Modding tuning and best performance upgrades on the Volvo GEP3 engine!

Tuning guide "GEP3 Modifications"

GEP3 Modifications Guide

How to modify and upgrade the Volvo GEP3

"Comprehensive guide to tuning the Volvo GEP3 engine!"

Sites like TorqueCars are always getting messages about how to improve the GEP3 from people inquiring about getting more power from the GEP3 and wanting to know what are the ultimate GEP3 mods that work. So let us look into Volvo GEP3 upgrades and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

Therefore we review GEP3 tuning and point out the greatest mods that work. Volvo GEP3 are fantastic to work on and with the optimum uprated modifications like remaps, turbo improvements and camshafts you will noticeably maximize your driving fun.

The greatest GEP3 modifications on an engine are in our opinion the ones that give the biggest return for your money.

We won't be swayed by popular GEP3 modifications, they need to be cost effective.

GEP3 induction kits

Improving air intake on the GEP3

You need air matched to fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is insufficient air it runs rich resulting in lost power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Forcing more fuel and air into the GEP3 engine is the main goal to any engine modification project.

It is not unusual that there is a limitation in the air flow sensor AFM/MAF on the GEP3 when loads 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 performance at a much lower level.

The intake plenum transmit the air from the intake filter and allow it to be pulled into the engine and mixed with fuel.

Shape and rate of flow of the Intake can make a substantial change to fuel mixing and power on the GEP3.

It's not uncommon that headers are needing performance upgrades, although a few car makers provide fairly well optimized headers.

Fitting big valve kits, getting 3 or 5 angle valve jobs and porting and head flowing will also lift torque, & importantly will afford you a better torque increase on other tuning mods.

GEP3 performance cam tips.

Some GEP3 engines respond better to extreme cam durations than others.

The engine timing and fuel pump and injectors also will make differences on the bhp gains you'll achieve.

Altering valve durations can alter the bhp 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.

Significant air intake, and exhaust improvements on the GEP3 can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

NB: Fast road camshafts usually increase the performance over the rev band, you might lose a little bottom end power but the top end will improve.

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

On a road car you must carefully try to match your torque band to your cars usage.

You will never have found a GEP3 Motorsport and race cam is a pleasure to live with when driving around busy urban areas.

Stage 1, 2 and 3 mods for the GEP3

Stage 1 GEP3 parts:

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

Stage 2 GEP3 parts:

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

Stage 3 GEP3 parts:

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

Carefully think through your options and then acquire your tuning parts and set yourself a power target to save yourself from expensive mistakes.

ECU flashing allows a tuner to release the full potential of all the upgrades you've done to your GEP3.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved may rely on the upgrades you've fitted and the condition of your engine.

Turbo modifications on the GEP3

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the GEP3.

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes massive power gains.

When the engine is fitted with a turbo parts are giving better power gains and you will discover turbo engines are made with harder and stronger components.

However engines have weakspots

It is important to find these restrictions and install better quality components to utilize the power.

There are many drivers spending a a stack of money on turbo charger upgrades on the GEP3 only to suffer the humiliation of seeing the engine literally blow up on it's first outing after it's used in anger.

Bigger turbo units often experience low end lag, and low capacity turbo units spool up quickly but don't have the high rpm bhp gains.

Thanks to new tech the market of turbos is always improving and we now see variable vane turbos, where the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large performance gains, although more difficult to get working. We have this article on twincharging if you want to read more.

Tips about fuel supply on the GEP3

Don't omit to improve the fuel system when you are increasing the power - it makes the car more thirsty. At this point we flag up the need to be generous with your flow rate on the injectors.

As a rule of thumb add another 20% when specifying an injector, helps cope with injector deterioration and gives a bit of spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended GEP3 performance exhaust upgrades

You should look to increase your exhaust system with an upgraded one is if the current exhaust is creating a restriction in flow.

On most factory exhausts you should find that your flow rate is good even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Sports exhausts balance the flow of gases through the engine.

But if your exhaust pipe is too big, ie: it's over two and a half inches diameter, you will lose a great deal of your flow rate and end up sapping power and torque.

Usual exhaust restrictions can be traced to the filters installed, so adding a freer flowing race alternative will help avoid this restriction.

Decats (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the GEP3

Like most engines an GEP3, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the GEP3, failure to do this will exacerbate engine wear, on a tuned GEP3 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your GEP3 why not pop over to the forums at TorqueCars where you can chat about GEP3 tuning options and read about others projects who may be planning to do similar modifications on their GEP3.

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