[bmwmmm]

I don't know if anyone saw this but the diagram that shows the 525d and 535d turbos have them pictured as twin scroll turbos/ The turbo exhaust intake port and exhaust manifold ports are divided so doesn't that make them twin scroll turbos as that's what twin scroll turbos are? But then again the exhaust manifold is not divided for each port as twin scroll setups should be.( =Bank 1 and 3 for first scroll and bank 2 and 4 for second scroll.)
So its confusing when people say its varible turbine geometry not twin scroll but hten it is setup almost like a twin scroll excluding the manifold.

[HighlandPete]

Originally Posted by bmwmmm

I don't know if anyone saw this but the diagram that shows the 525d and 535d turbos have them pictured as twin scroll turbos/ The turbo exhaust intake port and exhaust manifold ports are divided so doesn't that make them twin scroll turbos as that's what twin scroll turbos are? But then again the exhaust manifold is not divided for each port as twin scroll setups should be.( =Bank 1 and 3 for first scroll and bank 2 and 4 for second scroll.)
So its confusing when people say its varible turbine geometry not twin scroll but hten it is setup almost like a twin scroll excluding the manifold.

I think you are confusing the "two-stage twin-turbo" setup of the 525d and 535d, with the totally different turbo setup of the 520d. Yes there is a dual port in the manifold of the 525/535d, one port houses the "turbine control valve" which has to be there to control the gas flow to one or other, or both of the turbos. Hence why there are two ports, one directly flowing to the high pressure turbo, the valve controlling flow and/or bypass, which allows more gas to the lower pressure turbo as the rpm increases. This setup is not a twin scroll turbo. The two turbines are housed in different turbo casings, both with independant compressor wheels. The turbos are technically "sequential turbos", although the two do work together at some rpms. So nothing wrong in using TwinPower as a description for a 'two' turbine setup.

Now the issue is really with the single variable vane turbo, to which BMW also add the label of TwinPower.

Another example would be in the 2.0d X1 which uses the standard N47 engine with one turbo. The BMW blurb reads, "BMW TwinPower Turbo four-cylinder in-line diesel engine" then BMW say, "Single turbo variable vane geometry".

TwinPower cannot just mean twin scroll, twin turbo, dual turbo, bi-turbo or sequential turbo in this instant.

So no confusion really about the turbo setup, but simply BMW speak, marketing terms, confusing the public.

HighlandPete

[bmwmmm]

Originally Posted by HighlandPete

I think you are confusing the "two-stage twin-turbo" setup of the 525d and 535d, with the totally different turbo setup of the 520d. Yes there is a dual port in the manifold of the 525/535d, one port houses the "turbine control valve" which has to be there to control the gas flow to one or other, or both of the turbos. Hence why there are two ports, one directly flowing to the high pressure turbo, the valve controlling flow and/or bypass, which allows more gas to the lower pressure turbo as the rpm increases. This setup is not a twin scroll turbo. The two turbines are housed in different turbo casings, both with independant compressor wheels. The turbos are technically "sequential turbos", although the two do work together at some rpms. So nothing wrong in using TwinPower as a description for a 'two' turbine setup.

Now the issue is really with the single variable vane turbo, to which BMW also add the label of TwinPower.

Another example would be in the 2.0d X1 which uses the standard N47 engine with one turbo. The BMW blurb reads, "BMW TwinPower Turbo four-cylinder in-line diesel engine" then BMW say, "Single turbo variable vane geometry".

TwinPower cannot just mean twin scroll, twin turbo, dual turbo, bi-turbo or sequential turbo in this instant.

So no confusion really about the turbo setup, but simply BMW speak, marketing terms, confusing the public.

HighlandPete

Underneath the turbo outlet port i outlined here's another exact port on the underside which is used for the other turbo.(I din't bother highlighting the underneath dual ports as well because you cannot see them at that angle and the diagram would confuse people.)
So the dual ports I highlighted are used for the small turbo and the dual ports on the underside are both used for the bigger turbo. It is not used as you describe, one port for one turbo and the other port for the other turbo controlled with a valve. My theory still stands and I would like to know what the turbos actually are. They are sequential turbos for sure, if they are twinscroll is what makes me confused.

[arnsbrae]

Originally Posted by HighlandPete

I think you are confusing the "two-stage twin-turbo" setup of the 525d and 535d, with the totally different turbo setup of the 520d. Yes there is a dual port in the manifold of the 525/535d, one port houses the "turbine control valve" which has to be there to control the gas flow to one or other, or both of the turbos. Hence why there are two ports, one directly flowing to the high pressure turbo, the valve controlling flow and/or bypass, which allows more gas to the lower pressure turbo as the rpm increases. This setup is not a twin scroll turbo. The two turbines are housed in different turbo casings, both with independant compressor wheels. The turbos are technically "sequential turbos", although the two do work together at some rpms. So nothing wrong in using TwinPower as a description for a 'two' turbine setup.

Now the issue is really with the single variable vane turbo, to which BMW also add the label of TwinPower.

Another example would be in the 2.0d X1 which uses the standard N47 engine with one turbo. The BMW blurb reads, "BMW TwinPower Turbo four-cylinder in-line diesel engine" then BMW say, "Single turbo variable vane geometry".

