Tuning the Volvo VEP4

"Comprehensive guide to tuning and performance parts on the Volvo VEP4 engine!"

We are always seeing threads requesting information on the things we recommend when it comes to VEP4 modifications. So let us look into Volvo VEP4 mods and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Volvo VEP4 are popular tuning projects and with the right upgrades like remapping, turbo improvements and camshafts you will substantially maximise your driving enjoyment.

This pages aim is outline options for your VEP4 tuning and show the best modifications for your car.

The top VEP4 mods on an engine are as we have found the ones that give the best power gain for you spend.

We won't be swayed by popular VEP4 mods, they need to be cost effective.

Significant gains on the VEP4 can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road camshafts usually increase the torque through the rev range, you may lose a little low down power but the higher rpm power will improve.

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

A Competition cam is not great in heavy traffic.

You should ideally match your engines power to your driving style so for a road car stick with a fast road VEP4 cam

Each engine responds better to more or less aggressive cam durations than others.

The ecu map and fuel pump and injectors 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.

VEP4 Tuning Stages

Stage 1 VEP4 modifications: Panel air filters, Sports exhaust manifold, Drilled & smoothed airbox, Fast road camshaft, Remaps/piggy back ECU, Intake headers.

Stage 2 VEP4 modifications: Ported and polished head, high flow fuel injectors, induction kit, Fast road cam, fuel pump upgrades, Sports catalyst & performance exhaust.

Stage 3 VEP4 modifications: Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Competition cam.

A remap should help to unlock the full potential of all the parts you've done to your VEP4.

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 usually vary depending on the parts you've applied and the condition of your engine.

It is vital to any car tuning task to pull fuel and air into the VEP4 engine

Intake manifold flow the air from the air cleaner and allow it to be drawn into the engine and mixed with fuel.

The size of bore and shape and flow rate of the Headers can make a noticeable improvement to fuel delivery on the VEP4.

I usually find intake manifold are in desperate need of an upgrade, although a few OEM provide reasonably well designed intake manifold.

Big valve conversions on the VEP4, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also lift performance, and significantly will raise potential for an improved performance increase on other upgrades.

Turbo upgrades for the VEP4

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 VEP4

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 an engine has a turbo already fitted upgrades are going to net you a larger power gain and you will discover turbocharged engines are made using more solid components.

However engines will need better parts at higher power limits

See where you'll find these restrictions and upgrade to forged components to survive the power.

We see many car owners spending a fortune on turbo upgrades on the VEP4 only to see the engine literally blow up just after it's completed.

Larger upgraded turbos will usually experience no power at low rpm, and little turbos spool up really quickly but don't have the peak end engines power gains.

Thanks to progress the world of turbos is always evolving and we now see variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbos divert the exhaust flow into a couple of channels and direct these at differently profiled vanes in the turbocharger. They also help the scavenging effect of the engine.

It is common that there is a limit in the air flow sensor AFM/MAF on the VEP4 when loads more air is being sucked 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 torque gains, although harder to install. We have this guide to twinchargers if you want to read more.

Uprating VEP4 fuel injectors

When you lift the power you will need to uprate to the fuel system.

More power needs more fuel. Don't forget to be generous with your injector capacity.

The accepted safe increase is to add 20% capacity when fitting an injector, which 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.

Best VEP4 performance exhausts

You may need to boost your exhaust if your exhaust is creating a restriction in flow.

On most factory exhausts you should find that your flow rate is 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 generally help improve air flow from 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 can be located the emissions filters installed, so adding a higher flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the VEP4

The VEP4 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the VEP4, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your VEP4 engine please join us in our friendly forum where you can discuss tuning options in more detail with our VEP4 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 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 VEP4 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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