- The idea for any type of project came about when I realized that
the stock boost gauge was inadequate. My friend (and Boss) thought
it would be cool to design a device which could monitor various car
operations, such as boost, RPM, speed, etc and log all this data to
be later sent to a Laptop computer via serial port for plotting in
a program such as Excel. Here is a new graph (plotted 02/24/97)
of Throttle Position (measure in percent) vs the signal from the O2
Sensor (not yet scaled). PLOT
- Currently the project is monitoring Boost Pressure (in psi), Throttle Position (in percent), Fuel/Air mixture via the Oxygen Sensor, Air flow (from the mass air flow meter), and a couple temperatures (before and after the intercooler). The temperature sensors were purchased from Analog Devices for about 2 dollars a piece. Already scaled for degrees Celsius and very accurate. All of this data is put to the serial port at regular intervals (about 3 times a second).
- The CPU is an 8051 variant called the 80535. An evaluation board was purchased from New Micros for about $120.00. A 20x4 backlite LCD was chosen for the beginning, although the board can support up to a 40x4 display. The evaluation board comes with a 10bit, 8 channel analog to digital converter, a bunch of digital IO's, and a keyboard controller. It is possible to have a 64k program (on an EPROM), and 64K of static RAM. This was the chosen configuration for the MR2 Turbo Project.
- Click here for a picture of the display
- Update! I have completed intercooler efficiency and am working on getting speed to come in correctly.
- What next?
- Once injector duty cycle code is completed (if that ever happens) all the information will be available in a real time format to determine the best combinations of performance modifications, ie boost controllers, intercooler/fan upgrades etc. An accelerometer was also purchased (about $20.00). I was unsuccessful so far in getting it to work, that is I think I broke it. Hopefully I will purchase a couple more, at which point acceleration could be measured accurately, and hence many other things calculated just like the GTECH device. More temperatures could be measured as well, a lot more! It would be relatively easy to measure as many as ten different temperatures from different locations....and easy to measure even more than that.
- Click here for actual data sampled using this project.
I haven't worked on the project in a long while, and have it currently removed from the car as there were some interference problems with connection to the display. I've been thinking about the idea of using a different platform to monitor and display information using a vacuum florescent display (similar to the Apexi AFC).