Solid boost pipe connections
Discussion
Otispunkmeyer said:
Not up to me. Customer wants/needs it that way for emissions and it's a fairly old engine. Can't really go into more detail unfortunately.
Dirty systems do not improve emissions of ay age.It's not hard to implement breather systems better, with filtration etc so such oil/vapours will not enter the inlet tract.
OEM's seem quite lazy in this regard and don't seem to care that the inlet's get utterly coked up with s
te. Largely because they know it will be fine for their warranty period.....and don't give a toss after thatstevieturbo said:
Dirty systems do not improve emissions of ay age.
It's not hard to implement breather systems better, with filtration etc so such oil/vapours will not enter the inlet tract.
OEM's seem quite lazy in this regard and don't seem to care that the inlet's get utterly coked up with ste. Largely because they know it will be fine for their warranty period.....and don't give a toss after that
It's a homologation requirement that they enter the inlet as they must be reburnt and managed by the exhaust after treatment accordingly. No homologation requirement in the last decade has allowed vent to atmostphere. It's definitely not a laziness thing as an awful lot of time and money goes into how to manage this effectively as if you don't get it to meet emissions then you can't homologate it which means you ultimately can't sell the car.It's not hard to implement breather systems better, with filtration etc so such oil/vapours will not enter the inlet tract.
OEM's seem quite lazy in this regard and don't seem to care that the inlet's get utterly coked up with s
te. Largely because they know it will be fine for their warranty period.....and don't give a toss after thatpoppopbangbang said:
It's a homologation requirement that they enter the inlet as they must be reburnt and managed by the exhaust after treatment accordingly. No homologation requirement in the last decade has allowed vent to atmostphere. It's definitely not a laziness thing as an awful lot of time and money goes into how to manage this effectively as if you don't get it to meet emissions then you can't homologate it which means you ultimately can't sell the car.
And nowhere did I state to vent it to atmosphere.The same way they go to lengths to filter the exhaust, it is incredibly easy to filter the breather system too. Yes they are lazy.
poppopbangbang said:
stevieturbo said:
And nowhere did I state to vent it to atmosphere.
The same way they go to lengths to filter the exhaust, it is incredibly easy to filter the breather system too. Yes they are lazy.
Really interesting, what do you suggest for filtering the breather system? The same way they go to lengths to filter the exhaust, it is incredibly easy to filter the breather system too. Yes they are lazy.
E-bmw said:
Could you not just install an oil catch can?
That gets you reasonable seperation of the gasses and liquids (see many OEM PCV solutions these days which use seperators) but not total and you still have to do something with the gasses element - as they're mostly combustion byproducts from ring pack blow by dealing with the hydrocarbon element is the tricky bit hence being interested to know what Stevies solution is. poppopbangbang said:
Really interesting, what do you suggest for filtering the breather system?
Other than filters like the provent that already exist ? It's not new, it's not difficult, just most manufacturers don't carehttps://oem.mann-hummel.com/en/oem-products/crankc...
stevieturbo said:
Other than filters like the provent that already exist ? It's not new, it's not difficult, just most manufacturers don't care
https://oem.mann-hummel.com/en/oem-products/crankc...
They are a packaging challenge on a lot of applications though, you need at least 350mm above oil level for the recirculation point and you have to deliver the filtered blowby into an area of vacuum or atmospheric pressure which means between air filter and turbo (which the turbo machinery guys get a bit fizzy about). They're also not suitable for some operating regimes where there is little to no stop time as there is at least one mode where they will only drop oil back to the sump when the engine is stopped due to relying on differential pressure to control the none return valve. https://oem.mann-hummel.com/en/oem-products/crankc...
They can absolutely work (and work really well), especially in HGV applications, but they're not a golden bullet to everything breather related. On a cost, supply chain, ongoing service, failure mode etc. basis you can end up with better overall viability for production without than with. Everything can be improved and optimised but on the cost > reliability > performance triangle maxing everything generally isn't possible. That doesn't mean the engine guys are lazy or that the manufacturer doesn't care, it's just a reality of production engineering.
PPBB, what do you reckon on a machine with no EGR (deleted, theoretically an off-road engine), Is it beneficial to have a catch can or to send the gases and oil back through using the standard UFO on the top of the engine? Ryan and co from Darkside Developments believe in doing the latter, extra lubrication for the turbo. Hard to know. I was tempted to switch to a catch can on my 1.8T which I reckon is a heavy breather (nothing scientific, it just tends to use a couple of litres between services so it's going somewhere), but I want standard levels of reliability and not to overstress anything.
mercedeslimos said:
Is it beneficial to have a catch can or to send the gases and oil back through using the standard UFO on the top of the engine?
