I had the idea, why can't I use my car normally with factory consumption, and some days with a tuned chip. So how to make this without removing the eprom each time?

I made myself a simple eprom switch. This board you can place in the ecu, and with the ENGINE NOT RUNNINGyou can easily switch between two eproms.

I have not tested it yet, because my engine is right now in many pieces...
But it works this way:
The two eproms are connected parallelly, except the Output Enable (OE) pin. With the switch you can choose between this pin of chip1 or chip2.
We also need 2 pull-up resistors with 22k value.
And theoritically thats all.

Here are some pictures:

To fix the board, you need to drill three holes, as marked on this picture:
100_3655.JPG

100_3662.JPG

100_3665.JPG

A picture of the Layout editor:
board.jpg

The PDF file of the board:
eprom_switch.pdf