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Location:
Perth
Registered:
May 2004
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SC vs Turbo -- Emissions
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Fri, 24 June 2005 06:50
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I have been searching the internet / forums (working hard today!)
Trying to find out,
Given An identical engine and all other params (boost, fuelling, temps etc..) being equal
Would a Supercharged or Turbo Charged version produce the lowest emissions?
Cheers,
Adam
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Location:
Rosanna, Melb
Registered:
June 2002
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Re: SC vs Turbo -- Emissions
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Fri, 24 June 2005 06:57
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In my opinion (and I am happy to be proved wrong by someone more learned) the emissions should be identical. If everything really is identical then you get the same air going into cylinder, same AFR, same combustion and so same emissions.
However the turbo car would be quieter so less noise emission if you count that.
Hen
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Location:
c'town, NSW
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Fri, 24 June 2005 07:00
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SC and TC are both compressors they do the same thing just in a different manner.
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Location:
Perth
Registered:
May 2004
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Re: SC vs Turbo -- Emissions
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Fri, 24 June 2005 07:24
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Right,
now the reason that i asked.
I applied to add F/I to my engine.
With turbo option, all I need is brakes and my car can be registered legally (no eng cert required - as stated in response to mod request from D.P.I)
However with SC (all other things being equal) they require me to get an Emissions test.
I submitted two individual requests (I was baffled)
-Adam
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Location:
Montrose, VIC
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Sat, 25 June 2005 06:06
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Reason being past habbits. Traditionally, and to the rego people, a supercharger means 6/71 and a couple of 4 barrels hanging through the bonnet, whereas turbo is one of those litle noisy things from those little gutless jap motors that can't possibly make any smog. Quite up with the times, aren't they!
However, there IS a little bit of truth in what they say - positive displacement blowers DO tend to blow unburnt charge straight through the motor during overlap at low revs, increasing HC emissions. Unfortunately, while doing this, they tend to give a big serve of bottom end torque... Therefore, you need to do a certain amount of fiddling with valve and fuel timing to clean this up, and they probably want to make sure you get this right. What do they say about centrifugal blowers?
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: SC vs Turbo -- Emissions
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Sat, 25 June 2005 06:11
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well a supercharged engine would tend to use more fuel (when you are caning it) as the turbo utilises the exhaust energy to drive the compressor, wheras the supercharger uses crankshaft power.
not that you get power for free with a turbo, it still takes engine power to drive, but not as much as a supercharger.
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: SC vs Turbo -- Emissions
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Sat, 25 June 2005 07:02
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| shinybluesteel wrote on Sat, 25 June 2005 16:11 |
well a supercharged engine would tend to use more fuel (when you are caning it) as the turbo utilises the exhaust energy to drive the compressor, wheras the supercharger uses crankshaft power.
not that you get power for free with a turbo, it still takes engine power to drive, but not as much as a supercharger.
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a supercharger will tend to use more fuel when your not canning it unless youve set it to come on at a certain throttle position or load ect ect and thats assuming your using an electronic clutch....
you are constantly boosting a s/c car when driving arround town to get away from traffic lights etc etc
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Location:
Sydney
Registered:
July 2002
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Re: SC vs Turbo -- Emissions
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Sun, 26 June 2005 05:50
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| 4agte wrote on Sat, 25 June 2005 17:02 |
you are constantly boosting a s/c car when driving arround town to get away from traffic lights etc etc
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Unless you have a bypass valve, like most modern positive displacement superchargers do (look at eaton for example). Such superchargers do not require much power to run when the engine is not under load.
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Location:
Melbourne
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Sun, 26 June 2005 06:20
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I am in a similar shitty situation with my 4AGZE AE92... having to get engineering and probably an emissions test... we'll see... might need to move states lol 
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: SC vs Turbo -- Emissions
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Sun, 26 June 2005 07:16
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| bored wrote on Sun, 26 June 2005 15:50 |
| 4agte wrote on Sat, 25 June 2005 17:02 |
you are constantly boosting a s/c car when driving arround town to get away from traffic lights etc etc
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Unless you have a bypass valve, like most modern positive displacement superchargers do (look at eaton for example). Such superchargers do not require much power to run when the engine is not under load.
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i still think you will find that it soaks up the petrol
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Location:
Perth
Registered:
May 2004
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 01:26
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| mrshin wrote on Sat, 25 June 2005 14:06 |
What do they say about centrifugal blowers?
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I am not sure, I did not ask about this, as I don't know where to get one cheap enough 
-Adam
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Location:
Melbourne
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 02:05
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typicaly a hoter exhaust with a turbo thus the cat gets its job done better
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Toymods Vice President
Location:
Sydney
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 02:23
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| Allan wrote on Mon, 27 June 2005 12:05 |
typicaly a hoter exhaust with a turbo thus the cat gets its job done better
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The opposite of this is generally the case. The fact that you have a big hunk of cast steal in the exhaust path up near the head that soaks up a huge amount of heat means that the gas after the turbo is cooler and it take longer for the cats to light off.
On the other hand any supercharged engine where there is valve overlap will end up with unburnt fuel air mix going through to the exhaust, whereas if it is turbo this does not happen because the pressure in the exhaust ports is higher than the pressure in the intake ports.
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Location:
Melbourne
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 02:30
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hmmmm debateable, the higher pressures seen outside of the combustion chamber on the exhaust side tend to also see higher temps pre cat (also more fuel tends to get burnt before reaching the cat
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Toymods Vice President
Location:
Sydney
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 02:50
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Debate it with Garrett then since that's where the info comes from.
This is one of the biggest things that Garrett have been working on, along with VATN and 48V turbo's, in order to keep the turbo relevant to future OEM emissions standards. There is a lot of research into lighter materials and also in methods to increase the temperature of the gas after the turbo.
The fact is that the hardest part of an emissions test for a turbo engine to pass is the initial startup. The turbo takes a long time to heat up and this reduces the temperature of the exhaust gasses. If you think that the pressure in the exhaust manifold at startup due to a turbo exhaust housing and turbine wheel will increase the temperature of the exhaust gas then I guess you subscribe to a different form of physics to most people.
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Location:
Melbourne
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 02:52
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hmmm defeintly at startup your right im thinking more along the lines of cruise
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Toymods Vice President
Location:
Sydney
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 03:15
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Fair enough. Yeah the emissions tests are all realtively easy for a turbo engine to pass except for the initial startup tests.
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Location:
Melbourne
Registered:
May 2002
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Re: SC vs Turbo -- Emissions
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Mon, 27 June 2005 08:31
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On a side note, anyone know if a MAP 4AGZE passes ADR37/00 ? 
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