I've been following this thread with some interest as I have a 2001 Defender Xtreme that was 'chipped' with a Bruce Davis ECU exchange in 2002 - I'm in Australia in Southern Victoria. So here is my twopennyworth. This changeover does give a 50% increase in power and torque and generates a great deal more heat in the engine bay. To combat the heat I fitted a Pacet bonnet fan ad reinforced the bonnet with alloy cheque plate, this acts as a great heat sink. An unexpected side effect of this was to improve the airflow through the engine compartment, even with the fan switched off, and consequently through the intercooler - very noticeable increase in power on cooler days. Recently I changed my foam filter to a K&N with dramatic improvement at the bottom end of the torque band. I can now trickle along smoothly in 1st gear high range on tick over, foot off the accelerator, no judder or signs of stalling like it used to. Turbo take up is smooth without any signs of the sudden leap in power that a standard engine gives. Finally a couple of days ago I replaced the Donaldson pre-filter with the standard Safari ram inlet to achieve further results. The engine is quieter and pulls even harder right across the power and torque band - if you hit the accelerator hard at 100 ks it shoves you back in the seat and rapidly goes to 140 ks, its truly astonishing. I've yet to get it seriously off road to check its ability up and down the Vic alps in low range. It's a much modified Defender with Maxidrive axles, drive flanges and rear diff lock, much plating underneath and a rear drawer system containing a load of recovery gear, so its no light weight. Fuel consumption averages 11.77L/100 ks (24 mpg), which could be better if I didn't use all that power. I use synthetic oils all round and change the engine oil each 10K and the TD5 runs as sweet as a sewing machine. Have done 147,000 ks so far. The secret as far as I can see is to get rid of the extra heat, I know of a chipped 130 with under the bonnet insulation that is now on its third replacement exhaust manifold because of the heat under the bonnet. Would love to hear of anybody else's experience in this area.
Reg Slawson