I have a comptech SC and a VAFC one. I am using the VAFC to tune but would like to use it also to see peek boost levels. I am afraid that if I hook up the ESM before the VAFC then I will not be able to change the map signal that the VAFC uses to tune since the ESM black box will cap it anyway.

How do you guys have it hooked up.

Is there a way I could wire up the black box in between the VAFC so I could see actual boost but still adjust it after it has been capped?

 

Anyone supercharged and have a VAFC?

 

I posted a thread somewhere. This is what I did...




FWIW, I wired the VAFC between the ECU and the ESM. As seen in the diagram.

 

think about what you are doing. the map sensor is getting a voltage for the amount of air, which the VAFC is then going to corrupt by a percentage, then it will be stopped from going to a certain voltage due to the ECU's inability to see positive pressure. (ESM) Where the map sensor stops working, the FMU is going to take over for the map and add more fuel. I ran a similar setup to yours when i first went FI, and i wouldn't do it again.

OT, Scott's w ay is how i set up the VAFC with ESM. I was able to get the actual voltage for the pressure the map was seeing, and then have the ESM stop the voltage from messing up the ECU.

 

So did I, but I wish there was a way to see actual boost but still be able to alter the signal.

 

^^ Get a boost controller

 

SC Boost Controller = Pulley

 

Whops I mean't to say boost gauge


Then you can alter the signal with the VAFC and still read boost

 

I have a boost gauge as well.

I was trying to do something a little different but I guess it won't work.

Does anyone know if the VAFC would still work if the black box was between it and the ECU?

 

The definitive fact is the ECU can't see boost, and it's controlling your injectors. So the ESM should go between the VAFC and the ECU and hence the VAFC will have no effect above ambient pressure. The VAFC is seeing the actual MAP signal so doubles as a boost gauge.

You can connect them the other way around though. What you have to do is make sure the car is running a little rich throughout the boost range, then only use the VAFC to pull fuel (It basically always sees 2.93V when in boost and sends a lower signal to the ECU).

Either way, it's ghetto tuning.