Tuning the Volvo D5252T

"Comprehensive guide to tuning and performance parts on the Volvo D5252T engine!"

We often are seeing threads asking how to improve the D5252T from people wanting to know what are the greatest D5252T modifications. So let us look into Volvo D5252T mods and outline the best upgrades on this great engine and point out some frequent tuning mistakes along the way.

TorqueCars will provide a guide to D5252T tuning and point out the best modifications for your car. Volvo D5252T are popular engines and with the right uprated upgrades like a remap, turbo kits and camshafts you will substantially maximise your driving pleasure.

The optimum D5252T parts on an engine are typically the ones that give the biggest return for your cash.

We won't be swayed by popular D5252T parts, they need to be cost effective.

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

NB: Fast road cams usually boost the performance throughout the rev band, you may sacrifice a little low end bhp but your higher rpm power will be better.

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

A Motorsport cam makes it harder when on the daily commute.

You should ideally match your power band to your preferences so for a road car stick with a mild fast road D5252T cam

Each engine responds better to more aggressive cam durations check your engine on a rolling road.

The ECU mapping and injectors and fuel pump also will say much on the torque gains you'll hit.

Altering valve durations can alter the torque 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.

D5252T Tuning Stages

Stage 1 D5252T modifications: Fast road camshaft, Sports exhaust manifold, Panel air filters, Drilled & smoothed airbox, Remaps/piggy back ECU, Intake headers.

Stage 2 D5252T modifications: induction kit, Sports catalyst & performance exhaust, Fast road cam, Ported and polished head, fuel pump upgrades, high flow fuel injectors.

Stage 3 D5252T modifications: Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Twin charging conversions, Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves).

Mapping allows a tuner to fully realize the full potential of all the tuning parts you've done to your D5252T.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage may rely on the tuning parts you've fitted and the condition of your engine.

Pulling more fuel and air into each cylinder is the main goal to any engine modification job.

Headers flow the air during the suck phase from the air filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

The size of bore and shape and flow rate of the Headers can make a noticeable effect on to fuel atomisation on the D5252T.

Many mass produced engine intake headers are improved through aftermarket parts, although a few OEM provide reasonably well designed intake headers.

Big valve conversions on the D5252T, doing a bit of port work and head flowing will also raise power, and as an added benefit will permit increasing the power increase on other upgrades.

Turbo upgrades for the D5252T

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 D5252T

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 a car is fitted with a turbocharger tuning parts are more reliable and we find turbocharged engines are made using many forged and stronger components.

However engines will need better parts at higher power limits

Research these restrictions and upgrade to stronger pistons, crank and engine components to utilize the power.

It's not unheard of mechanics spending a fortune on turbo upgrades on the D5252T only to have the motor catastrophically fail on it's first outing after it's used in anger.

Large upgraded turbos tend to experience low end lag, and low capacity turbos spool up much more quickly but won't have the peak end bhp gains.

Thankfully the range of turbo chargers is always evolving and we are seeing variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo chargers divert the exhaust gases into two channels and push these at differently designed vanes in the turbo. They also boost the scavenging effect of the engine.

It is common that there's a limitation in the air flow sensor MAP/MAF/AFM on the D5252T when considerably more air is being drawn into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp gains, although harder to setup. We have this article covering twinchargers if you want to read more.

Uprating D5252T fuel injectors

You will need to ensure that the engine is not starved of fuel so must ramp up the fuelling when you start extending past 20% of a bhp increase.It is important to over specify your flow rate on the injectors.

As a rule of thumb add 20% to the flow rate when specifying 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 D5252T performance exhausts

You only need to to replace your exhaust if the current exhaust is creating a flow problem.

On most factory exhausts you'll see your flow rate is fine 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 big or you could will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Typically exhaust restrictions are traced to the emissions filters installed, so adding a better flowing race alternative will help avoid this restriction.

Problems and issues to look out for on the D5252T

The D5252T engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the D5252T, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your D5252T engine please join us in our friendly forum where you can discuss tuning options in more detail with our D5252T 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 D5252T guides and tips are kept up to date.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Volvo. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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