GM L36 Tuning

"All you need to know about performance parts and tuning the GM L36 engine!"

We were emailed for more information on tuning and building a modified L36 and particularly which turbo upgrades work best, so we've put together this page that covers our go to parts for this engine and what we feel are the ultimate value parts you can do.

We shall review L36 tuning and summarise the best mods that work. GM L36 have loads of potential and with the best uprated tuning mods like remapping, turbo kits, and camshafts you will greatly enhance your driving opportunities.

History of the L36 Engine

Compression ratio was set to 9.4:1 in the L36 compared with 8.5:1 for the L67 (which was  essentially a supercharged version of the L36). The engine appeared in 1995.

  • 1996–2005
    Buick Park Avenue Ultra
  • 1997.5–2004
    Buick Regal GS / GSE / GSX (SLP)
  • 1996–1999
    Buick Riviera (optional 1996-97, std. 1998-99)
  • 2004–2005
    Chevrolet Impala SS
  • 2004–2005
    Chevrolet Monte Carlo SS Supercharged
  • 1996–2003
    Pontiac Bonneville SSEi
  • 1997–2003
    Pontiac Grand Prix GTP / GTX (SLP)
  • 1996–2004
    Holden Commodore VS (series II), VT, VX, VY
  • 1996-2004
    Holden Caprice and Statesman VS (Series I, II & III), WH, WK
  • 2001–2004
    Holden Monaro (V2) CV6

Tuning the GM L36 and best L36 performance parts.

Best L36 upgrades

When talking about the best modifications for your L36 engine, we are going to focus on the mods that provide the biggest return for your cash.

Getting a fast road cam will work better at higher RPM power and are better suited on petrol engines, than diesels. This will usually provide good top end power gains 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 usually boost the performance through the rpm range, you might lose a little bottom end torque but your high end rpm power will improve.

Motorsport cams, boost the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race camshaft is not great in heavy traffic.

You should ideally optimize your engines power to your usage of the car so for a car used daily stick with a fast road L36 camshaft

L36 Camshaft Upgrades

Different L36 engines respond differently primarily due to the airflow when camshafts are fitted depending on the camshaft being more extreme camshaft durations so view each engine and camshaft as unique due to manufacturing tolerances and quality variations so check your engine on a rolling road.

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

A longer valve duration can amend the power curve, 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: Remaps/piggy back ECU, Panel air filters, Fast road camshaft, Sports exhaust header/manifold, Drilled & smoothed airbox, Intake manifolds.

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

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

    The L36 power plant respond well to upgrades and we're pleased to see that there is a growing number of parts and tuning parts out there.

    ECU Mapping Improvements for the L36

    Remaps allows a tuner to unlock the full potential of all the upgrades you've fitted to your L36.

    (Sometimes chip tuning the ECU is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it correctly setup.)

    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 upgrades you've applied and the condition of your engine.

    Air Flow improvements on the L36

    It is the whole point to any engine tuning task to get air and fuel into your L36

    Air Intake manifolds take the air from the air cleaner and allow it to be drawn into the engine and mixed with fuel.

    Shape and flow characteristics of the Intake manifolds can make a substantial change to fuel engine efficiency on the L36.

    Many mass produced engine plenum chambers are begging for aftermarket tuning parts, although some manufacturers provide well optimised plenum chambers.

    Increasing valve sizes on L36, carrying out L36 port enlargement and head flowing will also lift torque, and significantly will afford you increasing the torque increase on other tuning mods.

    L36 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 L36.

    We note that Gm reduced the 9.4:1 compression ratio in the L36 compared to 8.5:1 for the L67 when they supercharged it, and the lower compression sets the car up nicely for some extra boost.

    One of our members was fitting a twin turbo setup to his 3.8 L36 Ecotec V6 and his plan included the following parts and specs, but as far as we know this project hasn't yet been finished, and there is quite a lot of work turbocharging your L36.

    • 2x TD05h-16G Mitsubishi turbos, 2x Tial 38mm external waste gates (8psi springs), Tial BOV, Autometer Boost and Oil gauges, Gaskets, Flanges iv fabricated, 500cc + injectors.

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

    When a car is turbo charged tuning parts are going to net you a larger power gain and you will discover turbocharged engines are made using better components.

    However every engines have weakspots. Research these limitations and upgrade to forged components to utilize the power.

    It's not unheard of people spending a loads on turbo charger upgrades on the L36 only to suffer the indignity of watching the car throw a rod on it's first outing after it's used in anger.

    Larger turbo units commonly experience no power at low rpm, and smaller turbo units spool up more quickly but don't have the high rpm power band gains.

    Thanks to new tech the selection of turbo units is always evolving and we are seeing variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end bhp.

    Twin scroll turbo units divert the exhaust flow into 2 channels and direct these at differently profiled vanes in the turbo charger. They also boost the scavenging effect of the engine.

    It is common that there's a limit in the air flow sensor (AFM/MAF/MAP) on the L36 when loads more air is being pulled into the engine.

    You'll see that 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 power gains, although more challenging to configure. We have this in depth look at twinchargers if you want to read more.

    L36 Fuelling Upgrades

    Don't miss you'll need to increase the fuelling when you are increasing the bhp - it makes the car more thirsty. Performance fuel pressure regulators can can improve throttle response.Most tuners we speak with say to over specify your injectors flow rate.

    The rule of thumb is to add 20% to the flow rate when specifying an injector, helps cope with injector deterioration and gives you 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.

    L36 Performance Exhausts

    Only look to increase your exhaust if the existing exhaust is creating a restriction.

    On most factory exhausts you should find that your 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.

    Note that with the widest exhaust you can find this will slow up the exhaust flow rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

    Usual exhaust restrictions come around the filters installed, so adding a freer flowing sports aftermarket catalyst unlocks that lost power, and rather than doing an illegal decat, will keep the car road legal.

    We should explain that performance catalysts perform comparably to decat and have the added benefit of keeping your car street legal, as decat or catalyst removal is illegal in most territories.

    Weak spots, Issues & problem areas on the L36

    The L36 engines are not bad as far as reliability goes as long as they are regularly serviced and maintained.

    Frequent oil changes are highly recommended on the L36, and more importantly so when the car is tuned and will help prolong the life of the engine.

    If you want to learn more, or just get tips on Tuning your L36 engine please join us in our friendly forum where you can discuss L36 tuning options in more detail with our L36 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 hearing what our visitors 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 L36 tuning guides which get regular updates and revisions.

    Please Check out my YouTube channel, we're regularly adding new content...

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