IRB Developments - Diesel Tuning and More

Td5 Variable Geometry Turbo Conversion

A joint project between Turbo Technics, and myself has lead to the development of the worlds only bolt on Variable Geometry Turbo conversion for all Td5 powered Land Rovers.

So what's special about a Variable Geometry Turbo?

All turbos' are method of forced induction - i.e. forcing a greater mass of air into an engine.

A conventual turbo consists of two main parts - a turbine (driven by the exhaust gas from the engine) and a compressor wheel (driven from the turbine wheel via shaft).

A turbo charger need to be exactly matched to an engine to ensure it works correctly. In simple terms, if the turbo is too big, you will get turbo lag due to the time taken for the exhaust gas to spin the turbine wheel fast enough to produce useable 'boosted' pressure.

If the turbo charger used is too small, then it will be spinning too fast (thus damaging the turbo due to overspeeding) and it will also 'throttle' the engine as it will not be able to supply the volume of air required. However at low speeds you will have next to no turbo lag.

As is often the case, turbo selection is always a compromise - you want a big turbo so you will be able to compress more air - thus get more power, but at the same time, if you go too big, you will induce turbo lag. But then if you go too small, you will restrict engine performance.

A Variable Geometry Turbo is basically a turbo that can adjust itself internally. So now you have the turbine wheel, the compressor wheel, and a set of vains that direct gas flow around the turbine wheel.

At low engine speeds (when the engine will be exhausting less gas) a Variable Geometry Turbo acts like a small turbo, so makes full use of the lower volume and lower speed of the gas being 'exhausted' by the engine. This means you make full turbo boost pressure at much lower engine RPM - which, when matched with correct fuelling - dramatically changes you low speed torque, and ultimately how your Land Rover drives at low speeds.

As engine speed (and load) increases, the turbo adjusts its internal vains to slow the speed of the turbine wheel down, but at the same time ensuring that it still spins fast enough to ensure the compressor does its job (i.e. making the required boost pressure). By doing this it ensures that the turbine doesn't over speed.

Our Variable Geometry Turbo conversion doesn't just make a difference at low speed though, a Variable Geometry Turbo ensures that the turbo is always working at its optimum setting regardless of load/engine speed (RPM) - this means that turbo lag becomes none existent. You put your foot down, and instantly you will feel the effects!! This can never be obtained with a standard Fixed Geometry Turbo.

If you just want to buy the turbo:

Turbo Options ST2 spec Turbocharger (used in our ST2v conversion)

- £750 + vat including all the required gaskets/seals. This is based on an exchange for your old standard Td5 Turbo.

(a £250 surcharge will be charged until we receive your old turbo - which must be complete and in working order)

Turbo's are normally in stock.

Already got a remap?? - in theory these turbo's will work with your current mapping, however to get the best from the turbo we recommend the use of one of our matched maps. Don't forget we were fundamental in the development of these turbo's, so we know them inside out and can do mapping to match the new characteristics exactly.

Want more...

We also offer a Ultimate Hybrid Version of our Variable Geometry Turbo - but this is only available as a package with out matched ECU calibration (mapping).

See ST3v conversion for more details

There is a 3 week build time for a ST3v conversion.