Last Modified 31 Mar 2007

When I first got the car I took it to the rolling road, AVA renfrew to see what kind of performance I was getting and how the car was running in general. The engine was knocking a bit in the midrange so the timing was retarded a little to dial this out. Power was recorded as 204BHP at the wheels with similar torque but the figure that really stood out was the intake temperature of 140degC! Blimey o reilly Even the second run with the changed timing was high but it was only 90degC

That panicked me quite a bit so I did some searching around and found an article on measuring both intake and exhaust temperature with a collection of home brew components. Now this kit used good quality components but because you built it yourself it is way cheaper than many of the other gauges out there. You can read the article on Autospeeds site

The Conclusion - for now at least

Like all good documents I have put the results at the start and if you want to read the story then please read the stuff below.

The gauge I'm using is a Hawco Refrigeration LAE LTS12 unit and it works very nicely although the usual problems of trying to read an LED display in bright light is forever present. The display is connected to the K type thermocouple which was purchased from Kalestead and is now mounted in the rubber sock betwen the throttle body and the intercooler pipe. For the actual display it's my intention to recess the unit into the DIN slot thus helping reduce the glare from the sunlight. A plus point of this gauge is its low and peak recall. Nice, anyway some pics of the unit in situ

First positioning level with radio	Second position mounted back avoiding sunlight

The Slightly Longer version of events

After some hunting around I managed to get a company Kalestead that supplied the required thermocouple but due to minimum order requirements I had to get 2. No biggie cost was only GB£24. I had the cables terminated into a mini block as I was going to measure the temps with a YELLOW Digital multimeter that I bought from Maplins for the pricely sum of GB£12 bringing the total cost so far to GB£36. Very reasonable considering some of these gauges are kicking around for nearly GB£100. Mounted the meter on the centre vents using a cable tie. Very professional I hear you cry

Now it was time to mount the sensor. On most normal cars, ie engine in the front the route through to the engine bay is dead simple. Crawl into the drivers foot well and hey presto loads of nice rubber bungs where the cables pass through the bulkhead between cabin and engine compartment. Not on an MR2 where the engine sits behind you

Getting info from IMOC again I found out there was a bung behind the passenger seat and a pretty big one at that. So it goes like this

• put passenger seat as far forward as it will go and fold it forward
• take out the plastic storage bin
• remove the screws holding the trim to the bulkhead remembering the coat hook on the top near the rear window
• prise off all the trim and peel it back to reveal the bung
• get a metal coat hanger, you do have one? and straighten it out
• the bung here is actually a thick piece of trim so its easy to pull out though there is a rubber bung there as well
• attach the wire of the sensor to the coat hanger and push it gently through into the engine bay
• climb back out of the car and
• looking through the side body vents you will see the coat hanger sticking into the engine bay
• remove the sensor wire from the coat hanger and pull through as much as you can
• from the top of engine bay stick your hand in and pull the cable up
• slacken the clamp on an air pipe in after the intercooler and slide the cable underneath and then re tighten the clamp

Now I must confess that when looking for a pipe to slip this wire under I took the easy option of this one here

because the pipe just slid off when I pulled on it. So I slipped the cable underneath and pushed the pipe back on. Now this was all a temporary arrangement until I built the gauge as described in the above Autospeed article, you did read it? That was August 2003 and its taken me until July 2004 to get a 'proper' display unit. mmmm

Actual temperatures measured on the road are significantly lower than the rolling road - no brainer that one

Anyway, now I had always noticed that when I hit the brake pedal although there was plenty of stopping power I did need to move my foot a far distance to get the brakes on nice and hard. However if I put the brakes on then released the pedal then put the brakes on again the second push was against a much harder feel. Now the pipe I slipped the temp sensor wire underneath is the brake booster pipe, you know the one that slipped off in my hand. Well when I was fitting the new display I decided to move the sensor to the main throttle piping in front of the throttle plate and put a new clip on the brake pipe. This would give me the most accurate reading of the temperature of air going into the engine and by fitting a new clip it would allow me to get a better seal on the brake pipe and hopefully a stronger pedal. So far it seems like a stronger pedal but I'll reserve judgement for a few days yet.

After much searching around the web I found that the prices of bespoke thermocouple display units ranged from GB£100 to GB£300 and almost none of them would fit into the DIN space in the car or indeed could be powered by 12VDC. After more searching and many months or doing nothing I found Hawco that sell various display units but more importantly 12VDC K type thermocouple units and at a delivered price of GB£40. Result thought I. The problem is that these units are LED display which is just a nightmare to read in direct sunlight. This is the reason I bought a back lit boost display as you can read it night time or in bright sunshine it really makes no difference. However the intake temps is not something I am going to be religiously reading and I'm sure I can come up with a shielding method to solve the sunlight problem if need be.

Anyway the display was wired in using the supply from the radio as a switched 12VDC and earth. The advantage of using these connections is I'm using the radio adaptor and not splicing into the main car wiring loom. This is an usual moment of sensibility from me and I'm very pleased with how it worked out. The advantage of this is I now have a re-usable 12V switched supply all I need now is a light source and the future gauge installation is off to a great start.

The gauge is just sitting on top of the radio for now while I decide what to do about the other gauges. I have a Greddy adaptor plate that fits between the engine block and oil filter that allows both an pressure and temperature sensor to be attached. The temp gauge is 72mm and I don't think I can fit in 2 x 52mm gauges and with the charge cooler I'm tempted to put in a water temperature gauge to monitor that.

First positioning level with radio	Second position mounted back avoiding sunlight