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They all say that.” Read the thread before commenting”.
No, you were not being ironic; if you are, it was a shite attempt.
You clearly still havent read the thread, I was not the first one to say what I said, its there in black and white, but you cant be bothered to read it.

They all say read thread before commenting cos its basic common sense, you need to get context before you shoot your mouth off.
 

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You clearly still havent read the thread, I was not the first one to say what I said, its there in black and white, but you cant be bothered to read it.

They all say read thread before commenting cos its basic common sense, you need to get context before you shoot your mouth off.
Surely the context is a question of having some weight behind assertions. That, in my opinion is about having something other than prattle behind one’s views on technical issues.

As for power losses due to strangulating manifold cats on any engine, you don’t seem to believe they exist!

So the plots of an unmodifiwd 40,000 mile pristine Brera and a lightly modified 112,000 mile should be identical. If your theory of modifications having no effect on engine performance.
 

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3,808 Posts
They all say that.” Read the thread before commenting”.
No, you were not being ironic; if you are, it was a shite attempt.
Typos 1 said,


I never suggested that close coupled cats have anything to do with NOx.

You appear to think that your engine having EGR means that it somehow doesnt need pre cats, that is incorrect, for a start EGR only reduces some emissions (mainly NOx and there are many more emissions in petrol exhausts) it does not remove them entirely so the pre cats are still needed.

Jet Thrust Stoichiometric engines can also run lean burn (the opposite of stoichiometric) just like a diesel, but running lean actually INCREASES the likelihood of NOx forming as there is more air and therefore more nitrogen (this is the reason that diesels make more NOx).

I never said man - cats reduce Nox either. It is clear you have no intention of looking at the sources of my research. Cambridge University, M.I.T., SAE. And others. If you had made the effort you would have spotted, MIT stands for Massachusetts, which along with SAE and Cambridge are internationally recognised and one has to pay for access to their research papers.

I think some of your ideas on EGR is erroneous. We have to methods of introducing EGR, external and Internal.

External is invariably associated with Turbo petrol and Diesels.

The 3.2 JTS uses Internal EGR.

Research indicated cats 1 - 2 metres away from the manifold for several reasons. But two principle reasons are:-

1.) The residency time of exhaust gases, in the catalytic converter has to be sufficiently long enough for conversion. If the cats are too close, the transit time is too short and emissions reduction is poor.

2.) Nox is reduced (catalized) at temperatures much lower than HC’s. A distance of 1 to 2 metres - two being preferred permits exhaust gas temperatures to fall sufficiently to bring temperatures to within he optimum window for Nox conversion.

The manifold cats on the JTS are intended to maintain light off temperatures in Urban/slow moving traffic, where lower power levels cannot sustain the optimum value.

However, in high speed conditions they over heat the cylinder heads, burn the oil and heavily tar the engines internals.

A sump oil temperature of 100 - 110 deg. C. Is far to high, given bearing temperatures - as indicated by research, can be 45 deg. C. higher. At those temperatures the sheer characteristics are extremely poor and the additives, the 40 in the 5w40 - polymers break down.

In an attempt to resolve this problem, experiments have been carried out, with trombone manifold pipe work to move the cats close to the heads during urban driving speeds, and then away when cruising at high speeds, dynamically switching sections of pipe work to achieve this.

The pre cat wide band lambda probes dynamically alter the AFR - via ECU control, to ensure the Nox and H.C.’s are kept in check to ensure the cats are working in the optimum region for the ratio of pollutants and their conversion.

Internal EGR on the 3.2 JTS is specifically there for the destruction of HC’s., which require the higher temperatures re - combustion gives.

I pointed that out more than once in previous posts.
 
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