Thread: Safe to run 90 octane with 10% ethanol in my 3.8 N/A?

Heres the deal,
The place I always go to get gas has the regular 87 for a couple cents higher than the other stations and they do not run ethanol in it. I have heard something about ethanol gumming up small engines and such and have heard that it can be kind of hard on cars. Now being a college kid now Im looking to save money here and there. This gas station sells the 90 for usually at least 10 cents cheaper than their 87 and is a couple cents cheaper than any of the other stations 87. The only thing is that it contains 10% ethanol. I probably do not need to run 90 because I have not modded my car at all yet and I may never. Just curious to see if this is a big no no. I realize that I will not be saving much but over time this adds up so every little bit helps. Do I need to worry about the ethanol causing problems or the octane being to high?

Sure, why not.

Ethanol is actually good for your engine, it helps to clean it out not gum it up. You might see a very small decrease in your gas mileage though.

Its only 10% ethanol so he might not even notice, the guys that switch to E85 only notice about a 2-3 mpg decrease.

Originally Posted by slick2500

Ethanol is actually good for your engine, it helps to clean it out not gum it up. You might see a very small decrease in your gas mileage though.

I can live with a couple mpgs lost. As long as its not more than like 5. lol

Originally Posted by matt5112

Only issue is, it'll collect water if you store it.

So use stabilizer if you're going to store.

More octane is good.

As slick said, mileage WILL go down.

Dont plan on ever storing it. Right now its my one and only so I dont think itll sit unused more than maybe one day. And if it collects water fairly easy compaired to the non ethanol gas should I be sure not to run it low in the winter due to higher risk of the water in the gas freezing? I know its generaly not good to run it under a quarter tank if you can help it anyway.

When would it be best to switch to the 90? Should I run it lower than normal like to the almost out of gas state or would it be better to slowly switch over to it by filling the tank when its half full?

Alright. Wasnt sure if it was bad to mix it or not. lol. Thanks for the advice.

Here in Maine ALL gasoline is 10% ethanol. Never had an issue with my engine and the vast majority of my 220k miles were driven on Maine gasoline.

I do wish i could get ethanol free gas... curious how it would run.

Originally Posted by Chadgervais

Here in Maine ALL gasoline is 10% ethanol. Never had an issue with my engine and the vast majority of my 220k miles were driven on Maine gasoline.

I do wish i could get ethanol free gas... curious how it would run.

I got slightly better gas mileage since I started using it. On the highway I was lucky to get 28mpg and then i was getting 30-31 about 4 weeks ago when I checked. Part of it was cleaning the throttle body and new plugs and wires I'm sure. And most places around here have ethenol in all grades except maybe the 91 at some places. This station is a little different than the norm. haha

Adding the seafoam that often is a waste of money. Its really not helping anything, if the filter is new and you've run a cleaner in there before the fuel system should be pretty clean. Gas itself now can cleaning agents in it.

Race fuel for a race car. /wut

I was going off of your previous post saying that you do it every other tank. If you really did it that much, its a waste.

Either way, with how often you change your filter and the gas quality these days, you shouldnt ever have to run any.