Boost control adjustability while using Flex fuel

[cwtt]

Im new to ECU master, but not new to tuning.

My question is I have a flex fuel setup:
85% ethanol targets 300kpa of boost
0% ethanol targets 218kpa of boost

The flex fuel "Boost Blend" table interpolates in between 300 and 200kpa. However, the user doesn't always need to drive around on 300kpa on the street. How can I manually lower the boost or have different boost settings while maintaining the Boost Blend table.

On the ProEFI's I tune I have 5 settings and you can target any setting as long as it has the ethanol % to support it.

What are my options?

[ATS_Scott]

The boost blend table interpolates between your DC Ref tables AND Boost target tables. If you are open loop don't bother with target tables. If you are Using E85 on table#1 and pump or whatever on table 2, the pre-existing blend tables are backwards. I use table #1 because it has additional enrichment on #1 ASE and WU tables.

For adjustable boost on top of the FF blending, one of the guys here, Chris72? suggested a trim pot in the gear input, and use the gear trim to allow up to 6 different boost settings, and it will work right on top of the FF blend affecting boost duty output. I have an AEM trim pot P/N 30-2056, but have not yet connected it. One of my customers had a leftover 5-position Pro-Efi trim switch that he connected to the gear input and it seems to work great.

[cwtt]

I did see a post about using the gear input. However I can't find any input for gear input. Any suggestions on where the gear input is?

[RHD]

There is a gear sensor input setting in the VSS and gear sensor setup you need to select one of the analog inputs, then connect a pull up resistor to power and a string of voltage divider resistors so that you get a graduated voltage signal from 0 to 5v for each boost setting you want ie 0, 1v, 2v, 3v, 4v, etc. then there is a gear calibration table that you can set the voltages to represent gears 0v=1, 1v=2, 2v=3 etc...

[cwtt]

There is a gear sensor input setting in the VSS and gear sensor setup you need to select one of the analog inputs, then connect a pull up resistor to power and a string of voltage divider resistors so that you get a graduated voltage signal from 0 to 5v for each boost setting you want ie 0, 1v, 2v, 3v, 4v, etc. then there is a gear calibration table that you can set the voltages to represent gears 0v=1, 1v=2, 2v=3 etc...

Thank your your help. I just hit one snag. How can you set the value for the gear. For exampe 2v= 3rd gear. As you can see in the picture it is greyed out, so I can not change the value.

[Kurt]

There's a table for gear vs volts.

[cwtt]

There's a table for gear vs volts.

You guys are awesome. This will work perfect. I wish it had a max boost x ethanol content from preventing a user from selecting the highest boost setting while on pump gas. Maybe that can be a future enhancement.

Here is what you need in case somebody in the future was curious about how to set it up:

[RHD]

there are still 2 separate boost target and DC ref tables so if you set them up correctly then you will have a different range of settings for each table set since the gear scale is only a percentage of the boost target (or ref DC ref im not sure but the result is the same)

so i guess you could actually have up to 12 separate boost settings?

[ATS_Scott]

there are still 2 separate boost target and DC ref tables so if you set them up correctly then you will have a different range of settings for each table set since the gear scale is only a percentage of the boost target (or ref DC ref im not sure but the result is the same)

so i guess you could actually have up to 12 separate boost settings?

Correct, if hes just switching from one boost table to the other. If he's using FF blending on boost control, the gear trim will only reduce from the pre-tuned boost level, unless he inputs higher than 100% in the gear scale, but only 6 settings max. Or virtually infinite depending on ethanol content.