Question on Octane req.

[Doglips]

Ok, I'm sure this is a dumb question to most here but I haven't gotten a straight answer to this yet. I will be getting the R/T 5.7L. I know it is recommended that mid-grade gasoline is used. What are the repercussions of using regular? Will it just lower it's performance or does it eventually cause damage somehow?

[thesteve]

In a nutshell, the engine in optimized to run a certain octane to perform its best. Modern cars have knockback sensors that can detect the grade of fuel you put in and adjust timing and other factors accordingly. While your engine can most likely cope with regular, the irregularities in lower grade gasoline might cause subtle misfires and put stress on the internals of your engine, and cause unnecessary wear and tear.

[Challenger5.7]

I kinda had this same question. However I was wondering if using an octane booster each time I fill up using regular gas would do the job. I'm getting the 6spd which recommends premium 93 octane though. It probably is still safer just to go ahead and fill up with the correct fuel....

[SF18C]

So I went to Denver Gas Prices - Find Cheap Gas Prices in Colorado and compared the Regular, Mid-Grade, and Premium fuel prices. I am sure there is a similar site in your area…Google for it.
Regular $3.39 X 19 Gal = $64.41
Mid-Grade $3.55 X 19 Gal = $67.45
Premium $3.65 X 19 Gal = $69.35

So the grand difference between the cheap stuff and the top grade is $4.94 for a full tank. Just get the good stuff and don’t think about it!

[billyjoebob1]

Oh boy someone with cheap gas, in milwaukee Premium $4.05 X 19 Gal = $76.95

[garylee]

SWEET!!!!!!!! So when are you going to open her up?

[garylee]

Just noticed 156 at 4800rpm, she still has a way to go before redline.

[It'sOnOrder]

So, there's usually a .20 to .30 difference between the lowest grade and the highest grade of gas- all other things being equal. Assuming that your car averages 20 mpg, doesn't it seem peculiar to get crappy performance from a $30k-40k muscle car for what works out to a .01 to .015 a mile price difference? Assuming a .30 price diff between low octane and high octane, the upfront cost of running premium for 15k miles (a nice round calculation for a year's driving) is $225 (15k/20mpg x .30 price diff). Same logic holds for buying quality gas (Chevron, Shell, Texaco, Exxon, etc...) rather than crappo 7-11 drudge.

[aviscomi]

Originally Posted by billyjoebob1

Oh boy someone with cheap gas, in milwaukee Premium $4.05 X 19 Gal = $76.95

Its all proportional though; simply put there's usually a 10 to 12 cents difference between the grades

[CaptBen]

Hi guys, I've got a 08...nothing but premium in her!! I think it's protecting your investment. I've been told with the premium fuel it will do slightly better mileage, should help a little closing price from the cheap stuff.

My question is are you guys using premium with that bloody ethanol in it? I live in Canada and the only station that told me that there is NO ethanol in their fuel is Shell. All the other didn't know for sure. I've been hearing some bad things about this stuff and I'm trying to stay away from it....any one else????