TwinPower cannot just mean twin scroll, twin turbo, dual turbo, bi-turbo or sequential turbo in this instant.

So no confusion really about the turbo setup, but simply BMW speak, marketing terms, confusing the public.

HighlandPete

When BMW publish stuff like this it doesn't help...

http://db.tt/vhRShPtA

(Assuming the link works).

[HighlandPete]

Originally Posted by bmwmmm

Underneath the turbo outlet port i outlined here's another exact port on the underside which is used for the other turbo.(I din't bother highlighting the underneath dual ports as well because you cannot see them at that angle and the diagram would confuse people.)
So the dual ports I highlighted are used for the small turbo and the dual ports on the underside are both used for the bigger turbo. It is not used as you describe, one port for one turbo and the other port for the other turbo controlled with a valve. My theory still stands and I would like to know what the turbos actually are. They are sequential turbos for sure, if they are twinscroll is what makes me confused.

The two ports to the high pressure turbo (above the manifold) one is the inlet to the exhaust turbine, the other the exhaust from the turbine, which exhaust gas must go back across the manifold and the exhausted gas flows to the low pressure turbo which basically allows the low pressure turbine to idle until the valve in the other port is open and full gas flow goes into the turbine. (BMW schematics support this gas flow). So only one port to the small high pressure turbo, and the gas waste to the bigger turbo, plus the controlled main port.

But it isn't this setup that is questioned as to being 'TwinPower', it is the 520d which hasn't got two turbos.

HighlandPete

[HighlandPete]

Originally Posted by arnsbrae

When BMW publish stuff like this it doesn't help...

http://db.tt/vhRShPtA

(Assuming the link works).

But that was correct in late 2009. The first F10 L/H drive cars were fitted with an N57 6-cylinder 3.0d engine.

HighlandPete

[SomeRandomer123]

My head hurts

[Dandle]

Originally Posted by arnsbrae

When BMW publish stuff like this it doesn't help...

http://db.tt/vhRShPtA

(Assuming the link works).

As above look at the date the N57 has been replaced by the twin turbo N47 in the 525d. That was roughly 12-18 months ago.

[bmwmmm]

Originally Posted by HighlandPete

The two ports to the high pressure turbo (above the manifold) one is the inlet to the exhaust turbine, the other the exhaust from the turbine, which exhaust gas must go back across the manifold and the exhausted gas flows to the low pressure turbo which basically allows the low pressure turbine to idle until the valve in the other port is open and full gas flow goes into the turbine. (BMW schematics support this gas flow). So only one port to the small high pressure turbo, and the gas waste to the bigger turbo, plus the controlled main port.

But it isn't this setup that is questioned as to being 'TwinPower', it is the 520d which hasn't got two turbos.

HighlandPete

So one port is used to keep the turbo spooling at idle/no throttle and then when gas pedal is used the other port is used to power the turbo right? I thunk I understand.

And yes I don't know why the 520d has twin power written on it as it doesn't have sequential turbos or variable turbos. I think it just marketing.

[arnsbrae]

Originally Posted by bmwmmm

So one port is used to keep the turbo spooling at idle/no throttle and then when gas pedal is used the other port is used to power the turbo right? I thunk I understand.

And yes I don't know why the 520d has twin power written on it as it doesn't have sequential turbos or variable turbos. I think it just marketing.

@bmwmmm

I think you'll find the 520d DOES have a variable geometry turbo...

[HighlandPete]

Originally Posted by bmwmmm

So one port is used to keep the turbo spooling at idle/no throttle and then when gas pedal is used the other port is used to power the turbo right? I think I understand. it just marketing.

Once we grasp the small high pressure turbo above the manifold has to exhaust back across the manifold, using the second port, (an efficient bit of design) and its waste exhaust gas flows into the low pressure turbine keeping it spinning ahead of higher gas pressures, (as the turbine control valve is opened), we see why it looks as if each turbo has two ports from the manifold.

The 1st stage high pressure turbo, has full exhaust flow (unregulated port) from idle. Once the turbine control valve starts opening, the exhaust gas will automatically start flowing towards the 2nd stage turbo, as it has less back pressure. Simple but effective, setting up the turbos in series.

It is partly this exhaust gas flow which makes a smooth transition of the 2-stage turbo setup across the rev range.

HighlandPete

[ipso_facto]

Originally Posted by HighlandPete

Once we grasp the small high pressure turbo above the manifold has to exhaust back across the manifold, using the second port, (an efficient bit of design) and its waste exhaust gas flows into the low pressure turbine keeping it spinning ahead of higher gas pressures, (as the turbine control valve is opened), we see why it looks as if each turbo has two ports from the manifold.

The 1st stage high pressure turbo, has full exhaust flow (unregulated port) from idle. Once the turbine control valve starts opening, the exhaust gas will automatically start flowing towards the 2nd stage turbo, as it has less back pressure. Simple but effective, setting up the turbos in series.

It is partly this exhaust gas flow which makes a smooth transition of the 2-stage turbo setup across the rev range.

HighlandPete

Incredible Pete ... you should still be charging for this!