Modding uprating the Hyundai Sigma engine!

Explore Sigma Modifications"

How to modify and upgrade the Hyundai Sigma

"Comprehensive guide to tuning and performance parts on the Hyundai Sigma engine!"

Sites like TorqueCars often are getting emails asking about how to improve the Sigma from people inquiring about getting more power from the Sigma and wanting to know what are the optimum Sigma mods that work. So let us look into Hyundai Sigma upgrades and outline the best mods that work on this great engine and point out some potential pitfalls along the way.

Therefore we consider Sigma tuning and provide tips on the best modifications. Hyundai Sigma make awesome project engines and with the ultimate motorsport mods like ECU maps, turbo improvements and camshafts you will dramatically maximize your driving opportunities.

The top Sigma parts on an engine are as we have found the ones that give the best gains for your money.

We won't be swayed by popular Sigma parts, they need to be cost effective.

Sigma induction kits

Improving air intake on the Sigma

You need fuel and air for an engine to work. If there is not enough fuel then it will run lean, if there is insufficient 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 aim to any engine upgrade job to force more air into the Sigma engine but this has a knock on effect with the air flow sensor.

It is not unusual that there's a limitation in the air flow sensor AFM/MAF on the Sigma 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.

Headers 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.

The bore size, shape and flow characteristics of the Plenum can make a large improvement to fuel atomisation and engine efficiency on the Sigma.

On popular production engines plenum chambers are needing motorsport parts, although a few car makers provide well optimised plenum chambers.

Adding a Sigma larger valve kit, doing a bit of port matching and head flowing will also improve torque, this will raise potential for a greater torque increase on other parts.

Sigma performance cam tips.

Different Sigma engines respond better to more aggressive camshaft durations so view each engine as unique.

The map and fuelling also will make differences on the bhp gains you'll make.

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.

Altering your Sigma cam will make a dramatic difference to the engine bhp. Choosing a higher performance cam profile raises the bhp accordingly.

NB: Fast road camshafts normally increase the bhp through the rpm range, you could drop a little low down bhp but top end will be higher.

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.

A Race cam will just annoy you whilst driving around busy urban areas.

You should ideally match your torque band to your preferences so for a typical daily driver stick with a mild fast road Sigma cam

Stage 1, 2 and 3 mods for the Sigma

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 Sigma parts:

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

Stage 2 Sigma parts:

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

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

Stage 3 Sigma parts:

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

The Sigma units make great tuning projects and we're pleased to see that there is a growing number of modifications and performance parts around.

Remapping should help to unlock the full potential of all the upgrades you've done to your Sigma.

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 your mileage usually rely on the upgrades you've done and the condition of your engine.

Turbo modifications on the Sigma

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 Sigma.

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.

When your car is turbo charged upgrades are simpler to install and you will discover turbocharged engines are made with many forged and stronger components.

However you'll find engines have limits

Research these restrictions and install more solid crank and pistons to utilize the power.

We see many mechanics spending a loads on turbo upgrades on the Sigma only to experience the car literally blow up when it's been enthusiastically driven.

Larger upgraded turbo units often experience a bottom end lag, and low capacity turbo units spool up quickly but don't have the peak rpm bhp gains.

Thankfully the choice of turbochargers is always developing and we are seeing variable vane turbochargers, permitting the vane angle is altered according to speed to lower lag and increase top end power.

Twin scroll turbochargers divert the exhaust flow into two channels and direct these at differently angled vanes in the turbo charger. 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 power gains, although more complex to setup. We have this article covering twinchargers if you want to read more.

Tips about fuel supply on the Sigma

Don't miss you'll need to uprate the fuel system when you are increasing the bhp - it makes the car more thirsty. Most tuners we speak with say to over specify your flow rate on the injectors.

The accepted safe increase is to add 15% to the flow rate when buying an injector, this allows for injector deterioration and affords 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 Sigma performance exhaust upgrades

You only need to to improve your exhaust system with an upgraded one is if your current exhaust is actually causing a restriction.

On most factory exhausts you'll see your 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 generally help improve air flow out of the engine but avoid an exhaust that is too wide or you could will reduce the flow rate. Stick to one and a half to two and half inches for best results.

The usual suspects causing problems in your exhaust flow rate can be located the filters installed, so adding a higher flowing high performance 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 Sigma

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

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