You could go back and forth safely by running the 93 tune until you had straight 100 in the tank or the mix of 93 and 100 in the tank that you were tuned for. For example some of our customers that have race gas tunes don’t want to drain their tanks so we figure out that they’ll run their car down to 1/8 tank or less on 93, then put in X gallons of the race gas they’re tuned on. Then in the future they just need to run their tank down to 1/8 tank or less on pump and put X or more gallons of the race gas they were tuned on in the tank, and switch to their race map.
You can’t do this with an ethanol mix. The mix in the tank has to be the same every time or you have to adjust the tune unless you have the ideal setup I talked about above.
As the cost of E98 (98% ethanol) comes down we’ll be able to bring the price down for the blends we sell. We currently pay way more here than people do in the mid west and other areas where ethanol is plentiful because we have to freight it here in drums over a significant distance and that isn’t cheap.
The rally car runs E98 with rally legal unleaded fuel. He mixes that himself.
For reference, the fuel I ran 3 years ago in my Subaru from an E85 pump in Ontario turned out to be 65% ethanol when tested and that was in the middle of summer.
i was thinking the same thing, maybe when e85 is more readily available then make the switch, looks like ill be doing a 100 oct. tune for kill mode and a 93 tune for cruising/ trips etc
My buddy (who I really trust) just convinced me to fill my 17 gallon tank with 13.5 gallons of 93 and 3.5 gallons of E85.
We did a control run on straight 93 and at WOT the computer advanced the timing 13 degrees. Did another WOT run after filling up with the combination and it advanced timing 16 degrees. So I’m thinking it helps me make more power.
My buddy assured me that because my car has a knock sensor that it will just adjust timing for different overall octane levels and therefore won’t mess anything up. Is any of this stuff true? He’s used it in working on the drag car he’s building and he’s put it in his DD and hasn’t had any issues. Schwidley put some in his DD and actually ran a slightly faster run at Thunderdome (lol) with a little bit of E85 in the tank.
I guess I’m just looking to see if anyone knows more about E85 and if it will fuck anything up if you put it into a regular car.
ADDED:
From wikipedia (with no citation):
Because of the lower heating value E85 has a cooler intake charge—which, coupled with its high stability level from its high octane rating—has also been used as a “power adder” in turbocharged performance vehicles. These modifications have not only resulted in lower GHG emissions, but also resulted in 10-12% power and torque increase at the wheels. Because of its low price (less than $2.00/gal in some places) and high availability in certain areas people have started to turn to using it in place of high-end racing fuels, which typically cost over $10.00/gal.
You are really supposed to add ~30% fuel to get a/f correct. E85 requires more fuel to get the same lambda. I’ve recently switched from 93, and honestly the car seems to run much smoother on the exact same map w/just the lambda dialed in. Feels like how my old engine did on Q16, engine feels nice and tight in the high revs compared to when running 93. Going back for a re-map this week, so I’ve yet to see any real power gains however my MPG has obviously dropped – from about 21 to 15MPG.