Performance modifications technical discussion.

[gar074]

Thank you, yes the camshaft cover was from an engine I destroyed in testing.

Ha - I think that's what I'm doing with mine!

[Czar]

Ha - I think that's what I'm doing with mine!

Self destruction of your engine ? They are quite resilient to enthusiastic driving in stock form, it's when re-mapped by the unknowledgeable who treat and change the timing, fuel and boost parameters of the GDI (gasoline direct injection) systems, like they would with a PI (port injection) system without understanding the complexity behind GDI.

[gar074]

Sorry czar - my poor attempt at a joke! Despite all the problems I've had with mine, it's proved resilient to self-destruction so far!

[Czar]

Sorry czar - my poor attempt at a joke! Despite all the problems I've had with mine, it's proved resilient to self-destruction so far!

More I misread in understanding your post, I apologise for that, when I'm in work mode, I find it very difficult to switch off, I spend 330 days out of 365 in full work mode.

[Fabian]

Hi Czar, realy great topic so far!! :cool:

Quation about the PCV at the back side.
What do you think about the "PCV Delete Mod"?
Instructions about the Mod: http://www.etuners.gr/en/index.php?s=12&t=299

I still want to do this Mod with my 2011 DS3 THP but don't know very good if this solves the problems?
Problems like Oil carbonising around the intake valves

Can please advise or give your opinion?! :cool:

[mattds3sport]

Hi Czar, realy great topic so far!! :cool:

Quation about the PCV at the back side.
What do you think about the "PCV Delete Mod"?
Instructions about the Mod: http://www.etuners.gr/en/index.php?s=12&t=299

I still want to do this Mod with my 2011 DS3 THP but don't know very good if this solves the problems?
Problems like Oil carbonising around the intake valves

Can please advise or give your opinion?! :cool:

+1 on this ,also would carrying out this mod , a remap , boost pipes , and air filter put too much strain on the engine. ? many thanks

[Mark]

Also like to know if the pvc delete mod is good or not

[Czar]

Hi Czar, realy great topic so far!! :cool:

Quation about the PCV at the back side.
What do you think about the "PCV Delete Mod"?
Instructions about the Mod: http://www.etuners.gr/en/index.php?s=12&t=299

I still want to do this Mod with my 2011 DS3 THP but don't know very good if this solves the problems?
Problems like Oil carbonising around the intake valves

Can please advise or give your opinion?! :cool:

When considering doing the PCV delete, you must be aware that although it is a method to close a direct route for the crankcase pressure vapour mist to access the back of the inlet valves via the intake manifold post throttle body, the crankcase pressure has nowhere to go when your engine is idling and cruising off boost (low RPM) however that said, this is far from ideal but not to much of an issue due to the fact that the camshaft cover is fitted with a excess pressure release valve at the rear of the camshaft cover, furthermore the front (side) PCV outlet which is plumbed into the air intake pre turbo will handle the crankcase pressure, this outlet although opened primarily under boost vacuum situations, does open and bleed the excess crankcase pressure when there is a positive pressure greater than the sprung central controlling diaphragm.

Furthermore to the above, I do not recommend doing or using the PCV delete when you are considering or have increased the turbo boost pressure above the stock factory settings!

Anytime you increase cylinder pressure either from increasing the turbo/supercharger boost operation or from raising the CR (compression ratio) you by default increase the amount of "blow by" the pistons rings efficiency at working with and sealing the extra increased cylinder pressure.

Crankcase pressure is a mix of wind created by the movement of the reciprocating mass (crankshaft, connecting rods and pistons) and cylinder pressure bleed, commonly known as "blow by" the piston and rings sealing threshold, windage is controlled to a degree by windage trays (mesh or louvred steel sheet) this reduces the wind (turbulence) on the oil in the sump, in an attempt to, reduce parasitic drag (reducing power) from oil holding onto the crankshaft webbs, from turbulent air forcing the oil into climbing waves.

"Blow by" is upper cylinder pressure that leaks (bleeds) round, through and past the pistons rings, piston and cylinder wall, now there is a myth that the greater the RPM the greater the "blow by" this is wrong, and here is why, when the engine is at its working temperature the piston, piston rings and cylinder walls have expanded from the heat generated by the engine working within its temperature parameter, there will now be an amount of "blow by" controlled by the expansion tolerance specific to the metallurgy material blend of each piston/piston ring manufacturer developing a package to work with the engines generated working temperature within the cylinder, produced by each individual cylinder.

