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Author Topic: funny noise  (Read 3534 times)

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Markjay

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Re: funny noise
« Reply #15 on: 11 February 2007, 23:59:48 »
So putting one and one together, it seems that:

Lower compression = lower combustion temperatures = less NOx
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omegaV6CD

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Re: funny noise
« Reply #16 on: 12 February 2007, 00:03:36 »
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No, those parts no longer exist. The lower compression ratio means no need for EGR, as little NOX anyway...
Sorry to hijack the thread, are you (or VX) saying that lower compression ratios result in lower NOX?


Anything that cause the combustion peak flame temperature to exceed 2700 degreen Kelvin will result to NOx formation. As Markjay says below the lower compression reduces it.
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Marks DTM Calib

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Re: funny noise
« Reply #17 on: 12 February 2007, 10:37:42 »
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Just for informatiom, you do not need an EGR valve to introduce EGR to an engine, you can allow exhaust gas recirculation with a certain amount of valve overlap(it is called internal EGR) You could go up to 40% EGR like that.


Although to do this effectively you need a full VVT setup....
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omegaV6CD

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Re: funny noise
« Reply #18 on: 12 February 2007, 11:37:22 »
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Just for informatiom, you do not need an EGR valve to introduce EGR to an engine, you can allow exhaust gas recirculation with a certain amount of valve overlap(it is called internal EGR) You could go up to 40% EGR like that.


Although to do this effectively you need a full VVT setup....

Indeed!
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Markjay

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Re: funny noise
« Reply #19 on: 12 February 2007, 11:51:58 »
This is interesting, but I think that if you rely on the intake stroke of the piston to suck exhaust gasses back into the chamber then you will have serious gas flow issues in the exhaust manifold? The traditional EGR system seems to minimise this sort of unwanted turbulence by taking the exhaust gasses out of the combustion chamber with the gas flow and then introducing them back into the intake manifold rather then pump it back-and-forth?
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sophos9

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Re: funny noise
« Reply #20 on: 12 February 2007, 11:57:16 »
Are we saying here that if the secondary air pump causes problems you can just unplug and forget?

97' 3.0 Elite...
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Markjay

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Re: funny noise
« Reply #21 on: 12 February 2007, 12:22:39 »
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Are we saying here that if the secondary air pump causes problems you can just unplug and forget?

97' 3.0 Elite...

 ;D yes...  :y

Seems like we got carried-off with this theoretical discussion...
« Last Edit: 12 February 2007, 12:23:36 by markjay »
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TheBoy

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Re: funny noise
« Reply #22 on: 12 February 2007, 14:51:13 »
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Are we saying here that if the secondary air pump causes problems you can just unplug and forget?

97' 3.0 Elite...
Correct!
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BigCat

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Re: funny noise
« Reply #23 on: 12 February 2007, 17:42:58 »
Apologies again for the hijack, but clearly an intersesting subplot here.

Just to say that I remember something in the technical blurb for the second generation of "emission V8s" that Holden introduced in the early Eighties. They had improved emissions over the previous generation partly acheived through the use of a very mild performance camshaft which had an increased inlet/exhaust valve overlap. It's all starting to make sense.

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sophos9

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Re: funny noise
« Reply #24 on: 13 February 2007, 12:37:12 »
Excellent bit of advice there, I like solutions that include unplugging and forgetting  :y
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