Lund E85r vs. Lund Flex tune

[mmakam2]

I switched back and forth from the flex tune and the e85r tune, the flex tune has way more power across the range and is smoother too. Especially under 3500rpm it has gobs of torque, the e85r tube feels dead in comparison. (still more power than factory)

Another issue is the 85r tune feels not as smooth coming into the throttle around 3500rpm. It almost jerks then smooths out.

Why is this? I thought the e85r tune was supposed to be more aggressive on the bottom end?

Lund keeps saying my logs look good.

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[datadatum]

I couldn't tell a difference between the two tunes on my '18. According to Lund, this is normal, as the Flex tune will adjust up to the E85R parameters over time (assuming the EtOH content is sufficiently high).

 

[mmakam2]

I couldn't tell a difference between the two tunes on my '18. According to Lund, this is normal, as the Flex tune will adjust up to the E85R parameters over time (assuming the EtOH content is sufficiently high).

The timing at WOT should be the same.
I think my e85r tune is a bit rich, my fuel trims are pulling fuel.

I'm really happy with how the flex file performs so it really doesn't matter but just curious why it does perform better than the dedicated tune.

 

[datadatum]

^ That's strange that the tunes would be fueling differently, assuming that you have confirmed that the gas is >85% EtOH. I'd be interested what Brandon has to say about that!

 

[Luv2gofst666]

I know this is a bit old. But in my 2020. My flex tune feels way better all around then my E85r Lund tune. Both with alch% 85.

 

[newmoon]

Interesting information. I would had have assumed the dedicated E85 tune would be superior especially below peak power and torque. Maybe Lund or another tuner can chime in.

 

[Angrey]

The flex tune ends up at nearly where the dedicated race tune starts. The race tune "forces" the timing into the tune whereas the flex tune "learns" how much timing it can gradually lean into it. The flex will reset to relearn everytime you change the fuel level more than a certain amount. The race tune is basically send it, and assumes you've put quality fuel in it.

I haven't seen actual data, but seen Lund employee indicate the flex tune will be very close (like within 5 hp) of the race tune if you're using top notch E and it has ample time to finish the learn routine.

 

[CobraCommander]

The "Flex" tune simply adjusts timing based upon the observed ethanol content the wide bands see.

The E85R tune operates under the assumption you have like 75%+ ethanol in there and puts more timing in down low/earlier.

If you are running an E85 only tune, you need to be testing the ethanol content of the "E85" you're putting into your vehicle. Just because the pump says "E85" doesn't mean you're actually getting fuel that is 85% ethanol. Governmental regulations allow for HUGE variances in what you actually get out of the pump in regards to true ethanol content so it could be complete crap and only truly be like E65 or something like that.

I, along with others here in Dallas, have found that our local Kroger fuel stations have the best quality E85 on a consistent basis. I've seen above 85% ethanol content on my nGauge before from there.

If you don't have a good source of pump E85 in your locale, you'll either need to travel with jugs/drum and fill up from somewhere that does or have One Ethanol or Ignite delivered to you so that you have a legitimate and consistent source of E85.

 

[newmoon]

The "Flex" tune simply adjusts timing based upon the observed ethanol content the wide bands see.

The E85R tune operates under the assumption you have like 75%+ ethanol in there and puts more timing in down low/earlier.

If you are running an E85 only tune, you need to be testing the ethanol content of the "E85" you're putting into your vehicle. Just because the pump says "E85" doesn't mean you're actually getting fuel that is 85% ethanol. Governmental regulations allow for HUGE variances in what you actually get out of the pump in regards to true ethanol content so it could be complete crap and only truly be like E65 or something like that.

I, along with others here in Dallas, have found that our local Kroger fuel stations have the best quality E85 on a consistent basis. I've seen above 85% ethanol content on my nGauge before from there.

If you don't have a good source of pump E85 in your locale, you'll either need to travel with jugs/drum and fill up from somewhere that does or have One Ethanol or Ignite delivered to you so that you have a legitimate and consistent source of E85.

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

 

[CobraCommander]

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

Things that are not good for the longevity of your motor.

 

[Ninjak]

Love my Flex on my car. E85 is pretty common in S. FL. The best station for me is right up the street.

 

[Tw00sh]

Sorry for the basic question, I am interested in getting the Lund tune, do you run the E85 in the flex tune or do you just run 93?

 

[Angrey]

Things that are not good for the longevity of your motor.

Otherwise known as sad face.

 

[Angrey]

Sorry for the basic question, I am interested in getting the Lund tune, do you run the E85 in the flex tune or do you just run 93?

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.

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