Whats the best and how do you get decent,reliable power out of any engine? By Steve Collins.

Speak to many 4WDers as we do and you soon learn there is a common desire for more power no matter what you drive. Its not surprising really,given that 4x4's are great big lumps of steel with the aerodynamics of a brick. Sure,they're designed to go anywhere,but no-one said anything about doing it fast. Petrol Vs Diesel,gee,that's a bloody can of worms. Diesel owners swear by their choice 'cause they've got more torque down low,use relatively less fuel,and are dead-simple (easier to fix in the bush). Petrol owners are first to bring up cheaper servicing costs,they're better on boggy terrains like sand and mud,and they can cope with the odd batch of dodgy fuel. So which is really best? And can you get reliable,efficient power increases from either engine?

The short answer is both engines have severe strengths and weaknesses,but reliable power is available to everyone. Talk to 50 different engine builders about what'll give you the best performance increase and you'll get 50 different answers. There are so many variables that mean deciding which way to go can be a real pain in the back-side. Plus,you've got to think about what each modification means in terms of flow on work (like fitting a turbo means modifying the exhaust and intake to suit). So where do you start?

I think of it this way-the world's most powerful engine is worth diddly-squat if it blows up the first time you squeeze the pedal-so an engine health check should be first up. Performing a leak-down test,compression test and radiator pressure test will give you an idea of the condition of the valves,pistons and head gasket (to some extent),then analysing the oil will give you an idea of how worn high-friction surfaces like your bearings are. Of course a visual inspection is always better,so if you've got the money,your best bet is to crack it open and give it a freshen-up,particularly if you're looking to extract a few extra ponies.
As we know,engines rely on a mix of air,fuel and timing to make power,so this where you'll make the best 'bang for bucks' gain. Manufactures usually build engines within reliability,pollution and budget restrictions. To make an engine quite,most will fit restrictive mufflers,smaller intake pipes and hide the intake within the wheel-well through a maze of pipework.

Instantly that means nearly every engine will benefit from a high-flow exhaust system,snorkel and intake pipework that removes unwanted bends. The next step is turbocharging (or supercharging),increasing the fuel injection capacity and getting it tuned to suit. The more air and fuel you can cram in with each stroke means each bang is bigger. Carbies,early EFI petrol's and mechanical-injection diesels are all relatively limited in tuning potential,so best bang-for-buck results usually lie in fitting a torbocharger and upping the fuel supply. Modern petrol and diesel engines,on the other hand,often come from the factory with highly engineered turbochargers and fuel injection systems that have little room for improvement,so easy gains on these will be made through fine-tuning the engine management first,then going down the other paths if your still not happy.

There's an old saying that goes 'the cheap man pays twice' When it comes to engine upgrades this couldn't be truer. A cheap air filter has the potential to write off your entire engine,as does a fuel filter,inferior turbo or dodgy tune. Before doing anything,it pays to get your engine checked by a specialist,and do your own research and ask around to make sure you're being led down the wrong track. Get all modifications done by an expert (someone that specialises in your make and model is best) then get it dyno-tuned to suit the modifications afterwards-no matter how small a difference you might think it makes.

This article is probably not much use to the more experienced engine guys on the forum,but i thought i would post it for the more novice owner. But there is still some good info in there for just about everyone.