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Digging into data and there is a ton to digest... but since this was the track and corner I noticed the oil pressure dip mentioned way back in the thread, I though I would show what the data reflected from yesterday for that particular example.
As has been mentioned, elevated oil temps certainly play a role in oil pressure. I saw 250F for much of the day yesterday and ambient was in the 70's. In the example below, a 22F degree difference in oil temp equated to a 16.4 PSI reduction in oil pressure. This is with comparable RPM and lateral G.
You can also see the pressure instability at the onset of G loading in the cool pressure line is flat where the hot pressure line begins to fluctuate as G's are applied.
I have a lot of data to dig into, but this jumped out at me.
The data points being reflected can be seen using the vertical line about 3/4 across the screen L to R with the hashes.
Thanks Randy - I was pushing, but with the traffic and first day out - was not going to turn it to 11, did not work out for some of the folks running that decided to punch above their weight.
Yeah... she was fat...2950 I think...its back a bit in the thread - QC was right.
Me too - for me, short drive, home track and you and Aaron will both be there... I think Aaron said he'll be driving the VW, we'll still let him hang out with us, right ?
Jason that was a great way to kick off the season, perfect weather and all. BTW your car's not fat - mine's the fat lady pushing almost 3600 pounds!
The only casualty we suffered was the front driver's side marker light departing my car sometimes in the second session. The same can't be said for some of the other drivers though.
If you and jenlso are going to Thompson on the 22nd I may have to bring the 6TT. Got to keep the 996 contingent together after all. I can always run the Corrado at a different track day.
Thanks for your encouragement during all the annoyance I had to get my car ready.
Jason that was a great way to kick off the season, perfect weather and all. BTW your car's not fat - mine's the fat lady pushing almost 3600 pounds!
The only casualty we suffered was the front driver's side marker light departing my car sometimes in the second session. The same can't be said for some of the other drivers though.
If you and jenlso are going to Thompson on the 22nd I may have to bring the 6TT. Got to keep the 996 contingent together after all. I can always run the Corrado at a different track day.
Thanks for your encouragement during all the annoyance I had to get my car ready.
So, ahh... Is there like a min QTY of people needed to being able to start a gang... cause we got 3, like do we need more than that or is that enough ?
Ya know... we tell the squares it's just a "club" but in reality - a gang of Stuttgart's bastard children 996's bullying miatas, BMW's and silly American muscle (kings of the straightaway...only) at tracks across the Northeast USA.
Digging into data and there is a ton to digest... but since this was the track and corner I noticed the oil pressure dip mentioned way back in the thread, I though I would show what the data reflected from yesterday for that particular example.
As has been mentioned, elevated oil temps certainly play a role in oil pressure. I saw 250F for much of the day yesterday and ambient was in the 70's. In the example below, a 22F degree difference in oil temp equated to a 16.4 PSI reduction in oil pressure. This is with comparable RPM and lateral G.
You can also see the pressure instability at the onset of G loading in the cool pressure line is flat where the hot pressure line begins to fluctuate as G's are applied.
I have a lot of data to dig into, but this jumped out at me.
The data points being reflected can be seen using the vertical line about 3/4 across the screen L to R with the hashes.
so are you thinking at first glance that extra oil cooler would be helpful?
so are you thinking at first glance that extra oil cooler would be helpful?
It can't hurt - the oil temps could certainly stand to come down. The data shows there is instability in pressure when the oil is hot, and that where pressure was dropping, the hotter oil caused it to drop further.
Ideally, I'd like to get rid of the dip there... the hotter oil is exacerbating the issue.
Water temp although not shown in the data above at the points being referenced was 210 F and 194 F.
So, a 3rd RAD with the bigger 997 cooler coupled with an oil feed solution to get rid of the dip to begin would be the solution I would like to implement. I may get the 3rd RAD and plan to install before the JUN track days, we'll see... because the water temps have always seemed to be manageable, I did not want to spend the money if it wasn't needed, kind of sucks that it may end up being the case as a way to address the oil temp issue.
With the water temps you are presently measuring I cannot see any value to a third radiator. It isn't going to get the water any cooler. I can perhaps see value to the larger oil/water heat exchanger. If the larger oil/water heat exchanger reduces oil temps by 20F and increases water temps by 10F you will be miles ahead. 230F should not be a problem for water temp.
Also before I went to the center radiator solution I'd upgrade the side radiators to the C4S/Turbo cores. Should be simpler, lighter, and cheaper.
