early dyno results
02-15-2011, 10:34 PM
#196
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two systems need oil
main rotating parts - main bearings and rods - might need greater flow at higher rpm. Probably better to say that they need higher pressure at higher rpm.
the top end is another matter.
flow control is either input or output
input is by decoupling the pump from pulley or using an external electric pump.
could be tough and/or expensive
output is by opening a by-pass or relief valve - rpm-based control would be best
the top end is another matter.
flow control is either input or output
input is by decoupling the pump from pulley or using an external electric pump.
could be tough and/or expensive
output is by opening a by-pass or relief valve - rpm-based control would be best
02-15-2011, 10:41 PM
#197
Drifting
First forgive me I'm an electrical engineer not a mechanic or fluidics expert.
If I understand what I have read, the channels that would normally drain the cylinder heads of oil via gravity are getting plugged by oil being forced upwards from either the crankcase or the sump ( I wasn't clear). This forcing of oil upwards is due to a pressure difference? The crankcase getting over pressured at higher rpm.
For fear of being ignorant, is there a way to have a one way check valve?
Or would this just mean oil would jam at the other side of the check valve
Alternatively, Is it possible to alter the opening at the bottom of these returns that resists the flow upwards by it's geometry.
Maybe my thought processs is all bassackwards
Thx for humoring me
Mike
If I understand what I have read, the channels that would normally drain the cylinder heads of oil via gravity are getting plugged by oil being forced upwards from either the crankcase or the sump ( I wasn't clear). This forcing of oil upwards is due to a pressure difference? The crankcase getting over pressured at higher rpm.
For fear of being ignorant, is there a way to have a one way check valve?
Or would this just mean oil would jam at the other side of the check valve
Alternatively, Is it possible to alter the opening at the bottom of these returns that resists the flow upwards by it's geometry.
Maybe my thought processs is all bassackwards
Thx for humoring me
Mike
02-15-2011, 10:43 PM
#198
Drifting
Totally as an aside, but I forgot to mention this earlier. To those suggesting to vent the breathers into the intake plumbing. While this does get rid of nasty crank case air, it also is burning oil vapor/oil. The amount of oil is somewhat proportional to the level of tune of the engine. The stronger the engine, the more air entrained oil you will suck through the intake. This is bad as this oily air knocks down the octane number of the mixture. You can get knock when you least want it.
02-15-2011, 10:48 PM
#199
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check valves would create pooling
you see many references to "extending the passages" - this extension should prevent the bottom end from flinging oil into the bottom end of passages and thus up into the head - bad even if it merely stops the oil from draining freely.
02-15-2011, 10:58 PM
#200
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This is what I get for having a real job: I miss the first 10 pages of the BEST 928 THREAD EVER!
First:
Second:
If anyone ever harbored it, this thread should erase all doubt that Doc Brown is The Man!
Third:
This explains something I've seen on two early (very-low mileage with very-close VINs that were AFAIK touched under the intake first my me) '93 GTSs that had the "between" filler neck with one port at the base rather than (S4/GT) two or (post-early '93) zero ports.
First:
Second:
If anyone ever harbored it, this thread should erase all doubt that Doc Brown is The Man!
Third:
This explains something I've seen on two early (very-low mileage with very-close VINs that were AFAIK touched under the intake first my me) '93 GTSs that had the "between" filler neck with one port at the base rather than (S4/GT) two or (post-early '93) zero ports.
02-15-2011, 11:08 PM
#201
Archive Gatekeeper
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Yep, the mythical early GTS '-08' filler neck:
02-16-2011, 01:47 AM
#203
Former Sponsor
I am curious as to what the thoughts are then regarding the work that Louie Ott did with the video camera on the covers. I believe that this shows evidence to the contrary. I've never seen this video. Anybody have a link or a copy?
However from your description you have all 4 breather port on the cam cover in use, but no breather from the filler neck. The breather from the filler neck was put into a pan and allowed to just "puke" at will. It was not capped....knew this would not work.These 4 ports are then connected to the airbox. This at WOT is going to generate a venturi on these 4 hoses creating a vacuum inside the crankcase. This will only aggravate the problem as all the air is going to be forced up the drainback holes and out the valve covers. Not all of the details/attemps to solve this were posted. It would take pages. The vents were very high on the wall of the intake "box" and there was no lid...they did not have vacuum acting on them, from the very beginning. We did remove them and raise them much higher...they still "puked".
