Toyota MR2 Supercharger

Intercooler Temperature / K-Type Thermocouple Datalogger
(Air Charge Temperature Monitor)

The unit that i have developed here allows the user to monitor and record three temps from k-type thermocouples, this allows you to measure ambient, intercooler inlet and intercooler outlet temperatures otherwise known as ACT (air charge temp). The air charge temp is important on forced induction cars due to the increase in temps from the compression of the intake air from a supercharger or turbocharger. This is especially important on modified engines with larger turbos or pulley modifications for superchargers. Notwithstanding the recording and monitoring before and after installing aftermarket intercoolers, ducting, water injection and the installation of chargecooling. Monitoring the ACT allows you to see if a modification has had a positive or negative effect on the temperature of your intake.

A kit consisting of PCB, parts list, schematic and pre-programmed micro controller will be available for you to build if your interested in this please email me through my contact page.

The project was written in MikroBasic with an EasyPIC4 Development board and features over 2500 lines of mikroBasic code.

32mhz CPU + 64Kbytes non-volatile RAM
16x2 red-on-black Backlit LCD
Probes: 3 K-Type Thermocouples (Ambient, Inlet & Outlet)
Real-time display of all temps with differential modes
Viewing and Data logging Rates: 0.20s, 0.25s, 0.5s & 1.0s
Logging resolution: 10bit / 0.25 deg C steps
Viewing resolution: 1 deg C with 1/4 degrees shown as mini-bar graph on each input and differential temp.
1/2 screen, 80 segment real-time bar graph showing % differential ratio between ambient/inlet, ambient/outlet or inlet/outlet
Max temp display for each probe and max differential temp
Selectable 2, 4 & 8 sample moving average for noise reduction
Working temps: Display Unit: 0 to +50C, Probes: 0 to + 999.75C
Output files open in Excel without adjustment
Auto start feature to automatically start recording when a probe is above or below a set temperature.

Logging times:
5Hz (0.20 sec): 43 min, 40 secs
4Hz (0.25 sec): 54 min, 36 secs
2Hz (0.50 sec): 109 min, 12 secs
1Hz (1.00 sec): 218 min, 24 secs

Typical output of data from Excel (data sampled at 5HZ, 0.25 DegC resolution with 4X averaging, all temps in DegC).

Driving on road with some long acceleration points, stock engine.

Intercooler datalog sample

Driving at Anglesey Circuit, big pulley, Toms style air scoop. (data sampled at 5HZ, 0.25 DegC resolution with 4X averaging, all temps in DegC)

intercooler datalog sample 2

Testing MAX6675 thermocouple drivers Beginnings: here i have two Maxim MAX6675 K-type drivers plugged into my PIC development board.

Testing MMC/SD card reader Quick lash up of a MMC/SD card port using SPI

Thermocouple datalogger test board After i'd proven the basic workings i began writing the code properly and created the first prototype on strip board. This version used 2 k-type drivers for the inlet and outlet temps and a Dalas one-wire sensor for the ambient temp sensor. The sensors connect to the terminals at the top of the pic, along with the card reader.

FRAM memory was used in the prototype. The Ramtron FM24C256 chip is located on the 20pin SOIC proto board above the PIC.

K-Type Datalogger prototype board his is the 2nd prototype built on a PCB, this in fact was the first PCB i'd ever created, which is why the components look like they have been mounted where they landed!! Barring a few minor mistakes the board worked perfectly.

At this stage i was not really considering how the board would mount. which is why the tactile switches dont work inside the box.

Thermocouple datalogger test mounting in box This shows the planned enclosure, from this i began to create the 3rd prototype board which was designed to fit this box properly.

2nd prototype k-type datalogger - component side

2nd prototype k-type datalogger - reverse side

The 3rd prototype was created, with everything in the right place for the enclosure. To allow enough room for the LCD the switches and MMC slot were mounted on the bottom.

Although this pcb version can accept two ram chips to allow longer recording using two Ramtron FM24C256 memories, instead one Microchip 24FC512 EEPROM is used instead. The separate bespoke ambient probe has been replaced by a third k-type sensor. This means all three channels are identical.

Everything located in the box... finished!

1997-2011 Mark Nias