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      07-10-2013, 02:16 PM   #243
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Quote:
Originally Posted by pkim1079 View Post
how about adding a supercharger to the turbo? twin charged.
Yes, I'm not sure why this isn't more frequently used for high output engines when VW uses it in small Seats, Golfs and people carriers it can't be very expensive or complex with today's tech. Must be some drawback otherwise you would think companies like Porsche would be allover it for their FI engines.
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      07-10-2013, 02:39 PM   #244
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Quote:
Originally Posted by pkim1079 View Post
how about adding a supercharger to the turbo? twin charged.
Lancia did that in rally in their Delta S4 in 1985 (I'd also guess it has been done before then by others)! They were able to reduce turbo lag and obtain and official 480 hp from a bit less then 1.8l. Some claim they made more like 560 hp. The engine was tested up to 1000 hp.

It's a pretty good idea and a neat system. However, electronics along with clever modern controls offer flexibility and capability that systems that are essentially all mechanical just can't offer.

By the way great contributions in the last few posts Boss330!
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      07-10-2013, 02:56 PM   #245
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What some call flexible with electronics others call artificial. A mechanically driven system tends to be provide a more natural feel than an electrically powered system. I would definately prefer a twin charged engine to an electrical + mechanical turbo setup.

A sequential system like twin charging but with turbos of different sizes like some Toyota Supras would also be preferable to me. I'm not a fan of "electrifying" everything. I don't really like EPS, EDC or hybrids all feels artificial to some degree.

Someone mentioned that they had talked to an M3 test driver who said something to the extent of the car having a "2nd surge of power". It sounds like some type of sequential setup wether it contains a electrical engine or is one of the mechanical systems.

Last edited by solstice; 07-10-2013 at 03:31 PM..
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      07-10-2013, 03:31 PM   #246
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Quote:
Originally Posted by solstice View Post
What some call flexible with electronics others call artificial. A mechanically driven system tends to be provide a more natural feel than an electrically powered system. I would definately prefer a twin charged engine to an electrical + mechanical turbo setup.

A sequential system like twin charging but with turbos of different sizes like some Toyota Supras would also be preferable to me. I'm not a fan of "electrifying" everything. I don't really like EPS, EDC or hybrids all feels artificial to some degree.
That might be true, but remember that a exhaust driven turbo is not mechanically driven in the first place...

It's not attached to a mechanical drive from the engine, it's propelled by the exhaust gases from the engine. That's where the issue of lag and delayed power delivery comes into play. Now, there is a solution to overcome some of the inherent issues that a turbo'd engine has. An electrical motor that is mechanically connected to the turbo and that can change the rpm of the turbine shaft. This is a more technologically advanced solution than attaching a supercharger to the crankshaft pulley. Not to mention that it doesn't steal power from the crankshaft to be driven (taking into consideration that it also can regenerate power from the turbo).

Whether such a engine's power delivery will feel more artificial than a engine with a mechanically driven supercharger and a turbo is hard to tell without having testdriven one...

To some, any turbo engine will feel artificial compared with a NA engine's power delivery.
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      07-10-2013, 03:40 PM   #247
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Quote:
Originally Posted by Boss330 View Post
To some, any turbo engine will feel artificial compared with a NA engine's power delivery.
You just through another bomb here
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      07-10-2013, 03:44 PM   #248
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Quote:
Originally Posted by Boss330 View Post
That might be true, but remember that a exhaust driven turbo is not mechanically driven in the first place...

It's not attached to a mechanical drive from the engine, it's propelled by the exhaust gases from the engine. That's where the issue of lag and delayed power delivery comes into play. Now, there is a solution to overcome some of the inherent issues that a turbo'd engine has. An electrical motor that is mechanically connected to the turbo and that can change the rpm of the turbine shaft. This is a more technologically advanced solution than attaching a supercharger to the crankshaft pulley. Not to mention that it doesn't steal power from the crankshaft to be driven (taking into consideration that it also can regenerate power from the turbo).

