Re: [Chrysler300] 110 octane gas

I agree. You already have hardened valve seats in your hemi, Carlton, so unless you're mercilessly beating on this car (which can be tempting as we know), the lack of lead in today's fuels is not likely to cause any damage at all. But it's an entirely different verdict for the potential of ethanol content to do some cruel things to your C anywhere from the tank to the intake manifold. You say you have non-ethanol premium available there (as I do here in West Michigan at 91 octane - and only about 4 bucks as well), and that is an ideal situation to be in. Creates more than a little envy in West Coasters and some other states. Burn that and you'll be golden.

With respect to octane requirements of the C engine, it's amazing how the lack of crazy corners in a hemi-design head can give a "knock" nowhere to start. A couple of years ago, on my way back to Michigan from the Lake George Meet, I thought I'd play with octanes a little and see what my C hemi would tolerate. It was interesting to find that even on a tank of 87 octane ethanol fuel, my engine never hinted at a knock - even when I would occasionally stand on it. But around home I'm delighted to have the 91 octane pure stuff available, and I stock the tanks of all my old iron with it.

Keith Boonstra

On Wed, Jan 22, 2014 at 8:55 PM, Rob Kern <robkern@xxxxxxxxxxxxx> wrote:

Carlton,

Octane does not equate to power. I did a 50/50 mix of 93 octane unleaded with 110 octane racing fuel in my C. After a while the car started to run rough and I was told that a lot of lead deposits and carbon was probably getting on the valves. I stopped using this mix and used a container of seafoam cleaner per tank of 91 ethanol free with a can of octane treatment which brought octane to 93. This I did for two full tanks of fuel. Car runs smooth and I don’t have any ping or dieseling in hot weather when shutting off the engine. For the 9.25:1 compression ratio on the standard 300C 392 Hemi, you really don’t need any more than 93 octane. What is best is if you can get ethanol free gas. 300’ly, Rob Kern

From: Carlton Schroeder

Sent: Wednesday, January 22, 2014 10:52 AM

To: Chrysler300@xxxxxxxxxxxxxxx

Subject: [Chrysler300] 110 octane gas

Hello,

It just came to my attention that right here in Eagle River, WI I can drive up to a gas pump and load my 300C with leaded, non-ethanol, 110 octane gas; I just have to tell a white lie and say I am using my car for ‘off road purposes’. It does cost $7-8 per gallon and originates at a Sunoco refinery in PA. The pump actually says 115 octane but by some government definition / computation method / regulation the supplier says it is designated 110 octane.

The supplier says most people (local racers) that buy it mix about 1 gallon of the 110 octane gas with 3 gallons of non-ethanol premium which is readily available around here.

I think the higher octane is primarily to prevent pinging in higher compression engines and that hasn’t been a problem for me, but getting the lead-in seems like it would be helpful. I only drive this 300C 200-300 miles a year.

I would appreciate advice or opinion about how to use this 110 octane gas.

Thanks,

Carlton Schroeder (in very cold and snowy Eagle River, WI - snowmobile capital of the world)