Now as we increase RPM we generate heat and the more heat the more material expansion we get, that said, there is a limit to this, however the engine manufacturer will know this metallurgy material expansion tolerance limit, and the engines internals will still be within their expansion tolerance range, for the stock engines working parameter limits, and so the greater the RPM the greater the expansion resulting in less amounts of "blow by" but although you will have less amounts of crankcase pressure from "blow by" you will have increased crankcase pressure from the increase of windage from the reciprocating mass.

So why do I recommend not installing the PCV delete when the boost has been or is going to be raised, quite simply the stock pistons and piston rings have not been designed to work with anything other than the factory limits!

[Fabian]

Many thanks for this great info!

So best thing to do is to fit an "Oil Catch tank" for the back PCV and only use one of the caps to fit on the intake?
This will also avoid that oil is sucked into the cylinders and avoid that the oil is carbonising around the intake valves!

[chiefnerd]

Odd then that most of the Mini R56 modders do it, and most of the tuners working on the DS3 do it or recommend it's done, in fact it's the same for almost any Modded turbo

Are you taking out adding a catchcan or breather filters in as part of the equation?

[Czar]

Many thanks for this great info!

So best thing to do is to fit an "Oil Catch tank" for the back PCV and only use one of the caps to fit on the intake?
This will also avoid that oil is sucked into the cylinders and avoid that the oil is carbonising around the intake valves!

Your welcome, you could as you say install a OCC (oil catch can) to the rear PCV line and fit a blanking cap to the intake manifold, however, there will be a slight issue with this particular arrangement, your installed oil catch can will then have to vent to atmosphere, the most common way, is to have a small breather filter either as a direct fit onto your chosen oil catch can or at the end of a hose line from your oil catch can, now this is where a slight issue comes into play, the noxious crankcase pressure gasses venting from your breather filter on your oil catch can, will find it's way inside your car, creating a very unpleasant smell whilst you drive, secondly the crankcase vapour venting from your breather filter will still have oil particles suspended within the passing vapour, and these suspended oil particles will very soon saturate your small breather filter, it will be at this pint of full saturation of your breather filter, that oil mist will now be blown around your engine bay, leaving you with a very light film on components, depending on the position of your oil catch can and a cleaning up job to do!

Odd then that most of the Mini R56 modders do it, and most of the tuners working on the DS3 do it or recommend it's done, in fact it's the same for almost any Modded turbo

Are you taking out adding a catchcan or breather filters in as part of the equation?

It's not odd that "modders and tuners" fit the blanking caps, sheep always follow never lead, what is alarming is the amount of "modders and tuners" that are sheep and don't understand any of the implications of their actions, regardless of the engine and application of forced induction.

Oil catch cans/tanks, here is another highly misconceived global debate, I get asked almost daily about this subject, I also see terrible installations on road and dedicated track vehicles, ranging from empty beer cans to very costly formed Aluminium and Stainless Steel cans and tanks, with one shared purpose and that is to entrap suspended oil particles, so why does an empty beer can venting to atmosphere seem to do the same job as a high end respected manufacturers formed Aluminium or Stainless steel can/tank ?

Both are collecting receptacles/vessels/containers with a common shared interest, this is where you now need to understand how an oil catch can/tank works and why they are installed in the first place, so those of you that have read my post and have grasped what PCV is (positive crankcase ventilation) and how it is created, you should be aware that we now have oil suspended within the venting positive pressure vapour (vapour being the key word) from the PCV venting lines, so without the installation of a OCC (oil catch can) we have a common situation where the suspended oil particles are carried along in the line/s feeding into the inlet manifold, this vapour is then vacuum drawn into each individual cylinder during the intake stroke, we now have a contaminated cylinder charge (oil particles) the more oil particles in the cylinder charge from poor PCV entrapment the greater the chances of pre detonation (knock) or for the old school (pinking) the issue of pre detonation from oil contaminated cylinder charge, can be discussed later on, if anyone has the interest to learn more on this subject.

So we now choose a oil catch can/tank and install it, and you are now ready to catch all the vapour (oil suspended particles) from your engine, through the particular PCV line your oil catch can is installed into, so presuming you have selected a oil catch can/tank with the correct sized hose barbs for your PCV line/s your ready to start collecting suspended oil particles from the passing through vapour, how does any oil fall out of suspension ?

