Subaru Flex Fuel
This long awaited, highly anticipated, feature is upon us!
What is COBB Flex Fuel?
Firstly, let’s define Flex Fuel. Flex Fuel allows seamless flexibility between using standard gasoline and ethanol based fuel which is where the term Flex Fuel is derived. The key component enabling flexible fuel usage is an ethanol content sensor. This provides a real-time measurement of the ethanol content feeding the car’s engine allowing the ECU to actively make adjustments based on the sensor reading. This is something several US manufacturers have had implemented for a number of years. You have probably seen several vehicles badging this capability during your commute. Although there are vehicles that have this functionality from the manufacturer, unfortunately, very few of them are models that are likely to be found in an enthusiast’s garage. Ergo: COBB Flex Fuel!
The COBB Flex Fuel kit consists of an ethanol content sensor and analyzer. This is a plug and play system that connects directly to factory hardware and mounting points. Couple this hardware with your COBB Accessport and a Protune and you get the OEM functionality of Flex Fuel with the added performance ethanol has to offer.
Why Do I Want It?
Compared to standard pump fuel, the higher ethanol content in E85 provides a substantially higher effective octane rating. The octane rating of a fuel indicates it’s ability to resist detonation. This added resistance allows tuning to be more aggressive through timing and boost, yielding greater horsepower output. These factors combined make for a fuel solution with more power potential over the standard gasoline you find at the pump. With an active Flex Fuel system, a vehicle’s ECU is able to seamlessly blend calibrations required for each type of fuel.
The COBB Flex Fuel kit will allow you to overcome any disparities in ethanol content from station to station or season to season. This is something a standard tune for E85 cannot do. Also, if there isn’t a station with E85 convenient, simply fill up with pump gas and avoid the need to change maps.
How Do I Get it?
COBB Flex Fuel will be available in January 2016! Several Flex Fuel packages will be available to compliment your existing modifications or to take a completely stock car the full distance. Stay tuned for additional details.
Read more about our Subaru Flex Fuel release in our most recent update: http://www.cobbtuning.com/subaru-flex-fuel-update/
Wonder if this will work well with my 140k fxt haha. Cant wait to see these kits released
Hi!
Can I jump the gun and install a gmc e85 sensor and just pnp with what’s coming out? Or is it something included or an option to add/ skip?
Hey Brad,
We’ll be offering a complete plug-and-play solution, including a sensor. I’d recommend waiting until next week as we’ll be releasing a list of components and packages that will lay everything out for you!
Marshall@COBB
With such big news coming out do you guys plan on releasing the Cobb FMIC you’ve been working on for the past two years for the 08-14 WRX/STi? I know jumped shipped to purchase other vendor kits but I’ve been waiting for the release. Would love to purchase this flex fuel kit with the FMIC… Thanks for the update.
We are definitely still planning to release the FMIC kits! We initially had some difficulties in sourcing cores that met COBB standards but have recently found a company able to produce what we were looking for. Be on the lookout for those in the next month or two!
Marshall@COBB
Hi Marshall,
Will I still be able to use my V2 Cobb accessport? I still have the version that came out prior to the new version.
John
Hey John,
This feature will be applicable to the V3 Accessport only. Luckily, we have a pretty awesome Trade-In Program that offers 50% off a V3!
Marshall@COBB
I have heard rumors that there will not be or will be limited support for Subaru Legacy GT’s and I wanted to comment to voice my concerns about what i’d consider an oversight. There is an overwhelmingly large population of Legacy GT owners that are running E85 or plan to in the future. I am one of them. I have a 2007 Subaru Legacy GT spec.B that has upgraded Injectors, Fuel Pump, soon to be VF52 turbo, and hopefully E85. However, i’ve been holding off on E85 due to not wanting to have a single tune for E85 and having to have another tune for when i’m not going to be near any stations that have E85. Please tell me support for the 2005-2009 (or specifically 2007 🙂 ) Legacy GT is being considered sooner than later.
Hey Brian,
We thank you for the request. I will certainly pass it on to the Subaru Expert Group so they are aware of the demand. I can say that we’ve discussed adding Legacy GT Flex Fuel support in the future, if it happens it would likely come after all of the planned WRX/STI support is released.
