MoTeC Global Forum

How do you measure the delay on a LSU 4.9.

Engine is CA18DET with Lamda measured in the turbo dump pipe.

The answer really isnt that straightforward. It depends how far it is from the header, and what rpm etc etc.

So the best way to measure this is to be data logging injector duty cycle, rpm, throttle.

Next put a huge fuel step in your fuel map. Example.

RPM fuel
5500 60
6000 62
6500 100
7000 65

now as you run the engine through the rpm range (on the dyno or the track), you will see that from 6000, the injector duty cycle will ramp up, and at 7000, it will have come back down.

Now look at your lambda readings, you will see the lambda go very rich. Look at the duty cycle of the injector, and compare it to you lambda trace, the offset between these two is your lambda delay. Log everything as fast as possible to increase accuracy.

-Jamie

I would use a RPM limit to check the delay,

Not running the engine on the limiter, but rather just touching it at the end of the ramp run.