2015 Nevada Open Road Challenge ORR
05-05-2015, 05:07 PM
#31
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If there are any winds, you have to be careful. Luckily the 928 is pretty stable at speeds and can handle light winds (< 10-15 mph) fairly well. It's better to finish the race below average, then leave the road trying to hit your average. Once we had 40-60 mph winds from the south, mostly headwinds since we are going south. Since the road curves and there are mountains and valleys that can change the direction of the winds/and or car. When I went over 170 mph the front end would start to wander, so I keep the speeds mostly below that (except at the end where the winds were calmer). I was trying to average 160 that day, but I finished with a 157 mph average. At least I finished. I did have a few mechanical issues I was dealing with, but the wind was the primary issue that day.
Oh as for tires, I'm using Michelin Pilot Super Sports, (Y) rated. (Y) rating is for speeds in excess of 186 mph. Before I switched to Super Sports 5 years ago, I was running Michelin Pilot Sport PS2 tires, but a few people had blow outs running those, so I switched. So far the Super Sports have a good record running at these speeds.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
Last edited by jorj7; 05-05-2015 at 05:14 PM. Reason: Add tire comment
05-05-2015, 05:20 PM
#32
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Oh and I forgot about the sand storm that limited visibility that race:
http://928.jorj7.com/2011-norc/2011-norc-dust-320.wmv
Higher resolution version:
http://928.jorj7.com/2011-norc/2011-norc-dust-720.wmv
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
http://928.jorj7.com/2011-norc/2011-norc-dust-320.wmv
Higher resolution version:
http://928.jorj7.com/2011-norc/2011-norc-dust-720.wmv
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
Last edited by jorj7; 05-05-2015 at 05:45 PM. Reason: Added HD version
05-05-2015, 05:31 PM
#33
Drifting
Matt,
If there are any winds, you have to be careful. Luckily the 928 is pretty stable at speeds and can handle light winds (< 10-15 mph) fairly well. It's better to finish the race below average, then leave the road trying to hit your average. Once we had 40-60 mph winds from the south, mostly headwinds since we are going south. Since the road curves and there are mountains and valleys that can change the direction of the winds/and or car. When I went over 170 mph the front end would start to wander, so I keep the speeds mostly below that (except at the end where the winds were calmer). I was trying to average 160 that day, but I finished with a 157 mph average. At least I finished. I did have a few mechanical issues I was dealing with, but the wind was the primary issue that day.
Oh as for tires, I'm using Michelin Pilot Super Sports, (Y) rated. (Y) rating is for speeds in excess of 186 mph. Before I switched to Super Sports 5 years ago, I was running Michelin Pilot Sport PS2 tires, but a few people had blow outs running those, so I switched. So far the Super Sports have a good record running at these speeds.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
If there are any winds, you have to be careful. Luckily the 928 is pretty stable at speeds and can handle light winds (< 10-15 mph) fairly well. It's better to finish the race below average, then leave the road trying to hit your average. Once we had 40-60 mph winds from the south, mostly headwinds since we are going south. Since the road curves and there are mountains and valleys that can change the direction of the winds/and or car. When I went over 170 mph the front end would start to wander, so I keep the speeds mostly below that (except at the end where the winds were calmer). I was trying to average 160 that day, but I finished with a 157 mph average. At least I finished. I did have a few mechanical issues I was dealing with, but the wind was the primary issue that day.
Oh as for tires, I'm using Michelin Pilot Super Sports, (Y) rated. (Y) rating is for speeds in excess of 186 mph. Before I switched to Super Sports 5 years ago, I was running Michelin Pilot Sport PS2 tires, but a few people had blow outs running those, so I switched. So far the Super Sports have a good record running at these speeds.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
I went 140 once and never forgot it. I could feel the tail end of the "whale tail"-less '86 Carrera was lifting and it made me slow down, (front of 911 is very active shape and stable) but i recall not thinking it would have gone much faster anyway. My younger Brother Dan had binoculars and was looking far ahead. This was a long time ago.
This is how racing began.. on public roads.
I have great interest in this and look forward to reading about your results this year.
Looked at your heat exchanger pics,
that's a lot of bug juice.
