1UZFE Engine Tuning

"Thanks for reading our Toyota 1UZFE tuning tips."

The 1UZFE is Toyota's 4.0 V8 engine, built primarily from aluminium and it sported a DOHC configuration (unusually for a V8). Between 1990 and 1995, looking under the Plenum, you'll see the 1UZFE had a cold start injector that kicks in at temperatures below freezing.

The compression ratio of 10.0:1 256 hp; 260lbft The 1UZFE is a well-built solid engine with plenty of tuning possibilities, with an additional 10-40% extra power just asking to be released.

• 1995 revisions include a lighter pistons and con rods and higher compression ratio 10.4:1, raising power to 256hp 260lb ft of torque.
• 1997 saw the introduction of the VVTi valve timing system and another bump in compression ratio to 10.5:1 (The GS400 model saw power hit 300hp and 210 lbft thanks to a few tweaks.)

The 1UZFE  was shipped in quite a few popular car models from Toyota and Lexus, and has been tweaked and revised over the years.

Tuning the 1UZFE engine

Thanks to a fast road camshaft, intake and exhaust updates, fuel streaming and porting head operation, and then balancing and blueprinting the engine to boost the redline, we have seen ventures hiking power on the NASP blocks to about 350bhp.

The firing order is 1-8-4-3-6-5-7-2 on these

Fast road cam profiles range from the mild 260/268 to the more extreme 298/298 and lift ranges from 9.35mm to 10.7mm

• Stage 1 mods: Intake manifold, Sports exhaust, Panel air filter,  Lighter flywheel, Piggy back ECU.
  (10% more power approx)
• Stage 2 mods:  Power/Sport clutch, high flow fuel injector, Fast road cam, fuel pump upgrades, Ported and polished head. Piggy back ECU.
  (This should give around 15% more power)
• Stage 3 mods: Engine balancing, Internal engine upgrades (pistons/head/valves), Competition cam, Adding or upgrading forced induction (turbo/supercharger), Sports gearbox. Piggy back ECU.
  (Power gains from 20-40% are achievable here)

Reprogramming the Toyota ECU's is not all that easy if not impossible. So you need to go the after market piggyback 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

Just ensure you get an aftermarket/piggyback ECU that supports good knock control, especially if going the forced induction route.

The early 1UZFE blocks with the lower compression really lend themselves to adding forced induction, they had stronger pistons. Just stick with a low boost, or remote turbo setup.

Maximum power gains come from a full induction system that feeds cold air on highly tuned motors, this can be put inside an air tank, but for most applications a panel filter should be appropriate. TorqueCars recommends that you use a panel air filter as it is easy to clean and manage and is generally better than paper filters.

Sports exhausts can usually air flow from the engine but avoid an exhaust that is too big or you may end up will reduce the flow rate. Stick to 2 to 2.5 inches for best results.

Head porting and polishing the head will allow you to maximise your air/fuel charge. Leave this to a professional though with a proper flow bench and machine tools

Best mods for the 1UZFE Engine

The best mods in our opinion for your 1UZFE are a remap, adding forced induction, a fast road camshaft and a sports exhaust, with a good air intake.

NASP engines do not achieve big power gains if you remap them, unless you have done extensive modifications.

Despite the huge cost involved and time it takes, adding forced induction to a NASP engine will give large power gains. Superchargers are usually easier to add than turbos.

We've also come across some owners toying with  twincharging conversions and making some impressively high power gains.

The nice steady boost and rpm characteristics of the supercharger make them easier to map. Adding forced induction will often require a lower compression ratio or if you are adding forced induction, so you'll need a stroker kit, and lower compression pistons or explore water injection.

Turbos provide boost in exponential proportion to increasing engine speed and this can make mapping difficult.

We think supercharger kits are a lot easier to setup on the 1UZFE rather than a turbocharger, but we've seen both achieved very well.

Expect to need to decrease the compression ratio if you are adding forced induction, so you'll need a stroker kit, and lower compression pistons.

The bottom end in the 1995 engines are prone to fail when hitting power regions of 400bhp, even the original blocks will struggle a little, so engine strengthening makes a lot of sense.

1UZFE engine problems

Valve adjustments required as part of the service.

Generally a very reliable engine, if serviced correctly.

Timing belt snapping can cause extensive damage on the VVTi engines

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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.

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