Everything You Need To Know About "TU Modifications"

How to modify and upgrade the PSA TU

"Comprehensive guide to performance tuning the PSA TU engine!"

Sites like TorqueCars are always getting messages asking how to improve the TU from people wanting to know what are the best TU mods that work. So let us look into PSA TU parts and outline the best modifications on this great engine and point out some problems along the way.

The PSA TU are popular tuning projects and with the ultimate motorsport enhancements like ECU maps, turbo upgrades and camshafts you will definitely maximize your driving pleasure.

Let us outline options for your TU tuning and highlight the best mods that work.

Just because particular parts are appear in lots of TU projects it doesn't mean it is good, instead we will focus on the best parts that will give your TU the best power gain for you money.

Without us subscribing to the popular myth 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'.

Improving air intake on the TU

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 not enough air it runs rich sapping power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the whole point to any car tuning project to pull more air into the TU engine but this has a knock on effect with the air flow sensor.

You'll commonly see there's a restriction in the air flow sensor AFM/MAP on the TU when a lot more air is being drawn into the engine.

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

Intake headers transmit the air from the air filter and allow it to be drawn into the engine cylinders.

Shape and flow rate of the Intake can make a noticeable change to fuel atomisation on the TU.

On popular production engines intake are crying out for aftermarket tuning parts, although a few car makers provide reasonably well designed intake.

Increasing the TU valve size, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also improve bhp, and importantly will allow you to get increasing the bhp increase on other parts.

TU performance cam tips.

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

The ecu map and fuel pump and injectors also will say much 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.

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

NB: Fast road camshafts tend to boost the torque across the rpm band, you could sacrifice a little low down power but the higher rpm power will be better.

Competition camshafts, 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 will just annoy you whilst in heavy traffic.

You should ideally optimize your bhp range to your preferences so for a car used daily stick with a fast road TU cam

Stage 1, 2 and 3 mods for the TU

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 TU parts:

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

Stage 2 TU parts:

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

Stage 3 TU parts:

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

Remaps helps unlock the full potential of all the tuning parts you've done to your TU.

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 will rely on the tuning parts you've fitted and the condition of your engine.

Turbo modifications on the TU

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 TU.

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.

If a car is turbocharged, tuning parts are giving better power gains and turbocharged engines are built with more solid components.

There are practical limits for every engine, with some being over specified and some only able to handle stock power

Discover these restrictions and upgrade to higher quality components to handle the power.

We see many people spending a loads of money on turbocharger upgrades on the TU only to see the motor catastrophically fail just after it's been finished.

Large upgraded turbo chargers will usually suffer low end lag, and low capacity turbo chargers spool up much more quickly but do not have the peak rpm power band gains.

In recent times the range of turbo chargers is always improving and we are seeing variable vane turbo chargers, allowing the vane angle 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 turbocharger. They also help the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large power gains, although more difficult to install. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the TU

When you increase the bhp you will need to ramp up to the fuel delivery.

More bhp needs more fuel. Experienced mechanics will tell you to be generous with your injectors flow rate.

As a rule of thumb add another 20% when fitting an injector, this accounts for injector deterioration and allows 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 TU performance exhaust upgrades

We'd only recommend you look to increase your exhaust system with an upgraded one is if your current exhaust is creating a flow problem.

On most factory exhausts you'll see the flow rate is still 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 generally help improve air flow from the engine but avoid an exhaust that is too wide or you may end up will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Usual exhaust restrictions come around the filters installed, so adding a higher 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 TU

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

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This entry was posted under Makes and Models. Tags: engine, PSA
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