Whether such a engine's power delivery will feel more artificial than a engine with a mechanically driven supercharger and a turbo is hard to tell without having testdriven one...

To some, any turbo engine will feel artificial compared with a NA engine's power delivery.
I agree with all of that even if exhaust driven is not mechanical it has a more analogue nature that is naturally in sync with the engine by being produced by the same combustion engine that is btw driven by gases itself

Maybe none of this matter as long as there is always more pressure than used but if all of the pressure available from the low rev source is used it could matter.
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      07-10-2013, 04:48 PM   #249
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Quote:
Originally Posted by CanAutM3 View Post
You just through another bomb here
Hahaha... I know

I love a good turbo engine, but I also love a high revving NA engine as well... Some adore the power delivery and thrust of a turbo engine when it comes on boost, some feel that it's artificial and not as "pure"...
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      07-10-2013, 04:50 PM   #250
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Quote:
Originally Posted by solstice View Post
I agree with all of that even if exhaust driven is not mechanical it has a more analogue nature that is naturally in sync with the engine by being produced by the same combustion engine that is btw driven by gases itself

Maybe none of this matter as long as there is always more pressure than used but if all of the pressure available from the low rev source is used it could matter.
In a delayed sync you mean

But, yes it will be interesting to see how such a engine's power delivery will be like (if it ever comes into production).
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      07-10-2013, 06:51 PM   #251
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Quote:
Originally Posted by Boss330 View Post
Whether such a engine's power delivery will feel more artificial than a engine with a mechanically driven supercharger and a turbo is hard to tell without having testdriven one...

To some, any turbo engine will feel artificial compared with a NA engine's power delivery.
+1 took the words right out of my mouth.
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      07-10-2013, 07:19 PM   #252
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What ever happened to variable vane technology that is used on Diesel engines? Are they too big and heavy to spin up fast enough?

Just decouple a supercharger that comes online when the primary turbos run out of steam. This would carry the power to redline that everyone is so worried about.

T
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      07-11-2013, 02:57 AM   #253
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Quote:
Originally Posted by Mangler View Post
What ever happened to variable vane technology that is used on Diesel engines? Are they too big and heavy to spin up fast enough?

Just decouple a supercharger that comes online when the primary turbos run out of steam. This would carry the power to redline that everyone is so worried about.

T
Variable vane is better for response than std, but it doesn't have the ability to regenerate energy from the exhaust. Nor is it able to operate independent of exhaust gas flow. An electrical motor/generator unit (MGU) can do both.

An MGU can spool up the turbo from 40,000 to 120,000 rpm in less than 450 ms. That is as near as instant!!!

And it's not just power to the redline that is an issue, it's response in the lower rpm scale (or turbo lag). With an MGU you can combine a fairly large turbo for high rpm's with the response (or in fact better response) of a small turbo
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      07-11-2013, 03:37 AM   #254
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Quote:
Originally Posted by clar View Post
In my recent M event at Sepang, I spoke with one of the instructors who drove the development F80/82 almost on a daily basis. He promised me that the new power-train contains something new and innovative. That means it's not a case of a simply slapping 2 turbos on the N55 and calling it a day. He even said there is a another power rush at the higher rpm range. I was interrupted by some clowns and didn't manage to probe further. I am still hitting myself on this. I was going to ask him if it contained a 3rd turbo, an electric turbo, or something else...
Yes it does
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      07-11-2013, 06:58 AM   #255
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Quote:
Originally Posted by Boss330
Quote:
Originally Posted by Mangler View Post
What ever happened to variable vane technology that is used on Diesel engines? Are they too big and heavy to spin up fast enough?

Just decouple a supercharger that comes online when the primary turbos run out of steam. This would carry the power to redline that everyone is so worried about.

T
Variable vane is better for response than std, but it doesn't have the ability to regenerate energy from the exhaust. Nor is it able to operate independent of exhaust gas flow. An electrical motor/generator unit (MGU) can do both.

