Alfa Romeo 155 Tuning

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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.

You can do a lot to improve the performance of your 155 with our step by step tuning tips. With the right mods your 155 can be transformed into a stunning project. Don't waste money, do your homework and follow our unbiased guides to each performance upgrade so you don't waste your money.

Improving the handling for DIY mechanics first priority in your 155 tuning project. We would go to a maximum drop of 35mm on most models. You risk rubbing on the arches if you go lower than this.

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

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.

Power mods.

The following sports modifications are usually fitted by our members, decide how far you wish to go in your tuning project before you get going.

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)

Getting the right uprated modifications for your planned usage of the car is essential. Stage 3 (competition) mods just won't work well on the road and will make the car undrivable.

Please watch our video which covers the 5 principles of tuning your car. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your 155

1. Turbo upgrades - forced induction is the most significant way to increase your intakes air supply, ensuring you are able to use more fuel and make higher power. Typically one of the most challenging mods you'll see massive gains.
2. 155 Handling Mods (Suspension) - Upgrading your suspension dramatically improves 155 handling Coilovers and Bushings are the usual go to mods
3. Intake and Sports Exhausts - Be aware on their own these mods won't ADD TORQUE for most setups, but they permit you to lift power after other mods by removing the restriction.
4. Brake Mods - Stopping your 155 needs to be near the top of your Mods list.
5. Lightened Flywheels - a lower weight flywheel will improve the engines rev changes. Not recommended for all 155 engines.
6. Fast road Camshafts are significant power adders, but we strongly suggest they be installed by someone qualified to set them up and it is often hard to find a suitable cam near you but we are sure you'l; find a local firm to regrind a stock camshaft for you.
7. ECU Tunes - A tune/remap provides the most advantage compared to your outlay, aftermarket ECU upgrades, and Tuning boxes are all alternatives.
8. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting

155 Tuning Stages

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

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

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

You really need to keep as much low end power as possible and aim for a wide power band rather than a narrow top end power hike.

In this article we shall give a little insight into the world to the best upgrades 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.One of the biggest mechanical motorsport modifications you can do to your NA (naturally aspirated) engine is to fit a fast road camshaft .

The intake and exhaust flow play a large part in your cars power band, but be careful here, getting this wrong can upset the idle and make the car difficult to drive in traffic. You'd need to follow a camshaft upgrade with other mods and finish with a performance chip to fully realise your gains.Don't forget to increase the fuelling when you are increasing the power - it makes the car more thirsty.

155 Turbo upgrades

NA (naturally aspirated) engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your 155

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.

If your car is turbocharged, mods are going to make more power and you'll see that turbo engines are built using uprated components.

However you'll find engines have limits.Research these limitations and upgrade to more solid crank and pistons to handle the power.

We've seen tuners spending lots of money on turbo upgrades on the 155 only to see the engine block throw a rod when it's used on the roads.

Larger turbo units commonly suffer a bottom end lag, and small turbo units spool up quickly but do not have the top end bhp gains.

Thanks to new tech the selection of turbo units is always improving and we are seeing variable vane turbo units, permitting the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo units divert the exhaust flow into two channels and flow these at differently profiled vanes in the turbo. They also boost the scavenging effect of the engine.

You'll commonly see there is a limitation in the air flow sensor MAP/MAF/AFM on the 155 when a lot 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.

Adding a supercharger or additional turbo will make large performance gains, although more difficult to install. We have this feature on twinchargers if you want to read more.

155 Fuelling Upgrades

You will need to ensure that the engine is not starved of fuel so must look at the fuelling when you start going beyond 20% of a bhp and torque increase. Fuel pressure boost valves raise the fuel pressure, providing a more snappy throttle response.We would recommend you to over specify your injector capacity.

The accepted safe increase is to add 20% when buying an injector, this accounts for injector deterioration and gives you some spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

If you find you get flat spots and power surges after your modified modifications you should check the fuelling and try a higher octane fuel as well. To get sufficient fuel you may need to uprate 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. Please note that WE DO NOT RECOMMEND INDUCTION KITS, unless you have tuned your car extensively and are finding that the standard air intake has become a restriction. 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 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 will certainly help air flow through the engine but do not go too big or you could very well end up with a reduced flow rate. So generally speaking, keep to 1.5 to 2.5 inches as a rule of thumb.

Getting the cylinder head ported and polished will further help more air into each cylinder. This is definitely a job for a pro with a flow bench. A good multi plate fast road sports clutch will help to keep that power going where it should.

Never cut corners or think that the standard OEM clutch to cope. NA (naturally aspirated) engines do not achieve big power gains if you tune/remap them, unless you have done extensive modifications. With turbocharged engines this is another story.

A tuned/remapped 2.0 turbo will give large power gains and take full advantage of the strength of the block. Despite the large cost involved adding forced induction to a NA (naturally aspirated) engine will give large power gains. It is usually simpler to add a supercharger than it is to get a turbo working. With a turbo the boost curve is related exponentially to the engine speed making it harder to map.

The nice steady boost and rpm characteristics of the supercharger make them easier to map. Decreasing the engines compression ratio will allow you to add forced induction, water injection may also help prevent detonation.

Alloy wheel upgrades.

Due to the fact that alloy wheels are less heavy they improve performance and they will help to cool the brake disks. The downside to large alloy wheels on your 155 is that you alter your final drive ratio and this will have a detrimental effect on acceleration and performance.

Due to this fact try to keep the overall rolling diameter of the wheel the standard factory sizes. In all cases avoid going over 17 inches.

If you would like to know more, or just get some friendly advice 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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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Alfa Romeo. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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