E85 Conversion

[rkasal]

Hey all, I am running a NA 99' 5.3 stock 411 PCM with a COMP cam 54-414-11 and a set of 8.1L 34lb injectors on a 255 LPH Holley pump in my 68 Chevelle. I have a Farm Service Station with E85 available 3 blocks from my house, otherwise I have to travel 20+ miles to fuel up with any non blended fuel. I am thinking about converting to a strictly E85 tune for convenience mainly. Right now on the logs I have, at WOT and 6200 RPM I am running 70% duty cycle on the injectors. I originally tuned with a Wide band o2 sensor in Lambda. Is it possible to tune this as is for E85? If so do I just flush out the old fuel and fill with E85 and redo the SD and MAF tuning? I have a tester to confirm the ethanol content and know some guys that run drag cars on E85 from this station who claim "its very clean E85 compared to most". Thanks in advance for any advice and have a great Wednesday!

[msassman]

I converted a couple of f-bodies to e85. The injectors need to be bigger, and compatible with e85. I bought a ractronix fuel pump, which connect directly to the alternator for power, and has the ability to use a 16v converter, which I don't need yet. I am running 48lb racetronix injectors and changed the os to a 2002 Tahoe os which has the flex fuel tables. I started by changing stoic but wanted to be able to mix high octane with e85 if one of them was not available. I wired an alcohol sensor in, I think you need a 5v positive on it, a negative, and wire it back to the PCM, can't remember the pin offhand (There's posts out there with more info.) initially i copied my existing settings to the os and flashed, then I made changes as needed and switched to alcohol. Be careful with timing on e95, I didn't advance mine as there will be no knock, so you really need to tune alcohol with a dyno and back off timing as hp drops in a given cell. I can give you the injector data I used, not all was given by the manufacturer, and there was a lot of math (Spreadsheet is out there somewhere) I did have dyno tuned afterward and the tuner left the injector settings. Once you confirm you are seeing data from the alc sensor, you can put e85 in as long as you have the stoic values from the e85 os. Alcohol uses about 30 more fuel, so that's the reason for higher fuel consumption. I have seen arguments that equal values use more fuel, but that can also be argued that if you increase compression, you gain some hp with lowers fuel consumption per same amount of power and it's not a full 30% loss. I subscribe to that thinking but have no data to support it. My compression ratio is about 13.5 to one. (Calculation seems to match compression test) You can gain some compression ratio by using a .030 gasket from cometic.

You will burn more credits with the new OS, make sure you change the VIN beforehand or you will burn more credits afterward. I used pcm hammer with an bluetooth odb2 which was about 80 bucks, not all work with it.

[Alvin]

The problem usually is that at certain times of year that station might be selling E50 and other times E85. They usually back off ethanol in the winter time since it doesn't run as well cold and can give cold start issues.

[Pulse_GTO]

I would probably convert to a 12216125 OS and install a flex fuel sensor. That was once tuned you won't have to worry about what ethanol content fuel goes into the tank.

[Estep40511]

I have a guy wanting to convert to E85. hes running a Gen 3 5.3 in his Camaro. can you convert without the injectors? just the sensor and different OS? I have heard of people doing this. Or can he pick up some stock OEM flex injectors and a new sensor? Can I wire in the sensor to his ECM? I can look up the pin etc, just not sure if his ECM is compatible. thanks, done some searching, but this thread is the closest I can find.

[TheMechanic]

As was answered in post #5 you need an injector that will flow enough E85 with a good dwell time and of course the entire system needs to be upgraded for E85. Not just the injectors

[Ben Charles]

Pin blue 56…. Change OS that has FF.. can tune away with sensor installed and making sure it’s actually working properly otherwise fuel will never be right

[Mreddieflo]

I have a 2003 Sierra 5.3 not a FFV ? is there any way of checking if the stock OS has the flex fuel tab for installing the flex fuel sensor? I just ordered the tuner but trying to get some info before it arrives?

[2xLS1]

All the 03-07 Classic P59 calibrations will have the FF enable switch but it has to be a FF OS for it to work.

[Mreddieflo]

I thought if it had the enable switch it was a FF OS. Would that mean I would have to get the OS from another vehicle then?

[2xLS1]

Yes. Some say there is a way to add it to a non FF OS with a program other than HP Tuners but I have not looked into it. It still needs to be changed from what you have now. It's easier for me to change the OS with the various tools I have.

