Chevrolet F18D3 Tuning

"All you need to know about performance tuning the Chevrolet F18D3 engine!"

Herein we consider F18D3 tuning and highlight the greatest upgrades. Chevrolet F18D3 really good project engines and with the ultimate tuning enhancements like remapping, turbo upgrades and camshafts you will improve your driving opportunities.

History, Power & Specs of the F18D3 Engine

121hp@5600 125lb ft @3800

This also was badged as a T18SED Engine

Tuning the Chevrolet F18D3 and best F18D3 performance parts.

Best F18D3 upgrades

Just because particular tuning mods are appear in lots of F18D3 projects it doesn't mean you should fit it, instead we'll focus tuning mods that will give your F18D3 the biggest power gain return for your cash.

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

Fast road cams tend to push up the power across the rpm range, you could drop a little low end torque but top end will improve.

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

A Motorsport camshaft will just annoy you whilst driving around busy urban areas. This is because a competition cam causes a very lumpy idle, and makes the car more prone to stall or jerk along in stop start traffic, sadly though many ignore this and end up ruining a perfectly good car and having to revert back to a fast road, or OEM cam profile.

You should ideally optimize your engines power to your driving style so for a road car stick with a fast road F18D3 camshaft

Each engine responds better to less aggressive camshaft durations so set your engine up on a rolling road.

The map and injectors and fuel pump also have an effect on the bhp gains you'll make.

Altering valve durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

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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:
    Intake manifolds, Fast road camshaft, Panel air filters, Remaps/piggy back ECU, drilled & smoothed airbox, Sports exhaust header/manifold.

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

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

    The F18D3 units make great tuning projects and we're finding that there is an increase of mods and tuning parts around.

    ECU mapping allows a tuner to release the full potential of all the upgrades you've done to your F18D3.

    (In some cases, as the factory ECU is locked flashing 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 setup properly.)

    It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but the end result may depend much on the upgrades you've carried out and the condition of your engine.

    It is the aim to any engine upgrade project to force more air into the F18D3 engine

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

    The shape and flow characteristics of the Intake manifold can make a noticeable change to fuel mixing and power on the F18D3.

    Most intake are ripe for a performance upgrade, although a few car makers provide well optimised intake.

    Adding a F18D3 larger valve kit, getting port matching and head flowing will also improve bhp, & importantly will raise potential for raising the bhp increase on other mods.

    F18D3 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 F18D3

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

    When an engine is fitted with a turbo tuning mods are more reliable and turbo engines are made with strengthened components.

    However every engines will need better parts at higher power limits.We recommend you find these limitations and install forged components to cope with the power.

    We've seen people spending a loads of money on turbo charger upgrades on the F18D3 only to suffer the humiliation of seeing the engine block throw a rod just after it's used on the roads.

    Bigger turbochargers often experience a bottom end lag, and little turbochargers spool up really quickly but do not have the top end bhp gains.

    Thanks to new tech the market of turbos is always evolving and we are seeing variable vane turbos, allowing the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

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

    It is not unusual that there's a restriction in the air flow sensor AFM/MAF on the F18D3 when considerably more air is being sucked into the engine.

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

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


    Don't miss you'll need to increase the fuel delivery when you are increasing the performance - it makes the car more thirsty.

    Don't forget to be generous with your flow rate on the injectors.

    The rule of thumb is to add 20% when buying an injector, this allows for injector deterioration and gives 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.

    All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

    4 Cylinder turbocharged engines

    • 58 PSI 340cc/min 200hp
    • 58 PSI 511cc/min 300hp

    4 Cylinder NA (naturally aspirated) engines

    • 58 PSI 285cc/min 200hp

    4 Cylinder supercharged engines

    • 58 PSI 312cc/min 200hp
    • 58 PSI 468cc/min 300hp

    F18D3 Performance Exhausts

    You should look to uprate your exhaust if the current exhaust is actually creating a restriction.

    On most factory exhausts you'll see your flow rate is ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

    Don't go with the biggest exhaust you can source this will reduce the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

    Common exhaust restrictions are traced to the catalyst installed, so adding a freer flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

    Weak spots, Issues & problem areas on the F18D3

    The F18D3 engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen 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.

    Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

    Regular oil changes are vital on the F18D3, especially when tuned and will help extend the life and reliability of the engine.

    If you would like to know more, or just get some friendly advice on Tuning your F18D3 engine please join us in our car forums where you can discuss F18D3 tuning options in more detail with our F18D3 owners. It would also be worth reading our unbiased Chevrolet tuning articles to get insights into each modification and how effective they will be for your car.

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    We love to hear what our visitors have got up to and which tuning parts work best for you on your car. Which helps us keep our guides and tips up to date helping others with their modified car projects. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these F18D3 tuning guides which get regular updates and revisions.

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