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True Flex Fuel Cruze

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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%.

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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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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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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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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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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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Discussion Starter · #19 ·

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Discussion Starter · #22 ·
This is cool! Keep it up! Are we going to see a full DIY with pics? :)
The writeup for the conversion is in the link to EFILives forums in the first post. ;)
 
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Discussion Starter · #31 ·
You need to log a run at full throttle all the way to the shift at full RPM to see what your max duty cycle is. It goes up as RPM goes up. I need to get my Duty Cycle PID setup and see where mine is, but I'm back to strait gas this tank so will be pretty low.

As far as the 42lbs Bosch injectors Vs Stock one's, the DIY install thread on them claimed they got better mileage with them cuz of better spay pattern/atomization, but I didn't really notice that. But then again, I had only run a couple tanks of fuel though my stock Cruze before I started doing all the mods, lol. I'm an auto trans too, so my mileage is lower anyway. I wouldn't think they would really be cost afective if you didn't plan to run E85, but that just me. ;)
 

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Discussion Starter · #33 ·
G'day KBRacing96, just wondering if you had a link to where you bought all the parts needed for this mod??
Cheers, Buk.
I got them all from different places, lol.

Sensor and pig tail from Ebay
2 GM fuel line fittings from Amazon,
The push lock hose and fittings from local speed shop,
Injectors from fuelinjectorconnection.com
 

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Discussion Starter · #35 ·
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Discussion Starter · #38 · (Edited)
Thanks KBRacing96, do I need to also get the ECM pins? Are they missing from the wiring harness?? Cheers, Buk.
That pig tail is just for the sensor. You'll still need the pins and some wire to get it to the ECM. I got those from a buddy who makes harnesses.
YES! I forgot to mention that I was interested in just the sensor upgrade, not the injector upgrade. If I never planned to run E85 I would have no need for the added fuel capacity of the larger injectors. I would still be interested in learning about the advantages of installing and programming for just the Ethanol sensor. How does the 1.4T adjust for Ethanol content? Is it just done by correcting the fuel trims? If this is how it happens, is this an accurate method? Are there separate fuel tables pre-loaded in the ECM for Ethanol content based corrections, or is it a simple offset of injector pulse width (or something like that)? What else changes with the Ethanol content... spark advance, anything else? Sorry about all the questions... I'm an uncurable information H0.
I don't think it's worth it if your not running E85. The low E content of normal gas can easily be adjusted for with the fuel trims and the gas is rated with the E content included, so your not running any more octane like you are with E85, so you really can't add timing or anything. When running E85, there are several more tables active that take into considerastion the amount of E and how much fuel and timing it will command. It also changes the Stoich to the correct number for the amount of E in the fuel. The more E, the lower, or richer it commands fuel.
 
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Discussion Starter · #40 ·
I just read the thread on EFILive and I wonder if that guy Boost is on here he claims to be the Fastest Cruze in Florida I wanna see video and pictures lol.

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He was but he got banned.
 
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Discussion Starter · #44 · (Edited)
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