Consider trying what I suggested in my earlier post. Use a large (1.5") tube connected to the oil filler neck port. Run this into a 3" ID canister with a couple copper scrubbers in it. This will have a very slow airflow speed which will then help the oil to drop out of the air. The copper scrubbers remove the rest of the suspended oil. This way there is zero vacuum and airflow up and through the heads. It's not on the dyno, right now, to try this. We did have some plastic material that acted like a "copper scrubber" down in the crankcase breather. Once the head drains got plugged, the crankcase quickly "blew" this stuff out. It may have been too restrictive.If you do with to vent the heads, route the exit of the for mentioned canister to the airbox, and vent the cam covers to atmosphere.
The venturi effect in the airbox will help to generate a suction bringing air through the cam covers and down into the sump, therefor drawing the oil back into the pan.
I would also recommend putting a vacuum limiting valve on MA drysump in the same fashion to help generate a high velocity air stream through the heads into the main crankcase. Thus helping to pull the oil out of the heads and back down.
Now then there is one question that remains, do both heads fill, or just 1. If just one then it is possible that the throw from the crank is having an effect and the addition of a guard to those ports could help. This was interesting. All four of the breathers ejected oil within seconds of each other. While that still could be the case, it is possible that there is too much oil to the heads, and the use of the 944S2 valve is a good idea, or another restrictor in the oil path to the heads.
Or simply do both. I'm not convinced that the 944S2 valve will provide enough oil, at idle with an automatic. That would require a long term test, to confirm.On my street car, I capped off the cam breathers, and only vent from the base of the oil fill neck with a 1" hose. I see zero ejection at high RPMS unless I am on track duty, and then I would need a larger canister with a separate drainback. Yes, I'm guessing that running the car at high rpms, for extended periods of time might show more oil thrown from your vent....I have no reason to see why your engine would not "pacK" oil into the breather oil like all the other engines seem to do...and like my engine obviously did. Pretty hard to run one of these cars at 6,000 rpms, for a minute and keep your license.
However from your description you have all 4 breather port on the cam cover in use, but no breather from the filler neck. The breather from the filler neck was put into a pan and allowed to just "puke" at will. It was not capped....knew this would not work.These 4 ports are then connected to the airbox. This at WOT is going to generate a venturi on these 4 hoses creating a vacuum inside the crankcase. This will only aggravate the problem as all the air is going to be forced up the drainback holes and out the valve covers. Not all of the details/attemps to solve this were posted. It would take pages. The vents were very high on the wall of the intake "box" and there was no lid...they did not have vacuum acting on them, from the very beginning. We did remove them and raise them much higher...they still "puked".
Consider trying what I suggested in my earlier post. Use a large (1.5") tube connected to the oil filler neck port. Run this into a 3" ID canister with a couple copper scrubbers in it. This will have a very slow airflow speed which will then help the oil to drop out of the air. The copper scrubbers remove the rest of the suspended oil. This way there is zero vacuum and airflow up and through the heads. It's not on the dyno, right now, to try this. We did have some plastic material that acted like a "copper scrubber" down in the crankcase breather. Once the head drains got plugged, the crankcase quickly "blew" this stuff out. It may have been too restrictive.If you do with to vent the heads, route the exit of the for mentioned canister to the airbox, and vent the cam covers to atmosphere.
The venturi effect in the airbox will help to generate a suction bringing air through the cam covers and down into the sump, therefor drawing the oil back into the pan.
I would also recommend putting a vacuum limiting valve on MA drysump in the same fashion to help generate a high velocity air stream through the heads into the main crankcase. Thus helping to pull the oil out of the heads and back down.
Now then there is one question that remains, do both heads fill, or just 1. If just one then it is possible that the throw from the crank is having an effect and the addition of a guard to those ports could help. This was interesting. All four of the breathers ejected oil within seconds of each other. While that still could be the case, it is possible that there is too much oil to the heads, and the use of the 944S2 valve is a good idea, or another restrictor in the oil path to the heads.
Or simply do both. I'm not convinced that the 944S2 valve will provide enough oil, at idle with an automatic. That would require a long term test, to confirm.On my street car, I capped off the cam breathers, and only vent from the base of the oil fill neck with a 1" hose. I see zero ejection at high RPMS unless I am on track duty, and then I would need a larger canister with a separate drainback. Yes, I'm guessing that running the car at high rpms, for extended periods of time might show more oil thrown from your vent....I have no reason to see why your engine would not "pacK" oil into the breather oil like all the other engines seem to do...and like my engine obviously did. Pretty hard to run one of these cars at 6,000 rpms, for a minute and keep your license.