An MGU can spool up the turbo from 40,000 to 120,000 rpm in less than 450 ms. That is as near as instant!!!

And it's not just power to the redline that is an issue, it's response in the lower rpm scale (or turbo lag). With an MGU you can combine a fairly large turbo for high rpm's with the response (or in fact better response) of a small turbo
Why not use the MGU on smaller variable vane twins rather than the large single but make them large enough to flow all the way to the top end. I'm still hoping its twins and not a large single.

T
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      07-11-2013, 07:57 AM   #256
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Quote:
Originally Posted by Mangler View Post
Why not use the MGU on smaller variable vane twins rather than the large single but make them large enough to flow all the way to the top end. I'm still hoping its twins and not a large single.

T
I'm pretty sure it's twin turbo, as that is what has been reported so far (unless there is the usual "BMW Twin Power Turbo" confusion...)

I agree that there is a possibility to take the best of both worlds, both MGU and variable vane. One doesn't necessarily eliminate the other
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      07-11-2013, 08:47 AM   #257
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Quote:
Originally Posted by Mangler View Post
Why not use the MGU on smaller variable vane twins rather than the large single but make them large enough to flow all the way to the top end. I'm still hoping its twins and not a large single.

T
If you look at the plumbing on the development car engine bay pics, the intake setup clearly points to multiple sources of combustion air.
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      07-11-2013, 09:15 AM   #258
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Quote:
Originally Posted by Needsdecaf View Post
If you look at the plumbing on the development car engine bay pics, the intake setup clearly points to multiple sources of combustion air.
Yes, there are clearly both two outlets coming from the turbos (as seen just under the Bimmerpost lettering in the first pic below), as well as two air filters and related inlet plumbing. All indicating at least two turbos



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      07-11-2013, 09:34 AM   #259
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Quote:
Originally Posted by Boss330 View Post
Variable vane is better for response than std, but it doesn't have the ability to regenerate energy from the exhaust. Nor is it able to operate independent of exhaust gas flow. An electrical motor/generator unit (MGU) can do both.

An MGU can spool up the turbo from 40,000 to 120,000 rpm in less than 450 ms. That is as near as instant!!!

And it's not just power to the redline that is an issue, it's response in the lower rpm scale (or turbo lag). With an MGU you can combine a fairly large turbo for high rpm's with the response (or in fact better response) of a small turbo
So tell us how long a turbo takes without MGU to spool between those ranges?

And also tell us if that was a disconnected turbo, or under load?
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      07-11-2013, 09:37 AM   #260
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Quote:
Originally Posted by pkim1079 View Post
how about adding a supercharger to the turbo? twin charged.
Have you driven a Golf 1.4TFSi with this? In case you haven't it is terrible, not seemless transition at all.
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      07-11-2013, 11:19 AM   #261
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Originally Posted by NISFAN View Post
Have you driven a Golf 1.4TFSi with this? In case you haven't it is terrible, not seemless transition at all.
Not everyone agrees with that.
http://www.gizmag.com/vw-twincharger...he-year/15542/
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      07-11-2013, 11:36 AM   #262
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It seems to me that instead of separate units, the turbo and supercharger could be one integrated compressor. Essentially, a turbocharger with optional mechanical assist from the crankshaft. In fact you could add e-assist to the mix as well and then have the ECU decide how to power the turbine using various parameters depending on operating conditions.
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      07-11-2013, 12:19 PM   #263
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Quote:
Originally Posted by NISFAN View Post
So tell us how long a turbo takes without MGU to spool between those ranges?

And also tell us if that was a disconnected turbo, or under load?
Are you not getting it, or just playing dumb?

Your first question shows you don't seem to understand how a engine and a turbo works... It's kind of asking how long a length of string is

How long a turbo, without MGU, takes to spool up between rpms depends on (amongst other):

- Throttle position (part throttle, WOT etc)
- Engine rpm
- Turbine A/R
- The engine's operating condition when you want the turbo to spool up (coasting, steady state driving, acceleration)
- Exhaust temperature
- Exhaust volume
- Exhaust speed

Those are some of the reasons we have something called turbo lag... With a MGU you can spool the turbo regardless of the above circumstances.