05-05-2015, 05:35 PM
#34
Drifting
Oh and I forgot about the sand storm that limited visibility that race:
http://928.jorj7.com/2011-norc/2011-norc-dust-320.wmv
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
http://928.jorj7.com/2011-norc/2011-norc-dust-320.wmv
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
05-05-2015, 05:51 PM
#35
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Here's the video at the finish of that event. Even though the wind was calmer, you can see the car wonder a little.
Low res:
http://928.jorj7.com/2011-norc/2011-norc-finish-320.wmv
Higher res:
http://928.jorj7.com/2011-norc/2011-norc-finish-720.wmv
You might have to download the video and play it locally if it breaks up or buffers.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
Low res:
http://928.jorj7.com/2011-norc/2011-norc-finish-320.wmv
Higher res:
http://928.jorj7.com/2011-norc/2011-norc-finish-720.wmv
You might have to download the video and play it locally if it breaks up or buffers.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
05-05-2015, 06:17 PM
#36
Rennlist Member
You are a brave man. I love how the 928 handles at high speed.
Have you ever hit an animal at high speed? Lots of Antelope and such out there in the desert.
Have you ever hit an animal at high speed? Lots of Antelope and such out there in the desert.
05-05-2015, 06:36 PM
#37
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It just bounced over the car. I think Bill hit a rabbit once in an earlier event.
I did get close to an antelope once. Came around a turn and it was in the middle of the road, straddling the centerline. Tim, my navigator at the time was yelling "Antelope! Antelope!", and I was asking "which direction on the next turn?" I just aimed at it's backside and motored by as it jumped out of the way. I wasn't going to swerve at those speeds, that's when accidents happen.
Cows are the worst, because they don't move when you approach them. Once three cows got loose on highway 225 at the Gambler's Run. Three cars passed them at 150 mph while they just stood in the road and watched the cars go by. The yellow flag came out and a wrangler (that was on site) helped herd the cows back behind the fence.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
Last edited by jorj7; 05-05-2015 at 06:47 PM. Reason: added some details
05-06-2015, 08:14 AM
#38
Drifting
Porsche ran the engine oil through passages in the hood (boot lid) of one of their early 550 Carreras to cool the oil as air flowed over it.
It was too complex so they stopped but I removed my hood insulation thinking it may shed a little heat along with a few grams.
Do you still use the hood insulation or have you removed it?
It was too complex so they stopped but I removed my hood insulation thinking it may shed a little heat along with a few grams.
Do you still use the hood insulation or have you removed it?
05-06-2015, 08:32 AM
#39
Nordschleife Master
This is interesting.
It seems that there's a wide variation between S4/GT engines on how bad these problems are. (Let's leave GTS engines out of this conversation for a little while.) Some have problems, others not so much. For example, George's engine has relatively mild problems based on what I've read here.
Two stock S4/GT engines, on of which has a big oiling and breather problem and another one that has only small one, have relatively few potential differences. One is the oil used. Let's assume the oil is the same. Another is the oil pump bypass valve spring. Let's assume that the spring is correctly calibrated in both engines. As far as I understand, the main remaining difference is the ring seal and the resulting amount of blow by.
Since the blowby is the main difference between really problematic and less problematic engines, my (current) thinking is that it's the gas flows inside the engine that cause many (but not all) of the oiling problems.
It seems that there are two main competing approaches to venting the S4/GT engine:
The first one is to vent it from the cam covers. This has the pro that it's somewhat easier to separate the oil inside the valve covers than at the block chimney. It also has the con that the crankcase gasses have to flow up against the oil drain, slowing down the oil drain. To mitigate the oil drain issue, it would be nice to get the gas to flow from the crankcase into the valve covers via some other route, other than the oil drains. Hence, the connection from either the center knock sensor port or the oil filler neck into the cam covers. The main risk in setting up this connection is that it's possible for that connection to make the oil drain issue worse: Namely, if the gas starts flowing from the cam covers into the block, now more, not less, gas is flowing against the oil drain. This is in my opinion a critical issue for the baffle design for the baffle under the oil filler neck -- for this setup that baffle can't be designed in a way that produces a low pressure in the oil filler neck.
The second one is to vent the engine from the oil filler neck only. The main pro of this approach is that there's now no gas flow up the oil drains. The main con is that it's difficult to effectively separate the air and oil in the block chimney and an external, second separator is usually needed. In this approach, the baffle or separator design under the oil filler neck can produce a somewhat low pressure in the oil filler neck, as long as the oil filler neck is not connected to the valve covers.
Do you agree that these are the two main ways to skin this cat?
