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Discussion Starter · #1 · (Edited)
So I converter my Cruze to a TRUE flex fuel car today. I installed the 42lbs/hr Bosch "green giant" injector (stock are 24lbs/hr) along with an actual flex fuel sensor and tuned my ECM with EFILive, so I now have an actual flex fuel Cruze!! :D Can run what ever fuel or mix I want and the ECM will adjust for it.

This is the write up I used on EFILives forum showing how to do this.
Chev/Holden 1.4L Cruze E85 FlexFuel Conversion

Here is the sensor I installed in the fuel line so the ECM know how much ethanol is in the gas. You can see on my V2 where it's reading 7.8% ethanol right now and commanding an AFR of 14.24. Which is right since I run pump 93oct that contains up to 10%.

E85 sensor.jpg E85 V2.jpg

Time to put some E85 in it and see what it does. I did this so I can run cheap 85/87 gas and mix in a little E85 (105oct) and get the performance of running 93 but with less cost. I think I can still get close to the same mileage with only about a 25-30% mix.
 

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Keep us posted on how it goes.
 

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Man I wonder if I do this if the premium tune from Trifecta can be tweaked to do this.

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Discussion Starter · #4 ·
Man I wonder if I do this if the premium tune from Trifecta can be tweaked to do this.

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There is no reason why they couldn't. It was actually quite easy to do with EFILive, just a couple of tables to change and a 45 second reflash of the ECM.

The sensor cost me $74, the pig tail was $15, the hose I made up with push lock connectors was $65 and the injectors where $180.
 

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There is no reason why they couldn't. It was actually quite easy to do with EFILive, just a couple of tables to change and a 45 second reflash of the ECM.

The sensor cost me $74, the pig tail was $15, the hose I made up with push lock connectors was $65 and the injectors where $180.
But your not going to get the same HP by doing it that way will you.

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Discussion Starter · #6 ·
But your not going to get the same HP by doing it that way will you.

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The ECM has tables that will adjust the timing and AFR for the amount of Ethanol you have in the fuel. Depending on how the tune is set up, you can put cheap gas in it and it will lower the timing and hp and then you put full E85 in it and it will run more timing and make more power with the high Oct E85. No need to make any external changes. With the sensor, it can auto adjust. It's very flexible.
 

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Trifecta certainly can tune this the exact same way. I know Vince did a full Flex Fuel conversion on his Cruze. I have the injectors sitting on my desk and I was all set to do the same thing. However, locating the fuel sensor from the Buick Regal was annoying. When I tried it was on GM Parts Direct back order. I waited 6 months and the back order was never lifted so I cancelled my order. I will probably revisit the project when my powertrain warranty is up. Screwing with e85 doesn't do yourself any favors in the warranty department and if you don't know what you are doing you can f something up real quick!
 

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Discussion Starter · #8 ·
I didn't have any trouble finding this sensor on Ebay, in fact I bought two of them to see if I can use the other on on my turbo truck to make it FF as well. The price did go up though. The list price is $112.86 which is still a LOT cheaper then the ones they used to use on my truck. They are like $350 and prone to failure.

Cadillac 13577379 Genuine Factory Original Sensor | eBay
 
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Discussion Starter · #9 ·
Well I filled it up with E85 tonight. Wast just under 3/4 tank so only took 5gal of E85. Watching my scanner, it changed to 27% E85 and AFR dropped down to about 13.20 like it should. Seems to run pretty good. The E85 was .79 a gallon cheaper then 93oct. I'm leaving to drive from Texas to WY tomorrow so I'll see how it does on at least this first tank with a mild mix of E85.
 
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Lead the way KB. This is how the DSM community got so big. It took years and years for some of these guys to come up with this stuff. Our big advantage is that all of our ECMs are programmable. On the DSMs only the first year of the new model were EPROM.
 
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I would like to see what the drop in MPG is with straight E85, as of today E85 is only 10 cents a gallon less than 87E10. It's 50cents a gallon less than the 91(no ethanol) has I usually run. 50cents X 15.6gallons = $7.80 saved per tank, however if MPG loss is as low as EPA indicates on other cars I'm not sure I would save any money.

I did drive a 2010 flexfuel Impala for a few weeks and even up to 50% tank of E85 saw no significant loss in MPG. Have read similar real world results with Flex fuel Tahoe/silverado's too.
 

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Nice project!

I'd love to hear your results on E85 as well, and how you made that fuel hose.
 

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Way cool..... keep us posted on the real world results.
 

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Discussion Starter · #14 · (Edited)
Well, I finished my road trip from Texas to Wyoming and here is my fuel stats for the trip. This was mostly highway 65-80 with some mixed in city driving. I drove the car as I always would and didn't try to do anything to fudge the numbers. My EFILive V2 shows the % of E that is currently going through the sensor, so I get a pretty exact reading of the amount. The lower numbers are strait pump 93 with up to 10% E.

1'st, 27% E... 365 miles, 29.5 mpg (added 5 gallon of E85 to pump 93 to test it out)
2'nd, 12.5% E... 326 miles, 32.6 mpg (pump 93)
3'rd, 9.5% E... 492 miles, 33.7 mpg (pump 93)
4'th, 75.1% E... 354 miles, 28.3 mpg (14.6 gal of E85, was almost out of fuel!!! lol)

It does feel quite a bit stronger on strait E85 and I think there is even more power to be had with some more tuning, maybe even some more MPG's with a little more timing in the cruse area of the tune.

I was able to fill up this last tank again with strait E85, so should be even closer to 85%. I currently have only 2 stations that sell E85 up here and both are in a town 70 miles away, so probable won't fill it this next time with E85 unless I happen to be near there.

I notice a price difference of 50 to 90 cents a gallon between E85 an 91/93 so I think its worth it. I still think a 25% mix of E85 and 85/87 will be my most cost effective formula for most performance and best MPG's
 

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Discussion Starter · #15 ·
Ok, so I've been driving the car a lot, put 3500 miles on it in the month I've owned it! lol and got to run a few tanks of e85 though it and a few of 91/93. Been mostly highway since I'm in Wyoming right now and its a trip to go anywhere! lol. But this is what I'm seeing.

Strait E85 (about 80% on my scanner) Seems to average around 28-29mpg's and is around 3.19 a gallon here. So fuel cost is about $.11 a mile.

Strait 91 (all I can get up here and shows about 9-11% E on my scanner) Seems to average about 34-35mpg's with the same driving conditions. It's about $3.89 a gallon, so fuel cost is about $.11 a mile too.

Pretty much a break even, just can't go as far on a tank of fuel. I will say, it seem to have more pep on the E85.

Another thing I noticed is my DIC mpg's is more accurate with the E85 then with the Gas, with E85 it is consistently about 1mpg high and with 91, it is about 4mpg high when compared to hand calculating it. Thought that was interesting.
 

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Discussion Starter · #17 ·
Ya, I was pretty happy with the E85. Once I get back to Texas, I'm gonna run it some more since it's only about $2.79 a gallon there and I suspect with more city driving, it will be around 25mpg and I'm still good with that since my other two trucks get less then half that in the city, lol.
 

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Yeah Trifecta can do this also, we do it on the Sonics all the time.
 
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