| capt_slo | 06-25-2014 01:30 PM |
Quote:
Originally Posted by underscore
(Post 8493105)
Does anyone have any science to back up this US 92 > CDN 94? I mean an actual fuel analysis comparing multiple brands, not some dyno pulls that leave a shit tonne of variables out of the equation.
| Disclaimer: I'm not an expert but this is the clearest answer I've pieced together without actually talking to a tuner in person.
From what I understand it's pretty much all down to the "zero" ethanol content of Chevron 94.
In FI applications, ethanol is more "stable" at compression and is wanted to prevent detonation (ethanol changes the RON vs MON ratio of that fuel), but it puts out less energy / burns cooler during combustion. So you typically add a bit more fuel to keep things right, especially as boost pressure increases. A lot of big power turbo builders seem to leap at the chance to run e85, presumably for this reason.
NA motors & tuners prefer fuel with as little ethanol as possible because boost/air density is less variable. They're just focused on spark timing and resultant AFR.
Many fuel maps written by tuners in the US or other regions may be writing in an assumed adjustment for a 10% ethanol content - which usually adds a certain % more fuel. On Chevron 94, this extra fuel will make your car seem bogged down due to a richer mix. | 