Modding uprating the VAG D24T engine!

Modifying and improving: "D24T Modifications"

D24T Modifications Guide

How to modify and upgrade the VAG D24T

"Comprehensive guide to tuning and performance parts on the VAG D24T engine!"

Popular tuning sites like TorqueCars are always seeing threads requesting info on how to improve the D24T from people wanting to know what are the best tips on D24T upgrades. So let us look into VAG D24T mods and outline the best mods that work on this great engine and point out some common pitfalls along the way.

The VAG D24T make awesome project engines and with the optimum parts like remapping, turbo upgrades and camshafts you will maximize your driving enjoyment.

Car Tuning Tips will examine the options for your D24T tuning and show the optimum modifications.

Just because particular tuning parts are appear in lots of D24T projects it doesn't mean its worth having, we shall concentrate on the greatest tuning parts that will give your D24T the biggest power gain return for your cash.

Without us subscribing to the mentality of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

D24T induction kits

Improving air intake on the D24T

You need air and fuel for an engine to work. If there is a lack of fuel then it will run lean, if there is little flow of air it runs rich resulting in lost power which risks damage to the D24T. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the aim to any car tuning task to force more air and fuel into your D24T but this has a knock on effect with the air flow sensor.

It is common that there's a limit in the air flow sensor AFM/MAF on the D24T when considerably more air is being fed into the engine.

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

Intake manifolds carry the on the suck phase from the air filter and allow it to be sucked into the engine and mixed with fuel.

Shape and flow rate of the Intake headers can make a noticeable effect on to fuel atomisation and engine efficiency on the D24T.

I usually find intake manifold are crying out for a performance upgrade, although a few OEM provide reasonably well designed intake manifold.

Larger D24T valves, getting D24T port enlargement and head flowing will also boost performance, & more importantly will make space for raising the performance increase on other tuning parts.

D24T performance cam tips.

Different D24T engines respond better to more aggressive cam durations so set your engine up on a rolling road.

The ECU mapping and fuelling also will say much on the power gains you'll achieve.

Longer 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.

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 engines power gains are on offer for camshaft upgrades.

NB: Fast road camshafts commonly raise the performance throughout the rev band, you may lose a little low down power but the top end will be higher.

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

On a daily driver you need to match your power band to your preferences.

I would be surprised if you have found a D24T Race camshaft is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the D24T

Stage 1 D24T parts:

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

Stage 2 D24T parts:

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

Stage 3 D24T parts:

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

Carefully think through your options and then source your upgrades and set yourself a power target to avoid wasting your time and money.

Remaps helps unlock the full potential of all the upgrades you've done to your D24T.

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 power output usually depend much on the upgrades you've done and the condition of your engine.

Turbo modifications on the D24T

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 D24T.

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 an engine is turbocharged, tuning parts are more reliable and you will discover turbo charged engines are built using uprated components.

There are weak spots for every engine, with some being extremely strong and some only able to handle stock power

Research these limitations and fit more solid crank and pistons to survive the power.

It's not unheard of people spending a fortune on turbo upgrades on the D24T only to experience the car explode just after it's used in anger.

Bigger upgraded turbos tend to experience low end lag, and smaller turbos spool up quickly but do not have the high rpm torque gains.

Thanks to new tech the market of turbo units is always evolving and we commonly find variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo units divert the exhaust gases into a couple of channels and flow these at differently profiled 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 torque gains, although more difficult to install. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the D24T

Don't miss you'll need to raise the fuelling when you are increasing the bhp and torque - it makes the car more thirsty. At this point we flag up the need to be generous with your injectors flow rate.

The rule of thumb is to add another 15% when fitting an injector, this allows for injector deterioration and provides some 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 D24T performance exhaust upgrades

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

On most factory exhausts you'll see your flow rate is still ok 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.

Do not go with the widest exhaust you can buy this will reduce the exhaust flow rate - the best exhausts for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

The usual suspects causing problems in your exhaust flow rate can be located the catalyst installed, so adding a better flowing performance 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 D24T

Like most engines an D24T, 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 D24T, failure to do this will exacerbate engine wear, on a tuned D24T 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 D24T why not pop over to the forums at TorqueCars where you can chat about D24T tuning options and read about others projects who may be planning to do similar modifications on their D24T.

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