Perfect, exactly what I needed.  Seems like a simple procedure.

I have access to the site.  However, trying to access the file this morning I received certificate error problem messages.

I have made a copy of the file and placed it in my online storage location.  

Visit the link below.  Look for and download a copy of "MPI_rev.doc"
https://sites.google.com/site/purlawson/home/files

I found that link  as well but it requires special access.  I asked the host to give me access and never heard back.  If you have access and can cut and paste those instructions, would appreciate. 

Download the document linked below.  I have not had occasion to carry out the conversion listed in the article but a couple of people on The Mini Forum have used it with good results.

//www.theminiforum.co.uk/forums/index.php?app=core&module=attach&section=attach&attach_id=91384

Put a second engine in the trunk and see if it averages out?

Some after-market tachs can be set for 4-, 6-, or 8-cylinders. I still have the one I put into my first Mini - it could also be set for positive ground.

Super-special engine with the redline at 13,000 rpm !!

paint halved numbers on the dial

The MPi injection & ignition is indeed a wasted spark system so the gauges will read double when connected to a traditional ignition system.

You'll need to halve the pulses somehow if you want to keep the tachometer.

You would have to be pretty handy with electronics to make a circuit that would match what that tach is looking for pulse wise, but it could be done. I would look for the correct tachometer. Is the MPI a waste spark system?

Ever since I bought my car, I noticed the RPMs on the tach seemed a lot higher than how the engine sounded.  I have the Seiki Japanese gauges.  After I checked with a timing gun, seems the tachometer reads 2X higher than actual RPMs.  I'm not sure if the tach is original to the car.  I researched and found that if the tach was from an MPI car, it would read 2X higher with a non-MPI car.   Is there a way to correct the gauge?