X51 cloud of smoke
#1
Racer
Thread Starter
X51 cloud of smoke
I have an '06 Cayman S w/ 3.8L X51 997 engine installed by FarnbacherLoles w/ 25000 miles on it.
At Barber last weekend I blew a huge cloud of smoke at the end of the straight after the 180 degree left-hand hairpin. Been there many times and this has never happened before. No oil leaking, no noises, no CEL, checked w/ PIWIS and NO codes or other evidence of trouble. Drove around a bit and it cleared up. When back out to check it and after a few laps it did the same thing twice in the same place and hen I parked it. Drove 250 miles home w/ no smoke.
Any ideas? AOS? Other oiling issues like scavenge pump?
At Barber last weekend I blew a huge cloud of smoke at the end of the straight after the 180 degree left-hand hairpin. Been there many times and this has never happened before. No oil leaking, no noises, no CEL, checked w/ PIWIS and NO codes or other evidence of trouble. Drove around a bit and it cleared up. When back out to check it and after a few laps it did the same thing twice in the same place and hen I parked it. Drove 250 miles home w/ no smoke.
Any ideas? AOS? Other oiling issues like scavenge pump?
Last edited by bldn10; 06-18-2013 at 10:05 AM. Reason: correction
#2
Rennlist Member
yeah, most typical suspect would be AOS.
keep an eye on your oil level now and inspect exhaust tips to make sure driver side is not getting noticeably more soot than other side.
keep an eye on your oil level now and inspect exhaust tips to make sure driver side is not getting noticeably more soot than other side.
#3
Racer
Thread Starter
I'd like for it to be the AOS but let me add that some nice guys at the track put a vacuum tester on the oil filler and it was w/i normal range. Apparently if the AOS diaphram is split there will be higher than normal vacuum - they say sometimes you can hardy get the cap off.
I'm not sure that the tips (Cayman, remember) relate to one side or the other.
BTW Paul, my car came your part of the country.
I'm not sure that the tips (Cayman, remember) relate to one side or the other.
BTW Paul, my car came your part of the country.
#4
Race Director
I have an '06 Cayman S w/ 3.8L X51 997 engine installed by FarnbacherLoles w/ 25000 miles on it.
At Barber last weekend I blew a huge cloud of smoke at the end of the straight after the 180 degree left-hand hairpin. Been there many times and this has never happened before. No oil leaking, no noises, no CEL, checked w/ PIWIS and NO codes or other evidence of trouble. Drove around a bit and it cleared up. When back out to check it and after a few laps it did the same thing twice in the same place and hen I parked it. Drove 250 miles home w/ no smoke.
Any ideas? AOS? Other oiling issues like scavenge pump?
At Barber last weekend I blew a huge cloud of smoke at the end of the straight after the 180 degree left-hand hairpin. Been there many times and this has never happened before. No oil leaking, no noises, no CEL, checked w/ PIWIS and NO codes or other evidence of trouble. Drove around a bit and it cleared up. When back out to check it and after a few laps it did the same thing twice in the same place and hen I parked it. Drove 250 miles home w/ no smoke.
Any ideas? AOS? Other oiling issues like scavenge pump?
Then out of the corner and on the gas the oil rushes past the whirling cams which whips the oil to a froth and on to the scavenge pump which adds to this.
Momentarily the engine crankcase has a huge load of oil vapor which overwhelms the AOS (which is in some cases is already
overwhelmed to begin with) and a big cloud of smoke is the result.
#5
Drifting
IIRC that setup results in a build up of oil under the right side camshaft cover. g-forces force the oil away from the scavenge pump and the oil really piles up.
Then out of the corner and on the gas the oil rushes past the whirling cams which whips the oil to a froth and on to the scavenge pump which adds to this.
Momentarily the engine crankcase has a huge load of oil vapor which overwhelms the AOS (which is in some cases is already
overwhelmed to begin with) and a big cloud of smoke is the result.
Then out of the corner and on the gas the oil rushes past the whirling cams which whips the oil to a froth and on to the scavenge pump which adds to this.
Momentarily the engine crankcase has a huge load of oil vapor which overwhelms the AOS (which is in some cases is already
overwhelmed to begin with) and a big cloud of smoke is the result.
#6
Racer
Thread Starter
"You my want to consider a deep oil pan with baffles."
For the occasional DE driver like I think the X51 pan should be sufficient. I've not had this happen before so something has changed - the AOS, an oil pump, pan baffles, something.
For the occasional DE driver like I think the X51 pan should be sufficient. I've not had this happen before so something has changed - the AOS, an oil pump, pan baffles, something.
#7
Rennlist Member
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#9
Racer
Thread Starter
"or you are faster... "
Yea, that must be it! No, actually the contrary - I was out on street tires just to test my brakes, having just replaced the master cylinder, put on braided lines, and fresh SRF. I was going relatively slow. and when I went back out later in the day to check it out I intentionally slowed down, but it still did it.
Also, if it only happens in high-G LH turns, doesn't that weigh against an AOS failure?
Yea, that must be it! No, actually the contrary - I was out on street tires just to test my brakes, having just replaced the master cylinder, put on braided lines, and fresh SRF. I was going relatively slow. and when I went back out later in the day to check it out I intentionally slowed down, but it still did it.
Also, if it only happens in high-G LH turns, doesn't that weigh against an AOS failure?
#12
Drifting
Was the engine "x51" from the factory? or was an "x51" kit added after the fact? Difference being that I don't recall the kit coming with an x51 pan + baffle. The baffles are key to address this type of symptom... it may be worth it to remove your oil pan to check if it has the x51 baffles.
#13
Low NOACK (and 50 grade) oil would at least help the cause.
ACEA A3/B4 require NOACK equal or less than 13. Redline, as an example only not a suggestion, offer NOACK = 6.
Indeed, AOS can be tested with accurate vacuum gauge.
Around 4" - 6" water column is about OK, 8" and above indicates AOS going South...
I agree with Macster's scenario.
#15
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Was the engine "x51" from the factory? or was an "x51" kit added after the fact? Difference being that I don't recall the kit coming with an x51 pan + baffle. The baffles are key to address this type of symptom... it may be worth it to remove your oil pan to check if it has the x51 baffles.