Lund E85r vs. Lund Flex tune

[WildHorse]

So what happens with a dedicated E85 tune when you are not getting 75%+ ethanol?

Knock sensors go bat shit crazy, kill a bunch of timing, and results in what the OP described in post #1. ALWAYS test the ethanol content of pump E85 when using the E85R tune. And don't assume 75% is good enough either. Don't believe me ? Go buy a pail of VP x85 and see the difference on a E85R tune.

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[Tw00sh]

You run E-85, but it gives you the flexibility to run 93 if you can't find any and also adjust to any low quality E-85 you might fill with (by law, stations can offer E-85 as low as 51% ethanol and still be compliant with the laws/weights and measures standards).

The flex tune will yield almost as good as the dedicated E-85 tune on high quality E, but provides the safety of a 93 tune if you happen to put junk in the tank.

I think the only E85 around my area is at Valero, not sure how good their gas is.

 

[CobraCommander]

I think the only E85 around my area is at Valero, not sure how good their gas is.

That's why you test it before you fill up to see what the ethanol content is.

 

[Tw00sh]

That's why you test it before you fill up to see what the ethanol content is.

Thats why I was wondering if I should just use a 93 tune? If it’s low ethanol gas would a 93 tune be better than the flex tune? I am not doing the dedicated 85, just not wanting to take the risk.

 

[CobraCommander]

Thats why I was wondering if I should just use a 93 tune? If it’s low ethanol gas would a 93 tune be better than the flex tune? I am not doing the dedicated 85, just not wanting to take the risk.

You do not need to test the ethanol content of 93-octane gas if you are running a flex tune. It will sense/read what it is and allow for the appropriate level of timing.

If you are using a dedicated E85 only tune, you definitely need to be testing the ethanol content of what you are potentially going to put in your vehicle to see if it is good enough or not to use on that tune. If it doesn't measure out to be at least 75%+, you need to just stick to your Flex tune when using that "E85."

 

[D K]

Does your car have an ethanol content analyzer?

How do you measure ethanol content?

 

[CobraCommander]

Does your car have an ethanol content analyzer?

How do you measure ethanol content?

https://www.amazon.com/REV-X-Super-...=ethanol+content+tester&qid=1604953876&sr=8-5

 

[D K]

No, you need a proper ethanol analyzer. Continental makes one, it about $75. To plumb it in, it's really easy.

 

[Strokerswild]

On a semi-related note, I'm wondering how accurate the alcohol percentage display on my nGauge really is.

Since winter is about to set in here in MN and my car will soon sit for several months, I've been putting non-oxygenated gas in it for the last few fills. For those that don't have it or have any idea what I'm talking about, non-oxy gas is 91 octane with no ethanol that is intended to be used in small engines, collector cars, or boats for between-use storage reasons. I've run the car down under the point of the low fuel warning going off before refilling, and I'm still getting readings in the high 20% once it learns.

I get that you should actually use a tester, but I'm always on the flex tune and have been amazed at the readings I'm seeing on the gauge now that I shouldn't be seeing much or any percentage.

 

[D K]

You could install the sensor above and plug in this display

Which would give you the actual precentage. From there you could compare what the 'calculated' number is on your N gauge and see how close you are.

From there, if someone can figure out how to run an input to the PCM, you could then run an actual flex fuel tune that adjusts the tune based on ethanol content and allows you to run 0-100% ethanol safely at all times.

On a semi-related note, I'm wondering how accurate the alcohol percentage display on my nGauge really is.

Since winter is about to set in here in MN and my car will soon sit for several months, I've been putting non-oxygenated gas in it for the last few fills. For those that don't have it or have any idea what I'm talking about, non-oxy gas is 91 octane with no ethanol that is intended to be used in small engines, collector cars, or boats for between-use storage reasons. I've run the car down under the point of the low fuel warning going off before refilling, and I'm still getting readings in the high 20% once it learns.

I get that you should actually use a tester, but I'm always on the flex tune and have been amazed at the readings I'm seeing on the gauge now that I shouldn't be seeing much or any percentage.

