Should I be using Ethanol Free Gas in my 2004 360 Modena? Using 93 Oc
Your car should be OK. Ethanol percentage was gradually phased in over the years to the maximum of 10% (E10). The 10% limit was specified in the 1990 Clean Air Act. Thus, car makers had ample notice that ethanol might be coming and most likely started equipping their vehicles with materials that would not be damaged by ethanol at 10% max concentration if it were to ever go that high, which it did by 2012. Image Unavailable, Please Login
Not sure how it translates to your American petrol but our regular unleaded is 10% ethanol now and I wouldn’t use that in my cars that don’t get driven frequently; you don’t really want ethanol sitting around in the system. I put ethanol free in the Ferrari (and my lawnmower)
Ethanol is hygroscopic. I don't want water sitting around in the fuel tanks and (in the case of my mower) carbs when I'm not using the car (/mower) for a long time. So I use fuel that minimises the chances of that happening.
Quick answer is absolutely run pure gas if you can get it in your area. Our cars tend to sit too long to put ethanol in them.
I've been wondering about this as well but the only pure gas I can find near me (rural Pennsylvania) is 90 octane. I've read that the F430 can adjust timings automatically, but I still don't want to risk it. Idk if it's worth mixing 90 + 93. I've not found a US manual page that lists the octane. My manual is mis printed and the ones I find online don't have US octane specs. I figure if 91 is safe then mixing roughly 1:1 should be ok
Shelf life of gas containing ethanol is about 30 days before it starts to varnish, verses about 6 months for non-ethanol gas. If you are going through lots of fuel, I would consider ethanol gas safe, but otherwise spend the extra money on pure gas and don't risk getting gummy deposits in your fuel system.
This may be purely coincidence, but when I use non-ethanol gas, the "SLOW DOWN" light does not come on. So doing a brief search, it seems that ethanol blended gas burns hotter that non-ethanol. I've gone through 2 tankful of gas and have done some spirited driving up in the North GA mountains and no "SLOW DOWN" light. Fingers crossed.
That's an interesting observation and at first seems counter-intuitive since one of the few advantages of ethanol is higher octane which is theoretically less prone to engine knocking. However, ethanol is a "hollow" molecule and contains less energy than an equivalent volume of gasoline. A gallon of 10% ethanol spiked gasoline has about 3% less energy than a gallon of "pure" gasoline. The SLOW DOWN light thing seems to make sense as a gallon of pure gasoline contains more energy (BTUs) and the car doesn't need to work as hard to accommodate spirited driving. Looks like this is a case of where energy trumps octane.
The slow down light is not caused by gas , you have a different problem, which ethanol free gas is covering. Pull the codes.
CEL does not go on, only the slow down light. No codes ever stored. I get the "Slow Down" when I go for a drive, shut it off, then start again. It'll come on for about 10 minutes then go away. Again I'm not saying that it is gas related. I said maybe a coincidence. BTW did a drive up GA mountains yesterday and no "SLOW DOWN" light at all. Stopped in multiple places along the way. Normally I would get it at least twice. If it's not going on anymore, then I would say that I don't have a problem. Fingers crossed it keeps on like this. So far about 500 miles. I do have 2 new Themocouples, that I was going to replace the old ones with. I'll just hold on them them for now.
