yes i know we have a Fuels Section but many don't visit and this is centrally important to anyone running a single turbo...

https://www.fordmuscle.com/tech-stor...or-less-money/

given the high combustion chamber pressure and heat of our turbo'd rotaries FUEL is foundational and there are many options.

alcohol should be an important part as we pass 450 rw. i choose to get my alcohol, in my case methanol, through my AI setup.

given my experience w E85 i really like the idea of running a reduced % which delivers most of the benefits while being easier on the internals. i realise this isn't news to most.

the linked article is an excellent source of all the numbers needed to do the mixing and calculate AFRs/octane etc.

the item that jumped out for me is the table that shows that given our typical 93/91 octane fuel has around 10% ethanol our various AFR numbers such as 14.7 Stoic, 13.2 best torque etc aren't accurate. given ethanol at 9.0 to 1 stoic and 10% in our fuel our real stoic is 14.1 not 14.7. best torque around 13.2 on 100% gas is 12.7. big difference.

while most of us just look at knock etc, it is still valuable to adjust our AFR guideposts to the actual reality of our fuel... which is impacted significantly by the 10% slice of ethanol.

lots of good stuff in the article.

 

In reality most are tuning in lambda, even if they think they are tuning in petrol AFR. As an extra, just in terms of knock suppression, on port injection motors, the vast majority of the ethanol benefit is achieved before 40% ethanol, beyond that there are only marginal intake cooling gains and thermal management improvements.

 

I’m a bit confused; it’s just a magazine article that explains the very basics as most magazine articles for the masses do. Maybe I take for granted having learned mass balancing equations several decades ago, but am failing to see anything new or revealing, rather just the usual generalities often seen in magazine articles.

 

To be fair, complete combustion equations are meaningless in reality. I came first and got a free subscription in that Engineering subject but that doesn't even scratch the surface of what is actually going on.

 

In my town there is a Grange station that offers Premiun unleaded gas with no ethanol added. Both this station and other major brand stations (10% ethanol) list the octane as 92. Am I right to assume the fuel with the 10% ethanol would be the best to run in out turbo'd rotary cars?

KK

 

If tuning to a similar lambda value there should be a small gain in evaporative charge cooling and effective knock resistance.

 

Correct. Somewhere between minuscule and non-existent.