odometer recalibration question

[molddad]

When changing the tire size would it be possible to recalibrate the speedometer/odometer input to correct all the computer readouts? MPH, MPG etc.

[retepsnikrep]

Not unless you made some electronic gizmo to intercept the VSS speed signal pulses and adjust them to the correct values before sending them to the gauges.

[Insightful Trekker]

The VSS signal processing for the speedometer is done in the gague cluster module's CPU. Not externally flashable like some manufacturers (Ford comes to mind). The chip itself _may_ be flashable, but Honda makes no interface for it. Without an interface _and_ the code its a dead end.

Like Peter stated it would have to be "preprocessed" before it entered the gauge cluster.

[molddad]

Thank you both for the information. I'm not happy with the truth, but it will let me avoid a deadend fix.

The reason I asked is that I am transplanting the whole drivetrain into a classic Mini and will be using 19.1 inch diameter tires. The 3.21 final drive is OK for this swap, but somewhere around 2.76 would be just right. Although the old Minis were barndoors, the 550 lb. weight reduction should be gold. The tallest aftermarket final drive I found was a 3.40. I have no idea where to start getting some gears made up special.

Does it seem like there are numerous wrecked Insights with intact power units and some great used parts? I have both a CVT and a MT besides my parts car, and I think we should have a good supply of most spares.

[MN Driver]

Is this primarily to bring better fuel economy and/or less emissions to a classic Mini or what is your overal motivation? You mentioned both CVT and MT, I figure the CVT would be more of a challenge but which are you planning to use?

[molddad]

I'm using the MT complete with stock cats and intake, IMA and instrument pod.

The original '59 Mini was an auto concept in answer to the Suez Canal blockage. The engine capacity was reduced to limit top speed as the car was so light it was too fast for its brakes. The economy concept was very similar to the Insight. My idea is to take a '59 Mini and update it with modern tech. The high performance Mini Coopers of the '60s were the boy-racer civics of today, but not the original intention of Sir Alec. The '59 commercials bragged about the 4 passenger capability and 50 mpg.

At 1325 lbs I'm expecting great city mpg. The builder intends to place the pod in the middle of the dash ala classic Mini. I would sure like the readouts to be accurate without having to make 14% adjustments. The final drive gears would be the best cure since the motor will have no problem moving the light weight.

[gsfent]

Originally Posted by molddad

When changing the tire size would it be possible to recalibrate the speedometer/odometer input to correct all the computer readouts? MPH, MPG etc.

See if this helps:

Universal Speedometer Signal Interface

Regards,
Jerry

[molddad]

gsfent

Thank you. That is well worth investigating.

[molddad]

gsfent,

I spoke with the Dakota Digital tech support about the SGI-5 Universal Speedometer Signal Interface you linked me to, and it will do the deed for $80. He even had some Honda Insight data, and said the Insight uses a 4000 ppm signal. He mapped me out on which wire to put where and how to set up the switches and adjust the input to the pod.

I just bought a unit and sent it to my builder.

Thanks again for the link.

[nayrhyno]

sounds like an incredible project. Make sure to come back and post lots of pics when the frankenbuild is complete.