Comparing Hull Effect to Joe Cell - Electronic Fuel Injected Engines

Comparing the Hull Effect to a Joe Cell on an electronic fuel injection system.

Honda Accord LXI

For reference purposes the fuel flow meter will read about 4.2 when cruising at 50 MPH without any devices installed., and the sweet spot for economy feels to be around 50 MPH.

Hull Effect

In general it feels like the HE setup provides maximum boost at the minimum rate of fuel flow. For example, the car at idle will run approximately 25 Miles per hour.

When cruising at highway speeds of around 50 MPH, the fuel flow is reduced to 3.8 but when starting up a hill, the flow needs to be increased significantly before a power increase actually kicks in – up to about 6 on the gauge.

The sweet spot felt to be closer to 55 MPH. With the gauge indication 3.8.

Very little difference could be felt between the Lutron Skylark device, and a standard lamp dimmer device.

Both devices had performance peaks at a couple locations in their adjustment range, which could be felt in the engine performance, provided the engine was not in an accelerating mode. IOW, the lower the throttle setting, the more noticeable the peaks were.

Joe Cell

The Joe Cell connected with the cathode to the chassis, and the anode connected to plus through the cigarette lighter seemed to provide a similar increase in idle RPM, but gave a more consistent boost across the throttle range. There was a cleaner transition from cruising on level road to increasing power to climb a slight grade. Probably only about a change from 4 to 5 on the gauge to get increased power.

The sweet spot for cruising speed was also about 55 MPH with a gauge reading of 3.8.

The dimmer and JC were tested together by inserting the JC between the dimmer and the oil. In this mode the effects appeared to be somewhat additive. The smoother transition from minimum cruising fuel flow to increased power for a grade was maintained, as was the more consistent boost across different throttle settings. It was possible with careful adjustment of the dimmer setting to get the sweet spot up to 60 MPH.

The gauge reading at 55MPH on level stretches dropped down closer to 3.6.

MPG Increase

My last fill-up had the fuel economy at 31.5 MPG, as compared to the normal 25.

8 - 23 - 2009
Bernie H


Meter referred to is an electronic Tachometer connected to one Fuel Injector Lead. It shows average time injectors are on, as fuel is being sent into cylinders. This gives an instant indication of the fuel flow rate.