MENUAlfa 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.
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How to tune your car
- Improve the handling
Focus on Suspension improvements, such as coilovers and make sure the bushings are in good order and that the alignment is correct. Then focus on improving the brakes, with a big disk brake conversion kit and fast road brake pads.
- Remove restrictions
Focus on the intake and exhaust with filters being the common point of restriction in a tuned car. Intercoolers may also become restrictive on turbo engines so this may also need to be uprated.
- Burn more fuel & air
Increase the fuelling so it matches the air coming into the engine. The ratio is important so you need to improve the fuel pump and injectors, so the head mods, big valve conversions, fast road camshafts and forced induction upgrades extra supply of air is adequately met.
- Test and replace any weak parts
Weak areas are commonly the clutch, the turbocharger and pistons and crankshaft in a highly tuned engine. Makes sure these components will cope with your power aspirations.
- The Tune or Remap
A cars ECU controls the fuel, timing, spark and even the turbo in some cases, so to fully extract your gains you should remap the car last and this will fully release the power. Some cars are easy to map, and others require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project.
Modifying to Stage 1:
Remap, Sports exhaust, Alloy wheels, Suspension upgrade (drop 30-40mm), Lighter flywheel, Panel air filter.
Modifying to Stage 2:
Power/Sport clutch, high flow fuel injector, Ported and polished head, Fast road cam, fuel pump upgrades.
Modifying to Stage 3:
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 NASP 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.
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 will reduce the flow rate. Stick 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. NASP engines do not achieve big power gains if you remap them, unless you have done extensive modifications. With turbocharged engines this is another story.
A 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 NASP 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.
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.
Please help us improve these tips by sending us your feedback in the comments box below. We love to hear what our visitors have got up to and which mods work best for them on each model of car. Comments are used to improve the accuracy of these articles which are continually updated.
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