Tuning the Volvo B6304S

"Comprehensive guide to tuning the Volvo B6304S engine!"

We are always getting emails asking how to improve the B6304S from people wanting to know what are the greatest B6304S mods that work. So let us look into Volvo B6304S mods and outline the best mods that work on this great engine and point out some potential pitfalls along the way.

The Volvo B6304S are popular engines and with the best sports upgrades like ECU maps, turbo kits and camshafts you will definitely increase your driving opportunities.

Let us outline options for your B6304S tuning and report on the premier mods that work.

When talking about the top parts for your B6304S engine, we are going to focus on the tuning mods that give the best power gain for you spend.

Altering your B6304S cam will make a dramatic difference to the engine engines power. Choosing a higher performance cam profile raises the engines power accordingly.

NB: Fast road cams tend to push up the torque throughout the rpm range, you may sacrifice a little bottom end power but your high end rpm power will be lifted.

Motorsport and race cams, push up 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 cam won't do well if driving in heavy traffic.

You should ideally optimize your power band to your preferences so for a daily driver stick with a fast road B6304S cam

Some B6304S engines respond better to extreme camshaft durations check your engine on a rolling road.

The ECU mapping and fuelling also have an effect 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.

B6304S Tuning Stages

Stage 1 B6304S modifications: Drilled & smoothed airbox, Remaps/piggy back ECU, Intake headers, Panel air filters, Sports exhaust manifold, Fast road camshaft.

Stage 2 B6304S modifications: Ported and polished head, Sports catalyst & performance exhaust, Fast road cam, induction kit, fuel pump upgrades, high flow fuel injectors.

Stage 3 B6304S modifications: Engine balancing & blueprinting, Competition cam, Crank and Piston upgrades to alter compression, Twin charging conversions, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger).

The B6304S engines respond well to upgrades and we're finding that there is a lot of mods and tuning parts about.

ECU flashing allows a tuner to fully realize the full potential of all the upgrades you've done to your B6304S.

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

Forcing more fuel and air into the B6304S engine is the aim to any performance tuning job.

Headers take the air from the air filter and allow it to be sucked into the engine cylinders with fuel for the squish phase.

Shape and flow characteristics of the Intake can make a big difference to to fuel delivery on the B6304S.

I usually find intake manifold are in dire need of motorsport parts, although a few manufacturers provide well optimised intake manifold.

Larger B6304S valves, carrying out 3 or 5 angle valve jobs and porting and head flowing will also lift performance, and importantly will make space for a better performance increase on other upgrades.

Turbo upgrades for the B6304S

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 B6304S

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.

If a car is turbo charged tuning parts are more reliable and turbo charged engines already contain harder and stronger components.

However you will find an engines will have power limits

See where you'll find these limitations and install better quality components to handle the power.

We've seen mechanics spending a lots of money on turbo charger upgrades on the B6304S only to have the B6304S catastrophically fail just after it's used in anger.

Larger turbochargers tend to suffer a bottom end lag, and low capacity turbochargers spool up more quickly but do not have the high rpm power band gains.

In recent times the range of turbo chargers is always developing and we are seeing variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

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

You'll commonly see there's a restriction in the air flow sensor MAP/MAF/AFM on the B6304S when a lot more air is being fed into the engine.

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

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

Uprating B6304S fuel injectors

When you improve the bhp and torque you will need to ramp up to the fuelling.

More bhp and torque needs more fuel. It makes sense to over specify your flow rate on the injectors.

The rule of thumb is to add another 20% when fitting an injector, this accounts for injector deterioration and affords a bit of 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 B6304S performance exhausts

Only look to improve your exhaust if the existing exhaust is actually causing a restriction.

On most factory exhausts you'll see the exhaust flow rate is still 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 generally help improve air flow out of the engine but do not go too big or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Common exhaust restrictions are traced to the catalyst installed, so adding a faster flowing sports alternative will help avoid this restriction.

Problems and issues to look out for on the B6304S

The B6304S engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the B6304S, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your B6304S engine please join us in our friendly forum where you can discuss tuning options in more detail with our B6304S 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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We really like hearing from our readers, and hearing about which upgrades were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our B6304S guides and tips are kept up to date.

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