It seems that there's a wide variation between S4/GT engines on how bad these problems are. (Let's leave GTS engines out of this conversation for a little while.) Some have problems, others not so much. For example, George's engine has relatively mild problems based on what I've read here.
Two stock S4/GT engines, on of which has a big oiling and breather problem and another one that has only small one, have relatively few potential differences. One is the oil used. Let's assume the oil is the same. Another is the oil pump bypass valve spring. Let's assume that the spring is correctly calibrated in both engines. As far as I understand, the main remaining difference is the ring seal and the resulting amount of blow by.
Since the blowby is the main difference between really problematic and less problematic engines, my (current) thinking is that it's the gas flows inside the engine that cause many (but not all) of the oiling problems.
It seems that there are two main competing approaches to venting the S4/GT engine:
The first one is to vent it from the cam covers. This has the pro that it's somewhat easier to separate the oil inside the valve covers than at the block chimney. It also has the con that the crankcase gasses have to flow up against the oil drain, slowing down the oil drain. To mitigate the oil drain issue, it would be nice to get the gas to flow from the crankcase into the valve covers via some other route, other than the oil drains. Hence, the connection from either the center knock sensor port or the oil filler neck into the cam covers. The main risk in setting up this connection is that it's possible for that connection to make the oil drain issue worse: Namely, if the gas starts flowing from the cam covers into the block, now more, not less, gas is flowing against the oil drain. This is in my opinion a critical issue for the baffle design for the baffle under the oil filler neck -- for this setup that baffle can't be designed in a way that produces a low pressure in the oil filler neck.
The second one is to vent the engine from the oil filler neck only. The main pro of this approach is that there's now no gas flow up the oil drains. The main con is that it's difficult to effectively separate the air and oil in the block chimney and an external, second separator is usually needed. In this approach, the baffle or separator design under the oil filler neck can produce a somewhat low pressure in the oil filler neck, as long as the oil filler neck is not connected to the valve covers.
Do you agree that these are the two main ways to skin this cat?
Since I've done a bunch of testing in these engines about oil and windage, I might be able to add some thoughts.
"Stock" ventilated 928 engines will frequently loose more than 2 quarts of oil during this particular style "race" event. Combine that with several quarts of oil pumped into and sitting in the cylinder heads, a quart or so suspended in crankcase windage, and there's not much oil left around the oil pick-up....a seriously dangerous situation at 200mph!
At higher rpms, the oil filler neck area is a real mess. Tremenous amounts of air mixed with tremendous amounts of oil. A baffle there does some good. A well engineered oil/air separator does better. A combination of both does even more. George is using one of my latest design oil/air separators, combined with the stock baffle (I hope.)
The balance of the crankcase vapors from this area are them vented into the valve covers, for additional separation.
The added vents in the valve cover help this dramatically....right up to the point where the oil volume in the valve covers overcomes the ability for the drains to deal with.
Far from a perfect solution, these items are designed to help in a situation where a dry sump system should be incorporated, but is not, for a variety of reasons. (Like when multiple used engines can be purchased, for the price of a correct dry sump system.....disregarding the potential costs/results of having an engine "explode" at 200mph.)
"Stock" ventilated 928 engines will frequently loose more than 2 quarts of oil during this particular style "race" event. Combine that with several quarts of oil pumped into and sitting in the cylinder heads, a quart or so suspended in crankcase windage, and there's not much oil left around the oil pick-up....a seriously dangerous situation at 200mph!
At higher rpms, the oil filler neck area is a real mess. Tremenous amounts of air mixed with tremendous amounts of oil. A baffle there does some good. A well engineered oil/air separator does better. A combination of both does even more. George is using one of my latest design oil/air separators, combined with the stock baffle (I hope.)
The balance of the crankcase vapors from this area are them vented into the valve covers, for additional separation.
The added vents in the valve cover help this dramatically....right up to the point where the oil volume in the valve covers overcomes the ability for the drains to deal with.
Far from a perfect solution, these items are designed to help in a situation where a dry sump system should be incorporated, but is not, for a variety of reasons. (Like when multiple used engines can be purchased, for the price of a correct dry sump system.....disregarding the potential costs/results of having an engine "explode" at 200mph.)
05-06-2015, 10:31 AM
#40
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Hey George.
First off, good luck. You must be getting pretty excited about now. I'll keep you in my thoughts. Bill is a great guy and will keep you well sorted.
