leans fuel mixtures and raises engine temperatures. Adding ethanol corrodes and degrades fuel storage ability. Adding ethanol does NOTHING to lower engine exhaust emissions - the 3 way catalytic converters produce near zero emissions regardless if fuel has ethanol in it. In fact, adding ethanol has been shown to INCREASE exhaust emissions with a new pollutant - aldehydes. So why is it everywhere?

Easy - we have the best government than money can buy. Archer Daniels Midland bought off congress years ago.

OK - so what to do? You are correct in that using 91 octane pure gasoline is wasting money and octane rating, as our engine is not designed to advance ignition timing far enough to burn all of it. This can also lead to excess unburned fuel deposits.

You are also correct in saying none of the lower octane rating gas in MN is pure gasoline. Do NOT use the 88 octane rating gasoline!!! This has more than 10% ethanol in it. Use the 89 octane gasoline that limits ethanol to 10%. It's the best we can do here.

Finally, use only Top Tier licensed gasoline - these have sufficient detergent additives to keep injector nozzles and intake valves clean. You can look them up online, or I can just tell you that Holiday, Costco, Shell have it. Kwik Trip is pushing the high ethanol 88 octane only - don't use it.

<end rant>

P.S. - the only pure gasoline octanes lower than 91 I've found were at the Cenex in Hayward, WI.

yeah kwik trip is where i typically fill up at they only offer 87,88,91 or 92 so maybe i just have to look around to see we just have way to many kwik trips here.

 

[HEMIMANN]

yeah kwik trip is where i typically fill up at they only offer 87,88,91 or 92 so maybe i just have to look around to see we just have way to many kwik trips here.

I go to Holiday or Shell. When Marathon bought Superamerica, they opted to only brand Speedway, which does not carry Top Tier gasoline. Only their Marathon stations do (I called them). Well, Superamerica had 50% of the Twin Cities gasoline market, since we're on the edge of civilization. So I plan to fill up when I do errands near a Holiday or Shell.

Kwik Trip is Top Tier, but I only stop there if I need 87 octane with my other vehicles. It's too bad the corn lobby legislated food for fuel to make money off of taxpayers.

 

[HEMIMANN]

https://www.aaa.com/AAA/common/AAR/files/Fuel-Quality-Full-Report.pdf

1. The test engine operated on a TOP TIER gasoline averaged 19 times fewer intake valve deposits than when it was operated on non- TOP TIER gasoline. (based on the ASTM D6201 test - TOP TIER gasoline averaged 34.1mg of deposits per intake valve versus non- TOP TIER average of 660.6mg) 2. Based upon secondary research findings, long-term use of a gasoline without an enhanced additive package can lead to reductions in fuel economy of 2-4%, drivability issues, and increased emissions. 3. In most cases, carbon deposits can be reduced or removed from critical engine components by switching to a gasoline that meets TOP TIER standards.

Comment - this should apply to fuel injector nozzles as well. Important because direct-injection engines don't impinge fuel on intake valves, so only injector nozzle cleanliness matters.

 

[SeppW]

i have a 2018 ram 3500 with the 6.4 hemi i been running it on 91 octane with no ethenal but its expensive at 3.54 a gallon. thinking about going to lower grade but here in minnesota we have 87, 88, 91 and 91 has no ethenal. 87 has 10% and 88 has 15% ethenal. and i think our trucks run on 89 right? so will 88 be ok?

Probably ok, as long as the ethanol content is less than 15%. The manual says you can run 87, but may hear light knocking. It says anything less than 87 octane could damage engine and void warranty. Or so it says for MY16.

Maybe useful or an utter scam, but Top Tier gasoline Web site https://www.toptiergas.com/licensed-brands/ lists all the top tier gas stations. or so they claim. Endorsed by AAA and Consumer Reports, I use it, surprisingly COSTCO is on the list and their gas prices are usually well below other stations, just such a PITA to fuel up because in this area it's all about waiting and time wasting in lines. I wonder though, because there is a tank farm here where all the fuel truck load up and you see the same trucks at different stations, both independent and big oil companies. Not clear how it works or how they vet gasoline retailers.

 

[HEMIMANN]

Seems there are more Shell gas stations in the Twin Cities Region than I thought. The region's been so dominated by SuperAmerica (Ashland) and now Speedway (Marathon), I wasn't aware. Those two have 50% of the gas market in the metro according to articles.

 

[Gr8bawana]

You can fill it it up with whatever is cheapest and I can assure you that you will never feel the difference in performance.

Base Hemi- Automatic Tansmission​

The standard or "base" Hemi engine has a slightly lower compression than the SRT8 performance version. When the Hemi is matched with an automatic transmission, Chrysler recommends 89 octane fuel for peak performance. 87 octane is the minimum octane rating listed for the base Hemi regardless of transmission.

 

[RamGuy110]

You're conjoining two separate fuel issues - alchohol and octane rating.

Our 6.4L engine is designed to run on octane rating up to 89. The manual says 89 is "preferred", because the compression ratio and ignition timing algorithm is such that it can burn 89 octane gasoline efficiently. This means the ignition timing can be advanced further without knocking / detonation, resulting in less fuel consumption and more power. So far, so good.

Now we get to the alcohol (ethanol, to be specific) part - adding alcohol to gasoline is a massive taxpayer lobby scam by corn processors and growers. Adding ethanol costs more than resultant energy delivered. Adding ethanol increases fuel consumption. Adding ethanol leans fuel mixtures and raises engine temperatures. Adding ethanol corrodes and degrades fuel storage ability. Adding ethanol does NOTHING to lower engine exhaust emissions - the 3 way catalytic converters produce near zero emissions regardless if fuel has ethanol in it. In fact, adding ethanol has been shown to INCREASE exhaust emissions with a new pollutant - aldehydes. So why is it everywhere?

Easy - we have the best government than money can buy. Archer Daniels Midland bought off congress years ago.

OK - so what to do? You are correct in that using 91 octane pure gasoline is wasting money and octane rating, as our engine is not designed to advance ignition timing far enough to burn all of it. This can also lead to excess unburned fuel deposits.

You are also correct in saying none of the lower octane rating gas in MN is pure gasoline. Do NOT use the 88 octane rating gasoline!!! This has more than 10% ethanol in it. Use the 89 octane gasoline that limits ethanol to 10%. It's the best we can do here.

Finally, use only Top Tier licensed gasoline - these have sufficient detergent additives to keep injector nozzles and intake valves clean. You can look them up online, or I can just tell you that Holiday, Costco, Shell have it. Kwik Trip is pushing the high ethanol 88 octane only - don't use it.

<end rant>

P.S. - the only pure gasoline octanes lower than 91 I've found were at the Cenex in Hayward, WI.

Back when I had a 6.4 in my 2014 and 2017, I found non-oxy 91 at a few stations, but haven't looked for it since I've had diesels from 2018 to just a few months ago when I bought a Hemi again. I've been using 87 from Holiday to save some $$$$ or trying to that is.