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Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - Printable Version

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Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - gsxr - 03-18-2010

My apologies if this was already posted:

http://www.caranddriver.com/features/09q4/mercedes_engine_transplant_modern_diesel_in_a_1992_190e_2.6-feature

http://media.daimler.com/dcmedia/0-921-658887-1-1233594-1-0-1-0-0-1-11702-854934-0-1-0-0-0-0-0.html?TS=1268875948531

http://www.theautochannel.com/news/2009/09/08/476730.html


[Image: 476730.2-lg.jpg]

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - ForcedInduction - 03-18-2010

(03-18-2010, 04:16 PM)GREASY_BEAST Oh wow. I'd buy one.
...without the EGR and a VNT instead of the 1980's sequential turbos.

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - gsxr - 03-18-2010

(03-18-2010, 05:21 PM)ForcedInduction ...without the EGR and a VNT instead of the 1980's sequential turbos.
You lost me here. You're saying you don't approve of their use of sequential turbos? Seems to work pretty well from the factory. Probably worked like crap with mechanical controls in 1980. But they are not using 1980's technology, now are they. I could care less if it has EGR or not...


Rolleyes

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - ForcedInduction - 03-18-2010

(03-18-2010, 05:26 PM)gsxr You're saying you don't approve of their use of sequential turbos?
No. Its antiquated technology to solve a problem that a VNT turbo does better.
The only reason the engine makes more rated HP and torque than a comparable VNT engine is that the turbos work as a compound for a brief period. In single mode (off idle and upper RPMs) it makes no more power than a VNT engine.

They used two turbos because of cost, they have to keep the diesel option reasonably close to the g@sser option or people won't want to buy them. Its cheaper to manufacture two normal turbos and associated parts than to cast, machine, weld and assemble a turbo with 15+ small inconel moving parts and a computerized actuator to control it.

Quote:Probably worked like crap with mechanical controls in 1980.
All the sequentials of the 80's were computerized (Mazda, Toyota, Subaru).

Quote:I could care less if it has EGR or not.
Except that its recirculating nearly 50% of the exhaust back to the intake.

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - Kiwibacon - 03-20-2010

(03-18-2010, 05:46 PM)ForcedInduction
(03-18-2010, 05:26 PM)gsxr You're saying you don't approve of their use of sequential turbos?
No. Its antiquated technology to solve a problem that a VNT turbo does better.
The only reason the engine makes more rated HP and torque than a comparable VNT engine is that the turbos work as a compound for a brief period. In single mode (off idle and upper RPMs) it makes no more power than a VNT engine.

They used two turbos because of cost, they have to keep the diesel option reasonably close to the g@sser option or people won't want to buy them. Its cheaper to manufacture two normal turbos and associated parts than to cast, machine, weld and assemble a turbo with 15+ small inconel moving parts and a computerized actuator to control it.

You cannot replace two staged turbos with a VNT and get anything near the torque curve.
You could size a VNT to get the same torque, you could also size a VNT to get the same topend power. But those are two different VNT turbos.

A VNT turbo uses a fixed geometry compressor. Staged turbos are used because there is no single compressor which can cover the same operating range. As you optimise a compressor for higher pressure ratios, the map gets narrower. As you optimise them for a wider map, the available pressure ratios drop.

If you think there is a single compressor that can suit this engine, please find the map and show us. With the operating range plotted.

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - ForcedInduction - 03-20-2010

(03-20-2010, 06:02 AM)Kiwibacon You cannot replace two staged turbos with a VNT and get anything near the torque curve.
Yes you can, its exactly what Ford did with the 6.4L. Well matched VNT for instant low-end and throttle response with a large non-wastegated turbo for power.

With their sequential system they get a big rush of torque from compound mode then it falls on its ass (relatively) as it goes to big single mode.

Quote:As you optimise a compressor for higher pressure ratios, the map gets narrower. As you optimise them for a wider map, the available pressure ratios drop.
Holset does both very well. Garrett, IHI and Borg's issue is they don't use something like Holset's map width enhancement on their small turbos, just 76mm and up.

Quote:If you think there is a single compressor that can suit this engine, please find the map and show us. With the operating range plotted.
Holset doesn't publicly distribute their maps.

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - Kiwibacon - 03-20-2010

(03-20-2010, 06:12 AM)ForcedInduction
(03-20-2010, 06:02 AM)Kiwibacon You cannot replace two staged turbos with a VNT and get anything near the torque curve.
Yes you can, its exactly what Ford did with the 6.4L. Well matched VNT for instant low-end and throttle response with a large non-wastegated turbo for power.

With their sequential system they get a big rush of torque from compound mode then it falls on its ass (relatively) as it goes to big single mode.

Quote:As you optimise a compressor for higher pressure ratios, the map gets narrower. As you optimise them for a wider map, the available pressure ratios drop.
Holset does both very well. Garrett, IHI and Borg's issue is they don't use something like Holset's map width enhancement on their small turbos, just 76mm and up.

Quote:If you think there is a single compressor that can suit this engine, please find the map and show us. With the operating range plotted.
Holset doesn't publicly distribute their maps.

Ford have not yet produced any engine running in anything near the boost levels of the german car diesels. The BMW 6 runs more than 42psi boost. Plot 42psi boost out on any compressor map and you'll see really quickly why single compressors can't fly.

Map width enhancement. Yeah good one.
How do you know holset does it well if you can't provide the maps?

RE: Factory SuperTurbo - W201 CDI - 190 D BlueEFFICIENCY - ForcedInduction - 03-20-2010

(03-20-2010, 06:30 AM)Kiwibacon Ford have not yet produced any engine running in anything near the boost levels of the german car diesels.
I'm sorry, exactly what cars are running more than 42psi of sustained (NOT peak!) boost pressure like Ford? How many of them can be modified to run 55psi of sustained boost using stock parts?

Quote:Plot 42psi boost out on any compressor map and you'll see really quickly why single compressors can't fly.
I'm sorry, but you're missing the entire point of this debate.
What you seem to not be understanding is the difference between a single VNT (old BMW), sequential turbos (80's cars), modulated compound-sequential (MB/BMW), compounds (common diesel mod) and a VNT compound (Ford).
Compounds are also known as a "two-stage" system.

   

Quote:The BMW 6 runs more than 42psi boost.
For only 1500rpm of the 4800rpm revv range, then it falls flat to only 22psi.

As you can see from the attachment above, above 2200rpm there is zero advantage over a wastegated, sequential or single VNT system.
With a compound system utilizing a VNT as the secondary stage, it boosts faster than a sequential system without falling on its ass half way through the run.

Quote:How do you know holset does it well if you can't provide the maps?
The fact they work as advertised.