Alfa Romeo 155 Tuning

"Tuning guide to the most effective Alfa Romeo 155 modifications."

Please note that we welcome comments and additions and are always looking to improve the articles here which are all based on our member comments, questions and tips that have been submitted by my readers.

Replacing the Alfa 75 the 155 fills it's shoes nicely. It represents a very different setup and configuration going to a FWD layout, which caused much anger at launch but Alfa have put together a really good car here and people have learned to love the car, it's handling and the engine options.

The 155 is a good car tuning project to do. The key to 155 tuning is balancing power and reliability you can waste loads of money if you do it wrong.

Tuning tips and articles

Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Our aim in 155 engine tuning should be to increase peak power and Torque at the top end.

Enjoy your 155 to the max with our awesome performance tuning tips - do the right mods in the right order.

The best power gains come from larger engine sizes. The more you start with the bigger the return on investment so engine swaps are good value mods for small engined cars.

Engine tuning mods.

The following engines were offered in the 155 and many had the twin spark engine.

  • 1.7 L I4 8V TS
  • 1.8 L I4 8V TS
  • 2.0 L I4 8V TS
  • 1.6 L I4 16V TS
  • 1.8 L I4 16V TS
  • 2.0 L I4 16V TS
  • 2.0 L I4 16V Turbo
  • 2.5 L V6 12V
  • 2.0 L I4 TD (diesel)
  • 2.5 L I4 VM 425 OHV TD (diesel)

This list of the stages and modified kits are usually fitted by our members, decide how far you want to go before you get going.

Getting the correct grade of sports upgrade kits for your planned usage of the car is essential. Stage 3 competition upgrades just don't work well on the road difficult in stop start traffic.

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Guide to the Best Tuning Mods & Upgrades

  1. Mods that Remove a Restriction

    If the intake or exhaust are restricted in any way this will have an impact on your cars performance, so use an induction kit/filter upgrade and better flowing exhaust whenever your tuning creates a flow restriction.

  2. Mods that Improve Handling

    Braking, Suspension and general alignment of the suspension components is vital for any tuning project even before you start increasing power.

  3. Fit Stronger Parts

    Tuned cars will show up weaknesses, typically in the turbochargers, clutch and internal engine components. Whilst most engines can cope with mild tuning mods, TorqueCars recommend that you upgrade the internal components before these weak spots manifest themselves.

  4. ECU Tunes & Remapping

    While some cars can be easily remapped, others may require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project as it fully releases the power from all of your mods and upgrades. Expect 10-20% on NASP engines and 30-40% on turbocharged units.

  5. More Power Needs More Fuel & Air

    Every tuning project will aim to increase the air supply, but fuel supply is just as vital and will need to match the air the engine can utilise. Fuel to Air ratio is vital so upgrade the fuel pump & injectors. Also you can look to perform head mods (flowing and porting), bigger valves, fast road cams and forced induction upgrades to improve fuel.

Stages of Tune

Stage 1 mods: Suspension upgrade (drop 30-40mm), Remap, Panel air filter, Sports exhaust, Lighter flywheel, Alloy wheels.

Stage 2 mods: high flow fuel injector, fuel pump upgrades, Ported and polished head, Power/Sport clutch, Fast road cam.

Stage 3 mods: Competition cam, Internal engine upgrades (pistons/head/valves), Sports gearbox, Adding or upgrading forced induction (turbo/supercharger), Engine balancing.

Peak power is all well and good but for a daily driven car you need a long torque band and perhaps extending the rev range.

In this article we shall give an overview and introduction to the best mods for your car, but we'd encourage you to spend some time on the site looking into the details of each type of performance mod.Fast road cams offer one of the biggest torque gains for your money as far as a stand alone modified parts goes on a NASP engine.

The intake & exhaust durations play a large part in your cars power band, but be careful here, getting this wrong can upset the idle and make the car impossible to drive in traffic. You'd need to follow a cam upgrade with other mods and finish with a reflashed ECU to fully release the power gain.

When pushing up the power you will need to ramp up to the fuelling. More power needs more fuel.

Frequently power losses, and erratic idling after performance kits are done can usually be traced to fuelling or timing issues.To get sufficient fuel you may need to increase the injectors on your engine.

Uprate the fuel pump to cope with the extra fuel requirements of your tuned 155s uprated injectors.

Intake and Exhaust Tuning.

Breathing mods are usually next up. Contrary to popular belief there is usually very little power gain to be had by fitting an induction kit, they only work well and are recommended after you boost the engines power to the point where the standard air intake box cannot cope!

Maximum power gains come from a full induction kit with a cold air feed on heavily tuned engines, this can be sited within an air box but a performance panel filter should suffice for most applications. TorqueCars suggest you use a panel air filter as these are easy to clean and maintain and generally perform better than paper ones.

Sports exhausts can help balance the flow of gases through the engine. But if the exhaust is too large, ie: it's over 2.5 inches bore, you will lose a great deal of the flow rate and end up lacking power and torque.

Head work including a polish and port and 3 or 5 angle valve job will really help to release the potential of the engine. Your clutch can lose you loads of power as the power goes up if it starts to suffer and the standard clutches are only ever good for power gains of up to 40%. Fit a power clutch to avoid power losses through the transmission. The best mods we recommend for your 155 are Remapping or piggy back ecu, fast road cam and air intake and exhaust.

Remaps offer big power gains on all turbo charged cars. On NASP engines the benefits are doubtful. However a chipped ECU on a NASP engine will help unleash the potential if you have done a lot of mods.

We've also seen some tuners toying with twincharged applications and making some very high power figures.

Despite the large cost involved adding forced induction to a NASP engine will give large power gains. Superchargers are usually easier to add than turbos. With a turbo the power curve is related exponentially to the engine speed making it harder to map.

It is easier to map a supercharger because the boost is correlating to engine speed on a linear curve. To cope with forced induction you will usually need to decrease the engines compression ratio .

Handling/Suspension upgrades

Handling modifications are high on most peoples lists for the 155.

If you set the toe out to 1 to 2 degrees on the front, and add a little negative camber then cornering will usually improve.

Drop the car by as much as 21mm - 38 mm and fit performance stiffer dampers, bigger drops will need other modifications in most instances.

Alloy wheel upgrades.

Due to the fact that alloy wheels are less heavy they improve performance and they help to cool the brake disks. We can't go into too much detail here about tyres but they are how the car puts the power down on the road so are a critical choice. directional tread pattern tyres work well on 155, and make a big difference over budget tyres. The drawback to large alloys on your 155 is that you're altering your effective final drive ratio and this will have a detrimental effect on performance.

Although some people have with bigger wheels without problems we would stick to a 17 inch rim size as the maximum.

There is a more updated version of this Alfa Romeo 155 Tuning article on TorqueCars.com.

For more information on Tuning your car please join us in our friendly forum where you can discuss 155 options in more detail with our 155 owners. It would also be worth reading our unbiased Alfa Romeo tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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