This chart is from Garrett's webpage:

http://www.turbobygarrett.com/turbob..._ball_bearings



400Hz = 24000rpm
2100hZ = 126000rpm

So, according to Garrett, it takes between 1,6 to 2 seconds to spool up a turbo from 24000rpm to 126000rpm

From 40000rpm (666Hz) to 120000rpm (2000Hz) it takes approximately 1-1,2seconds.

And that is when the throttle is suddenly opened at 2000rpm on the engine. The MGU can operate idependently of engine rpm obviously.

To quote Garrett engineer:

Quote:
by incorporating a very high speed electrical motor in rotating assembly of a turbocharger, you can drive it up to very high speeds, before you have exhaust gases to do so. It is very powerful, specifically when there is no exhaust gas available, such as at idle, or in stop and go.
This presentation has some comparisons on throttle response between a regular turbo and a electrically boosted turbo.

http://www.aeristech.co.uk//userFile...esentation.pdf

The chart on e-Booster acceleration (1) shows that it takes 0,38s to spool from 60000rpm to 100000rpm at 0,51Bar



In June this year Aeristech displayed their first low voltage system (48V).

www.aeristech.co.uk

Engineers at Renault F1, Garrett and others agree that a MGU/eBoost turbo can help eliminate lag, and spool up the turbo quicker than the exhaust gases can do under many circumstances. Exactly which parts of those companies engineering expertise is it that you disagree with? I'm sure Renault F1 and others would love to get some inside knowledge from you
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      07-11-2013, 02:19 PM   #264
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Quote:
Originally Posted by Boss330 View Post
Are you not getting it, or just playing dumb?

Your first question shows you don't seem to understand how a engine and a turbo works... It's kind of asking how long a length of string is

How long a turbo, without MGU, takes to spool up between rpms depends on (amongst other):

- Throttle position (part throttle, WOT etc)
- Engine rpm
- Turbine A/R
- The engine's operating condition when you want the turbo to spool up (coasting, steady state driving, acceleration)
- Exhaust temperature
- Exhaust volume
- Exhaust speed

Those are some of the reasons we have something called turbo lag... With a MGU you can spool the turbo regardless of the above circumstances.
Yep and the MGU claim is also a piece of string without all the details.

You also can't expect an MGU to constantly keep the turbo spinning on a road car can you?

Quote:
Originally Posted by Boss330 View Post
This chart is from Garrett's webpage:

http://www.turbobygarrett.com/turbob..._ball_bearings



400Hz = 24000rpm
2100hZ = 126000rpm

So, according to Garrett, it takes between 1,6 to 2 seconds to spool up a turbo from 24000rpm to 126000rpm

From 40000rpm (666Hz) to 120000rpm (2000Hz) it takes approximately 1-1,2seconds.

And that is when the throttle is suddenly opened at 2000rpm on the engine. The MG
To show lag don't you think you need to show engine flow? It seems reasonable that a petrol 4cyl 2000cc engine (the example test engine used by Garrett), could take a few seconds to go from 2000rpm to 5-6000rpm under load, do you not agree? So what does the 1-1.2 seconds represent? Lag? ICE engine rpm gain controlling Turbine speed?

What if full boost was reached at 60,000 rpm and then the wastegate controlled turbine flow from there on? Wouldn't that mean lag ended at fractions of a second?

[IMG][/IMG]

I liked this graph, showing that from throttle pedal application, it was actually the standard turbo that responded marginally quicker. Without knowing other details it would be difficult to say whether for example the wastegate was starting to open thus cropping the torque gain. So a pretty meaningless comparison. No?

The graph earlier in your post showing increased fuelling increased turbo response, yet they used the disadvantaged one?
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