Marshall
Will this require bigger injectors and higher flow fuel pump? I’m running an 2012 wrx with walbro 255 fuel pump, perrin tmic, grimmspeed intake, grimmspeed 3-port bcs, grimmspeed up-pipe, gt-spec header and invidia tbe. Would the ots map be able to be used with these mods?
With that setup you’re right on the edge of the capabilities of the factory fuel injectors. We would recommend 1000cc Injectors at a minimum. Our hopes are to offer an OTS map that is compatible with Flex Fuel, however those maps will not be compatible with the Grimmspeed 3-port EBCS or Grimmspeed Intake.
Marshall@COBB
How will this work with existing custom E85/93 pro tunes? Will complete re-tune be required? Will just one protune be required?
Hey Sarah, a Protuner should be able to adapt an E85 and 93 Protune into a Flex Fuel tune without much effort. There will be more on that when we announce full details of the software support!
Marshall@COBB
Will this work with stock injectors and fuel pump??
You could, in theory, use a flex fuel setup on an otherwise stock car. However, there would be very little, if any, gains to be had without supporting modifications.
Marshall@COBB
Will it be compatible with the 2015+ wrx?
The initial release will not, however we are already working on compatibility for the 2015+ WRX so it will follow shortly behind! More on that next week.
Marshall@COBB
Will the flex fuel be compatible with Speed density? Would be a big bummer if it was only maf.
Absolutely! Unlike other systems currently available, our implementation will not come at the cost of other features.
Marshall@COBB
Evo’s are feeling a little left out…. I know they are stopping production but any chance this will happen for us?
Hey Tyler,
We do not have any current plans to develop a Flex Fuel solution for the EvoX platform. That said, we are going to be spending some time in the near future working on some improvements and new features for those users.
Marshall@COBB
will this be compatible with 2006 Sti using APv3
We do plan to make Flex Fuel available for the 2006 STi, however it will not be a part of the initial release in January. More information on that will be coming next week!
Marshall@COBB
What range of years will this product be for? I have an 05 sti, and I’m interested in something with this kind of flexibility.
We plan to support almost all WRX/STi model vehicles. While it may not be a part of the initial release in January, GD STi support is in the plans!
Marshall@COBB
Ive already voiced my concern on the NASIOC “cobb flexfuel” thread, but why not go straight to the source, right? From what i’ve read you guys will not be releasing the flex fuel option to 02-07 WRXs for “lack of demand”. I and many other people (as seen on the thread) believe that is a huge mistake. The demand for flexfuel among 02-07 WRXs is just as, if not greater than any other model WRX or STI. We would jump all up on that flexfuel deal if you just gave us a chance, so what i’m trying to say is, GIVE US THE GOODS!
OK, so can we get a list of the WRX/STi years that WILL be covered in the January release? As I plan on upgrading to a V3 ( again 🙁 ) if my year is covered…
Hey Steve, we’re preparing all of that information to be released next week along with all of the hard-parts configurations we’ll be offering.
Marshall@COBB
I was on e85 tune but switched back to my 91 tune for the winter months because of cold start issues. Will this kit allow me to run a blend of e85 and 91 to assist with starting in the cold?
It sure will! We are doing our best to help with alleviating cold-start issues on E85 however in severe cases it may not be possible.
Marshall@COBB
Is it next week yet? I have been waiting so long for this!
It is! We have a TON of information we’ll be pushing out tomorrow.
Marshall@COBB
I am running a 2015 STI with Cobb stage 3. Will there be a flex fuel STage 3 map?
Our goal is to offer an Off The Shelf Map for that setup. As setups become more complex (related to a stock car) it does become more difficult to offer an OTS solution, but we are doing our best and hope to have good news on that front very soon!
Marshall@COBB
I already have a Zeitronix ethanol sensor & guage wired up to my vehicle. Is the dynamic compensation of ethanol fuel feature from the accessport compatible with this unit?
It should be. More info on that tomorrow!
Marshall@COBB
If I have FIC 2150 injectors, is that enough to run the E85 with Flex Fuel Kit?
That would depend on your power goals. For most people, those injectors should provide plenty of overhead.
