GM L2B Tuning

"All you need to know about tuning and performance parts on the GM L2B engine!"

As many of our site visitors have asked questions about the L2B and recommendations on how to modify one, so we've created this guide which covers our go-to modifications that make for improvement and tuning success on this great car.

The GM L2B makes a good tuning project and with the best upgrades like remaps, turbo kits and camshafts you will dramatically improve your driving enjoyment.

TorqueCars will detail the best approach to L2B tuning and show the ultimate upgrades.

History of the L2B Engine

  • L2B 1.5 L (1,485 cc) 85 kW (116 PS; 114hp @6000 rpm 144Nm (106 lbft @3800 rpm

Tuning the GM L2B and best L2B performance parts.

Best L2B mods

When talking about the top modifications for your L2B engine, we are going to concentrate on the ones that give the best power gain for you spend.

Getting a fast road cam will come into their own at top end power and are better suited on petrol engines, than diesels. Most cars will see top end power increases through performance camshafts on most engines.

Significant gains on the L2B can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

Fast road camshafts usually bump the bhp and torque through the rpm band, you might lose a little low down bhp but your top end will improve.

Race camshafts, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Race camshaft will just annoy you whilst on the daily commute.

You should ideally optimize your bhp range to your usage of the car so for a typical daily driver stick with a shorter duration L2B camshaft

L2B Camshaft Upgrades

Different L2B engines respond differently primarily due to the airflow when cams are fitted depending on the cam being more or less aggressive cam durations and cam duration as unique due to manufacturing tolerances and quality variations so set your engine up on a rolling road.

The ecu map and fuel pump and injectors also will make differences on the bhp gains you'll hit.

Extending exhaust or intake durations can amend the bhp band, 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 car

  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.
  6. Typical stage 1 mods often include: Sports exhaust header/manifold, Fast road camshaft, Remaps/piggy back ECU, Panel air filters, Drilled & smoothed airbox, Intake manifolds.

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

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

    The L2B units are fantastic to work on and we're happy to report there is a growing number of upgrades and performance parts around.

    ECU Mapping Improvements for the L2B

    ECU flashing allows a tuner to to establish the full potential of all the parts you've done to your L2B.

    (Sometimes engine tuning/remapping the ECU is not an option, so an aftermarket ECU is the route to take, and most of these exceed the specs and performance of your factory ECU's but check 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 rely on the parts you've fitted and the condition of your engine.

    Air Flow improvements on the L2B

    It is the main goal to any engine upgrade task to get fuel and air into each cylinder

    Intake manifold take the air from the air cleaner and allow it to be drawn into the engine cylinders.

    Design and flow rate of the Plenum can make a substantial effect on to fuel atomisation on the L2B.

    Commonly we find the intake manifold are ripe for aftermarket parts, although a few makers provide reasonably good intake manifold.

    Increasing valve sizes on L2B, carrying out L2B port enlargement and head flowing will also raise bhp, and importantly will allow you to get a greater bhp increase on other tuning mods.

    L2B 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 L2B

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

    If a car is turbocharged parts are going to net you a larger power gain and most turbocharged engines are made using stronger components.

    However you will find engines will need better parts at higher power limits. It is important to find these restrictions and upgrade to better quality components to utilize the power.

    We see many tuners spending a fortune on turbocharger upgrades on the L2B only to have the engine catastrophically fail when it's been finished.

    Larger upgraded turbochargers commonly experience a bottom end lag, and low capacity turbochargers spool up more quickly but won't have the high rpm torque gains.

    Thanks to progress the selection of turbos is always improving and we now see variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

    Twin scroll turbos divert the exhaust gases into 2 channels and flow these at differently designed vanes in the turbo. They also help the scavenging effect of the engine.

    It is common that there's a restriction in the air flow sensor MAF/MAP on the L2B when a lot more air is being sucked into the engine.

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

    Adding a supercharger or additional turbo will make large bhp gains, although more challenging to get working. We have this feature on twinchargers if you want to read more.

    L2B Fuelling Upgrades

    Don't dismiss the need uprate the fuelling when you are increasing the torque - it makes the car more thirsty. Fuel pressure boost valves raise the fuel pressure, can improve throttle response.Most tuners we speak with say to over specify your injectors flow rate.

    The accepted safe increase is to add 20% to the flow rate when specifying an injector, this accounts for injector deterioration and allows 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.

    L2B Performance Exhausts

    You may need to uprate your exhaust if your current exhaust is actually creating a restriction.

    On most factory exhausts you'll see 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 generally help improve air flow from the engine but do not go too big or you may end up choke your flow rate. Stay at around 1.5 to 2.5 inches for best results.

    For road going cars mods such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed.

    This keeps the car road legal and will allow the full exhaust flow due to it's higher internal surface area and design. The alternative decat or cat removal should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars (and in some you can't even replace a working catalyst).

    Weak spots, Issues & problem areas on the L2B

    The L2B engines are not bad as far as reliability goes as long as they are regularly serviced and maintained.

    Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

    Service time oil changes are vital on the L2B, especially when tuned and will help ensure reliability of the engine.

    If you want to disover more, or just get feedback on Tuning your L2B engine please join us in our friendly forum where you can discuss L2B tuning options in more detail with our L2B 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 appreciate people taking the time to tell us what our users have got up to and which mods work best for them on each model of car. We use your comments and feedback to improve the accuracy of these L2B tuning guides which get regular updates and revisions.

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