GM LAF Tuning

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

A site visitor recently commented asking for more information on the LAF and how to tune it up and modify it, so this web page has been assembled to go over what we feel are the primary areas we rate and are the optimum tuning modifications you can do to this engine.

The GM LAF really good project engines and with carefully picked modified tuning mods like remapping, turbo improvements and camshafts you will positively maximise your driving enjoyment.

Here we examine the options for your LAF tuning and point out the optimum upgrades.

History of the LAF Engine

Part of the GM ecotec family of engines, the LAF had a revised design, with forged conrods and cast crankshaft as per the original LE5 but used direct injection and a unique piston design to improve efficiency.

  • 2.4 167 hp  230Nm

Tuning the GM LAF and best LAF performance parts.

Best LAF parts

The optimum LAF tuning parts on an engine are obviously the ones that give the best value for money.

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

Fast road cams helps you to boost upper RPM range power so are more suited to petrol engines, than diesel ones. Most cars will see top end power increases through performance camshafts on most engines. So altering your LAF camshaft will make a difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power curve accordingly.

Fast road camshafts commonly bump the bhp and torque throughout the rev band, you might lose a little bottom end power but your high end rpm power will improve.

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

A Competition cam won't do well if driving in heavy traffic.

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

LAF Camshaft Upgrades

Each engine responds differently depending on how well made they are, when camshafts are fitted depending on the camshaft being more or less aggressive camshaft durations and cam profile 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 map and fuelling also have a large bearing on the bhp gains you'll get.

Altering valve durations can alter 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. 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.
  6. Typical stage 1 mods often include: Sports exhaust manifold, Intake headers, Drilled & smoothed airbox, Fast road camshaft, Remaps/piggy back ECU, Panel air filters.

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

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

    The LAF engines respond well to upgrades and we're finding that there are quite a few choices of parts and performance parts out there.

    ECU Mapping Improvements for the LAF

    ECU flashing should help to fully realize the full potential of all the tuning parts you've done to your LAF.

    (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 check it has knock protection and that you get it installed right.)

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

    Air Flow improvements on the LAF

    Pulling more air and fuel into your LAF is the main goal to any performance tuning job.

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

    Design and flow characteristics of the Headers can make a substantial change to fuel atomisation on the LAF.

    Many mass produced engine intake manifold are improved through aftermarket parts, although a few OEM provide fairly well optimized intake manifold.

    Fitting big valve kits, doing a bit of port work and head flowing will also raise bhp and torque, this will give you a better bhp and torque increase on other modifications.

    LAF 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 LAF

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

    If the engine has a turbo already fitted mods are going to net you a larger power gain and we find turbo charged engines are made with better components.

    There are reliable limits for every engine, with some being over specified and some just sufficiently able to handle stock power. Discover these limitations and upgrade to higher quality crank and pistons to utilize the power.

    We've seen guys spending a loads on turbo upgrades on the LAF only to have the motor throw a rod soon after it's completed.

    Big capacity turbochargers often experience low end lag, and little turbochargers spool up more quickly but do not have the peak rpm engines power gains.

    Thanks to progress the market of turbos is always developing and we are seeing variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end power.

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

    It is not unusual that there's a limitation in the air flow sensor AFM/MAP on the LAF when loads more air is being drawn into the engine.

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

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

    LAF Fuelling Upgrades

    You will need to ensure that the engine is not starved of fuel so must look at the fuelling when you start exceeding 20% of a bhp increase. Performance fuel pressure regulators can can improve throttle response.It is important to be generous with your injectors flow rate.

    As a rule of thumb add 20% when fitting an injector, this accounts for injector deterioration and provides some 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.

    LAF Performance Exhausts

    You only need to to upgrade your exhaust if your exhaust is creating a restriction.

    On most factory exhausts you'll see the 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 will reduce the flow rate. Keep the exhaust pipes to around 1.5 to 2.5 inches as a rule of thumb.

    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, but keeps the car road legal. And will allow the full exhaust flow due to it's higher internal surface area and design. The alternative catless mod or catalyst 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 LAF

    The LAF engines are pretty solid and give little trouble as long as they are well maintained.

    Frequent oil changes are essential on the LAF, and more importantly so when the car is tuned and will help maintain the long life of the engine. Always use good quality oil.

    Oil leaks are something to watch out for as the engine ages, gasket failure is the most common issue, but keep an eye on oil levels.

    Carbon build up is a noted problem, this can cause loss of power, misfires and poor idling. This is a common issue on direct injection engines and requires an intake clean. Using good fuel and avoiding short journeys will minimize this problem and issue.

    If you want to know more, or just get tips on Tuning your LAF engine please join us in our friendly forum where you can discuss LAF tuning options in more detail with our LAF 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 readers have got up to and which parts work best for them on each model of car. Comments are used to improve the accuracy of these LAF articles which are continually updated.

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