So pondering the thought of how my valve seals are starting to meet their maker, and knowing the s2000 in 2002 wasn't really tuned or designed for any ethanol, Im wondering if it would be better, safer, worth it to switch to 91 octane corn-free fuel rather than running 93 octane with 10% ethanol. Has anyone done any real world testing? Losing two RON is a little bit of a concern, but I know the s2000 was tuned for a minimum of 91 and still make peak power. Any thoughts on the idea? Let's assume you could get the at the same price per gallon for now.

 

No corn opinions? :/

 

Back in 02 when I got my S I ran 93/94 non ethenol. After a few years only 10% 93 ethenol was for sale in these parts, car seemed to run fine. 2 years ago 91 ethenol free became available at a couple places and I've mostly been using that....I've noticed my mpg has increased by a few miles. It may cost a bit more but I like the peace of mind.
Levi

 

I wouldn't hesitate to run 91. Might perform better for you overall. Try a few tanks and see.

 

You are probably already aware of this site, it seems there is 93 octane available at one station in Raleigh.

Ethanol-free gas stations in NC

 

A couple of years back i did some research and came to the conclusion ethanol free was superior. If I had access to both I'd probably run the 91 for around town and 93 w/ethanol for the track, especially if it was hot out to get that little bit of buffer against detonation.

 

I use to run ethanol free 93 from time to time when it was available where I lived. I noticed better gas mileage, but that was about it. I've heard it burns a little less clean than than ethanol gas, which could potentially clog the cat. But I doubt it makes that much of a difference.

 

I wanna blame my failing valve seals on ethanol Car smokes like a bitch when warm and only has 30k miles on the clock.

 

93 E10 > 93 E0 > 91 E0 ; unless you solely want fuel economy, then the order is reversed.

The ECM will adjust fuel trims for closed loop operation. Open loop operation is rich enough where the change in the stoichiometric air to fuel ratio isn't significant.

 

I noticed the fuel I ran at the track(what ever it was) made the car run significantly richer then what I normally saw on my wideband at the pump. Nearly a full point. Depending on where your fuel tune currently rest in open loop, you might feel the car is down/up on power just from that. It makes sense form an emissions/standard pump station standpoint, that leaner afr in open loop for a zillion cars everyday will produce less carbon emissions.