Marshall@COBB
Any progress on the 2015 wrx when can we get it
Hey there! We are making great progress on the DIT WRX Flex Fuel release. The current goal is to release that sometime this summer.
Marshall@COBB
I am checking on the 2015+ WRX kit. Any update on when it will be available?
We are still shooting to have something available by the end of this summer! Hoping to have some significant updates for everyone in the next month or so.
Marshall@COBB
is there a release date on the cobb flex fuel for 2016 wrx yet?
While we do not have a hard date set, we are getting very close to release. We unfortunately encountered a safety concern towards the end of development however that has been addressed and implemented for internal testing. I believe the current goal has been pushed to mid-November.
Marshall@COBB
You guys would see the largest demand for the flex fuel kit from the people with the 02-07 wrx, hopefully you guys are planning something for us as well as I and many others would love the kit for our cars.
Hey I was just wondering if you guys are still on track for a summer update. Thanks!
Hey Chris! The DIT Flex Fuel project has been pushed a bit in order to develop support for the 2017 WRX and STI. We’re still hoping to have Flex Fuel available for release by early October.
Marshall@COBB
So…When is the kit coming out for the 04-07 STI?
Hopefully around the end of this year. We’ve had to adjust some timelines due to adding 2017 WRX and STI support.
Marshall@COBB
Hey Marshall,
Are you guys still on target for the end of “this year” for Flex Fuel on the 04-07 STI?
We should know more in the coming weeks, but I’m still optimistic! With DIT Flex Fuel nearing completion, we will be digging into the GD ECUs and will hopefully be able to get an accurate scope on the work required to add these features for the older cars.
Marshall@COBB
Have any updates on that time frame we can expect FF ready for 04-07 STi?
We are currently looking at an early Q2 release for GD Flex Fuel.
Marshall@COBB
Any update for the GD platform flex fuel.
Coming along nicely! Currently tracking to release around the end of April.
Marshall@COBB
End of April, come and gone. Any GD update? 😀
We had an unfortunate delay with one of our suppliers on the hardware side. Looking promising for late this week or early next week, though!
Marshall@COBB
Yaaay! Is the FF hardware kit for the ’07 STi going to be identical to the 08-16 STi kit since the TGV plugs are the same? 04-06 will obviously be different. Thanks again!
Yes, the only difference for the 2007 STi Kit will be the included mounting bracket however the plugs and brain are all the same as the current GR kits.
Marshall@COBB
any update on 04-05 SG FXT support?
No updates on the Forester or Legacy front a of yet.
Marshall@COBB
2 years after initial announcement…. any closer to Legacy GT (spec.B) support? Cramping my style/plans….. 🙂
We are definitely closer than we were 2 years ago! This project has moved up our priority list over the last few months and will hopefully pick up pace here in the near future. No ETA as of yet, though.
Marshall@COBB
I’ve seen great results from stock FA wrx’s running E50-E85 fuel, would be fantastic if we could get an OTS map for stock FA wrx’s for this kit.
That’s actually something we’ve been toying around with!
Marshall@COBB
Any update on 02 wrx? I’m running a 04 STI block with 02 WRX heads
Hey Terrance, unfortunately we do not currently plan to add COBB Custom Features such as Flex Fuel to the 2002-2005 WRX ECUs. In your case, swapping to a 2004 STI ECU may be the best way to take advantage of those features.
Marshall@COBB
Any updates on flex fuel for the 02 wrx? I really am hoping I do not have to spend 1.5k on a new ecu.
Hi Ryan,
As it turns out, it’s unlikely we’ll ever have Flex Fuel for that ECU. You would be able to use that feature on different ECUs that could be used with your car. Most go with an 04 STi ECU. These can usually be found for less than $1500.
Kyle@COBB
Awesome thanks for the advice.
Hello, I am a COBB enthusiasts and am hoping that COBB will create and emission compliant variant of the e85 flex fuel kit for the sti. Is there any word on an updated version of the flex fuel kit. Thanks Glenn
Hi there! We are in the process of emissions and compliance testing on a replacement Flex Fuel solution for Subaru and are hoping to share some more information in the coming months.
Marshall@COBB
Is the release for the new flex fuel kit for the WRX going to be released 20April2023?