Quote:
Originally Posted by Boss330
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
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?
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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?