 

[NGOT8R]

On a semi-related note, I'm wondering how accurate the alcohol percentage display on my nGauge really is.

Since winter is about to set in here in MN and my car will soon sit for several months, I've been putting non-oxygenated gas in it for the last few fills. For those that don't have it or have any idea what I'm talking about, non-oxy gas is 91 octane with no ethanol that is intended to be used in small engines, collector cars, or boats for between-use storage reasons. I've run the car down under the point of the low fuel warning going off before refilling, and I'm still getting readings in the high 20% once it learns.

I get that you should actually use a tester, but I'm always on the flex tune and have been amazed at the readings I'm seeing on the gauge now that I shouldn't be seeing much or any percentage.

I just put my car on the Flex tune today for the first time and the nGauge read 65.5%. I backed that up with a test kit when I got home and here is what it read (a difference of 7%).

 

[CobraCommander]

I just put my car on the Flex tune today for the first time and the nGauge read 65.5%. I backed that up with a test kit when I got home and here is what it read (a difference of 7%).

Yeah, it's definitely not going to be a 100% EXACT match and what your nGauge will end up reading may also vary with what you do with the vehicle once you do fill it up with E85 and then start it up.

For the most accurate reading, you need to let the vehicle idle for a few minutes and then drive normally without doing any crazy WOT hits. Once it locks in, then you can go rip on it. Either way, you'll probably see some variance between what the tester might say and what the nGauge ends up reading. The only true way to get a 100% accurate reading and the computer to utilize that is a stand-alone system i.e. MoTeC.

 

[NGOT8R]

Yeah, it's definitely not going to be a 100% EXACT match and what your nGauge will end up reading may also vary with what you do with the vehicle once you do fill it up with E85 and then start it up.

For the most accurate reading, you need to let the vehicle idle for a few minutes and then drive normally without doing any crazy WOT hits. Once it locks in, then you can go rip on it. Either way, you'll probably see some variance between what the tester might say and what the nGauge ends up reading. The only true way to get a 100% accurate reading and the computer to utilize that is a stand-alone system i.e. MoTeC.

Yes, that’s exactly what I did. Gassed up, moved away from the pump, sat in the lot idling for at least 10 minutes and then drove very conservatively until a 1 popped up in the Alcohol Learned box. After that, I applied moderate throttle, but never went WOT.

I’ve never heard of the MoTec, but will check it out.

 

[Grimreaper]

The ngauge e level is based on the fuel trims needed to trim back to zero. It is only as accurate as the rest of the data in the tune. It's a ball park. Not exact. inaccuracies in the maft curve, air leak, o2 sensor aging etc all contribute to variance in the fuel trims which translates to a different learned alch level. Anything that can cause fuel trims to move +/- will cause a different alch learned.

Did you check the pump gas alch level was actually e10 before your tuner adjusted your maf curve based on fuel trims?

The flex fuel logic shuts off the ltft and runs solely on stft. This can be replicated easy enough with out turning on flex fuel too. Others have reported it feels smoother in this mode. I suspect its more about fine tuning though. Ltft break the maf curve into 5 or 6 blocks. Where as the stft react only to the immediate response from the o2 sensors.

Post a log in 3rd or 4th. Punch it at 25to3000rpm and take it to redline.

I've had aggressive op fueling settings cause a stumble on heavy throttle tippin. Like it misses for a revolution then clears and away we go.

 

[NGOT8R]

Lund did request that I data log and perform a WOT hit on the Flex tune, as well as the E85R tune.

With the Alch content currently at 65.5%, I think I am going to run this tank of fuel to almost empty, fill up with E85 again and then perform a WOT data log for the Flex (and possibly the E85R tune, provided I see 85% Alch on my nGauge and test kit). If not, I’ll run the car down to almost empty again, add 10 gallons or so of One Ethanol and then perform a WOT data log for the E85R tune. That way I can get Lund the best data possible in case they need to tweak the tunes again.

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