Have not been able to determine by what means my car is able to tell the difference in octane as I believe the car has no knock sensors. My car is 4.3 with power upgrade. Also, any recommendations on fuel ? My car seems to definitely have less power with Sunoco. I have yet to try ethanol free gas. Any info, comments or suggestions would be greatly appreciated

 

I think the earlier v12's didn't have knock sensors but the 4.3 and 4.7's both do..

 

Thanks for the info!

 

i've been dealing with this a lot lately, so here goes:

93 octane in GA was great, no issues at all. 93 octane up here barely cuts it. much of the problem from what i've seen/heard/experienced/been told/etc is that stations up here put WAY too much ethanol in the fuel, many as much as 15% (as opposed to the 10% they say). this causes our cars to have a lot of problems.

i'm glad you mentioned Sunoco. STOP USING IT. my car barely runs on that crap. it's the worst gasoline i've used of all the major brands. so far Shell and BP are okay, surprisingly 76 Stations are pretty good, but Sunoco is absolutely horrible!!!

in PA, you can find pretty good gas. Rutters (i think that's what it's called) is really good from what i've been told and from what i've experienced using it myself.

if you can find ethanol-free gas, use it!

different stations will have different quality. some experimenting is probably necessary to find the ones your car respond best to. i'd start with Rutters, and any ethanol-free 93 you can find.

 

Here's my understanding, but as usual comments would be appreciated. Ethanol has much higher Octane (knock resistance) than gasoline. However, with that said, Ethanol has a much, much lower Energy content than gasoline. So gasoline producers can get higher Octane by adding Ethanol, rather than refining to get higher Octane, but the more Ethanol they add the worse your MPG will be.

 

ethanol has a very long list of negatives. i absolutely hate the stuff and i'll spare my ranting, save this: the benefits? it isn't a fossil fuel, and it's sourced domestically. it damages the fuel system, produces less energy than gasoline, causes running problems for cars not designed for it, creates more heat, puts more strain on the car's cooling system... plus all the indirect aspects of using a food crop for fuel (increased food prices, lower crop rotation, etc).

 

Is ethanol free gas even available anywhere? There was a website that had a list of stations that sold ethanol free gas but, the few that I checked in my area were listed incorrectly. Said the were ethanol free but had ethanol....

 

I can still get 94 octane with 0% ethanol at Chevron stations near me. Costs a small fortune, and my car can't really use the octane, but zero ethanol sways it for me. But just across the border in Washington state, 92 octane with 10% ethanol is the best that Chevron offers.