Performance Upgrades

SD33

It is possible to increase the performance of a NA SD33 engine, however the gains are minimal and the end result would still not be as good as a stock turbo engine.

Extractors are available for this engine, and when coupled with an upgraded exhaust can get the engine revving easier and making more power. Improving the air intake to the engine (ie higher flowing filter, cold air intake) would also improve power. To make the most of these mods, the fuel could be increased slightly.

The NA engine would also benefit from the modifications listed below in the ‘Other’ section.

SD33T

Turbo Upgrade

Refer to the dedicated wiki page.

Boost Increase

TBA

Intercooling

Refer to the dedicated wiki page

Exhaust Upgrades

3” dump pipe is a popular mod. Refer this thread: http://www.patrol4x4.com/forum/nissan-patrol-mq-mk-12/diy-mainfold-gasket-3-zorst-61334/

Fuel Mods

None have been found.

Intake Mods

None have been found.

Other Common Mods

The mods listed above are the common upgrades to a turbo engine. If you wanted to go to the extreme with your engine though, here are some more ideas.

Diesel Gas

This provides great gains in power and economy on other diesel engines, so there is no reason why it wouldn’t work on an SD33. Quoted from wikipedia; The above systems add small quantities of LPG with the primary aim of improving economy, but much larger quantities of LPG can be injected in order to increase power. Even at full output a diesel engine runs about 50% lean of stoichiometric to avoid black smoke production, so there is a substantial amount of oxygen in the intake charge which is not consumed in the combustion process. This oxygen is therefore available for the combustion of a substantial addition of LPG resulting in a large increase in power output.

Exhaust Heat Management

Keeping the heat in the exhaust manifold and preventing it from heating the engine bay is important for all engines. If the exhaust is unprotected, the heat can increase the temperature of the intake manifold and incoming air. This means less oxygen into the engine. In extreme cases, the fuel can get hot and expand, similarily effecting performance.

Keeping the heat contained within the exhaust keeps the intake cooler. The hotter exhaust gasses also move faster, providing a 2-fold performance increase. On a turbo engine, the hotter and faster moving exhaust gases will provide further benefits, as the turbo will spool earlier and faster.

There are a number of ways to contain the heat. The cheaper option is to use an exhaust wrap, which is basically a cloth tape wrapped around the exhaust. This has some disadvantages, as it can look bad and some people report it corrodes the wrapped metal rather quickly. The more expensive option of ceramic coating does not have these problems and can also be applied to intakes (keep the heat out) and also turbo housings.

Electric Water Pump

The standard water pumps are belt driven and this drains a few horsepower from the engine. Replacing the water pump with an electric alternative will restore this power and often make the engine more responsive (‘snappier’). Electric water pumps can also improve engine cooling. Belt driven pumps are tied to the engine speed. At idle, the stock pump may not have sufficient flow, whereas at high RPM it may flow too fast. The electric pumps keep the coolant flowing at a steady and optimum rate at all RPMs.

There are 2 options available for the SD33. First is an in-line pump such as the Davies Craig, which gets mounted in the bottom radiator hose. Second is a kit which uses an electric motor mounted to the front of the engine, which then drives the stock water pump.

Electric (Thermo) Fans

Similar to the water pumps discussed above, the stock fan is belt driven and this drains a few horsepower from the engine. Replacing the fan with an electric alternative will restore this power and often make the engine more responsive (‘snappier’).

Reducing Other Engine Drain

Further to the water pump and thermo fans discussed above, there are also other items that drain power on the SD33. If you wanted to maximise every horespower, take the following into consideration.

The alternator places a fairly constant load on the engine, especially if running a big stereo, spot-lights etc. If your vehicle was purely a weekend-warrior, and you could make do without a stereo or driving lights, you could effectively get rid of the alternator all together. If your car sees regular use, upgrading your alternator to a new design may save some power due to efficiency increases.

The MQ Patrols are available with manual steering. Removing the power steering setup from your vehicle would free up some more power. Similarily, removing air-con will have a positive effect.

As you can see, it is possible to remove all accesories from your SD33 and still have a functioning vehicle. You could even remove the pulley from the engine all together (but should still keep the balancer, presuming these are seperate items).

Lastly, you could lighten the flywheel or even use the smaller (ie lighter) NA clutch.