fiestaturbo.com

[IanRST]

If you are running say 10 psi boost on a std T2 turbo what difference would there be if any if you ran 10 psi on a hybrid T3? On the fiesta?

[Stoned]

I thought the idea was bigger turbo's allow for higher boost levels, if so running both at 10psi would provide exactly the same results...

[MadcatCraig]

Stoned is incorrect

T3 is a bigger turbo spinnign at the same speed as a t2 it is flowing more air.

the boost pressure is just that pressure 10psi on a t3 is 10 psi on a t2 but due to the t3 being physically bigger its flowing more air at 10psi then the t2 at the same pressure

[Quantum]

The T2 should come on boost earlier than the T3, but the T3 will hold the boost for longer than the T2. Craig is this what you mean by the T3 being able to flow more air than the T2, if not could you please explain what you mean?

Regards,
Stephen

[MadcatCraig]

nope steven thats not what i mean but is true.

Imagine a wind tunnel with a small fan at one end standing in the middle

run that fan upto a certain speed

it will spin up quickly and u may feel the force.

now imagine a bigger fan it will take longer to spin due to its size btu as its much bigger once upto speed the force of the fan will be much greater due to its size.

this goes for T2 (small fan) and T3 (bigger fan)

the compressor wheel in it is physically bigger thuis the greater VOLUME of air it will flow

im not the sharpest tool in the box when it comes to xplainign things so im sure someone else can do a better job

[xrsi]

basically imagion a small container and a big container sitting next to each other!

the small one will take less air to pressureise it to say 10psi than the larger one! this is exactly the same principle with the two turbos! t2 - small t3 big (in compairison!! )

[chumkila]

Why are different size turbochargers used?

The size of the turbo dictates the response and maximum boost capacity. A small turbo gives quick response, and a big turbo has a high maximum boost capacity. Any turbocharger choice will be a compromise of these two considerations. As an indication, the T025 turbo used on the latest generation Escort Cosworth can produce 1.4 bar boost pressure from 2000 RPM, but by 5500 RPM, this is reducing acutely. The T04 turbo used on the RS 500 does not produce any significant boost pressure below 4500 RPM, but can still produce over 2.0 bar of pressure at 8000 RPM. (Both examples are with a 2 litre engine.)