FWIW I saw highest water temps of ~210 and highest oil temps of ~220. These are polled numbers as in that's what I saw when I looked at the gauges, I don't have datalog of these.
Always maintained stock cooling on my 02 even though I have done nearly 80 track days over the past 18 years. 15+ of those days were at Road America, which is killer on the car for oil starvation due to the very long, high speed turns. Never ran into a problem. However, I run an extra 2 quart deep sump pan with baffle that has probably helped out considerably. Also run a motorsport AOS. Rev ranges are much higher because you are trying to stay in the sweet spot of power (4500-7000). I suspect that may help to keep oil pressure up, but have no data to prove it other than never having a problem nor check engine light ever on the track.
With that being said, I have always wondered if any additional cooling would help to insure against potential problems.
So, ahh... Is there like a min QTY of people needed to being able to start a gang... cause we got 3, like do we need more than that or is that enough ?
Ya know... we tell the squares it's just a "club" but in reality - a gang of Stuttgart's bastard children 996's bullying miatas, BMW's and silly American muscle (kings of the straightaway...only) at tracks across the Northeast USA.
I have the LN 2QT deep sump and baffle... I also try to never let it dip below 4K RPM's, logs prove that out.
I'm not saying that the low oil pressure example shown is destructive to the engines because I do not know enough to know, just that I don't like it. Lots have people have never had an issue - some have... who knows what the differences are.
I also don't KNOW, but am willing to bet, the stock cooling system is adequate for keeping WATER temps at safe levels in the vast majority of conditions, but these cars use the cooling system for oil temp control as well - 250 oil temp to me, seems hot. Especially given ambient in the mid-low 70's.
I'm just super interested to be able to geek out on this stuff I could never quantify before... If peeps are interested, I'll share interesting things I find along the way.
I have the LN 2QT deep sump and baffle... I also try to never let it dip below 4K RPM's, logs prove that out.
I'm not saying that the low oil pressure example shown is destructive to the engines because I do not know enough to know, just that I don't like it. Lots have people have never had an issue - some have... who knows what the differences are.
I also don't KNOW, but am willing to bet, the stock cooling system is adequate for keeping WATER temps at safe levels in the vast majority of conditions, but these cars use the cooling system for oil temp control as well - 250 oil temp to me, seems hot. Especially given ambient in the mid-low 70's.
I'm just super interested to be able to geek out on this stuff I could never quantify before... If peeps are interested, I'll share interesting things I find along the way.
Jason, it's great info. Keep it coming. Your questions are the same ones that I have. You are just going the extra step to quantify it. I may have been damn lucky with my engine, or I may have been lucky enough to have done all of the preventative stuff early before the problems actually started. As an example, I was the first guy that I know of that was running a 2 qt deep sump with a baffle back in 06 or 07. Same with the motorsport aos. Have a good Porsche shop that paid attention to what the Grand Am guys were doing with racing the 996 with the same engine as ours back in the late 90's early 2000's and they did a number of upgrades to my car before it became mainstream.
Jason that was a great way to kick off the season, perfect weather and all. BTW your car's not fat - mine's the fat lady pushing almost 3600 pounds!
The only casualty we suffered was the front driver's side marker light departing my car sometimes in the second session. The same can't be said for some of the other drivers though.
If you and jenlso are going to Thompson on the 22nd I may have to bring the 6TT. Got to keep the 996 contingent together after all. I can always run the Corrado at a different track day.
Thanks for your encouragement during all the annoyance I had to get my car ready.
Aaron, would love to see your 996 TT, hope you bring it to Thompson on the 22nd.
Jason, it's great info. Keep it coming. Your questions are the same ones that I have. You are just going the extra step to quantify it. I may have been damn lucky with my engine, or I may have been lucky enough to have done all of the preventative stuff early before the problems actually started. As an example, I was the first guy that I know of that was running a 2 qt deep sump with a baffle back in 06 or 07. Same with the motorsport aos. Have a good Porsche shop that paid attention to what the Grand Am guys were doing with racing the 996 with the same engine as ours back in the late 90's early 2000's and they did a number of upgrades to my car before it became mainstream.
Your efforts are appreciated.
You've run the car for a long time, very successfully - whatever you're doing, I would keep doing it. Your car is a great example of the brighter side of 996 use as a track car, a brighter side that is not often put in the light.
04-11-2021, 10:58 AM
