Modding upgrading and tuning the Toyota UZ engine!

Tuning guide "UZ Modifications"

UZ Modifications Guide

How to modify and upgrade the Toyota UZ

"Comprehensive guide to tuning the Toyota UZ engine!"

Our friends at TorqueCars are always seeing threads asking about how to improve the UZ from people wanting to know what are the best tips on UZ modifications. So let us look into Toyota UZ modifications and outline the best modifications on this great engine and point out some problems along the way.

The Toyota UZ are good project engines and with the best modified tuning mods like a remap, turbo upgrades and camshafts you will dramatically enhance your driving opportunities.

Our aim here is to detail the best approach to UZ tuning and provide tips on the premier upgrades.

When talking about the best parts for your UZ engine, we are going to focus on the parts that give the best value for money.

UZ induction kits

Improving air intake on the UZ

You need fuel and air for an engine to work. If there is too little fuel then it will run lean, if there is a lack of air it runs rich sapping power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the primary aim to any engine performance tuning job to pull more fuel and air into your UZ but this has a knock on effect with the air flow sensor.

It is not unusual that there is a limitation in the air flow sensor AFM/MAF on the UZ when loads more air is being sucked into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped performance at a much lower level.

Air Intake manifolds take the air from the filter and allow it to be drawn into the engine cylinders.

The size of bore and shape and rate of flow of the Air Intake manifolds can make a large effect on to fuel engine efficiency on the UZ.

Commonly we find the intake are in dire need of performance upgrades, although a few car makers provide decently flowing intake.

Increasing the UZ valve size, carrying out UZ port enlargement and head flowing will also increase power, & importantly will make space for a greater power increase on other mods.

UZ performance cam tips.

Some UZ engines respond better to different cam durations check your engine on a rolling road.

The ECU mapping and injectors and fuel pump also have an effect on the bhp gains you'll achieve.

Extending exhaust or intake durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

Altering your UZ cam will make a dramatic difference to the engine engines power. Choosing a higher performance cam profile raises the engines power accordingly.

NB: Fast road camshafts usually boost the bhp and torque across the rev band, you may sacrifice a little low down bhp but the high end rpm power will be better.

Competition camshafts, boost the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport camshaft is not great on the daily commute.

You should ideally optimize your engines power to your usage of the car so for a car used daily stick with a fast road UZ camshaft

Stage 1, 2 and 3 mods for the UZ

Stage 1 UZ parts:

Intake headers, Fast road camshaft, Remaps/piggy back ECU, Sports exhaust manifold, Drilled & smoothed airbox, Panel air filters.

Stage 2 UZ parts:

fuel pump upgrades, Fast road cam, Ported and polished head, high flow fuel injectors, induction kit, Sports catalyst & performance exhaust.

Stage 3 UZ parts:

Competition cam, Twin charging conversions, Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger).

Carefully think through your options and then buy your parts and set yourself a power target to avoid expensive mistakes.

Remaps will help to establish the full potential of all the modifications you've done to your UZ.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage usually differs on the modifications you've carried out and the condition of your engine.

Turbo modifications on the UZ

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the UZ.

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.

If the engine is fitted with a turbo upgrades are relatively easy and you will discover turbo charged engines use better components.

However you'll find engines will need better parts at higher power limits

Discover these limitations and fit higher quality components to survive the power.

We've seen drivers spending a lot of money on turbo charger upgrades on the UZ only to experience the car go up in smoke just after it's completed.

Large upgraded turbo chargers often suffer low end lag, and little turbo chargers spool up more quickly but do not have the top end torque gains.

In recent times the market of turbochargers is always improving and we commonly find variable vane turbochargers, permitting the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbochargers divert the exhaust gases into two channels and feed these at differently angled vanes in the turbo. They also improve the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large bhp gains, although more complex to get working. We have this article on twincharging if you want to read more.

Tips about fuel supply on the UZ

You will need to ensure that the engine is not starved of fuel so must look at the fuelling when you start exceeding 20% of a bhp and torque hike. It makes sense to be generous with your flow rate on the injectors.

The accepted safe increase is to add 15% to the flow rate when buying an injector, this allows for injector deterioration and gives you some spare capacity should the engine need more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended UZ performance exhaust upgrades

Only look to increase your exhaust system with an upgraded one is if your exhaust is actually creating a restriction.

On most factory exhausts you'll see the exhaust flow rate is fine even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts increase the flow of air through the engine.

But if the exhaust is too large, ie: over two and a half inches diameter, you will lose a lot of the exhaust flow rate and end up losing power and torque.

The usual suspects causing problems in your exhaust flow rate are in the emissions filters installed, so adding a higher flowing performance alternative will help avoid this restriction.

Cat bypassing (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the UZ

Like most engines an UZ, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the UZ, failure to do this will exacerbate engine wear, on a tuned UZ this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your UZ why not pop over to the forums at TorqueCars where you can chat about UZ tuning options and read about others projects who may be planning to do similar modifications on their UZ.

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