Where does the head temp sensor go for an EFI conversion?

[David]

My heads are almost ready to be shipped to EBS for the valve job and twin plug conversion. I've bored out the intake ports to match the carrera intake, plugged the exhaust air ports, and cleaned up the casting flash in the ports.

It seems like most people using an aftermarket EFI system use the Carrera head temp sensor for the engine temp input. Is that right?

Since I don't have a Carrera and since Masraum sold his I don't know of one nearby and I don't know where to put the sensor. Anyone have advice? Pics would be even better, thanks.

[dean]

I am using the oil in the cam line for my engine temp. If I was in your shoes I would also mach the head for a sensor. Sorry I don't know were to put it.

[kqw]

The sensor on the Carrera's is located on the #3 cylinder.

[Bob Goding]

Have a look at tbitz--simple and cheap

[911Mac]

I second Bob's suggestion. I'm running Tony's kit and the temp sensor works fine, just attaches to one of the timing chain cover studs.

Mac

[David]

I looked at the bitz manual, very impressive. The temp sensor looks simple enough.

One concern I have, especially with a turbo motor, does the Carrera give a good enough resolution to sense detonation or lean mixture problems or is it really just telling you if the motor is hot or cold?

[911Mac]

David,

The temp sensor is only used for richening up the A/F ratio when the engine is cold. Once the engine warms up it doesn't do anything. A knock sensor would have to be used to detect and deal with detonation.
The A/F ratio using the megasquirt EFI controller depends on the O2 sensor, the VE Table ( manifold pressure X RPM ), and several acceleration variables.
Tony's working on a turbo kit that would work with the megasquirt controller, you may want to take a look at some of the discussion on that thread.

Mac

[David]

I'm planning to use the Autronic system so I can use low impedence injectors, have sequential injection, and drive a twin plug ignition.

[turbo6bar]

I recall on the Megasquirt forum (tbitz's ECU), the recommended location for the temp sensor is near the cylinder head and not the oil, since the cylinder head temp reflects the engine temps. Oil temps lag the engine temp. That's just what I read. I have no experience with this stuff.
Jürgen