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#1 |
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
|
![]() I used to put 1-3 Gallon of Ethanol when I still had stock tune. I wonder if I can still do that with Cobb Stage 2 OTS map.
Cobb Intake, Cobb Downpipe, some catback, AP with Cobb St2 ots tune.
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Last edited by 3eyesraver; 12-02-2019 at 05:45 PM. |
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#2 |
Scooby Newbie
Member#: 431550
Join Date: Oct 2015
Location: South Florida
Vehicle:2016 WRX ALL THE STAGES |
![]() So a little bit of corn wont do damage even when not tuned for it. A LITTLE BIT being the important part.
The only time I used a gallon or 2 of corn in the tank was when my DAM dropped due to some bad gas. It helps pick up the octane. If you have no issues, I would not do it. If you want the most out of the E content, get a tune for it --- pro-tune flex fuel or a canned e30 tune. |
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#3 |
Scooby Newbie
Member#: 458914
Join Date: Nov 2016
Chapter/Region:
SCIC
Location: SoCal
Vehicle:2017 WRX Premium WRB |
![]() I'm on an OTS tune and occasionally throw 2gal of e85 in my tank when i'm near a station that offers it. Seems to help combat knock, but if you're doing it in hopes of gaining noticeable hp on your butt dyno, then you'll probably be disappointed - I can't really tell the difference between pure 91 and the 91/e85 mix.
Phatbotti says: "The simple answer is to just try it. If you put the ethanol in and the car knocks worse...stop doing it. If the knock decreases and the car feels better, then you're likely fine." So to answer your question, yes, you can, but to actually reap any power benefits, you should get tuned for it like noobultimatum stated. |
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#4 |
Scooby Newbie
Member#: 454461
Join Date: Sep 2016
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![]() Ask Cobb and get a definitive answer.
I'll venture to guess that they've built the tune to handle common fuel blends, which in many places includes a mandatory 10% ethanol. In my experience, with two exceptions, I've never found any performance differences with running 0-10% ethanol blends in any of my vehicles. Exception #1 is running on MAP's E30 OTS which is just fantastic, and Exception #2 is in carbuerated motors and leaving it for a month (untreated) is likely going to result in difficulties starting and sometimes require a carb cleaning. |
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#5 |
Scooby Specialist
Member#: 453427
Join Date: Aug 2016
Chapter/Region:
MWSOC
Location: Detroit, MI
Vehicle:2017 WRX Crystal White Pearl |
![]() One to two gallons of E85 is not going to kill you on an OTS map, should get you around E15-E20 ish at most when combined with pump gas.
If you want performance for E85 get a flex fuel tune, or you can try an E30 map from various tuners, but then you have to guess on your blend which is not ideal. |
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#6 |
Scooby Newbie
Member#: 382724
Join Date: Feb 2014
Chapter/Region:
MWSOC
Location: MN
Vehicle:09 WRX Sedan SWP |
![]() Pretty sure the map notes explicitly state they're designed for 10% ethanol content...with the implication that they need at least 10% to properly protect from knock/detonation.
Do you live somewhere with E0 as the standard fuel, or why did you previously add corn on the stock tune? Any issues when you datalog without it? |
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#7 |
Scooby Guru
Member#: 428511
Join Date: Aug 2015
Location: philadelphia
Vehicle:2016 STI |
![]() any OTS tune is for UP TO 10% ethanol
reason is because pretty much every pump in the US has UP TO 10%, not 10%. So nobody knows any small amount of ethanol is fine because you can't even tell what you are getting from 0 to 10 |
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#8 | ||||||
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
|
![]() Thanks guys for all the replies
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I had the AP for awhile since I was still on Stock tune but my chicken self didn't want to plug it in so I couldn't monitor knocks. I noticed car drive like **** sometimes especially 3 of this elements change: temperature, elevation, and load. I started to ask around - a friend with a heavily modified fa20dit suggest me to run 3 gallon of E. The most I put in is 2.5 gallon, never 3. I "felt" a significantly improvement where the issue doesn't come back that often. Did that for every 2-3 empty tank for 8k miles. Again, no data log, no number to back it up just the "feel". So I would say I did this not because of +HP but for reliability. Thank you guys. I will keep put corn in my mix once in a while to combat with knocks until going full Flex mode! ![]() |
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#9 | |
Scooby Newbie
Member#: 431550
Join Date: Oct 2015
Location: South Florida
Vehicle:2016 WRX ALL THE STAGES |
![]() Quote:
You would still have to mix BUT the flex fuel sensor would adjust the tune accordingly based on registered E-content. As far as I know, tuners have found that anything above a max E-content of E-55 or 60 has no additional benefits for the fa20dit motor. Plus, more E means less lubrication for the HPFP. So, you want to find a happy compromise between E and gas... even then, you want to run straight gas occasionally in order to avoid any issues with our HPFP. My local flex fuel buddies pretty much daily on 93 and then run their desired E-mix for max power potential when they take it to the track or "mexico". |
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#10 |
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
|
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#11 |
Scooby Specialist
Member#: 453427
Join Date: Aug 2016
Chapter/Region:
MWSOC
Location: Detroit, MI
Vehicle:2017 WRX Crystal White Pearl |
![]() Just tell them you are filling up with gap sauce, stare right at them to assert dominance.
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#12 |
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
|
![]() lmfao. Will do chief
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#13 |
Scooby Specialist
Member#: 460907
Join Date: Jan 2017
Chapter/Region:
RMIC
Location: Colorado
Vehicle:2016 WRX |
![]() FWIW the pump probably already has E10 as the fuel, so putting 3 gal of E85 is putting you closer to E25 than E10. Watch your 1) fuel trims, though those will probably decrease, and 2) watch your AFR, make sure it doesnt get too lean. Ethanol takes more fuel to reach the same stoich, so your AFR will lean out the more ethanol you use because you are scaled for a different fuel. Stick with 1.5 gal, if that doesnt work consider getting a custom E Tune.
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#14 | |
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
|
![]() Quote:
I was told keeping 14 while driving is good and it is 14.xx most of the time. My max is varies sometimes hit 25 depends on the acel. |
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#15 |
Scooby Specialist
Member#: 460907
Join Date: Jan 2017
Chapter/Region:
RMIC
Location: Colorado
Vehicle:2016 WRX |
![]() I assume you're talking about your AFR?
14.7 is what you should be seeing at cruise, that's what your car is targeting at least. Your car operates in Closed Loop Fueling when cruising around and not at WOT, you should always be targeting 14.7 at low load and cruise. That's not what you need to worry about, your car will correct fueling at low load. When you're at WOT is when you need to watch AFRs because you are no longer relying on your O2 sensor because you're operating in Open Loop Fueling. Make sure you aren't running too lean (high 11s to 12s) at WOT with only 1.5-3 gal of E85 or you're winding up getting detonation. Look up open vs closed loop fueling if this sounds too foreign. You see 22.8 or whatever when you're injectors "turn off" on deceleration. 22.8 is just the highest voltage your O2 sensor reads. In reality it's leaner, but it's not under load so it doesn't matter. |
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