First off, good luck. You must be getting pretty excited about now. I'll keep you in my thoughts. Bill is a great guy and will keep you well sorted.
05-06-2015, 10:47 AM
#41
Rennlist Member
George,
First of all good to see you back on the open road and as usual I will be following your exploits with great interest. Be fast but above all please be safe!
I also note with interest your issues with oiling and mods to help deal with it- an area of specific interest to me on my S4 motor. I was of the opinion that there was something wrong with my motor but in reality it is probably no more than "one of the problem ones" as Tuomo calls them.
For what it is worth I went with John Kuhn's baffle plate as it fitted my perception of what might work and vented the lower side of the filler neck with a 1 inch hose through to the Pro Vent separator. I vent the separator into the engine bay directly - interestingly I have seen no signs of oil whatsoever so either the baffle works very well or it restricts the amount of gases vented but it did not stop the oil consumption issue. I then vented the front two cam cover vents into the pro vent as well- no difference and no oil caught and the last mod was to pull the 1/4 cam cover, drill out the restrictor and plumb that into the pro vent circuit- that seemed to make some difference to the rate of oil consumption. Recently I have been back to the sharktuner trying to improve my tune and test for hot ambient air impact and after a period of spirited driving to test top end/full load tune I noticed the oil level had dropped about a pint after what amounted to about 20 minutes of clog. This made me wonder if connecting the last of the 4 cam cover positions might help balance the venting process a bit more.
Now I see Greg's post which talks in terms of getting more of the mush out of the crankcase and into a bigger external separator. The dilemma with any separation device is that they work on the principle of coalescence of the oil particles - baffle plates help but it really needs extended surface area for the oil droplets to settle on and coalesce. That I see no oil in the Pro vent suggests that my flow path may be too restrictive and therefore not enough gases going through the pro vent to create work for it yet alone overwhelm it. The design on George's car is interesting in that it equalises the crankcase front section back into the cover annulus and then via separate connection, directly from the cam cover to the catch can. My latest mod did seem to improve things but then the other day I spotted something interesting. My plumbing is a bit rudimentary at the moment and I used 1/2 inch Yorkshire fittings to couple the various connection points. To date I have not inserted any copper pipe stubs but I simply slipped the hoses over the branches and used a jubilee clip to retain it. The other day, I found that the section that interconnected the two vents from the 1/4 bank had come adrift but there was no sign of any oily mess that i might have expected at that location- this has me baffled.
Trust the above is of interest to the current direction of George's thread that for me at least has opened up new avenues for further exploration - kindly ignore if not strictly relevant to the current dialogue.
Regards
Fred
First of all good to see you back on the open road and as usual I will be following your exploits with great interest. Be fast but above all please be safe!
I also note with interest your issues with oiling and mods to help deal with it- an area of specific interest to me on my S4 motor. I was of the opinion that there was something wrong with my motor but in reality it is probably no more than "one of the problem ones" as Tuomo calls them.
For what it is worth I went with John Kuhn's baffle plate as it fitted my perception of what might work and vented the lower side of the filler neck with a 1 inch hose through to the Pro Vent separator. I vent the separator into the engine bay directly - interestingly I have seen no signs of oil whatsoever so either the baffle works very well or it restricts the amount of gases vented but it did not stop the oil consumption issue. I then vented the front two cam cover vents into the pro vent as well- no difference and no oil caught and the last mod was to pull the 1/4 cam cover, drill out the restrictor and plumb that into the pro vent circuit- that seemed to make some difference to the rate of oil consumption. Recently I have been back to the sharktuner trying to improve my tune and test for hot ambient air impact and after a period of spirited driving to test top end/full load tune I noticed the oil level had dropped about a pint after what amounted to about 20 minutes of clog. This made me wonder if connecting the last of the 4 cam cover positions might help balance the venting process a bit more.
