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Anyone have a Chevy Volt running on E85?

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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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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.com/forum/showthread.php?63020-First-Gen-Volt-Tune-(Volterado)

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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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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.​

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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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