Tuning the Toyota 5A

"Comprehensive guide to tuning the Toyota 5A engine!"

In this article we examine 5A tuning and report on the best mods that work. Toyota 5A are good project engines and with the best modified modifications like remaps, turbo improvements and camshafts you will positively increase your driving enjoyment.

Just because particular modifications are popular with 5A owners it doesn't mean its worth having, instead we will highlight what we would class as the best modifications that will give your 5A the best power gain for you money.

Altering your 5A camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road camshafts normally boost the torque over the rpm band, you may sacrifice a little bottom end power but higher rpm power will be higher.

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

A Competition cam is not great in heavy traffic.

You should ideally match your bhp range to your usage of the car so for a typical daily driver stick with a mild fast road 5A cam

Some 5A engines respond better to more aggressive cam durations than others.

The ECU mapping and injectors and fuel pump also will say much on the power gains you'll make.

Altering valve durations can alter the power 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.

Stage 1 modifications: Intake headers, Sports exhaust manifold, Remaps/piggy back ECU, Fast road camshaft, Panel air filters, Drilled & smoothed airbox.

Stage 2 modifications: Sports catalyst & performance exhaust, Ported and polished head, Fast road cam, fuel pump upgrades, induction kit, high flow fuel injectors.

Stage 3 modifications: Adding or Upgrading forced induction (turbo/supercharger), Twin charging conversions, Crank and Piston upgrades to alter compression, Competition cam, Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves).

ECU flashing will help release the full potential of all the parts you've fitted to your 5A.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved may rely on the parts you've applied and the condition of your engine.

Pulling more fuel and air into the 5A engine is the aim to any engine performance tuning job.

Intake headers flow the air from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

Design and flow rate of the Air Intake manifolds can make a noticeable difference to to fuel mixing and power on the 5A.

We often see air intake manifolds are crying out for motorsport parts, although some car makers provide decently flowing air intake manifolds.

Larger 5A valves, getting port matching and head flowing will also improve bhp, & importantly will allow you to get raising the bhp increase on other mods.

Turbo upgrades

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your 5A

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.

When a car has a turbocharger parts are relatively easy and you will discover turbo charged engines are made using harder and stronger components.

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

See where you'll find these limits and upgrade to better pistons and crank to survive the power.

There are many people spending a lots of money on turbo upgrades on the 5A only to suffer the indignity of watching the engine block catastrophically fail when it's used in anger.

Big upgraded turbos will usually suffer no power at low rpm, and smaller turbos spool up much more quickly but do not have the peak rpm bhp gains.

In recent times the selection of turbo chargers is always developing and we commonly find variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbo chargers divert the exhaust flow into two channels and push these at differently designed vanes in the turbo. They also help the scavenging effect of the engine.

It is not unusual that there is a limitation in the air flow sensor (AFM/MAF/MAP) on the 5A when a lot more air is being pulled into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited torque at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to configure. We have this feature on twinchargers if you want to read more.

Fuelling upgrades and mods

When you increase the bhp you will need to ramp up to the fuelling.

More bhp needs more fuel. We strongly recommend you to over specify your flow rate on the injectors.

As a rule of thumb add another 20% when fitting an injector, this accounts for injector deterioration and affords a bit of spare capacity should the engine need more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Exhaust upgrades and mods

You may need to boost your exhaust if the current exhaust is actually causing a flow problem.

On most factory exhausts you should find that your flow rate is fine even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts can help increase the flow of gases through the engine.

But if your exhaust pipe is too large, ie: it's over 2.5 inches bore, you will lose a great deal of the flow rate and end up lacking power and torque.

Usual exhaust restrictions can be traced to the catalysts installed, so adding a freer flowing race alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the 5A

The 5A engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the 5A, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

History of the Engine

The 5a launched in 1987  and production ran to 2006. it came with DOHC and 4 valves per cylinder, was revised over the years with 3 versions released.

5A-F 85 hp 90 lbft

• AT170 Carina 1988–1990 (Japan only)
• AE91 Corolla 1987–1989 (Japan only)
• AT170 Corona 1987–1989 (Japan only)
• AE91 Sprinter 1987–1989 (Japan only)

5A-FE 104 hp 97 lbft

• AT170 Carina 1990–1992 (Japan only)
• AT192 Carina 1992–1996 (Japan only)
• AT212 Carina 1996–2001 (Japan only)
• AE91 Corolla 1989–1992 (Japan only)
• AE100 Corolla 1991–2001 (Japan only)
• AE110 Corolla 1995–2000 (Japan only)
• AE100 Corolla Ceres 1992–1998 (Japan only)
• AT170 Corona 1989–1992 (Japan only)
• AL50 Soluna 1996–2003 (Asia)
• AE91 Sprinter 1989–1992 (Japan only)
• AE100 Sprinter 1991–1995 (Japan only)
• AE110 Sprinter 1995–2000(Japan only)
• AE100 Sprinter Marino 1992–1998 (Japan only)

5A-FHE 120 hp

• AE91 Corolla 1989–1992 (Japan only)
• AE91 Sprinter 1989–1992 (Japan only)
• AE91 Toyota G Touring 1994–1999 (Japan only)
• AE100 Toyota G Touring 1994–1999 (Japan only)

For more information on Tuning your 5A engine please join us in our friendly forum where you can discuss tuning options in more detail with our 5A owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help improving this article, so please send us your feedback in the comments box below and pass on any tips, points or facts we have wrong or have not covered.

We really like hearing from our readers, and hearing about which parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our 5A guides and tips are kept up to date.

Please Check out my YouTube channel, we're regularly adding new content...

Click to accept YouTube Cookies & Play.

This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Toyota. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.