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Examples of Flex-Fuel Vehicles (FFVs)

 
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Anyone have a Chevy Volt running on E85?


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#1 Billyk24

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Posted 13 May 2017 - 04:31 PM

Checked out the HPT forum and found many topics and will have to re-check every once in awhile to see what other vehicles are being tuned to run on E85



#2 TD

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Posted 12 May 2017 - 07:12 PM

Thanks Billy,

 

It's really changed how I think about running anything higher than E30 in a non-FFV. You have to tell the vehicle what blend to expect (Stoich) and set the fuel density to match the same fuel so the dash mpg gauge is accurate. If you want to run say E60 (for example) it makes running with that fuel much better and makes it easier to tolerate E85 (assuming the fuel pump can keep up). After that it's just about having the right amount of timing to take advantage of the fuel. Of course tweaking the cam timing helps a lot too. I wonder how many vehicles were modified with larger injectors when that's not really what they needed. We proved the Volt didn't need them and Jeremy removed the ones he initially added to his Volt to run E85.

 

Also a big surprise to me this year is that E85 doesn't have the octane it used to have. E85 used to be around 103 octane and now it's closer to 97, only 10 more than E10. Apparently they take the crappiest gas they can find and add ethanol to it to make E85 these days.

 

Love the ethanol sensor. I won't consider an ethanol conversion without it.


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#3 Billyk24

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Posted 12 May 2017 - 06:48 PM

Keep up the "good" work.  I especially enjoy reading that you can boost high blend ethanol mpg with your tuning.  I hope posting of this information continues -especially with other car models- so future automobile purchases can be made with current information.   I assume vehicles with the "older" oxygen sensor that just reads "+" or "-" are not good candidates for HPT ethanol tuning.​



#4 TD

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Posted 10 May 2017 - 04:31 PM

Hi Billy,

 

I installed an ethanol sensor (about $40 on eBay) and wired it to the ECM as it was intended. (Wiring for it was found in a service manual.) I can read E% any time I have HPTuners software running and plugged into the OBD port. Since the sensor is by the engine, if I fill the tank, it takes a 2-3 miles before I can read the actual %. Although I can read the % with HPT s/w, the software isn't required to run the engine.

 

The sensor then adjusts everything to work with any blend from E0 to E85, possibly higher, if climate allows it. (E100 hates temps near freezing.)

 

Bear in mind it takes a flex-fuel tune work with the sensor. Just plugging it in may or may not work, depending on the vehicle. HPT software is about $500, but you do get 10 licenses and only 2 are needed for 4 cyl and 4 or more for V8's.


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#5 Billyk24

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Posted 10 May 2017 - 04:14 PM

Thanks for the post.  Do you have an ethanol reader that displays the %ethanol in the fuel?



#6 TD

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Posted 22 April 2017 - 08:27 AM

Just an update, lately we've been updating cam timing a LOT, which required starting over in our tune. Since the Volt is a heavy vehicle with a full-time motor generator, originally we used cam timing from the high compression Silverado V8 FFV, with good results. Later Laz found the 2017 Malibu 1.5 L turbo gave us better mileage/low rpm torque with his lean cruise (leaner for 1400-2200 rpm with low load). Although we tried cam timing from the Chevy Cruze (similar sized vehicle, same engine), the results were poor because the Cruze is a light vehicle, without the load the full-time motor generator gives us. Because of this load, the Volt idles at 1400 rpm, which we were unable to lower.

 

Because ethanol can mask knock retard, we have to tune with lower ethanol blends first and E70/85 last. We're currently seeing about 49 mpg highway (37 mpg stock) on 93 octane premium just from optimized cam timing and lean cruise, everything else stock. Re-adding our fueling, volumetric efficiency and maf tuning should easily push us over 50 mpg, or at least that's the goal.

 

More info here: http://www.hptuners....une-(Volterado)


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#7 TD

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Posted 18 February 2017 - 09:47 PM

We have released our HP Tuners-based tune in their forum. http://www.hptuners....une-(Volterado)


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#8 TD

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Posted 02 January 2017 - 02:07 PM

When I said there was a lot of knock at high load and rpm, I meant cruise speed and normal load and higher.

 

Jeremy has finished his Volumetric Efficiency and MAP tuning and Laz and Jeremy are working on merging that with our current tune. I'm hoping they have something for me to test soon as Wed/Thursday will be subzero temps, which has found a lot of knock in the past.

 

It'll be interesting to see if Laz's mileage has changed any. It's difficult to see changes in mileage when there's now and ice and subzero temps involved.


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#9 TD

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Posted 30 December 2016 - 11:51 AM

We have come to the conclusion that the first gen Volt's tune is half-done at best.

 

The EV portion is well engineered and has a very low failure rate, but they must have decided that 90% of the time EV would be used and that the ICE didn't matter much. The GM buy-out and lower than expected sales of a niche vehicle didn't help much either.

 

There's a lot of knock (6-8°) at higher load and higher rpm, and knock-learning was disabled, so the high octane timing table is always used. Since the Cruze has a similar engine and ECU (and is a lot more polished), Laz and Jeremy have copied a lot of Cruze tune and used it in the Volt.

 

No doubt about it, this is going to be a very nice tune when finished.


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#10 TD

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Posted 16 December 2016 - 10:29 PM

Please read this link:  

http://www.hptuners....-2012-Cruze-Eco

 

Someone has already did what you are seeking.

 

The world is a very small place these days with the Internet.

 

The guy who was trying to install an ethanol sensor in his Volt (Mr. Comment) is a friend of mine now and has a 2 Volt family. He managed to get his sensor working (it was a tuning issue) after I reached out to him and is working on his tune. I believe he has already removed his larger injectors (or soon will), since they weren't needed.

 

Laz (in Florida) is helping me with my tune, also based on an ethanol sensor which I had installed a few weeks ago. We also have Fuelverine in the wings, but he's busy moving closer to work and hasn't been active in tuning yet. So we have 4 Volt owners, one at sea level in Florida (Laz), another in the mountains in Colorado (Fuelverine), Mr. Comment is in Illinois and I'm at 900 ft above sea level in ND.

 

With a sensor, the premise is simple. You need a base tune compatible with a low ethanol level (E10). When that's solid, you work on the upper end (E85/70) and once you're done with that, in theory any level in-between should have pretty close timing. Of course there's ways to tweak in the middle. With the Volt, that appears to be the only way to make it a true FFV since GM has set barriers in place to make it difficult.

 

I thought we were done with the E10 portion of my tune. It was solid using the virtual sensor built into HP Tuner and still worked great when I installed the physical sensor, then cold weather arrived and I had to remove timing as the temp dropped. I think we have that under control, but the true test will be the next two days when the temp is projected to hit -24°F.


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