Dual Performance Chips
Many of you racers, must have heard or read about dual chips. Dual chips are chips that their memory capacity doubles the one of the original chip, so two different, same size programs can be written inside so it can be selected between them on the fly, simply by using a small switch.
It is useful for selecting between the stock program and the performance program. That is, a “Normal” and “Sport” selection switch. Also, if your performance chip doesn’t pass smog tests, the stock program can be selected in a flip of the switch at the time of the inspection test.
If the stock or “Normal” program is not to be used anyway, then the dual chip can accommodate two different performance programs like “Mild” and “Hot” selection switch.
If the original chip is small enough in capacity, there can be installed more “versions” or “power levels”, but a more complex switching would be needed. We will cover here the dual program chip only, using a 27C512 (64KB) EPROM where the original is a 27C256 EPROM (32KB).
If you don’t have or don’t know how to use or manage the chip burning equipment, you may ask somebody skilled on this to do the burning part. If using the “Normal” and “Sports” version, then you would ask the stock program to be burned in the lower memory page of the chip (0000h-7FFFh) and the performance program in the higher memory page (8000h-FFFFh). This is done by combining the programs in that order, in a single binary file, before transferring it (burning) to the new chip.
There are many products out there to do this dual chip switching in form of a socket with jumpers, averaging between $30 and $80 , like the Moates one, and it is a very nice product, but if you need to do it in many ecus or simply don’t have much to spend, then this trick will be useful.
You will just need a 1 kohm resistor, a small switch and some thin electrical cable. Below is the simple schematic:
The connection diagram is something like the one blow:
Installation
The resistor must be soldered directly in the pins #1 and #28 of the chip. Do this with the chip out of the socket or you will ruin it. Solder must only cover the upper part of the chip leads, or the chip could not be reinserted in the socket. Then, the switch must be wired to leads #1 (carefully, in the same spot as the resistor) and #14 in the upper part of the leads also. Now the chip can be carefully reinserted in the socket, but VERY IMPORTANT, pin #1 must be hanging out the socket, unconnected, nor touching any part of the socket metal contact.
The above happens because pin#1 is used only when programming (writing) the chip and it is of no use for the ecu (the ecu only reads it), but for some reason, Honda and many other manufacturers wire it directly to the +5V supply of the ecu. That will make a short circuit that WILL damage the ecu when the switch is flipped to the ground position (Pin#14), which corresponds to “Normal” mode.
Special Details
There are two details about this installation;
(1) In some cars, switching on the fly will have no effect. In these cars, for changes to take place, the car must be turned off, the switch flipped, and then the car turned on. Then changes are available.
This is because in those cars, as soon as turned on, the ROM chip is read and then transferred to a faster RAM memory. That is called shadowing or masking. When the car is turned off and then on, it is forced to re-read the ROM and with the switch already flipped, it will read the newly selected program and transfer it to RAM.
(2) In most cases, the cables for the switch must not be longer than 12 inches. That is why we recommend to install it in the ecu body instead of the car dash. This is done to prevent any electrical noise to be picked up by the switch wires, just like an antenna would do. Electrical noise either might cause that the switching of programs become unstable and turn on the check engine light or might also cause the ecu to act erratically or make it to lock up.
Summary
The method described above, is a precise one and have been tested with no problems. It is offered as an economical option for who which to implement a system like this, but, if you don’t have, or have insufficient experience or knowledge in electronics to do this, we recommend that you either do not try it or bring it to a trained person that can do it for you. A trained person might charge a small fee, but damaging the ecu will be really expensive.
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OtherDeal.Com
Where can i buy a chip with two programs for switching? thanx
Please, send a message through the “Contact” section at the page listed below, with details like the model of your car and ecu number, the programs you need, etc. Include whatever you think is relevant.
http://www.otherdeal.com
Regards,
Richard
Would this chip work in a 1995 starlet GT turbo?
No, sorry. We do not have chips for Toyota. I don’t know of any seller that does so far…
That is why piggy backs and programmable engine management systems (EMS) are often used on Toyota models.
Of course, there are very few exceptions, but it will require modifying the ecu in a very costly way.
I regret I can not help.
Rick
Hello is there any chip that is smaller than 27c256 but can store all data, and work in same way, also is there a module that can comunicate with it so the burning can be done on the fly, and memory can be read as well?