Tuning the Volvo B4204

"Comprehensive guide to tuning the Volvo B4204 engine!"

We are regularly getting messages requesting info on the ultimate B4204 mods that work. So let us look into Volvo B4204 modifications and outline the best upgrades on this great engine and point out some common pitfalls along the way.

We shall detail the best approach to B4204 tuning and show the ultimate modifications for your car. Volvo B4204 make a good tuning project and with the right performance upgrades like ECU maps, turbo kits and camshafts you will increase your driving fun.

The ultimate B4204 modifications on an engine are typically the ones that give the biggest return for your cash.

We won't be swayed by popular B4204 modifications, they need to be cost effective.

Altering your B4204 cam will make a dramatic difference to the engine power band. Choosing a higher performance cam profile raises the power band accordingly.

NB: Fast road camshafts usually bump the bhp throughout the rpm range, you may sacrifice a little low end power but the higher rpm power will be better.

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

A Competition camshaft is not great driving around busy urban areas.

You should ideally match your torque band to your typical driving style so for a car used daily stick with a fast road B4204 camshaft

Each engine responds better to more or less aggressive camshaft durations check your engine on a rolling road.

The engine timing and fuelling also will say much on the power gains you'll achieve.

A longer valve duration 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.

B4204 Best Tuning Mods & Upgrades

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Guide to the best tuning mods & Upgrades

  1. ECU Map Tuning & Remaps

    Some cars may require a piggyback ECU's or aftermarket ECU's to change the OEM map, but remapping is the most vital step of your tuning project to fully maximise your mods. Expect 10-20% on NASP engines and 30-40% on turbocharged units.

  2. Strengthen Your Engine

    Tuned cars will show up weaknesses, typically in the turbochargers, clutch and internal engine components. Whilst most engines can cope with mild tuning mods, TorqueCars recommend that you upgrade the internal components before these weak spots manifest themselves.

  3. Mods that Remove a Restriction

    A restricted intake or exhaust will have an impact on your performance, so use a better flowing air filter/induction kit and better flowing exhaust (sports cats where legal are a good option) whenever your tuning creates a flow restriction. Turbo engines also benefit from intercooler upgrades as these resist heat soak for longer periods of time.

  4. Mods that Improve Fuelling

    Every tuning project will aim to increase the air supply, but fuel supply is just as vital and will need to match the air the engine can utilise,  a fuel pump and injector upgrade are usual mods, but also in many cases the fuel regulator will need improvement.

  5. Mods to Provide better Airflow

    Increasing the air supply is just as essential as improving fuelling, we suggest you look at head mods (flowing and porting, 5 angle valve jobs), fit bigger valves, fast road cams and forced induction upgrades (adding a better flowing turbo) to improve air intake.

Tuning Stages

Stage 1 B4204 modifications: Panel air filters, Fast road camshaft, Sports exhaust manifold, Drilled & smoothed airbox, Remaps/piggy back ECU, Intake headers.

Stage 2 B4204 modifications: Sports catalyst & performance exhaust, high flow fuel injectors, fuel pump upgrades, Fast road cam, Ported and polished head, induction kit.

Stage 3 B4204 modifications: Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Crank and Piston upgrades to alter compression.

The B4204 engine blocks respond well to mods and thanks to their popularity there is an increase of parts and performance parts out there.

ECU flashing helps unlock the full potential of all the upgrades you've done to your B4204.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the outcome often rely on the upgrades you've carried out and the condition of your engine.

It is the main goal to any engine modification project to pull air into each cylinder

Intake headers carry the air during the suck phase from the air filter and allow it to be pulled into the engine and mixed with fuel.

Shape and rate of flow of the Headers can make a substantial effect on to fuel atomisation and engine efficiency on the B4204.

It's not uncommon that air intake manifolds are in dire need of aftermarket parts, although some OEM provide fairly well optimized air intake manifolds.

Big valve conversions on the B4204, doing some port matching and head flowing will also boost bhp, the fantastic side effect is it will allow you to get a greater bhp increase on other parts.

Turbo upgrades for the B4204

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 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.

If a car has a turbo already fitted parts are simpler to install and you will discover turbo charged engines already contain uprated components.

However you'll find engines have limits

See where you'll find these restrictions and upgrade to more solid crank and pistons to handle the power.

We see many mechanics spending a loads of money on turbocharger upgrades on the B4204 only to suffer the indignity of watching the car literally blow up when it's completed.

Large capacity turbos commonly experience no power at low rpm, and little turbos spool up quickly but do not have the top end torque gains.

In the last 10 years the choice of turbochargers is always evolving and we commonly find variable vane turbochargers, where the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbochargers divert the exhaust gases into 2 channels and direct these at differently profiled vanes in the turbocharger. They also boost the scavenging effect of the engine.

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

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

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

Uprating B4204 fuel injectors

You will need to ensure that the engine is not starved of fuel so should ramp up the fuelling when you start extending past 20% of a power increase.We strongly recommend you to over specify your injectors flow rate.

As a rule of thumb add another 20% when specifying an injector, helps cope with injector deterioration and provides a little 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.

Best B4204 performance exhausts

You should look to boost your exhaust if the existing exhaust is creating a restriction in flow.

On most factory exhausts you should find that the exhaust flow rate is good 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 can usually air flow through the engine but do not go too wide or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Usual exhaust restrictions are traced to the catalysts installed, so adding a freer flowing high performance alternative will help avoid this restriction.

B4204 Engine bhp specs and history

The VEA comprised straight 4 setup the straight 3 was dubbed the B2154 and B33154

2.0L I4 (145 hp)

  • B4204S5 B4204S3
  • 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

Problems and issues to look out for on the B4204

The B4204 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the B4204, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your B4204 engine please join us in our friendly forum where you can discuss tuning options in more detail with our B4204 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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