Modding tuning and best performance upgrades on the VAG 1.8 TFSi engine!

All you need to know about "1.8 TFSi Modifications"

1.8 TFSi Modifications Guide

How to modify and upgrade the VAG 1.8 TFSi

"Comprehensive guide to performance parts and tuning the VAG 1.8 TFSi engine!"

Sites like TorqueCars are always getting emails requesting information on how to improve the 1.8 TFSi from people wanting to know what are the things tuners are recommending when it comes to 1.8 TFSi modifications. So let us look into VAG 1.8 TFSi tuning mods and outline the best modifications on this great engine and point out some problems along the way.

The VAG 1.8 TFSi are popular engines and with the ultimate performance parts like a remap, turbo improvements and camshafts you will substantially increase your driving fun.

Car Tuning Tips will detail the best approach to 1.8 TFSi tuning and outline the ultimate upgrades.

The optimum 1.8 TFSi modifications on an engine are obviously the ones that give the best gains for your money.

We won't be swayed by popular 1.8 TFSi modifications, they need to be cost effective.

1.8 TFSi induction kits

Improving air intake on the 1.8 TFSi

You need air and fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is a lack of air it runs rich sapping power which risks damage to the 1.8 TFSi. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the aim to any engine modification project to feed air and fuel into each cylinder but this has a knock on effect with the air flow sensor.

You'll commonly see there is a limitation in the air flow sensor MAP/MAF/AFM on the 1.8 TFSi when considerably more air is being pulled into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting power at a much lower level.

Air Intake manifolds take the on the suck phase from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

Design and rate of flow of the Air Intake manifolds can make a big effect on to fuel delivery on the 1.8 TFSi.

Most intake are crying out for aftermarket tuning parts, although a few makers provide well optimised intake.

Larger 1.8 TFSi valves, carrying out port matching and head flowing will also increase bhp, the fantastic side effect is it will permit an improved bhp increase on other tuning parts.

1.8 TFSi performance cam tips.

Each engine responds better to extreme cam durations so view each engine as unique.

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

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.

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 power band gains are on offer for camshaft upgrades.

NB: Fast road cams tend to bump the bhp through the rev range, you could sacrifice a little low end bhp but higher rpm power will improve.

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

On a typical daily driver you must carefully try to match your power band to your typical driving style.

You will never have found a 1.8 TFSi Race cam is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the 1.8 TFSi

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 1.8 TFSi parts:

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

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

Stage 2 1.8 TFSi parts:

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

Stage 3 1.8 TFSi parts:

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

The 1.8 TFSi engines are great to work on and thankfully there are plenty of mods and performance parts around.

Remaps should help to release the full potential of all the parts you've done to your 1.8 TFSi.

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 rely on the parts you've applied and the condition of your engine.

Turbo modifications on the 1.8 TFSi

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 1.8 TFSi.

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

If your motor has a turbo already fitted parts are simpler to install and turbocharged engines are made using harder and stronger components.

However every engines have limits

Research these limits and upgrade to stronger pistons, crank and engine components to handle the power.

It's not unheard of mechanics spending a fortune on turbo upgrades on the 1.8 TFSi only to have the 1.8 TFSi throw a rod just after it's been enthusiastically driven.

Larger turbo units will usually experience no power at low rpm, and small turbo units spool up much more quickly but won't have the top end torque gains.

Thanks to new tech the selection of turbos is always improving and we commonly find variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust gases into two channels and push these at differently angled vanes in the turbocharger. 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 bhp gains, although more challenging to get working. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the 1.8 TFSi

You will need to ensure that the engine is not starved of fuel so should uprate the fuelling when you start going beyond 20% of a performance hike. At this point we flag up the need to over specify your injector capacity.

The rule of thumb is to add 20% capacity when buying an injector, this takes into account injector deterioration and allows a little 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 1.8 TFSi performance exhaust upgrades

We'd only recommend you look to replace your exhaust system with an upgraded one is if the existing exhaust is creating a restriction in flow.

On most factory exhausts you should find that the flow rate is fine 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 can usually air flow out of the engine but do not go too large or you could will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Usual exhaust restrictions are in the filters installed, so adding a better flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the 1.8 TFSi

Like most engines an 1.8 TFSi, 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 1.8 TFSi, failure to do this will exacerbate engine wear, on a tuned 1.8 TFSi 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 1.8 TFSi why not pop over to the forums at TorqueCars where you can chat about 1.8 TFSi tuning options and read about others projects who may be planning to do similar modifications on their 1.8 TFSi.

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