Holley EFI How To: Set Up A Flex Fuel Sensor

Holley EFI How To: Set Up A Flex Fuel Sensor


I’m Ryan Woody with Holley EFI and today we
are going to talk about flex fuel. Pretty much everything I’m going to go over
is in the help contents under the V4 software update overview. Down at the end is an appendix that covers
Flex Fuel capability. So if you want to reference that as well if
you can’t get to the video, you can look there. The first thing you need to do is set up a
flex fuel sensor, which will be in input, you can title it whatever you want. It will be a digital speed frequency and it
will be GM flex fuel in the drop down. So after that, all you do is you go and you
add an advanced ICF to your tune if you do not have one. Then the first thing you do is you set up
a fuel modifier and you use a fuel flow multiplier, depending on your tune, either use a VE based
or a fuel flow multiplier. The fuel flow multiplier multiples the fuel
volume on everything in the tune, including cranking, AE fuel, all of it. So this will correct the fueling everywhere. The next thing to do is to select the flex
fuel sensor to reference and there you have at the bottom your flex fuel, your ethanol
percent from 0-100. Now the baseline in the help file goes from
0-34 percent and that assumes that you have built your base tune off of 100 percent gasoline. A lot of times that doesn’t actually happen
so you’ll end up taking the S curve and offsetting it for whatever your base fuel ethanol level
was. You know most of the time you’ll have somewhere
between 10 and 15 percent ethanol and you’ll just use the sensor during your tuning to
read that and then whatever that point is, you know, let’s say you have 20 percent ethanol
is where you are at for all of your base tune, what you’d do is offset this entire curve
by 6.8 because of that because that is actually your real baseline, your zero point. So you highlight the whole thing, offset minus
6.8 and now you’re entire curve is accurate based on a base tune of E20 fuel. The next thing that you do is, so you are
doing this because you want to be able to dump in E85 so what you do is you want to
be able to add boost, add fuel, add timing, whatever you want to your tune between the
two settings. So the next thing you can do is set up a,
if it’s boosted you can set up a boost offset based on the same things, table type will
be a boost offset, your X axis would be a flex fuel sensor, whatever you have titled
it, and from there based on your ethanol percent you can just add boost, so you want to add
five pounds at 60 percent ethanol, it’s really that easy, you just pick your tables for however
you want, you can do whatever you want based on the ethanol percent, another thing that
you may want to do is an AFR offset. Again you just set your X-axis for whatever
you are using, in this case, the flex fuel sensor and the table type to whatever you
want to modify. So the flex fuel sensors at the bottom, ethanol
percent and your new target air-fuel ratio is here. Now this one, I’m showing it in a 1D table,
really you probably want to do it in a 2D table on this one, you know this is offsetting
it at all times so any time your ethanol percent is above 27, in this case, it will start modifying
it. Really you’d want to do this one as a 2D table
and sort of mimic your actual target. You’d set up your table as an AFR offset due
to target air-fuel ratio offset. Make your X axis your ethanol percent, your
Y axis boost effectively and then you have your table for how much you want to offset
your boost. You may want to allow an extra two points
richer here and fade it back to no richer down here and same over here and then same
thing with the timing offset. So you set up a table type as timing offset,
X-axis as your ethanol percent, your Y axis as boost and you do the same thing, you can
offset your timing based on ethanol percent and boost. You can also use other things, you can use
RPM and flex-fuel percent, it’s really up to you how you want to utilize the advanced
tables for anything, in this case, flex fuel, I mean there’s, we don’t lock you into any
specific way to do this. So really that’s all there is to flex fuel
and EFI with us, it’s that simple. Thanks for tuning in to Holley tech tips,
be sure to let us know if you have any ideas for future videos, I’m Ryan Woody, have a
great day.