Now I see Greg's post which talks in terms of getting more of the mush out of the crankcase and into a bigger external separator. The dilemma with any separation device is that they work on the principle of coalescence of the oil particles - baffle plates help but it really needs extended surface area for the oil droplets to settle on and coalesce. That I see no oil in the Pro vent suggests that my flow path may be too restrictive and therefore not enough gases going through the pro vent to create work for it yet alone overwhelm it. The design on George's car is interesting in that it equalises the crankcase front section back into the cover annulus and then via separate connection, directly from the cam cover to the catch can. My latest mod did seem to improve things but then the other day I spotted something interesting. My plumbing is a bit rudimentary at the moment and I used 1/2 inch Yorkshire fittings to couple the various connection points. To date I have not inserted any copper pipe stubs but I simply slipped the hoses over the branches and used a jubilee clip to retain it. The other day, I found that the section that interconnected the two vents from the 1/4 bank had come adrift but there was no sign of any oily mess that i might have expected at that location- this has me baffled.
Trust the above is of interest to the current direction of George's thread that for me at least has opened up new avenues for further exploration - kindly ignore if not strictly relevant to the current dialogue.
Regards
Fred
05-06-2015, 10:49 AM
#42
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This is interesting.
It seems that there's a wide variation between S4/GT engines on how bad these problems are. (Let's leave GTS engines out of this conversation for a little while.) Some have problems, others not so much. For example, George's engine has relatively mild problems based on what I've read here.
Two stock S4/GT engines, on of which has a big oiling and breather problem and another one that has only small one, have relatively few potential differences. One is the oil used. Let's assume the oil is the same. Another is the oil pump bypass valve spring. Let's assume that the spring is correctly calibrated in both engines. As far as I understand, the main remaining difference is the ring seal and the resulting amount of blow by.
Since the blowby is the main difference between really problematic and less problematic engines, my (current) thinking is that it's the gas flows inside the engine that cause many (but not all) of the oiling problems.
It seems that there are two main competing approaches to venting the S4/GT engine:
The first one is to vent it from the cam covers. This has the pro that it's somewhat easier to separate the oil inside the valve covers than at the block chimney. It also has the con that the crankcase gasses have to flow up against the oil drain, slowing down the oil drain. To mitigate the oil drain issue, it would be nice to get the gas to flow from the crankcase into the valve covers via some other route, other than the oil drains. Hence, the connection from either the center knock sensor port or the oil filler neck into the cam covers. The main risk in setting up this connection is that it's possible for that connection to make the oil drain issue worse: Namely, if the gas starts flowing from the cam covers into the block, now more, not less, gas is flowing against the oil drain. This is in my opinion a critical issue for the baffle design for the baffle under the oil filler neck -- for this setup that baffle can't be designed in a way that produces a low pressure in the oil filler neck.
The second one is to vent the engine from the oil filler neck only. The main pro of this approach is that there's now no gas flow up the oil drains. The main con is that it's difficult to effectively separate the air and oil in the block chimney and an external, second separator is usually needed. In this approach, the baffle or separator design under the oil filler neck can produce a somewhat low pressure in the oil filler neck, as long as the oil filler neck is not connected to the valve covers.
Do you agree that these are the two main ways to skin this cat?
It seems that there's a wide variation between S4/GT engines on how bad these problems are. (Let's leave GTS engines out of this conversation for a little while.) Some have problems, others not so much. For example, George's engine has relatively mild problems based on what I've read here.
Two stock S4/GT engines, on of which has a big oiling and breather problem and another one that has only small one, have relatively few potential differences. One is the oil used. Let's assume the oil is the same. Another is the oil pump bypass valve spring. Let's assume that the spring is correctly calibrated in both engines. As far as I understand, the main remaining difference is the ring seal and the resulting amount of blow by.
Since the blowby is the main difference between really problematic and less problematic engines, my (current) thinking is that it's the gas flows inside the engine that cause many (but not all) of the oiling problems.
It seems that there are two main competing approaches to venting the S4/GT engine:
The first one is to vent it from the cam covers. This has the pro that it's somewhat easier to separate the oil inside the valve covers than at the block chimney. It also has the con that the crankcase gasses have to flow up against the oil drain, slowing down the oil drain. To mitigate the oil drain issue, it would be nice to get the gas to flow from the crankcase into the valve covers via some other route, other than the oil drains. Hence, the connection from either the center knock sensor port or the oil filler neck into the cam covers. The main risk in setting up this connection is that it's possible for that connection to make the oil drain issue worse: Namely, if the gas starts flowing from the cam covers into the block, now more, not less, gas is flowing against the oil drain. This is in my opinion a critical issue for the baffle design for the baffle under the oil filler neck -- for this setup that baffle can't be designed in a way that produces a low pressure in the oil filler neck.
