Popular articles

Diesel tuning
Remapping ECU
Double declutch
Safety mods
Induction Kits
Customize a car
Performance Chips
Insuring Modified Cars
Insuring Track days
Diesel Remaps
MPG calc

Nos Nitrous

Adding NoS nitrous oxide to boost power gains.

Performance Tyres

Tyres and tread patterns for High performance cars

Wide Body Kits

Wide body kits and flared arches

Suicide Doors

Suicide doors

Brake Pads

Changing brake pads and discs a DIY guide

Car Technology

In car technological developments

MPG Calculator

MPG calculator UK miles per Gallon – calculate MPG

Member Benefits



Sign up now!!!

Forum Hot topics

    Sign up now
  • Problem adding headlight conversion ...
    Sign up now
  • Hi from me in Lincolnshire...
    Sign up now

Twincharging your engine

"Seeing double"

Volkswagen were one of the first mainstream car companies to pioneer and introduce twin charging, although Lancia pioneered a Twincharger set up back in the 80's on the Delta S4 rally car.

What is twincharging and why is it beneficial? Are there any downsides?

Twincharging is where both a supercharger and a turbo are fitted to an engine.

The merits of superchargers lie in the fact that they produce linear power gains in relation to the RPM of the engine, mimicking a large capacity engine.

Superchargers can run out of steam at higher RPM levels which is where a turbo charger comes into its own.

A turbocharger takes a while to get going as it needs a good flow of exhaust gases but when it does it can make large power gains from mid range right up to the high end of the RPM range.

When you have both fitted you quite literally have the best of both worlds, lots of low down power and plenty of extra boost in high RPM levels. The reason for doing this is that in applications where you need loads of boost and not a lot of air flow like in diesel engines (due to lack of revs) and small petrol engines you need forced induction.

No turbo will flow 30 lbs/min at 40 psi.  So you use 2 to make it up and keep both of the turbos or supercharger and turbo operating efficiently.

You have the smaller of the 2 making loads of boost pressure and the bigger being able to flow the total volume of air not just half, it needs to flow all of it. So put the larger/better flowing unit nearest the engine and leave the smaller compressor near the air intake.

Thanks to compounding, the effect of two stages of compression will actually mean the air compression is much higher than that just adding the two compressors boost amounts together. For this reason you can get a substantial boost increase from relatively low cost components. (10psi Turbo + 10psi supercharger = just under 30psi of boost!)


Most Twincharging applications will follow a few common routes. 



Twincharging allows you to get high boost levels from relatively low cost components. It is a great way to increase the power of a small engine with a high RPM range.


So how do you create a Twincharging application for your car? Our members have played around with various set ups and Claymores Turbo volvo is a good example of what can be achieved quite easily. His set up takes the output of compressed air from the turbo and then uses the supercharger to compress this further.

Obviously there is quite a large heat build up issue so a larger intercooler is a pre-requisite. Some set ups use a twin intercooler at each stage, others stick with a larger capacity intercooler and these can always be sprayed with water or nitrous to further reduce the intake temperatures.





The trick after you have plumbed in the second compressor is getting the mapping and air fuel ratios right. Failure to get this right can lead to over fueling and/or detonation in the engine. A twin charged engine is best set up on a rolling road with proper diagnostic equipment and most cars will need an aftermarket ECU to cope with the extra mapping requirements.

A small word of caution on Twincharging relating to throttle body placement: It needs to go between the Turbo and supercharger if used in compound charging or the back pressure when the throttle is closed at high revs can destroy the supercharger.

You will also need to lower the compression ratio of the engine if you want to run high boost and the overall principles of adding a turbo to a non turbo engine apply to situations where a second charger is added.

There are an increasing number of Twincharging kits coming on to the market for popular turbo engines. A kit will usually provide all the mechanical components you need to get a Twincharger set up  and working correctly.



Quarter mile time calculatorSuicide door conversionsRemapping guideWhat is your car thinking



Help us improve, leave a suggestion or tip

Your Constructive comments on this article

One Response to “Twincharging an engine”

  1. scott says:


Search this site