GM LUK Tuning

"All you need to know about performance tuning the GM LUK engine!"

We were emailed and asked questions for more information on tuning and building a modified LUK and particularly which turbo upgrades work best, so this guide has been assembled which covers our go to modifications for this engine and what we feel are the optimum value modifications you can do.

The GM LUK make awesome project engines and with the right modified tuning mods like ECU maps, turbo kits and camshafts you will noticeably maximise your driving experience.

Here we review and look at LUK tuning and highlight the premier upgrades.

History of the LUK Engine

This is a version of the LEA engine but has been adapted to allow the BAS hybrid drivetrain to be used. It produced 182 hp and 172 lbft of power. The hybrid drivetrain (eAssist) adds around 15hp to the engines output.

The engine is a DOHC, with direct injection and CVVT which offers great fuel economy.

Tuning the GM LUK and best LUK performance parts.

Best LUK tuning mods

The greatest LUK parts on an engine are sensibly the ones that give the biggest return for your cash.

We won't be swayed by popular LUK parts, they need to be cost effective.

Getting a fast road cam will raise the higher RPM power which makes it a best mod for NASP and turbo petrol engines, but not so much on diesels. We've always seen peak power hikes through performance camshafts on most engines

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake & exhaust durations will alter depending on the chosen cam profile, so large engines power gains are on offer for cam upgrades.

Fast road cams tend to increase the bhp across the rpm band, you might lose a little low down power but the top end will be lifted.

Competition cams, increase the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race cam makes it harder when driving in heavy traffic.

You should ideally optimize your torque band to your usage of the car so for a typical daily driver stick with a fast road LUK cam

LUK Camshaft Upgrades

Different LUK engines respond differently depending on how well made they are, when cams are fitted depending on the cam being more aggressive cam durations and cam duration as unique due to manufacturing tolerances and quality variations|so set your engine up on a rolling road|check your engine on a rolling road.

The engine timing and fuel pump and injectors also have a large bearing on the torque gains you'll hit.

Altering valve durations can alter the torque range, and on most engines there are some advantages to extending the intake or exhaust durations and valve lift.

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Best Engine Mods for your GM LUK engine

    1. Engine Tunes - engine tuning/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 filters, Intake manifolds, Fast road camshaft, Drilled & smoothed airbox, Sports exhaust header/manifold, Remaps/piggy back ECU.

Typical stage 2 mods often include: fuel pump upgrades, Sports catalyst & performance exhaust, Ported and polished head, high flow fuel injectors, induction kit, Fast road cam.

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

The LUK engines are great to work on and we note that there is a lot of mods and performance parts around.

ECU Mapping Improvments for the LUK

A remap will help release the full potential of all the parts you've done to your LUK.

(Sometimes flashing the ECU is not an option, so an aftermarket ECU is the route to take, and most of these exceed the specs and prefromance of your factory ECU's but make sure it has knock protection and that you get it setup properly.) It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but your results usually vary depending on the parts you've carried out and the condition of your engine.

Air Flow improvements on the LUK

Forcing fuel and air into the LUK engine is vital to any performance tuning task.

Intake manifolds take the air during the suck phase from the air cleaner and allow it to be drawn into the engine cylinders.

Shape and flow rate of the Intake manifold can make a noticeable improvement to fuel engine efficiency on the LUK.

Commonly we find the plenum chambers are ripe for aftermarket tuning parts, although a few makers provide reasonably well designed plenum chambers.

Adding a LUK big valve conversion, getting port work and head flowing will also improve performance, and more importantly will allow you to get an improved performance increase on other upgrades.

LUK Turbo upgrades

NA (naturally aspirated) 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 LUK

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

If a car is turbo charged upgrades are more reliable and we find turbocharged engines are made using better components.

There are common areas of failure for every engine, with some being incredibly solid and some only just able to handle stock power. It is important to find these limitations and install higher quality components to utilize the power.

We see many tuners spending a loads on turbo charger upgrades on the LUK only to watch the engine block explode just after it's used on the roads.

Bigger upgraded turbo units will usually suffer no power at low rpm, and low capacity turbo units spool up really quickly but don't have the peak rpm engines power gains.

Thanks to new tech the world of turbos is always moving on and we commonly find variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust flow into two channels and feed these at differently profiled vanes in the turbo charger. They also boost the scavenging effect of the engine.

You'll commonly see there's a limit in the air flow sensor AFM/MAF on the LUK when a lot more air is being drawn into the engine.

We note 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 difficult to get working. We have this feature on twinchargers if you want to read more.

LUK Fuelling Upgrades

When you increase the torque you will need to look at to the fuelling.

More torque needs more fuel. Performance fuel pressure regulators can can improve throttle response.We would recommend you to be generous with your flow rate on the injectors.

The rule of thumb is to add 20% when fitting an injector, which takes into account injector deterioration and affords some spare capacity should the engine require 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.

LUK Performance Exhausts

Only look to increase your exhaust if the existing exhaust is actually creating a flow problem.

On most factory exhausts you should find that the exhaust flow rate is still ok 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 increase the flow of air through the engine.

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

Typically exhaust restrictions come around the emissions filters installed, so adding a freer flowing high performance aftermarket catalyst improves flow, and rather than doing an illegal catalyst removal, will keep the car road legal. We note that performance catalysts and filters perform comparably to decat and have the added benefit of keeping your car street legal, as decat or catalyst removal is not a street legal modification.

Weak spots, Issues & problem areas on the LUK

The LUK engines are reasonably reliable and solid as long as they are regularly serviced. Neglect oil changes and servicing and you'll be storing up a host of problems for yourself later on.

Carbon build up in the head, particularly around the valves which will reduce power, this is a very common problem on direct injection engines but should be looked out for on all engines and the LUK is no exception. We have tips in our intake cleaning guide. By avoiding short journeys on a cold engine and using good quality fuel you can reduce this risk.

Service time oil changes are essential on the LUK, and more so when the car is modified and will help prolong the life of the engine.

Oil leaks around the valve cover gasket are quite common and these tend to escalate in seriousness as oil is lost from the engine and wear and tear is exacerbated.

If you want to learn more, or just get more pointers on Tuning your LUK engine please join us in our friendly forum where you can discuss LUK tuning options in more detail with our LUK owners. It would also be worth reading our unbiased GM tuning articles to get insights into each modification and how effective they will be.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our users have got up to and which upgrades work best for them on each model of car. We use your comments and feedback to improve the accuracy of these LUK tuning guides which get regular updates and revisions.

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