From the point of view of peak engine power you absolutely don't want that lovely cool fresh air diluted with blowby gases and low octane hydrocarbons. The only reason to put the breather gases back through the engine is to protect the environment. Which is important, of course, but don't imagine it's good for the engine performance. mercedeslimos said:
PPBB, what do you reckon on a machine with no EGR (deleted, theoretically an off-road engine), Is it beneficial to have a catch can or to send the gases and oil back through using the standard UFO on the top of the engine? Ryan and co from Darkside Developments believe in doing the latter, extra lubrication for the turbo. Hard to know. I was tempted to switch to a catch can on my 1.8T which I reckon is a heavy breather (nothing scientific, it just tends to use a couple of litres between services so it's going somewhere), but I want standard levels of reliability and not to overstress anything.
You can use a catch can and still recirculate the left over back into the inlet, this is about as ideal a solution as it gets for a performance engine (and what a lot of OEMs are now doing with staged oil sepeators which return to the sump). My 1.8T in the Boxster has a small oil seperator which retains any drop out and recirculates the left overs into the inlet infront of the turbo (to create sufficient vacuum under boost to evacuate the crank case). This is considered bad by the OEM guys due to the interaction between possible oil in the inlet and the compressor wheel at high RPM, however turbo life on engines running 2bar boost and anti-lag is generally too short for that to be a problem and the seperate design I use is copied from an OEM design and seems very effective in testing. A catch tank / seperator of some description would also allow you to monitor how much it is breather/loosing.The Darkside chaps know what they are doing and that approach sounds very sensible to me. You can of course breathe to atmosphere but to be honest these days for a road used car its the lazy option, if the engine is breathing heavily enough that it has any impact on the effective octane rating of the charge then it's already broken or a truly ancient design which likely breathed to atmosphere originally.
GreenV8S said:
FTFY
Not really, when there is opportunity to enhance the scavenging of the crankcase one should always take it for a number of performance reasons (not just emissions but also seal life, oil seal bypass reduction, ring pack sealing, blow by gas removal etc. etc.), this includes using vacuum present elsewhere on the engine. Breathing an engine to atmosphere will not acheive anywhere near the crank case evactuation that a well designed PCV system will as you are essentially relying on each blow by event to overpressure the crank case forcing an existing amount of blow by gasses out. This has been pretty well understood since the prewar era where draught tubes were used to create the vacuum by placing them in the vehicle slipstream to create some vacuum to scavenge the crank case, even going so far as to have crank case inlets at the front of the vehicle using road speed to create as much pressure differential as possible. When you look at bleeding edge modern racing engines you'll see oil pumps desgined specifically to over achieve scavenge ratios with pressure regulators on the inlets to the crank case which maintain an ideal crank case depression for ring pack sealing and blow by evacuation etc.
The only reason not to use intake vacuum to scavenge the crank case is if you have a well designed dry sump system where the scavenge stages are already over achieving or if the engine is such an old design or so worn that the crank case blowby amount is excessive to the point it would have a negative impact recirculating it, at which point some sort of vacuum (i.e. draught tube) is still preferable.
It's all a balancing act, especially on turbo charged engines or diesels where you have very little vacuum in many use regimes but maximising the crank case evacuation is never, ever a bad thing. Popping a K&N breather filter on the rocker cover is rarely the best solution.
GreenV8S said:
On a well designed engine at wide open throttle there is no significant intake vacuum.
Which is why in some operating regimes you rely on things like Bernoulli's principle to create the neccesary pressure differential (you have many 100's of grams a minute of air moving after all), see recirculation between air filter and turbo for a good example. If you're doing it properly you'll use one way valves to ensure that the crank case is evacuated by vacuum when its present in the inlet and pressure drop when it isn't (e.g. when the manifold pressure becomes positive in a boosted application). Here's a good example from a BMW Turbo charged application:
This is the turbo intake hose showing the detail of the crank case breather connection, specifically the shape of it within the interior of the pipe, this designed shape creates vacuum when high speed air is passed over it, at the same time it creates very little turbulance in the pre-turbo air stream. It's a great example of how modern CFD allows some really optimised designs.
This is also the reason why everyone complains about how much pipework there is on a modern engine
The ideal requirement for vacuum at all times is also why draught tubes were a popular solution for so long on everything from land speed cars to aircraft as the vacuum generated was dependant on the vehicle speed and not the engine load.
I think we've rather strayed off the boost pipe connector topic now too
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