The second one is to vent the engine from the oil filler neck only. The main pro of this approach is that there's now no gas flow up the oil drains. The main con is that it's difficult to effectively separate the air and oil in the block chimney and an external, second separator is usually needed. In this approach, the baffle or separator design under the oil filler neck can produce a somewhat low pressure in the oil filler neck, as long as the oil filler neck is not connected to the valve covers.
Do you agree that these are the two main ways to skin this cat?
Why is it a connection in the girdle between the rear and the second oil drain on passenger side?
Lower part in the picture. https://rennlist.com/forums/928-foru...fications.html
The two-valve engines do not ventilate at the cam housing, only at the oil filler neck. Those engines seems not to have the same problems as the four-valve engines but of course the heads are much smaller and cannot keep that much oil.
Tuomo, I do not want to skin our cat, she is far to nice for that.
Åke
05-06-2015, 02:11 PM
#43
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Porsche ran the engine oil through passages in the hood (boot lid) of one of their early 550 Carreras to cool the oil as air flowed over it.
It was too complex so they stopped but I removed my hood insulation thinking it may shed a little heat along with a few grams.
Do you still use the hood insulation or have you removed it?
It was too complex so they stopped but I removed my hood insulation thinking it may shed a little heat along with a few grams.
Do you still use the hood insulation or have you removed it?
The hood insulation is removed and vents added to the back of the hood.
You probably already seen the write up ( http://928.jorj7.com/wk-hood/ )
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
05-06-2015, 03:14 PM
#44
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George,
First of all good to see you back on the open road and as usual I will be following your exploits with great interest. Be fast but above all please be safe!
I also note with interest your issues with oiling and mods to help deal with it- an area of specific interest to me on my S4 motor. I was of the opinion that there was something wrong with my motor but in reality it is probably no more than "one of the problem ones" as Tuomo calls them.
For what it is worth I went with John Kuhn's baffle plate as it fitted my perception of what might work and vented the lower side of the filler neck with a 1 inch hose through to the Pro Vent separator. I vent the separator into the engine bay directly - interestingly I have seen no signs of oil whatsoever so either the baffle works very well or it restricts the amount of gases vented but it did not stop the oil consumption issue. I then vented the front two cam cover vents into the pro vent as well- no difference and no oil caught and the last mod was to pull the 1/4 cam cover, drill out the restrictor and plumb that into the pro vent circuit- that seemed to make some difference to the rate of oil consumption. Recently I have been back to the sharktuner trying to improve my tune and test for hot ambient air impact and after a period of spirited driving to test top end/full load tune I noticed the oil level had dropped about a pint after what amounted to about 20 minutes of clog. This made me wonder if connecting the last of the 4 cam cover positions might help balance the venting process a bit more.
Now I see Greg's post which talks in terms of getting more of the mush out of the crankcase and into a bigger external separator. The dilemma with any separation device is that they work on the principle of coalescence of the oil particles - baffle plates help but it really needs extended surface area for the oil droplets to settle on and coalesce. That I see no oil in the Pro vent suggests that my flow path may be too restrictive and therefore not enough gases going through the pro vent to create work for it yet alone overwhelm it. The design on George's car is interesting in that it equalises the crankcase front section back into the cover annulus and then via separate connection, directly from the cam cover to the catch can. My latest mod did seem to improve things but then the other day I spotted something interesting. My plumbing is a bit rudimentary at the moment and I used 1/2 inch Yorkshire fittings to couple the various connection points. To date I have not inserted any copper pipe stubs but I simply slipped the hoses over the branches and used a jubilee clip to retain it. The other day, I found that the section that interconnected the two vents from the 1/4 bank had come adrift but there was no sign of any oily mess that i might have expected at that location- this has me baffled.
Trust the above is of interest to the current direction of George's thread that for me at least has opened up new avenues for further exploration - kindly ignore if not strictly relevant to the current dialogue.
Regards
Fred
First of all good to see you back on the open road and as usual I will be following your exploits with great interest. Be fast but above all please be safe!
I also note with interest your issues with oiling and mods to help deal with it- an area of specific interest to me on my S4 motor. I was of the opinion that there was something wrong with my motor but in reality it is probably no more than "one of the problem ones" as Tuomo calls them.
