Top or front mount in the 80 series.

PDI only develop and supply front mounted intercoolers. This is simply because we know the efficiency so so much better with front mounting and this is better for almost every 4WD drive user - particularly for the 80 series where there is no temperature compensation on the injection pump.

We once had the idea that while our front mounts are very good at dropping heat, for low boost levels a small top mount would be sufficient. This was dispelled soon after, as we had this setup on the dyno. It produced less power than with a PDI front mount (due to tuning with air fuel ratios AND a quick check on the outlet temperatures showed it wasn’t doing very much. We would always recommend a front mount with the 1HZ if you ever load it up.

We expect the temperature difference to be 50-100degC - more for higher load as front mounts can maintain their efficiency better as the load comes on.

If you are concerned a PDI front mount will put too much heat load in the front of the radiator, we have a smaller core option for low boost applications. Contact us for more information.

At Performance Diesel Intercoolers, we stock a wide range of products for your 80 Series upgrades. From intercoolers, airboxes, MAP sensor filters to diff ratio crown wheel and pinion sets, there is a product suitable for your requirements. We also stock a range of products from other suppliers

Intercooling a turbocharged 1HZ.

For the basic level of upgrade, people have the HZJ105 non turbo engine 40-50kW at wheels and look to bolt on a turbo to double the power (75-80kW at wheels). Next, need to consider an intercooler for power (110-130kW at wheels) as well as to drop EGT.

High combustion temperatures are really the only thing that kills the 1HZ so effort should be made to tune to keep them under control as well as monitor EGT with a gauge or display - PDI have a well price digital display EGT.

1HD-FT upgrades.

The 24V engine drives more like a car than the previous gen (1HDT). these should have around 90kw at the wheels, but lots seem to have around 70kW at wheels. The injection pump can deliver enough fuel to make our 180kw at the wheels, with correct boost and intercooler setup.

A turbo that can boost up to 28psi is a great option for these to achieve the 160-180kw (at wheels). If you want more power and torque, then high flow injectors with a modified injection pump will also be required.

Auto upgrades (A442F 4 speed with 4 and 5 solenoid valve body).

These mods are required to improve transmissions ability to handle the power. This is to reduce time spent between gears as well as having more line pressure to clamp the wet clutches together.

A number of companies are able to provide modified valve bodies but from some testing we did late 2021, we have decided on a improved way to strengthen the box with better line pressure control.

Read more about our recommendations on our news page link HERE

Differential Upgrades.

When you’ve upgraded the power and torque on your engine you may find that it pulls much harder and you are shuffling through the gears constantly. A nice improvement can be to install taller gears to give longer legs in each gear as well as drop your highway cruising RPM. The standard gears can be easily swapped from 4.1 to 3.72 or with more cost (parts) to 3.55 (PDI specific) or 3.909 (are as VDJ79).

Also considering improving traction there are a few ways of going about this. Generally people know that the front diff is an open centre and the rear diff is a LSD, which is probably operating as a open centre with power being sent to the wheel thats easiest to turn. Most people aren’t aware that mechanical LSDs called Torsen (short for torque sensing) exist.

These have become well used in vehicle as they are fully gear driving and can send up to 4 x the torque to the wheel that has traction - from the wheel that is spinning. One should note that if the wheel is spinning with no load then 4x zero is still zero, but this can be overcome by applying the brakes, which should result in forward movement

1HDT upgrades.

The 12V arrangement for the 1HDT means they start choke at high rpm but they tend to be more torquey at lower rpm and therefore can be a great 4WD/offroad engine.

All 1HDT engines were originally fitted with a 12mm head injection pump and as long as the pump isn’t worn, it will deliver enough fuel for you power requirements. High flow injectors aren’t a great plan as they will already start to smoke once the revs come up.

When first released there were issues with big end bearing de-lamination and flakes of the bearing surface would come off. This was not seen in Japan where different oil types were in use. The fix was to install aftermarket bearings like ACL and runs good oils. Some would suggest changing every 100,000km, which isn’t too hard, but might seem a bit excessive.

With the factory turbo going over 12-14psi is risky and may result in turbo failure.

Aftermarket turbos can be bolted on that will give well over 30psi boost, but due to bad experiences lots of companies won’t want to talk about going over 20psi, due to head gasket failure.

ONLY use genuine head gaskets unless you can get something even better

An intercooled setup with 20psi works very well. We have done runs along the beach with the front mounted kit and in soft sand the engine is working hard but the cold side piping and whole intake manifold is cold to touch.

If you want to go with more boost ARP head studs have been shown to give success. It that case I like the idea of running up to 25-27psi using a turbo that is efficient around 25psi. This is to work with the 1HDT characteristics of low rpm torque, but limited flow at the top as the turbo is able to pump more air at 25psi than another that can do a better job at low rpm. This will result in a more linear torque curve.

If rebuilding a 1HDT, I prefer to for a crankshaft from the 1HDFTE or 1hz from the same generation (105 or 79 series) as these are better casings and are stronger. 1HDT crankshafts have a reputation for having cracks in them. Also, if rebuilding, you could use a 1HDFTE head gasket but this will require machining of pistons to get compression correct as the gasket is thinner and will result in higher compression. Always use the later model 1HDT pistons as they burn cleaner and make more power.

Engine Swaps.

The most common swap is to install the Toyota factory turbo engines, being 1HD-T, 1HD-FT (from 80 series) and the most popular 1HD-FTE (from the HDJ100 series or HDJ79).

Other conversion options are a V8 diesel, but these deviate from the design too much and will not compare to power output, given money spent to a modified 1HD engine.

There are a range of other conversions that are done including the Barra turbo engine from the Falcon.

1HDFTE Engine swaps.

Many ways to do this, but doing it right is the important. Installing the engine management system is the part that must be done right for reliability, but deciding what the objectives are is very important so the correct parts can be chosen.

We have done this conversion many times and have helped lots to complete their builds with advise and parts. Working out the power objectives, if you will be towing or want auto/manual transmission is a good place to start. Possibly starting with another body is also worth considering for a cost effective build.