VS S3 Ute - MAF to MAP

[GTS323]

Hi all,

Has anyone successfully changed their VS series 3 (304 roller motor) from MAF to MAP by simply wiring in the MAP to the input where the MAF goes and configuring? Is there an XDF & ADX capable of doing this, as it doesn't appear that MAP is an option in $A6 (Enhanced mode)? I'm sure it's not this easy, but I'm keen to get your experience and input. Would the below work?

Part 1: Hardware Changes
Get the Correct MAP Sensor:

Typically, for Holden VS conversions, a 1-bar, 2-bar, or 3-bar MAP sensor is used, depending on the boost level.
1-bar MAP sensor: Normally aspirated engines (up to atmospheric pressure, ~0 psi boost).
2-bar MAP sensor: Engines with up to 14.7 psi (1 atmosphere) of boost.
3-bar MAP sensor: Engines with up to 29 psi (2 atmospheres) of boost.
The Delco 12223861 (commonly referred to as the GM 3-bar MAP sensor) is a popular choice.
Install the MAP Sensor:

Locate a spot on the intake manifold to install the sensor, preferably near the throttle body. The MAP sensor needs to measure vacuum/pressure from the intake manifold.
Use appropriate vacuum lines to connect the MAP sensor to the intake manifold. Ensure there are no leaks, as any air leaks will affect pressure readings and engine performance.
Wire the MAP Sensor:

The MAP sensor typically has three wires:
Signal wire: Connect this to the ECU where the MAF sensor input was originally connected (or to the appropriate pin for MAP input if you are using a custom ECU wiring setup).
5V reference: This is a power wire that supplies the MAP sensor with 5 volts.
Ground wire: Connect this to a good ground source (often the ECU’s sensor ground).
You may need to consult the ECU wiring diagram to make sure the MAP sensor is wired correctly.

Part 2: Tuning Adjustments in TunerPro RT
Open the BIN File in TunerPro RT:

Start by loading your existing BIN file that contains the MAF-based configuration.
Go to File > Open Bin and load the current tune.
Switch from MAF to MAP in the XDF Settings:

The primary goal here is to modify the fueling strategy in the ECU from MAF-based to MAP-based.
In TunerPro, look for the following settings in the XDF file:
MAF vs MAP Switch: This option tells the ECU to use the MAP sensor instead of the MAF sensor for fuel calculations.
Typically, this setting will be a flag or a switch that changes between MAF and MAP modes.
Set the switch to use MAP sensor.
Edit the VE Table (Volumetric Efficiency):

When switching to a MAP sensor, the ECU will use the VE (Volumetric Efficiency) table to calculate airflow and fuel delivery.
Open the VE table in TunerPro:
XDF > View/Edit Parameter > Volumetric Efficiency Table
You will need to populate this table with values that reflect the engine's VE based on RPM and manifold pressure (MAP sensor readings).
You can start with base VE values from a similar MAP-based tune or manually tune the VE table by data logging.
Adjust the Fueling and Timing Maps:

Now that the engine is using a MAP sensor, the fueling will depend on both the manifold pressure (boost/vacuum) and engine RPM.
Fuel Maps: You will likely need to adjust the Base Fuel Map and possibly the Power Enrichment (PE) Tables to account for boost (if using a 2-bar or 3-bar MAP sensor).
In higher MAP regions (positive pressure for boost), make sure your fueling is enriched to prevent detonation (target around 11.8-12.2 AFR for boost).
Timing Maps: You'll need to review the Spark Timing Maps and adjust ignition timing based on manifold pressure.
In boosted regions, you'll need to pull timing as boost increases to avoid detonation.
Disable MAF Codes and Faults:

When switching to MAP-based tuning, you should disable any MAF sensor-related diagnostic codes to prevent the ECU from throwing errors.
In TunerPro, look for MAF Diagnostic Codes (DTCs) in the XDF file and set them to "Disabled" or "Ignore".
Adjust the Barometric Correction Table (if necessary):

Depending on your specific ECU setup, there may be a Barometric Pressure Correction Table or a switch to adjust how the ECU accounts for changes in atmospheric pressure.
If your ECU relies on barometric pressure for fuel trims, ensure it’s set to reference the new MAP sensor.
Save the Modified BIN File:

Once you've made all necessary changes, save the new BIN file.
Go to File > Save Bin or Save Bin As to create a backup of your MAF-based tune in case you need to revert later.

If No Existing MAP-Enabled XDF/ADX is Available
If you can’t find a pre-configured XDF or ADX file, you may have to manually configure the MAP sensor input and tables:

1. Add MAP Sensor to XDF
In TunerPro, you can manually add a MAP sensor by creating a new parameter in the XDF file:
XDF > View/Edit XDF Header > Add New Parameter.
You’ll need to know the exact memory locations for the MAP sensor data (these addresses should be documented for your ECU).
You’ll then need to modify the fuel and spark tables to reference manifold pressure (MAP) instead of mass airflow (MAF).
2. Adjust Fuel and Spark Maps
For MAP-based tuning, you'll need to switch to VE tables that use MAP values (kPa or psi) to determine the correct fuel delivery.
Adjust the timing tables to reference manifold pressure instead of airflow.

[immortality]

Fairly sure that if you want to run MAP then you need to start with a PCM that runs MAP from the factory. These PCM's aren't like the newer LS stuff that have both MAF and MAP functionality.

Going from MAF to MAP is a completely different set of calculations and tables and would take a significant re-write of the code.

The only off the shelf option for this ATM is probably Kalmaker.

[antus]

Yeah thats right. Its not just the sensor, VS S3 has the VT engine, PCM etc. Possibly VT BCM but I am not sure on that. It seems was Holden doing to the typical move to the new platform in the old body, then I assume they were thinking if it turns to shit, they trash the outgoing models reputation and have a chance to fix it before the new model is headlines. You'd need to move back to the S1/S2 loom, computer, sensors, maybe BCM and be ready to solve any problems you came up against on the way while mixing and matching modules, sensors and wiring, then finally tune for the engine.

[Dylan]

Fit a VS series 1 or 2 loom and ECU

[GTS323]

Thanks guys, appreciate the inputs. Figured it wouldn't be that simple. I really don't want to go down the aftermarket route but might be the only option to get flex fuel and convert to MAP.

I think I'll stick with what I have. It's due to get tuned for the supercharger, injectors, pump etc in the next 2 weeks. Once I start throwing parts I've been buying to build the motor next year, then it might be time for a Haltech.

[Dylan]

Series 2 VS loom and ECU will give you everything you're asking for as well as a custom OS ($11P).
Also retains full control of the OEM cluster and transmission.

[brindo]

What supercharger? There's plenty of scope with The1s enhanced bins for MAF PCMs, but not flex fuel.

[Wade]

I done a vt roller motor into my brothers vq caprice. Just used all his accessories and loom ect. Being a vs wouldn’t to hard or difficult.

[GTS323]

Thanks Wade. It’s the Raptor R kit. I’ll just go straight E85 and have a separate chip for 98 and can plug it in if stuck.

Trying to read as much as I can to see what needs to be changed to get it running a base tune on E85 then start tweaking the tune from there. I was hoping someone may have had one posted on this forum for a centrifugal pump on a 5L.

[Wade]

Things that come to mind would be adding things like 20-30% more fuel. Obviously removing timing ect and re scaling the maf as I’d assume you’d go a larger maf. Getting all your injector data correct as I’d also assume you’d go larger injectors. And all your cold start fuelling ect. Probably starting off on pulp98 to build a good safe tune then switching over to E. Making sure pe and commanded afr’s are right for boost. And then looking at the max mass air table. There all things that come to mind