MAP & IAT Sensor Locations

[natedawg]

I am running a microsquirt efi on a small (<100cc) single cylinder 4-stroke engine. The throttle body mounts directly to the engine and the intake valve is only roughly 1 in. away. Where would I need to hook up my MAP sensor and IAT sensor? I assume it would be before the injector for both?

Thanks.

[Matt Cramer]

The IAT can be anywhere it gets incoming air so it can be upstream of the throttle body. The MAP sensor needs to be downstream of the throttle blades - you may have to use a MAF or alpha-N on this one.

[natedawg]

Hrrmm....alpha-n you say....

Can I get your opinion of my setup? It may be doomed for the get go.

2hp engine, throttle body with one injector mounted to side of engine. For my efi controls, I have an optical sensor mounted on crank shaft (for rpm only?), throttle position sensor mounted on throttle body, IAT sensor (soon to be upstream), and MAP sensor (soon to be downstream of throttle body by magic). My ignition is a stock magneto and is not adjustable. From this setup, is it still possible to use the EFI? It seems like the biggest challenge right now is to get the EFI to inject when the stock ignition is sparking...

[gboezio]

As said before, the MAP sensor will be unusable, ask me how I know, you can't tune a pulsing MAP signal, you will have a narrow load range, maybe at higer RPM but I'll use alpha-N all the way, it's the motorcycles are working

[natedawg]

let me display a super amount of ignorance here...alpha-n is an algorithm within megatune and not separate hardware, correct?

[mfro]

let me display a super amount of ignorance here...alpha-n is an algorithm within megatune and not separate hardware, correct?

Alpha-n can be activated in Megatune/Tuner Studio. It's the simplest mode to get MS to work. In this mode, it basically ignores any sensor feedback besides throttle position (alpha) and engine RPM (n). Dumb but effective - thus ideal to begin with.