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Haltech elite flex fuel with primary fuel as e85

Ethanol & Flex Fuel Tuning

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Discussion and questions related to the course Ethanol & Flex Fuel Tuning

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Hi all,

looked through previous posts didnt find anything applicable to this.

I have a 300zx Twin Turbo with an elite 2500 and NSP and an innovate flex fuel sensor. The vehicle has e85 in the tank and dialing in the base fuel map on e85. Scalar is set to 100% at current e content (e90) and 0% flex fuel compensation. Is there a way to now use flex fuel comp tables essentially to adjust for 93oct as my “secondary” fuel , or do i need to tune on 93oct on the base map?

would i be able to use - numbers in my compensation table to make this work?



That's not an ECU I use so please take the following with a grain of salt and as an attempt to help, but I've never seen this software before I just downloaded it to try and help.

It appears the "Fuel Composition Corr" tables for lambda target, fuel delivered, ignition timing are applied based on the current "Fuel Composition Scalar" value. If current "Fuel Composition Scalar" is 100%, 100% of the correction table value is applied, if "Fuel Composition Scalar" is 0%, 0% of the correction table is applied.

Based on that, and your current fuel composition being e90, it seems you could set "Fuel Composition Scalar" to 0 at 90-100% composition so the "Fuel Composition Corr" tables have no impact on your current tune while at e90, set "Fuel Composition Scalar" to 100% at 0% composition, then linearize the z data between compositions 0-90%. Then set the "Fuel Composition Corr" values to make the adjustments you want for lower than 90% ethanol i.e. negative timing corrections.

It seems you'll also need to set primary fuel density.

Again, don't take what I've said as gospel, it's just my quick interpretation on my first look at the software and the context help on those tables, but I hope it makes sense and helps you out.

Semi related, it's a bummer there's just the one scalar table and it impacts fuel, timing, etc. all in one. Usually I'd vary fuel, timing, boost targets with ethanol composition in a manner that's not uniform. It seems you could somewhat bandaid this with additional trim tables though.

Let us know how it goes.

In case a visual aid helps. You may not want to leave this linear, but I think it would get you going as a starting point.

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Thanks for the insight! After more digging, it seems the haltech does the base FF corrections in the back end, the correction table is just for addl trimming as needed. And the scalar table has an effect on both the correction table, and the automatic background corrections. Having a feeling what i’m shooting for is not an option.

also, for your future reference, you can adjust the scalar/trim tables for ign or boost separately from your fuel scalar table. Just need to enable the tables in your ignition settinngs or boost control settings.

still looking for insight here, maybe i missed something or gave up too quick. At this point i have a fully tuned fuel and ign table on just e85 and all correction tables 0’d, scalars left alone for most part.

Will edit this post with my tune file shortly

What response have you had from Haltech, they should know their ECU the best?

Can't attach my NSP file here. bummer.

Gord, I have not reached out to haltech about this, i did not consider that as an option, not their fault that i am not familiar with their prodict! i guess thats the customer facing me knowing what thats like. Haltech will offer assistance with this, you think?

Paul, that's good news that additional scalar tables can be enabled.

It still seems what I mentioned should work, but pending what they've done on the back end, like you said, they may force you to run your "gas" fuel as base and correct for high ethanol. It should only take a couple minutes to try, or you can certainly give them a call.

We usually reply within 12hrs (often sooner)

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