For what it is worth I went with John Kuhn's baffle plate as it fitted my perception of what might work and vented the lower side of the filler neck with a 1 inch hose through to the Pro Vent separator. I vent the separator into the engine bay directly - interestingly I have seen no signs of oil whatsoever so either the baffle works very well or it restricts the amount of gases vented but it did not stop the oil consumption issue. I then vented the front two cam cover vents into the pro vent as well- no difference and no oil caught and the last mod was to pull the 1/4 cam cover, drill out the restrictor and plumb that into the pro vent circuit- that seemed to make some difference to the rate of oil consumption. Recently I have been back to the sharktuner trying to improve my tune and test for hot ambient air impact and after a period of spirited driving to test top end/full load tune I noticed the oil level had dropped about a pint after what amounted to about 20 minutes of clog. This made me wonder if connecting the last of the 4 cam cover positions might help balance the venting process a bit more.
Now I see Greg's post which talks in terms of getting more of the mush out of the crankcase and into a bigger external separator. The dilemma with any separation device is that they work on the principle of coalescence of the oil particles - baffle plates help but it really needs extended surface area for the oil droplets to settle on and coalesce. That I see no oil in the Pro vent suggests that my flow path may be too restrictive and therefore not enough gases going through the pro vent to create work for it yet alone overwhelm it. The design on George's car is interesting in that it equalises the crankcase front section back into the cover annulus and then via separate connection, directly from the cam cover to the catch can. My latest mod did seem to improve things but then the other day I spotted something interesting. My plumbing is a bit rudimentary at the moment and I used 1/2 inch Yorkshire fittings to couple the various connection points. To date I have not inserted any copper pipe stubs but I simply slipped the hoses over the branches and used a jubilee clip to retain it. The other day, I found that the section that interconnected the two vents from the 1/4 bank had come adrift but there was no sign of any oily mess that i might have expected at that location- this has me baffled.
Trust the above is of interest to the current direction of George's thread that for me at least has opened up new avenues for further exploration - kindly ignore if not strictly relevant to the current dialogue.
Regards
Fred
By the way, during the dyno session I ran the engine up to 6300-6400 rpm, so it's higher then I'll get during the race, but the duration is a lot shorter. Here is a video from the first dyno session, run 11:
http://928.jorj7.com/mpeg/150320-Dyno-Run11.mp4
Also loading it onto YouTube, but it's still "processing":
I have a short section of clear tubing on the passenger side breather hose (cam cover to catch can). I "filmed" the whole 1 1/2 hr session so I could look for when the oil discharge occurred. As it was, I didn't need to worry.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
05-06-2015, 04:31 PM
#45
Rennlist Member
George,
As always "Great stuff" and I'll be thinking of you as you run!
That you have a connection from the filler neck back to both cam towers and separate breathers to catch cans is rather interesting- seems counter intuitive but hey if it works it works. That you did not see a drop of oil in the catch cans is quite something- sounds as though the gases are in effect being "pumped" [pulsed might be a better word- hot gases tend to rise] into the cam tower which in turn [it would seem] helps push the oil back down the cam drain chimneys- no excess oil in there no blow to the catch can. Any excess pressure [we must be talking minimal amounts here] then blows through to the catch can and as the gases cool water vapour [combustion product in the blow by gas] then drops out as it cannot condense in the engine due to the heat inside.
It will be very interesting to learn how much oil you use during your run.
Let's hope the race conditions replicate the dyno session and possibly back to the drawing board with my efforts. I have nice alloy catch can lying around somewhere! At the moment I use a spent water bottle [& catch nothing]!
Regards
Fred
As always "Great stuff" and I'll be thinking of you as you run!
That you have a connection from the filler neck back to both cam towers and separate breathers to catch cans is rather interesting- seems counter intuitive but hey if it works it works. That you did not see a drop of oil in the catch cans is quite something- sounds as though the gases are in effect being "pumped" [pulsed might be a better word- hot gases tend to rise] into the cam tower which in turn [it would seem] helps push the oil back down the cam drain chimneys- no excess oil in there no blow to the catch can. Any excess pressure [we must be talking minimal amounts here] then blows through to the catch can and as the gases cool water vapour [combustion product in the blow by gas] then drops out as it cannot condense in the engine due to the heat inside.
It will be very interesting to learn how much oil you use during your run.
Let's hope the race conditions replicate the dyno session and possibly back to the drawing board with my efforts. I have nice alloy catch can lying around somewhere! At the moment I use a spent water bottle [& catch nothing]!
Regards
Fred