91 octane with ethanol

[pwr2tow]

My car: late build 2009 Challenger R/T.
Modifications: Full flow exhaust, CAI, going to buy the predator.

The gas in my part of the country has 10% ethanol in it. Can I run the canned 91 CAI tune without problems or willl I need a custom tune.

Thanks,

[Mike_Levy]

You're probably gonna see quite a bit of knock. The Hemi does not like Ethanol. You'll need to fine tune the tuning on your car.

[concoursd]

we have the same thing here in California. Its not a problem but I would monitor your knock and seriously think about investing in a catch can for that new challenger to keep the oil vapors from causing major knock issues. Its a common hemi upgrade and a must in my book.

[brandy16]

you can also data log to check for KNK STN and KNK LTN and the make any fule adjustments that may be needed to get rid of the knock. You add fule at the rpm range that showed knock until you get rid of it or get it down as far as possible.

[gdragich]

You'll also see mileage drop about 2mpg. Here is WA state the ethanol blends come in Oct through about April and mileage sucks then.

[neidan]

I'm not getting the KNK issue with Ethanol. Doesn't make sense to me? The octane should be the same (or higher). I can see less power as the ethanol contains less energy, but I need help understanding why knk would increase. I run 93 non ethanol when I can but I do travel places where it's not readily available...