Most 80 Series engines respond well to a well engineered turbocharger
installation. Kits are available for the 1HZ diesel engine and the 1FZ-FE
gasoline engine. Unfortunately the 3F doesn't take kindly to a turbo installation
due to engine longevity issues.
It is important however to be somewhat conservative with this motor when it comes to extracting lots of power. While the bottom end is very robust there are structural issues in the head (especially around the pre-combustion chambers) that dictate how much power can be extracted reliably. Whilst there is no doubt a good degree of over design is incorporated in the 1HZ, adding a turbocharger will stress the motor further and bring the performance envelope that bit closer to the limit. Things like the condition of the injectors and injector pump adjustment can have a significant effect on longevity. Hence the importance of a well engineered unit that is installed by professionals who are experienced in this field.
There are many examples of turbocharged 1HZ's with over 250,000km on them and running strong. There are also a small number of people in our group with bad experiences through mainly trying to over fuel, over boost and/or lack of injector/pump maintenance. The feeling amoungst most in the group is that a boost compensator is a worth while addition to avoid overfueling at low rpm/low boost. A boost compensator allows the pump to be adjusted leaner for low boost conditions and increases the injected volume under high boost. This results in better economy and drastically reduces the amount of exhaust smoke.
Turbocharging the 1HZ is a popular option and one that can be considered
from new. Toyota here in Australia frown on turbo installations (since
it took sales away from the high priced 1HD-T and 1HD-FT factory turbos).
The turbo may affect the factory driveline warranty and some companies
will warrant the driveline for the same period as the factory warranty
in the case of driveline failures attributed to the turbo installation.
The kit is quite comprehensive and as a consequence fairly expensive, however the quality of components and workmanship of this Safari kit is very impressive indeed.
An additional injection management unit is used to meter the amount of fuel injected via a dedicated injector in the inlet tract. The factory ECU and injectors are left untouched. A problem common with turbocharged gasoline engines is pinging or detonation. Whilst this kit does a good job of keeping detonation to a minimum it can occur when using regular unleaded. As a safeguard, the factory knock sensors are retained to retard the ignition timing if 6 successive detonations are monitored.
There aren't a great number of these on the road in Australia and only
one in our group. There is however a great deal of interest and we're waiting
for more of us to take the plunge.