Tuning the Volvo B5254

"Comprehensive guide to tuning the Volvo B5254 engine!"

We are regularly getting emails inquiring about getting more power from the B5254 and wanting to know what are the things we recommend when it comes to B5254 upgrades. So let us look into Volvo B5254 upgrades and outline the best modifications on this great engine and point out some problems along the way.

The Volvo B5254 make a good tuning project and with the ultimate performance enhancements like ECU maps, turbo improvements and camshafts you will increase your driving pleasure.

We shall review and look at B5254 tuning and outline the ultimate upgrades.

Just because particular upgrades are are common on B5254 it doesn't mean its worth having, we will highlight only those upgrades that we reckon are the best and that will give your B5254 the best power gain for you money.

Altering your B5254 camshaft will make a dramatic difference to the engine power band. Choosing a higher performance camshaft profile raises the power band accordingly.

NB: Fast road cams commonly bump the performance through the rev range, you may lose a little low down power but top end will be lifted.

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

In a typical daily driver must carefully try to match your power band to your typical driving style.

I would be surprised if you have found a B5254 Race cam is a pleasure to live with when in heavy traffic.

Some B5254 engines respond better to more aggressive camshaft durations so set your engine up on a rolling road.

The ecu map and injectors and fuel pump also have a large bearing on the power gains you'll hit.

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.

B5254 Best Tuning Mods & Upgrades

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Guide to the best B5254 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 B5254 modifications: Drilled & smoothed airbox, Fast road camshaft, Remaps/piggy back ECU, Panel air filters, Sports exhaust manifold, Intake headers.

Stage 2 B5254 modifications: induction kit, high flow fuel injectors, Sports catalyst & performance exhaust, fuel pump upgrades, Fast road cam, Ported and polished head.

Stage 3 B5254 modifications: Crank and Piston upgrades to alter compression, Twin charging conversions, Competition cam, Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (head flowing porting/bigger valves).

The B5254 power trains are fantastic to work on and we note that there are increasing numbers of mods and performance parts around.

ECU flashing should help to unlock the full potential of all the parts you've done to your B5254.

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 will differs on the parts you've applied and the condition of your engine.

It is the main goal to any engine tuning job to feed more air and fuel into your B5254

Air Intake manifolds flow the air during the suck phase from the air filter and allow it to be drawn into the engine cylinders.

The bore size, shape and rate of flow of the Plenum can make a big change to fuel atomisation on the B5254.

On popular production engines intake manifold are crying out for aftermarket parts, although some makers provide well optimised intake manifold.

Larger B5254 valves, doing a bit of port matching and head flowing will also lift bhp and torque, & more importantly will raise potential for a better bhp and torque increase on other mods.

Turbo upgrades for the B5254

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 B5254

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 fitted with a turbocharger upgrades are giving better power gains and we find turbo engines are built using more solid components.

However you will find an engines will need better parts at higher power limits

Research these restrictions and fit better pistons and crank to survive the power.

We've seen guys spending a lot of money on turbo charger upgrades on the B5254 only to suffer the indignity of watching the B5254 throw a rod on it's first outing after it's finished.

Bigger capacity turbos will usually experience no power at low rpm, and small turbos spool up really quickly but don't have the peak end bhp gains.

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

Twin scroll turbos divert the exhaust gases into two channels and push these at differently profiled vanes in the turbocharger. They also help the scavenging effect of the engine.

You'll commonly see there is a limit in the air flow sensor MAP/MAF/AFM on the B5254 when considerably 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 bhp and torque at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to setup. We have this in depth look at twinchargers if you want to read more.

Uprating B5254 fuel injectors

You will need to ensure that the engine is not starved of fuel so should pay attention to the fuelling when you start exceeding 20% of a power increase.We would recommend you to over specify your injector capacity.

As a rule of thumb add 20% to the flow rate when specifying an injector, this accounts for injector deterioration and affords a little 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.

Best B5254 performance exhausts

Only look to increase your exhaust if your exhaust is actually causing a flow problem.

On most factory exhausts you'll see the 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 will certainly help air flow through the engine but do not go too large or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Typically exhaust restrictions come around the catalyst installed, so adding a better flowing performance alternative will help avoid this restriction.

B5254 Engine bhp specs and history

  • 2.5 L T5 turbocharged I5 (227 bhp) B5254T7
  • 2.5 L T5 turbocharged I5 (217 bhp) B5254T3

Problems and issues to look out for on the B5254

The B5254 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the B5254, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your B5254 engine please join us in our friendly forum where you can discuss tuning options in more detail with our B5254 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We really like hearing from our readers, and hearing about which tuning mods were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our B5254 guides and tips are kept up to date.

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