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Quote:

Originally Posted by The Gorilla (Post 102711)

Hi,

Quote- '' but stops blow by gasses mixing with your intake mixture, which decreases the octane rating of the mixture.''

How ?

Regards,

The Gorilla.

How what?

How does it stop gases going into the intake, well the hose no longer goes into the intake thats how.

Hot gases that come out of the crankcase breather no longer feed back into the intake and mix with cold fresh air. Simples

Quote:

Originally Posted by northernjim (Post 102716)

Is the s54 engine known to suffer from increased crankcase pressure from 'leaky' piston rings then?

No but all engines breathe. This stops that breathing re entering your clean intake air and gumming up your trumpets,throttle bodies,air rail etc etc. Also any oil that is in that breather won t be going in your airbox etc.

S54 does not/should not breathe much oil if any. Have had mine installed for a year and have not empied it once, in fact the sight tube on the side of the catch can shows no oil, but looking in from the top there is some in there.

Hi,

How does the re-routing of a breather
pipe alter the ''Octane'' rating of the fuel mix ?

I fitted a small Oil Catch Tank on my E30 M3 a number
of years ago, [S54, CSL Engine] but the ''Octane''
rating of the fuel mix has never altered.

Its never had anything in it hence why I did not waste
the money repeating, for the CSL.

Regards,

The Gorilla.

Quote:

Originally Posted by The Gorilla (Post 102739)

Hi,

How does the re-routing of a breather
pipe alter the ''Octane'' rating of the fuel mix ?

Regards,

The Gorilla.

I think its more of a case of ensuring that the oil vapour cannot re-enter the engine, whereas as it's plumbed as standard there is a chance that it could....

The Vapour that comes out of the crankcase breather goes straight into the intake. This vapour then mixes with the fresh air coming in through the Airbox/Filter.

This air/mix is then taken into the throttle bodies and mixed with the fuel in the combustion chamber.

Hence this cylinder mixture now not only contains fuel and air(as it should), but oil vapour from the engine and possibly some oil.

Its this vapour and oil particles which decreases the octane rating of that cylinder at that particular instant.

Tell you what, turn your engine on leave it idling.

Remove the breather hose at the end that fits into the airbox, see how much dirty vapour is coming out at idle. If you like take a smell!

Its hot gas and full of hydrocarbons. Not what you really want going back into your intake.

As your RPM increases the volume of vapour increase...

Hi,

The 'volume' of Oil particles returned
to the Plenum which are then subsequently
''re-used'' would not make any difference to
the Octane of the Fuel entering the
engine whatsoever.

Oil Vapours do not have the ability to
alter the Octane /Mix of any given Fuel.

''An octane number is a measure of gasoline's ability to resist pre-ignition, also known as "knocking" or "pinging".
Octane is a rating, similar to a ratio of measurement, not a substance chemical or product you can add to gas. Determining octane measurements involves a complex methodology.''

Above extracted from a Paper on Fuel Sampling and Testing.

Oil vapours, if there was enough of it,
might alter Air Density, but on the
total Volume entering into a S54 which
if I remember correctly is something around
475 gpm, then the small volume being
re-cycled would be so slight as it would not make
any difference in the real world.

Regards,

The Gorilla.

Gorilla was being a bit of a pedant, but we know he means well. ;)

Quote:

Originally Posted by The Gorilla (Post 102757)

But it keeps your trumpets cleaner you numpty:hahaha:.

I agree it will make fuck all performance difference, but if it makes people think it helps the engine run better, then let them do it.

Its all relative to personal appiness, :beer:

Edited to add, I reckon if you add oil to fuel it might raise the "octane" slightly

Quote:

Originally Posted by lawsy (Post 102759)

But it keeps your trumpets cleaner you numpty:hahaha:.

:hahaha::hahaha: