BMW tri-turbo

[Elliott819]

I've just read the article where it states there could be a tri-turbo diesel for the new 5-series. Does anybody know if this means that the turbo's are going to be of different sizes, or is there just 1 for every 2 cylinders?

[DrTre]

Isn't one electrically operated or something? For spooling up the other two more quickly? Or something? Could be bks.

[varsas]

DrTre said:

Isn't one electrically operated or something? For spooling up the other two more quickly? Or something? Could be bks.

That was my understanding. Not sure how that will work, if it's in front of the 'normal' turbos then the air from it will get blocked by those, and it will restrict air flow to the two main turbos at high revs. If it's closer to the engine then it will restrict flow once the other turbo's have got up to pressure, and not be able to suck air past the two main ones anyway.

I can only imagine the electric turbo has it's own air feed, and a separate feed from it to the engine which bypasses the other two turbos?

[Nick3point2]

DrTre said:

Isn't one electrically operated or something? For spooling up the other two more quickly? Or something? Could be bks.

and if they have any sense whatsoever they will use it for energy recovery once the other two are at full chat.

[The1Driver]

Do more turbos equal less lag?

[Sixpackpert]

The1Driver said:

Do more turbos equal less lag?

Smaller turbo first to spool up quicker and then larger turbo takes over once it has spooled up is the way it works I think?

[off_again]

The1Driver said:

Do more turbos equal less lag?

Thats the theory!

I have a twin turbo BMW (diesel though) and to be honest, you would struggle to tell that it was anything other than a high power but relatively lightly turbo'ed engine! You definately know its a turbo, but there is no stepping, no sudden boost and no sudden drop off either! The boost comes in nice and early and with the two turbos its spread across the whole (and limited cos its a diesel) power range. Its VERY impressive and makes the engine very responsive and eager.

If they can do the same with the tri-turbo, I would be expecting big things with more power, more flexibility and boost from even the lowest rev's. It should be very impressive indeed!

[Codswallop]

varsas said:

DrTre said:

Isn't one electrically operated or something? For spooling up the other two more quickly? Or something? Could be bks.

That was my understanding. Not sure how that will work, if it's in front of the 'normal' turbos then the air from it will get blocked by those, and it will restrict air flow to the two main turbos at high revs. If it's closer to the engine then it will restrict flow once the other turbo's have got up to pressure, and not be able to suck air past the two main ones anyway.

I can only imagine the electric turbo has it's own air feed, and a separate feed from it to the engine which bypasses the other two turbos?

Could the electric turbo be exhaust mounted to help get more exhaust gasses to spool up the regular turbos? I've seen in PPC mag some exhaust mounted turbos before abnd didn't fully understand them, but that to my mind at least seems like it could work in reducing lag, while not obstructing airflow at the engine end.

Or have I just had an ambiwlans moment

[The1Driver]

You dont happen to have the 535d do you?

If so I've been out in one of those. Epic car. Must admit.... I didnt notice a touch of lag. Very sophisticated.

Not like the sub 20k turbo powered cars (Astra, Focus, Corsa, ect)... You can def feel lag in these cars

[Gizmo!]

Codswallop said:

Could the electric turbo be exhaust mounted to help get more exhaust gasses to spool up the regular turbos? I've seen in PPC mag some exhaust mounted turbos before abnd didn't fully understand them, but that to my mind at least seems like it could work in reducing lag, while not obstructing airflow at the engine end.

Or have I just had an ambiwlans moment

I don't think you understand how turbos work...

[Codswallop]

Gizmo! said:

I don't think you understand how turbos work...

I have a fair idea of how normal turbos work. Just not much knowledge about exhaust mounted ones such as this one. Besides, it was just an idea of how three turbos might be mounted. I didn't say it would work

Eta to add another picture;



Now you can say you've seen everything

[StottyZr]

Gizmo! said:

Codswallop said:

Could the electric turbo be exhaust mounted to help get more exhaust gasses to spool up the regular turbos? I've seen in PPC mag some exhaust mounted turbos before abnd didn't fully understand them, but that to my mind at least seems like it could work in reducing lag, while not obstructing airflow at the engine end.

Or have I just had an ambiwlans moment

I don't think you understand how turbos work...

I'm going to use something I learnt last week and be a smart arse here.

If its electric powered its not a turbo. Its a supercharger. A turbo is a turbine driven supercharger

[nottyash]

StottyZr said:

Gizmo! said:

Codswallop said:

Could the electric turbo be exhaust mounted to help get more exhaust gasses to spool up the regular turbos? I've seen in PPC mag some exhaust mounted turbos before abnd didn't fully understand them, but that to my mind at least seems like it could work in reducing lag, while not obstructing airflow at the engine end.

Or have I just had an ambiwlans moment

I don't think you understand how turbos work...

I'm going to use something I learnt last week and be a smart arse here.

If its electric powered its not a turbo. Its a supercharger. A turbo is a turbine driven supercharger
Thats right.
A turbo charger uses exhaust gasses, so by nature will be situated on the exhaust. A super charger is driven, mostly by belt but it this case an electric motor.

I remember when these electric chargers were for sale on ebay, there must be a reason they dont work or we would all be buying them. BMW must of managed to perfect it using variable vane technology.
Just a though

[The1Driver]

Are are we not seeing more SCs in cars?

BMW used SCs in their first gen Minis... Yet later they switched to Turbos. What was the reason behind this?

[StottyZr]

The1Driver said:

Are are we not seeing more SCs in cars?

BMW used SCs in their first gen Minis... Yet later they switched to Turbos. What was the reason behind this?

Superchargers were very expensive and destroyed fuel consumption IIRC

[The1Driver]

So it was an eco decision then...

[StottyZr]

The1Driver said:

So it was an eco decision then...

Well, a common sense one really...

[The1Driver]

StottyZr said:

Well, a common sense one really...

Common sense wouldve told them to not to consider a charger in the first place...

[Goa'uld]

doogz said:

Codswallop said:

Gizmo! said:

I don't think you understand how turbos work...

I have a fair idea of how normal turbos work. Just not much knowledge about exhaust mounted ones such as this one. Besides, it was just an idea of how three turbos might be mounted. I didn't say it would work

Eta to add another picture;



Now you can say you've seen everything

All turbo's are mounted on the exhaust.

Those, must surely induce a fecking huge amount of lag, being so far from the inlet manifold, no?

Need more info - that looks like it could be a good read at lunchtime.

[Old Gregg]

doogz said:

Those, must surely induce a fecking huge amount of lag, being so far from the inlet manifold, no?

That's what I've always thought when I've seen this kind of set up. I'll be honest and say I don't know if that's actually the case though.