I've put some more information/notes in your text, Colin. They are "blue".
02-16-2011, 01:56 AM
#204
Former Sponsor
First forgive me I'm an electrical engineer not a mechanic or fluidics expert.
If I understand what I have read, the channels that would normally drain the cylinder heads of oil via gravity are getting plugged by oil being forced upwards from either the crankcase or the sump ( I wasn't clear). This forcing of oil upwards is due to a pressure difference? The crankcase getting over pressured at higher rpm.
For fear of being ignorant, is there a way to have a one way check valve?
Or would this just mean oil would jam at the other side of the check valve
Alternatively, Is it possible to alter the opening at the bottom of these returns that resists the flow upwards by it's geometry.
Maybe my thought processs is all bassackwards
Thx for humoring me
Mike
If I understand what I have read, the channels that would normally drain the cylinder heads of oil via gravity are getting plugged by oil being forced upwards from either the crankcase or the sump ( I wasn't clear). This forcing of oil upwards is due to a pressure difference? The crankcase getting over pressured at higher rpm.
For fear of being ignorant, is there a way to have a one way check valve?
Or would this just mean oil would jam at the other side of the check valve
Alternatively, Is it possible to alter the opening at the bottom of these returns that resists the flow upwards by it's geometry.
Maybe my thought processs is all bassackwards
Thx for humoring me
Mike
Since the crankcase vent was open, I'm guessing that the drains were not being blocked by crankcase pressure, but more just "overwhelmed" by the sheer volume of oil that needed to be returned. However, if the crankcase vent gets "plugged" by a big slug of oil that is thrown off of the crankshaft and the drains get covered pretty early in the whole process, crankcase pressure could get pretty high, very quickly.
02-16-2011, 02:00 AM
#205
Using the three holes in the V was mentioned. You can't go OUT of them and IN the head breather fittings? Skip the "I can see france...." gaping hole in the oil filler neck area?
02-16-2011, 02:01 AM
#206
Former Sponsor
Yes, this is the '08 filler neck. Leave it to Edwards to not only have one, but it being clean enough to lick. Very high tech solution. Porsche overdid themselves, there!
Overheard at the Porsche factory...circa 1992.
"Hans...go grab a bolt and shove it in that hole...we don't seem to have a hose to attach there and it seem to be leaking oil. Yes, just put some sealant on it and thread it in...it will be fine."
Overheard at the Porsche factory...circa 1992.
"Hans...go grab a bolt and shove it in that hole...we don't seem to have a hose to attach there and it seem to be leaking oil. Yes, just put some sealant on it and thread it in...it will be fine."
02-16-2011, 02:06 AM
#207
Rennlist Member
02-16-2011, 02:08 AM
#208
Former Sponsor
I'm going to vent out of the unused "middle" plugged hole in the valley, in this next attempt. The vent from "France" is still under discussion.
02-16-2011, 02:18 AM
#209
Former Sponsor
Ed:
Thanks! That's very nice of you to post that!
As I recall, the upper row of cam caps (intake cam) are always numbered 1-4...I'll look tomorrow, at the shop. if this is true, this is the intake cam...and it pretty much looks like a "paint roller" most of the time. Any idea how many rpms the engine is running when this was taken...or are the "paint roller" times at the higher rpms?
Imagine what the exhaust cam must look like...if it is submerged in oil, like I suspect.
Thanks! That's very nice of you to post that!
As I recall, the upper row of cam caps (intake cam) are always numbered 1-4...I'll look tomorrow, at the shop. if this is true, this is the intake cam...and it pretty much looks like a "paint roller" most of the time. Any idea how many rpms the engine is running when this was taken...or are the "paint roller" times at the higher rpms?
Imagine what the exhaust cam must look like...if it is submerged in oil, like I suspect.
02-16-2011, 02:27 AM
#210
Former Sponsor
All of this is great stuff...but the real question that needs to be answered is:
Does Amsoil have molecules that are more slippery than other oil molecules, which allow it to return to the crankcase quicker?
Paging Kibort.
You "new" guys might not get this...hang around for awhile...you will!
Does Amsoil have molecules that are more slippery than other oil molecules, which allow it to return to the crankcase quicker?
Paging Kibort.
You "new" guys might not get this...hang around for awhile...you will!