Asked Questions

What is a turbo expander?

It’s basically a ‘cold air’ turbocharger

How does it work?

The engine charge air passes through the compressor; it’s then cooled and flows into the turbine.  The turbine drops the temperature and the power generated drives the compressor. Under road conditions the charge air temperature can be up to 15 degC BELOW ambient temperature

What are the benefits of a turbo expander?

Increase knock margin, allowing increased ignition advance and higher boost pressures

Why have I never heard of these before?

Because it’s not been done before, although known about in R&D circles

Who else uses turbo expanders?

No one

How else can I get lots of extra power for my car?

Increasing boost pressure is the only way. Without the ACT system the boost temperatures rise, leading to early onset of knock.  This in turn requires ignition retards and over-fuelling.  For very highly boosted engines ‘mega-knock’ is a big risk ~ two ‘bangs’ followed by piston failure

Will it work on my car?

The system will work on all turbocharged petrol engines.  The results will depend on the state of tune and any changes already made to the main boost system. It works in a different way of diesel engines, but can still produce power increases

Can I buy a kit?


Can I fit it myself?

No, the installation requirements are very specific to this new technology

Where do I have to go for a fitting?

To ACT for first-fit systems is required.  Standard kits will be fitted by an ACT distributor

What extra power can I expect?

The actual power increase depends on the state of tune of your engine.  The higher the tune and the more knock-sensitive is it, then the greater the gain with the ACT system

How reliable is this device?

Completely, it operates like a ‘cold’’ turbocharger, so has a much longer life

How long does fitting take?

The time required is installation-specific; we will quote for your exact requirement

Do you test the car before and after fitting?


What if it goes wrong?

If it fails due to our workmanship we’ll replace it !!!

What guarantee do you offer?

12 months

How much does it cost?

Please contact us

Does it work for Trains, boats, Planes, Generators?

It will operate on all turbocharged engines, both petrol and diesel

When will you be able to offer fitting in the North of England/Scotland/Wales/N Ireland etc.?


Will the turbo expander reduce my car’s harmful emissions?

Yes, it will reduce unburnt fuel emissions on high power petrol engines. On diesel engines it will reduce NOx emissions

ACT Turbo Expander