Volvo B4204 Tuning

"All you need to know about tuning and performance parts on the Volvo B4204 engine!"

The Volvo B4204 really good project engines and with carefully picked tuning upgrades like remapping, turbo kits and camshafts you will substantially increase your driving enjoyment.

Let us provide a guide to B4204 tuning and outline the best modifications for your car.

History, Power & Specs of the B4204 Engine

The VEA comprised straight 4 and a straight 3 the B2154 and B33154

  • 2.0L I4 (145 hp) B4204S5┬áB4204S3
  • B4204T5
  • B4204T9
  • B4204T10
  • B4204T11
  • B4204T12
  • B4204T14
  • B4204T15
  • B4204T17
  • B4204T18
  • B4204T19
  • B4204T20
  • B4204T21
  • B4204T23
  • B4204T26
  • B4204T27
  • B4204T28
  • B4204T29
  • B4204T30
  • B4204T31
  • B4204T32
  • B4204T33
  • B4204T34
  • B4204T35
  • B4204T36
  • B4204T37
  • B4204T38
  • B4204T41
  • B4204T43
  • B4204T44
  • B4204T45
  • B4204T46
  • B4204T47
  • B4204T48

Tuning the Volvo B4204 and best B4204 performance parts.

Best B4204 parts

Just because particular modifications are popular with B4204 owners it doesn't mean its worth having, we shall concentrate on the ultimate modifications that will give your B4204 the best value for money to power increase.

Altering your B4204 camshaft will make a dramatic difference to the engine torque. Choosing a higher performance camshaft profile raises the torque accordingly.

Fast road cams normally push up the performance through the rev band, you could sacrifice a little low end torque but the higher rpm power will be higher.

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

In a typical daily driver should ideally to match your torque band to your usage of the car.

You will never have ever asserted that a B4204 Motorsport and race camshaft is a pleasure to live with when driving in heavy traffic. The low end idle will be very lumpy and irregular, so something you would notice on a track when you drive in the upper third of the rpm band, but on roads this is a serious issue and we've heard from lots of drivers lamenting their decision to add an extreme competition cam profile to their engine.

Some B4204 engines respond better to mild camshaft durations than others.

The ECU mapping and injectors and fuel pump also will make differences on the power gains you'll get.

Altering valve durations can alter the power 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. 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 header/manifold, Fast road camshaft, Intake manifolds, Remaps/piggy back ECU, drilled & smoothed airbox, Panel air filters.

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

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

    The B4204 engines are great to work on and we see that there is a lot of mods and performance parts about.

    Mapping allows a tuner to establish the full potential of all the mods you've done to your B4204.

    (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 power output may differs on the mods you've applied and the condition of your engine.

    Pulling air and fuel into each cylinder is vital to any performance tuning job.

    An intake manifold will channel 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.

    Shape and flow characteristics of the Air Intake manifolds can make a noticeable improvement to fuel delivery on the B4204.

    Commonly we find the plenum chambers are needing motorsport parts, although a few manufacturers provide fairly well optimized plenum chambers.

    Increasing the B4204 valve size, carrying out port work and head flowing will also lift bhp and torque, the fantastic side effect is it will make space for increasing the bhp and torque increase on other parts.

    B4204 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 B4204

    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.

    When a car is turbo charged parts are going to make more power and you'll see that turbocharged engines are built using strengthened components.

    However you'll find engines will need better parts at higher power limits.We recommend you find these limitations and upgrade to better quality components to handle the power.

    We see many drivers spending a lot of money on turbo upgrades on the B4204 only to experience the motor throw a rod just after it's been enthusiastically driven.

    Big turbochargers often experience no power at low rpm, and smaller turbochargers spool up really quickly but won't have the top end torque gains.

    Over the last 20 years 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 performance.

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

    You'll commonly see there's a restriction in the air flow sensor (AFM/MAF/MAP) on the B4204 when loads more air is being fed into the engine.

    We note 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 bhp and torque gains, although more difficult to get working. We have this article on twincharging if you want to read more.


    You will need to ensure that the engine is not starved of fuel so will have to look at the fuelling when you start extending past 20% of a bhp increase.We would recommend you to be generous with your flow rate on the injectors.

    The rule of thumb is to add 20% to the flow rate when fitting an injector, this takes into account injector deterioration and allows you 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.

    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
    • 58 PSI 682cc/min 400hp

    4 Cylinder NA (naturally aspirated) engines

    • 58 PSI 285cc/min 200hp
    • 58 PSI 426cc/min 300hp
    • 58 PSI 568cc/min 400hp

    4 Cylinder supercharged engines

    • 58 PSI 312cc/min 200hp
    • 58 PSI 468cc/min 300hp
    • 58 PSI 625cc/min 400hp

    B4204 Performance Exhausts

    You only need to replace your exhaust if the existing exhaust is actually creating a restriction in flow.

    On most factory exhausts you'll find 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.

    Sports exhausts will certainly help air flow out of the engine but do not go too wide or you could very well end up with a reduced flow rate. So generally speaking, keep to 1.5 to 2.5 inches for best results.

    Common exhaust restrictions are in the catalyst and filters installed, so adding a better 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 B4204

    The B4204 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 B4204, 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 B4204 engine please join us in our car forums where you can discuss B4204 tuning options in more detail with our B4204 owners. It would also be worth reading our unbiased Volvo tuning articles to get insights into each modification and how effective they will be for your car.

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