[Mreddieflo]

I?m unable to see any files from the repository until I register the device I ordered, but I have an 03 Sierra 4x4 5.3. I?m assuming I?ll have to find a file for any 03-05 FFV or would it have to be a specific one? I?m still looking into how the whole process works but I have a pretty good idea so far. I?ve read I will have to change the vin and have to pay for more credits to do so. I?m trying to do a budget swap and considering trying my luck getting used injectors possibly from a junk yard trying to find the the tune for that model. If I were to get any other injectors I would assume I would need to tune them in as well, is that correct?

[gtstorey]

I?m unable to see any files from the repository until I register the device I ordered, but I have an 03 Sierra 4x4 5.3. I?m assuming I?ll have to find a file for any 03-05 FFV or would it have to be a specific one? I?m still looking into how the whole process works but I have a pretty good idea so far. I?ve read I will have to change the vin and have to pay for more credits to do so. I?m trying to do a budget swap and considering trying my luck getting used injectors possibly from a junk yard trying to find the the tune for that model. If I were to get any other injectors I would assume I would need to tune them in as well, is that correct?

Only get injectors that you can find good GM data for. For the most part that eliminates Amazon and most of EBay (but not all of EBay). Blindsquirel has posted some on EBay for cheap that are the real deal.

[Mreddieflo]

I?m going to try my luck with getting used stock injectors. At $20 each I think I should be at a good enough point to try out this project. If everything works well I?ll look into getting new ones.

[Fast4.7]

Yes. Some say there is a way to add it to a non FF OS with a program other than HP Tuners but I have not looked into it. It still needs to be changed from what you have now. It's easier for me to change the OS with the various tools I have.

All P59s have flex fuel code that I have encountered and can be easily enabled to run an actual sensor. I find it easier to enable the flex fuel code and leave the stock OS.

I run one on my 4x ignition L31 350 based 383.

I also use factory Ford injectors and have for years. Can easily calculate good data for them. I have new OE replacement 2014ish Ford 6.2L injectors on my 383.

[Fast4.7]

Only get injectors that you can find good GM data for. For the most part that eliminates Amazon and most of EBay (but not all of EBay). Blindsquirel has posted some on EBay for cheap that are the real deal.

I mostly use Ford injectors. The Ford Motorsport units are inexpensive and have good data that can easily be converted to GM data. Even some of the production replacement units are easy to use as well. I converted the data I needed out of a stock Raptor tune for the 41# 6.2L injectors I run in my 383. I have also used the 30s and 42s for years.

[gtstorey]

I mostly use Ford injectors. The Ford Motorsport units are inexpensive and have good data that can easily be converted to GM data. Even some of the production replacement units are easy to use as well. I converted the data I needed out of a stock Raptor tune for the 41# 6.2L injectors I run in my 383. I have also used the 30s and 42s for years.

But is this something a first time tuner needs to take on? It can already be hard enough so why add another step?

[Fast4.7]

But is this something a first time tuner needs to take on? It can already be hard enough so why add another step?

It can actually be easier, IMO. The GM data is often tweaked for specific applications if you pull it out of a factory tune.

I do not see the need to go and buy Injector Dynamics Injectors for example.

[Alvin]

But is this something a first time tuner needs to take on? It can already be hard enough so why add another step?

You might want to ask your tuner first.

I built a calculator to get GM data from Ford and I wouldn't say it's simple at all. 1,2,3 order polynomial function fitting.. lots of extrapolating (read best guess) because the pressure ranges are so different. etc.

[Fast4.7]

You might want to ask your tuner first.

I built a calculator to get GM data from Ford and I wouldn't say it's simple at all. 1,2,3 order polynomial function fitting.. lots of extrapolating (read best guess) because the pressure ranges are so different. etc.

I do it by graphing the data points. My old TI-83 calculator does the job beautifully. I can graph the curve then pick the flow and offset multipliers at GM pressures. Then I graph the High and Low flow fuel delivery vs time with the offset added. That gives you the Short Pulse Limit. Then you are able to pick the time units along the axis and the difference between the graphs at the poing is the short pulse adder. Difficult to explain but easy to do. It is close enough that it runs very well. If it is a returnless system, I graph the offsets and flow at both ends of the table as well as the center and interpolate the rest.