[omerakz]

Hello,

I own a 220D with N47 twin-scroll single turbo engine.

As far as i know some 2.0 Liter diesel engines are twin turbo (123D, 225D) and i am wondered if it is possible to turn a twin-scroll single turbo engine to twin turbo.

Would it be too much work?

[Enabled]

For what it's worth, your current turbo is not a twin scroll, it is a variable geometry turbo, labeled as "Twin Power".

Upgrading to two turbos would require programming the ecu to know this, to be able to control both, but, it wouldn't add any power without increased fueling capacity.

So it really depends what your goals are. It would be a lot of work with minimal to no gains at all if not upgrading everything else around it. And then if you're upgrading other things, it becomes a huge custom job.

[Watsey]

Originally Posted by omerakz

Hello,

I own a 220D with N47 twin-scroll single turbo engine.

As far as i know some 2.0 Liter diesel engines are twin turbo (123D, 225D) and i am wondered if it is possible to turn a twin-scroll single turbo engine to twin turbo.

Would it be too much work?

In all honesty have you considered that you may be driving the 'wrong' car for your needs/wants ?

You've posted about removing the DPF, increasing the diameter of the exhaust, and now you want to attempt a twin-turbo conversion.

Sounds to me like you need a 328d/330d/335i/340i.

[omerakz]

Originally Posted by Watsey

In all honesty have you considered that you may be driving the 'wrong' car for your needs/wants ?

You've posted about removing the DPF, increasing the diameter of the exhaust, and now you want to attempt a twin-turbo conversion.

Sounds to me like you need a 328d/330d/335i/340i.

You may be right, i am driving 220D right now and it is the fastest affordable 2 series in my country. (~$45K)

If there were 228i or 225D, i would of course choose that. But since we only have 218i (136hp), 220D (184hp) and M235i (~$140K because of taxes) my only option in 2 series was 220D.

I am driving it as daily and track car, that's why i am trying to get more power from it's 2.0 L diesel engine.

I may upgrade to M235i/335i or some other fast cars in the future, but right now, this one is my "experimental" car that teaches me a lot about tuning and track driving.

[omerakz]

Originally Posted by Enabled

For what it's worth, your current turbo is not a twin scroll, it is a variable geometry turbo, labeled as "Twin Power".

Upgrading to two turbos would require programming the ecu to know this, to be able to control both, but, it wouldn't add any power without increased fueling capacity.

So it really depends what your goals are. It would be a lot of work with minimal to no gains at all if not upgrading everything else around it. And then if you're upgrading other things, it becomes a huge custom job.

Thanks for the answer.

Since there is Twin-Turbo version of the same engine, i tought it would be possible to convert Twin-Power to Twin-Turbo.

But it seems like it will be a lot of work with a risk of no power gain.

[AleeL]

Originally Posted by Enabled

For what it's worth, your current turbo is not a twin scroll, it is a variable geometry turbo, labeled as "Twin Power".

Upgrading to two turbos would require programming the ecu to know this, to be able to control both, but, it wouldn't add any power without increased fueling capacity.

So it really depends what your goals are. It would be a lot of work with minimal to no gains at all if not upgrading everything else around it. And then if you're upgrading other things, it becomes a huge custom job.

Sorry for bringing up an old thread, but I came across this when looking up information on my 328D and felt the need to respond.

A turbo can have a twin scroll setup and variable geometry at the same time. In a twin scroll setup, the exhaust manifold splits the exhaust coming from the cylinders so that a cylinder that is pushing exhaust out is never connected to a cylinder that is in over lap; which is that brief moment when the exhaust and intake valves are open at the same time) so it does not suck exhaust gases into the cylinder on it's intake stroke.. This overlap is more pronounced in engines designed for performance since they have more aggressive timing.

Twin scroll setups will generally have an exhaust manifold that will split the front bank of cylinders from the back bank of cylinders so as the piston in the front bank pushes exhaust out, it cannot be drown into the piston doing the adverse thing on the back bank. This allows for decreased turbo lag, quicker turbo spool, and increased valve overlap without negative effects of drawing in exhaust gases.

A variable geometry turbo is just one that uses a vane(or some other device) to change the aspect ratio of the turbine inlet causing the turbine blade to spin faster or slower. Both can be done on the same setup and would compliment each other in a performance diesel engine.

[Watsey]

Originally Posted by AleeL

Sorry for bringing up an old thread, but I came across this when looking up information on my 328D and felt the need to respond.

A turbo can be twin scroll setup and variable geometry at the same time. In a twin scroll setup, the exhaust manifold splits the exhaust coming from the cylinders so that a cylinder that is pushing exhaust out is never connected to a cylinder that is in over lap; which is that brief moment when the exhaust and intake valves are open at the same time. This overlap is more pronounced in engines designed for performance since they have more aggressive timing.

Twin scroll setups will generally have an exhaust manifold that will split the front bank of cylinder from the back bank of cylinders so as the piston in the front bank pushes exhaust out, it cannot be drown into the piston doing the adverse thing on the back bank. This allows for decreased turbo lag, quicker turbo spool, and increased valve overlap without negative effects of drawing in exhaust gases.

A variable geometry turbo is just one that uses a vane(or some other device) to change the aspect ratio of the turbine inlet causing the turbine blade to spin faster or slower. Both can be done on the same setup and would compliment each other in a performance diesel engine.

OK, but the OP was asking whether a single turbo engine can be converted to a twin turbo setup.

[AleeL]

Originally Posted by Watsey

OK, but the OP was asking whether a single turbo engine can be converted to a twin turbo setup.

Understood, but the person I quoted said the OP's current setup is not twin scroll, which it is.

How does BMW TwinPower Turbo work: The technology explained


I was just clarifying that.