Modifying and tuning the 1MZ FE engine

"Thank you for reading our guide to the 1MZ FE"

The 1MZ FE engine has a displacement of 3 liters, 2994cc to be exact. It was available in power figures ranging from 168 to 242hp proving itself to be a versatile engine block.

Optimised to be a silky smooth engine, with nice flat torque band the 1MZ FE rewards the tuner with plenty of potential power

The higher power figures tend to come with forced induction.

There are a few supercharger kits around for the 1MZ FE, with the one from TRD which seem to be the most popular manufacturer and this can lift power to around 250bhp, but be careful you don't run lean on your fuelling.

If you fit a supercharger kit like the TRD please make sure your mapping is spot on, most supercharger kits provide an ECU map or plug in replacment with the right setup.

VVTi variable valve timing was introduced on this engine, which helped raise the power.

The 1MZ FE is a solid well built engine, and there is plenty of tuning opportunities, to get a little more from this block.

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Best Engine Mods for your car

  1. Mapping - remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.

Typical stage 1 mods often include:
Panel air filter, Sports exhaust, Lighter flywheel, Piggy back ECU.

Typical stage 2 mods often include: Fast road cam, fuel pump upgrades, Power/Sport clutch, high flow fuel injector, Ported and polished head.

Typical stage 3 mods often include: Engine balancing, Internal engine upgrades (pistons/head/valves), Competition cam, Adding or upgrading forced induction (turbo/supercharger), Sports gearbox.

Remapping the Toyota ECU's is not easy and most go the after market piggy back ECU route to get around this restriction.

There are quite a few available, here are the popular ones but we cannot vouch for them as we haven't formally tested or tried them.

  • Apexi AFC neo
  • Apexi SAFC II
  • Power Enterprise Camcon
  • Megasquirt  MS-I PCB2.2 or PCB3.0

Some come with their own sensors, others work in tandem with your stock ECU sensors. Research them carefully and on the 1MZ FE you really should include one with good knock control especially if you are boosting it.

The exhaust and intake flow play a large part in your cars power band, but be careful here, getting this wrong can upset the idle and make the car impossible to drive in traffic. You'd need to follow a cam upgrade with other mods and finish with a reflashed ECU for the best performance gains.

Don't forget to ramp up the fuelling when you are increasing the power - it makes the car more thirsty.

Frequently power losses, flat spots and erratic idling after uprated parts are done can usually be traced to timing or fuelling issues.To get sufficient fuel you may need to uprate the injectors on your engine.

Boost levels and power increases.

A fast road cam, depending on the profile will add another 10-15% of peak power and seems to be the simplest power mod you can do on the 1MZ FE.

The next area for modification is the intake and exhaust. 

Please note that WE DO NOT FIND IMPROVEMENTS WITH INDUCTION KITS, unless you have tuned your car with over 30 percent more power and are finding that the standard air intake has become limited.

For most 1MZ FE engines TorqueCars would suggest you just go with a washable panel air filter. On heavily tuned engines and turbocharged vehicles an induction kit will help release the power providing you address the problem of supplying cold air to it.

Sports exhausts equal out the flow of air through the engine. But if your exhaust pipe is too big, ie: over 2.5 inches bore, you will lose much of the exhaust flow rate and end up sapping power and torque.

Airflow through the head can be dramatically increased with some professional gas flowing. These should match and be setup to take into account any other engine mods. A good heavy duty fast road upgraded clutch will help to keep that power going where it should. Never make false economies or assume your standard OEM clutch to cope. The best mods we recommend for your 1MZ FE are remaps, sports camshafts and induction improvements.

Adding forced induction

The stock engines power boost limit is around 5-6psi.

4psi will push power to (200 - 240bhp) and if you tune it properly with a piggy back ecu you should hit around (220-260bhp).

5.5psi will provide 190 kw of power but stock fuelling will not cope with this, you'll need larger injectors, fuel pump and a piggy back ECU.

Going over 5.5psi you'll hit detonation problems on the stock engine so should be looking to reduce the compression ratio, maybe even adding water injection or looking a direct cylinder injection as an answer. The Knock sensors will probably also fail to cope with this much boost.

10PSi appears to be the maximum the standard block can handle but at this point you'll have done many mods to the engine, and it would be daft not to have already fitted stronger pistons, toughened crank and connecting rods and adjusted the compression ratio.

When adding forced induction such as a supercharger or tubocharger you really should add an intercooler, to help reduce the high intake temperatures that come with forced induction.

Bear in mind that cars with the 1MZ FE are all front wheel drive, and when you hit 200bhp you start to hit traction issues. There is a practical power limit on a FWD setup. Adding a clever diff and traction control will help but you'll start to be robbed of your power.

Conversion to RWD is the way to go if you want really large power gains.

Problems and weak spots on the 1MZ FE engine block.

Thankfully the 1MZ FE is a very well built reliable engine. But there are a few things to look out for.

Engine oil takes a while to warm up, and as we all know driving a cold engine at high RPM will dramatically increase wear and tear. When the car is used for short drives this slow warm up can create sludge in the oil which will eventually hamper flow and lubrication, so regular oil changes are essential if you only do short journeys. Do not buy a 1MZ FE engine if there is little evidence of regular oil & oil filter changes.

Knock sensors can be a little temperamental causing flat spots in the engine.

If you would like to know more, or just get some friendly advice on Tuning your car please join us in our friendly forum where you can discuss i30 options in more detail with our i30 owners. It would also be worth reading our unbiased Toyota tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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