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I’m using a station called race track. It tested at e68. The only place to get true e85 is out of a can or drum. Race e85 is not 2.75 per gallon though
I went out to do some testing because I'm not really interested in running e30 or trying to mod my car for the quarter mile but I do have a lot of interest in our cars systems.
Here are key rpm points (4500, 5000, 5500, 6000, 6500) across the rev band in 4th gear on 93 octane fuel.
Look at the Short term fuel trims to see the car is pretty much perfectly fueled for e10. Very little fuel trimming.
Look at the timing values for max timing at those rpm points
Look at the air intake volume for a rough estimate of power at those rpm points.
Look at air intake temps to make sure I standardized both runs.
93 octane...
Here are the same rpm points now on e30. I suspect it's closer to e25 based on fuel trim data.
Look at the fuel trims to know there is more ethanol in there. They are now up around 10 percent additive to add fuel to maintain the same specified air fuel ratio.
Looks like there was probably plenty of headroom to add more e85 or possibly my pump was only putting out e60 or so out of their e85 pump. E85 pumps do not put out exactly e85. They can be a bit all over the place. I should have brought an ethanol tester.
Nevertheless here is the e25 or e30 run. Same surface area. Same gear.
As you can see from the results, they are less than what I had been told. I was told we target 28 degrees and I suspect that's with a tune only.
It looks like possibly 24 degree targets and that our stock ECU is good to take advantage of up to around 96 octane or e25 ish.
With an e30 tune I suspect we could pick up another 16hp or so.
On the stock ECU it looks like perhaps around an 8hp gain from e25 to e30
I live in central California where premium is 91. I used to have a 2016 GT350 with a flex fuel tune. I always ran straight pump e85. The N-gauge tuner gave an ethanol % readout. During the four years I had the car the ethanol % was never less than e80. In CA e85 is considered a clean fuel so it is exempt from the most recent fuel tax that was added a few years ago. As such I suspect that the fuel quality is pretty strictly controlled.
If one runs e30 consistently would the long term fuel trim gradually take this into account resulting in less short term trim or is that not the way it works?
I live in central California where premium is 91. I used to have a 2016 GT350 with a flex fuel tune. I always ran straight pump e85. The N-gauge tuner gave an ethanol % readout. During the four years I had the car the ethanol % was never less than e80. In CA e85 is considered a clean fuel so it is exempt from the most recent fuel tax that was added a few years ago. As such I suspect that the fuel quality is pretty strictly controlled.
Correct! VERY tightly regulated in California and required to meet very specific specifications. It's commonly sold at a $2-3/gal discount.
If one runs e30 consistently would the long term fuel trim gradually take this into account resulting in less short term trim or is that not the way it works?
Ford recommends running an occasional tank of e10 in their flex fuel vehicles. That's what I did in my flextuned GT350. I definitely felt a difference going from straight e85 back to 91 octane e10 as the ECU compensated and pulled timing.
If one runs e30 consistently would the long term fuel trim gradually take this into account resulting in less short term trim or is that not the way it works?
LTFT is an average of STFT over time stored in KAM (retained and stored in FTC) which the vehicle will remember on next startup and effectively set as the “baseline” for that cell. You add the two together to get your total fuel trim. LTFT is basically a long-term coarse tuning dial and STFT is an immediate fine-tune adjusted from that point as needed to maintain stoich. As long as you run consistent fuel your LTFT and subsequently STFT should stay near zero after learning appropriate LTFT and storing in KAM.
How long would it take realize the effect of switching from 91 octane to e30?
The "effect" would be immediate (well, a minute or so of driving to mix the fuel properly) as trims would compensate in closed loop to adapt AFR, but if you're asking about populating the FTCs in the KAM so your STFTs stay in range that's just a few minutes of normal driving under varying conditions to store the values.
I haven't looked at any unlocked c8 pcms and mine is being built this week, so I don't know the timing constraints or how aggressive the pcm adjusts forward but I wouldn't imagine more than a couple degrees stock. I personally wouldn't (and won't) bother with it until tuned and I absolutely love E85 as a fuel - then again I have 93 here and if you only have 91 it'd be fine to blend to E30. Pump 91 is just 89~ blended with E to bring it to 91 anyway.
I just ran the calculation for our 18.5 gal tank: 13.5 gals 93 E10 + 5 gals of E85 = E30 @ 96-octane
This assumes the E85 is actually a true 85% which is not very common; your real-world result will be more like E27 @ 95-octane.
Fun fact: "standard" gasoline at the pump in Brazil is actually E27
Hey Kracka, I need your help. I have about 2.5 gallons of pump E85 that tests with my tester to be E65. My cars low fuel light came on and I figure there is only about 2 gallons in the tank now and its 93 (E10), how much more 93 E10 gas should I add to the tank before I dump the 2.5 gallons Of E65 in to get me a solid E30 fuel. I am guessing 4.5 gallons add to the approx 2 gallons in the tank now ... Thank you in advance.
Drove to the track Friday with a nine 9 gallon mixture of 93 and E65 to create E30 thanks to Forum members Kracka's Formula and 65sohc. The DA was about 1000, 7-9 mph head wind. My car is a base 1LT, non Z51, Non npp, factory all season tires. The entire exhaust system is untouched, have a blue attack air filter, and 1st time introducing a E30 mixture utilizing the 2 gallons left in the tank to create the mixture, the car has never been tuned.
Tire pressure set at 25psi rear, 41 psi fronts, front sway bar links disconnected to enhance weight transfer. Nothing removed to save weight other than the windshield wiper jug is empty. The car ran 11.100 @ 123.17 mph. My 70 mile drive to the track on the highway included some 3rd gear wot pulls to redline shift into 4th 3 times, I can feel the power difference. The ET and trap speed tells the story I truly believe.