97% of all oil catch cans/tanks simply rely on a change of direction, inlet/outlet at different orientation points and heights, to slow down the passing through vapour, this simple slowing down (change of direction) of the passing vapour will at best encourage no more than 35% of the total passing through vapour volume to fall out of suspension, then there are oil catch cans/tanks which incorporate a baffle plate between the inlet/outlet ports, this again not only slows down the passing through vapour, it also adds resistance (turbulence) encouraging more of the suspended oil particles to fall out of suspension, this system at best will offer no more than 50% oil particle separation, we then move onto oil catch cans that incorporate direction change, a baffle and a filtration gauze between the inlet/outlet ports, these again are not much better than the afore mentioned two versions, as generally the filtration gauze has such void volume (aperture holes) it offers very little in the way of separation entrapment.

Now lets move onto when your chosen oil catch can/tank has collected, what has it collected ? This is the misconceived global debate, it is thought and wrongly understood that all the collected contaminants within your chosen oil catch can/tank are out of and from your particular engine, this is where the misconception and understanding comes into play, engines go through many heat cycles, cold oil on first starts all the way through to oil which reaches it's working temperature, now when oil cools down along with the engine and coolant system, the oil, engine and coolant system cools at different thermal rates, it's this thermal exchange rate, which introduces internal sweating and the formation of water droplets, ever taken an engine oil cap off and seen the creamy emulsified mix ? This is formed from internal sweating .

Internal sweating forms water droplets, and the same also happens in your oil catch can/tank, the misconception is that this emulsified mix (water and oil) collected in your oil catch can/tank has come form your engine, and had your oil catch can not collected it, this would have found it's way into the combustion cylinders and process, adversely affecting your engines power, what you have to realise is, as your engine, coolant system and oil warm up, and water droplets formed during the cooling down thermal exchange process are boiled away.

So why do we get the emulsified contaminated mix in the oil catch can/tank ? You have a hot vapour entering a cold receptacle/vessel/container, the thermal exchange process happens a lot faster than the engine, and subsequently sweats more often, producing it's own internal water droplets, and as the oil catch can does not become hot enough to boil off the self condensing condensation, it's a never ending condensing cycle the more it collects the more it sweats, resulting in a collection mix of 98% self condensing water from rapid heat cycles and 2% oil entrapment per passing through vapour volume.

[gar074]

That's the most authoritative & persuasive explanation I've read on here for a long time (no disrespect intended to other posters, as all constructive contributions are valued as contributing to the debate and helping to advance our knowledge and understanding).

Many thanks.

[chiefnerd]

So in your honest opinion then, no performance engine should be fitted with a catch can? You don't think the oil burn issue carbonising the exhaust valves is at issue?

If it isn't I was wondering what you think is causing the issue.

[Czar]

That's the most authoritative & persuasive explanation I've read on here for a long time (no disrespect intended to other posters, as all constructive contributions are valued as contributing to the debate and helping to advance our knowledge and understanding).

Many thanks.

Your welcome, it's always a pleasure to help.

So in your honest opinion then, no performance engine should be fitted with a catch can? You don't think the oil burn issue carbonising the exhaust valves is at issue?

If it isn't I was wondering what you think is causing the issue.

Any engine whether it be for road or dedicated track use, can benefit from the addition of an oil catch can/tank, especially the GDI (gasoline direct injection) engines, as they have a completely dry air intake system, unlike regular port injection and carburation systems, that have a constant flow of fuel washing down the inlet tracts and over the backs of the inlet valves, the carbonising of the inlet (not exhaust) valves as seen and experienced in all GDI (gasoline direct injection) engines is attributed by the direct and non direct feed of the crankcase pressure vapour via the inlet manifold and the air intake path pre turbo route, with no fuel present within the inlet manifold and cylinder head inlet tracts, this lack of fuel wash, in all GDI (gasoline direct injection) engines, creates a very very hot environment for the air and crankcase pressure vapour passing over the backs of the inlet valves, this dry hot environment is responsible for burning the passing crankcase pressure vapour onto the the backs of the very hot inlet valves creating the carbonisation build up, we are all now familiar with, so in summary, although 97% of oil catch cans are just empty cans, offering no more than 35% oil particle separation, a 35% reduction in oil particle entrapment from the passing through crankcase pressure vapour is better than nothing!

[chiefnerd]

In other words you'd advise leaving the pcv in place but adding a catch can on the breather?