I spent my birthday tearing down my 3.4 and found what failed
02-05-2018, 01:53 PM
#16
Rennlist Member
Yeah....that is a great point. I did put in a center radiator a few couple of years ago to get my coolant temps lower because they tended to be on the high side. In fact, I am so concerned about temps that even with the new 997S engine (expecting between 400-420HP) I am putting in 996 Turbo radiators which are much larger +center radiator cause I want to make sure the engine stays cool.
One thing I forgot to mention is the engine only had 54K miles on it but the car was tracked through its whole life....thus the starvation.
One thing I forgot to mention is the engine only had 54K miles on it but the car was tracked through its whole life....thus the starvation.
02-05-2018, 02:54 PM
#17
Rennlist Member
A low temp thermostat will certainly help along with larger radiators (and the upgraded center), but oil temperatures will still be over 240F easy on the track. Adding the 2 quart deep sump with baffling will help with oil control (the added volume doesn't hurt either), but if you use crappy oil, you can still suffer from engine failure. Aeration of the oil as well as loss of viscosity are still a possibility with a 2 quart deep sump and added engine cooling, so the key is to use a race oil on the track. We run Driven XP9 in all engines that will see track use - it's a must. Street oils aren't made for the track.
02-05-2018, 03:54 PM
#18
Rennlist Member
A low temp thermostat will certainly help along with larger radiators (and the upgraded center), but oil temperatures will still be over 240F easy on the track. Adding the 2 quart deep sump with baffling will help with oil control (the added volume doesn't hurt either), but if you use crappy oil, you can still suffer from engine failure. Aeration of the oil as well as loss of viscosity are still a possibility with a 2 quart deep sump and added engine cooling, so the key is to use a race oil on the track. We run Driven XP9 in all engines that will see track use - it's a must. Street oils aren't made for the track.
And regarding street oil vs race oil, are there any aeration tests that compare street vs track oil? There seem to be quite a few tests for strength and temperature, but I don’t see much on aeration.
02-05-2018, 04:28 PM
#19
02-05-2018, 04:59 PM
#20
Rennlist Member
That’s a good point. The larger oil volume can keep temps down only for shorter runs, but at some point, the heat has to be removed.
And regarding street oil vs race oil, are there any aeration tests that compare street vs track oil? There seem to be quite a few tests for strength and temperature, but I don’t see much on aeration.
I'm a big fan of DT40, but it's no good for the track. But then again, all street oils are just for that - street use. You need a true race oil for the track, even if it's only a DE event. To be perfectly honest, most race cars are better maintained than mixed use street/track driven cars.
02-05-2018, 06:18 PM
#21
Tests for foaming and aeration aren't something you see, nor is viscosity at higher oil temperatures approaching 300F.
I'm a big fan of DT40, but it's no good for the track. But then again, all street oils are just for that - street use. You need a true race oil for the track, even if it's only a DE event. To be perfectly honest, most race cars are better maintained than mixed use street/track driven cars.
I'm a big fan of DT40, but it's no good for the track. But then again, all street oils are just for that - street use. You need a true race oil for the track, even if it's only a DE event. To be perfectly honest, most race cars are better maintained than mixed use street/track driven cars.
from the thread I linked above:
The idiot light comes on at a very low pressure. I am not sure of the exact number but it is under .5 bar. Since the oil pump creates this much or more pressure pumping pure air (at least at rpm > 4000) the idiot light is never going to alert anybody to oil pressure fluctuations.
My long experience with various engines leads me to conclude that most of the time, the brand of oil matters very little, and the weight of that oil matters even less. Engines that receive an uninterrupted supply of oil, even at a very low pressure, seem to last forever. Engines that do not, fail regardless of oil brand, weight, or temperature.
That said, everything in racing takes place in that last 1% of performance, so very small things can matter. I use Mobil 1 (the weight depends on expected oil temp) in my dry sump engines, but I don't recommend it for wet sump M96 engines that are used on track.
My long experience with various engines leads me to conclude that most of the time, the brand of oil matters very little, and the weight of that oil matters even less. Engines that receive an uninterrupted supply of oil, even at a very low pressure, seem to last forever. Engines that do not, fail regardless of oil brand, weight, or temperature.
That said, everything in racing takes place in that last 1% of performance, so very small things can matter. I use Mobil 1 (the weight depends on expected oil temp) in my dry sump engines, but I don't recommend it for wet sump M96 engines that are used on track.
02-05-2018, 06:54 PM
#23
Rennlist Member
One interesting thing about the broader discussion is that a true dry sump seems to work ok even with mobil1, which is flagged by many (even the guy that uses M1 in dry sump) as being inadequate for track when used in conjunction with the stock M96 wet sump.
from the thread I linked above:
from the thread I linked above:
That said, there are better choices the M1 for Mezger engines, but that's a different topic.
02-05-2018, 08:06 PM
#24
Rennlist Member
Originally Posted by murphyslaw1978
There’s no question in my mind that a stock 996 suffers from oil starvation at the track.
02-06-2018, 12:29 PM
#25
Rennlist Member
I cannot give you a number as there are many things that will affect this. What I can tell you the race cars originally fitted with the 2 quart deep sump and campaigned professionally using racing oil suffered zero oil pressure drops after the addition of the 2 quart deep sump including 997 oil returns and the anti-slosh tray that is included in our kit.
02-06-2018, 01:20 PM
#26
Rennlist Member
I cannot give you a number as there are many things that will affect this. What I can tell you the race cars originally fitted with the 2 quart deep sump and campaigned professionally using racing oil suffered zero oil pressure drops after the addition of the 2 quart deep sump including 997 oil returns and the anti-slosh tray that is included in our kit.
02-06-2018, 01:28 PM
#27
Rennlist Member
I have seen multiple times where the customer forgets to turn the system on or improperly fills the oil and causes an engine failure. The EPC valve must be tested regularly to ensure it is operating as well as there have been problems in the past where the solenoid does not excite properly and the system is non-functional.
That said, I ran one for years in my Boxster before I came up with the 2 quart deep sump.
02-06-2018, 01:58 PM
#28
Rennlist Member
Thanks for the info! Sorry lowpue, don't mean to hijack thread. I would love to tear down a motor to learn more about M96.
02-06-2018, 05:23 PM
#29
Rennlist Member
Thread Starter
No worries....I am learning a lot from my own thread even though it has taken a tangent... btw, Charles Dundon has a GT3 motor he wants to tear down for parts and he asked my buddy and I if we want to tear that down too. Charles gets free labor and I get a free lesson....win..win.
02-06-2018, 07:21 PM
#30
Rennlist Member
Yes, we do offer the Accusump as an option, but most choose the route of the 2 qt deep sump as it's fool proof and doesn't require driver input for proper operation.
I have seen multiple times where the customer forgets to turn the system on or improperly fills the oil and causes an engine failure. The EPC valve must be tested regularly to ensure it is operating as well as there have been problems in the past where the solenoid does not excite properly and the system is non-functional.
That said, I ran one for years in my Boxster before I came up with the 2 quart deep sump.
I have seen multiple times where the customer forgets to turn the system on or improperly fills the oil and causes an engine failure. The EPC valve must be tested regularly to ensure it is operating as well as there have been problems in the past where the solenoid does not excite properly and the system is non-functional.
That said, I ran one for years in my Boxster before I came up with the 2 quart deep sump.