Alfa Romeo Twin Cam Tuning

"All you need to know about tuning the Alfa Romeo Twin Cam engine!"

The Alfa Romeo Twin Cam make awesome project engines and with carefully picked uprated modifications like a remap, turbo upgrades and camshafts you will definitely increase your driving pleasure.

Let us consider Twin Cam tuning and summarise the optimum upgrades.

History, Power & Specs of the Engine

  • 0.9 L 54.7 cu in (896 cc)
  • 1.3 L 78.3 cu in (1,283 cc)
  • 1.3 L 78.7 cu in (1,290 cc)
  • 1.4 L 82.8 cu in (1,357 cc)
  • 1.5 L 90.9 cu in (1,489 cc)
  • 1.6 L 95.6 cu in (1,567 cc)
  • 1.7 L 106.7 cu in (1,749 cc)
  • 1.8 L 108.2 cu in (1,773 cc)
  • 1.8 L 108.6 cu in (1,779 cc)
  • 2.0 L 119.7 cu in (1,962 cc)
  • 2.0 L 121.7 cu in (1,995 cc)
  • 2.1 L 125.5 cu in (2,056 cc)

Tuning the Alfa Romeo Twin Cam and best Twin Cam performance parts.

Best Twin Cam tuning parts

The top Twin Cam upgrades on an engine are usually the ones that give the best value for money.

We won't be swayed by popular Twin Cam upgrades, they need to be cost effective.

Significant gains on the Twin Cam can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

Fast road camshafts tend to bump the bhp through the rev range, you could sacrifice a little low end power but your high end rpm power will improve.

Motorsport camshafts, bump the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a daily driver must carefully try to match your engines power to your typical driving style.

I'd be surprised if you find a Twin Cam Motorsport and race camshaft is a pleasure to live with when in heavy traffic because low end power will be very lumpy. Competition cams are designed for maximum power at the top end of the RPM range, a place that most daily commutes will not permit!

Some Twin Cam engines respond better to more aggressive cam durations so view each engine as unique.

The ECU mapping and injectors and fuel pump also have a large bearing 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.

Typical stage 1 mods often include: Remaps/piggy back ECU, Sports exhaust manifold, drilled & smoothed airboxPanel air filters, Fast road camshaft, Intake headers.

Typical stage 2 mods often include: high flow fuel injectors, Ported and polished head, Fast road cam, Sports catalyst & performance exhaust, fuel pump upgrades, induction kit.

Typical stage 3 mods often include: Crank and Piston upgrades to alter compression, Competition cam, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Twin charging conversions.

Review your options and then acquire your tuning parts and set yourself a power target to save yourself from expensive mistakes.

ECU flashing should help to to establish the full potential of all the parts you've fitted to your Twin Cam.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your results usually rely on the parts you've done and the condition of your engine.

It is the whole point to any performance tuning task to pull air and fuel into the Twin Cam engine

Headers take the air from the filter and allow it to be sucked into the engine cylinders.

The size of bore and shape and flow characteristics of the Plenum can make a large effect on to fuel atomisation and engine efficiency on the Twin Cam.

We often see headers are ripe for performance upgrades, although some car makers provide reasonably good headers.

Increasing the Twin Cam valve size, getting Twin Cam port enlargement and head flowing will also improve performance, and more importantly will permit increasing the performance increase on other parts.

Turbo upgrades

NASP 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 Twin Cam

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 an engine is turbocharged, upgrades are giving better power gains and turbo charged engines are built using uprated components.

There are common areas of failure for every engine, with some being extremely strong and some just sufficiently able to handle stock power

It is important to find these limits and upgrade to more solid crank and pistons to utilize the power.

We've seen people spending a loads on turbo upgrades on the Twin Cam only to experience the Twin Cam literally blow up when it's been completed.

Larger turbochargers commonly suffer a bottom end lag, and small turbochargers spool up quickly but don't have the peak rpm engines power gains.

We are pleased that the market of turbos is always developing and we now see variable vane turbos, where the vane angle is altered according to speed to lower lag and increase top end power.

Twin scroll turbos divert the exhaust flow into 2 channels and feed these at differently profiled vanes in the turbocharger. They also help the scavenging effect of the engine.

It is not unusual that there is a limitation in the air flow sensor AFM/MAP on these engines when a lot more air is being sucked into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp and torque at a much lower level.

Adding a supercharger or additional turbo will make large torque gains, although more difficult to setup. We have this article on twincharging if you want to read more.

Fuelling

Don't overlook the need to pay attention to the fuel system when you are increasing the bhp and torque - it makes the car more thirsty. Don't forget to over specify your injector capacity.

The rule of thumb is to add 20% to the flow rate when fitting an injector, this allows for injector deterioration and affords some spare capacity should the engine need 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.

Exhaust

You only need to to increase your exhaust if the current exhaust is actually creating a restriction.

On most factory exhausts you should find that the flow rate is fine even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts can help equal out the flow of gases through the engine.

But if your exhaust pipe is too large, ie: over 2.5 inches bore, you will lose much of your flow rate and end up sapping power and torque.

Usual exhaust restrictions are traced to the catalysts installed, so adding a freer flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots Issues & problem areas on the Twin Cam

The Twin Cam engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the Twin Cam, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your Twin Cam engine please join us in our friendly forum where you can discuss tuning options in more detail with our worldwide members, or read our tuning articles  to get a full grasp of the benefits and drawbacks of each modification.

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