Discussion
Before I start this I want to express to Stu Copper that if I could make the point without using your video and leaving any mention of your name off of this I would. But your video makes my point and you have already stated that you see the value of dry sump on these cars.
If you look at the recent video posted about Stu's car running laps you will see mention of the warning light for oil pressure coming on in right hand corners. This is only partially correct, if you look closely the light also illuminates under braking in one corner and under acceleration in another. This means that at the pressure sender you are seeing 20 lbs of oil pressure which in this setup means the Accusump has fired and whatever oil it has trapped is released to the system. How much oil under what pressure, we don't know because the events are occurring close enough to each other that we as outsiders looking in have no way to know how much oil has been moved back into the accusump. Next point the rule of thumb is you should see 10 lbs of pressure for each 1000 RPM. Now I think its safe to say that there is a point of diminishing returns on this rule by which I would suggest that probably 10 lbs at a 1000 RPM idle is to low and 70 lbs at 7000 RPM may not be needed. But looking at the tach and seeing 5000 rpm with a 20 lb light on is not giving me the warm and fussys. In the old days, 7-8 years ago on this forum we use to see a lot of complaints about American crap Chevy small blocks spitting rod and main bearings after a very few track days with a Accusump. I made the point several times here that small block Chevy's have been spinning to 7500 rpm in dirt track cars for multiple race weekends in sprint cars with no such problem. With the advent of the LS7 with its stock dry sump this issue has lessened. But I will again say to anyone building these cars with any engine. When you have a car that will generate this kind of G loading on street tires let alone slicks INSTALL A DRY SUMP ITS CHEAP INSURANCE.
Again Stu all said with due respect. Lee
If you look at the recent video posted about Stu's car running laps you will see mention of the warning light for oil pressure coming on in right hand corners. This is only partially correct, if you look closely the light also illuminates under braking in one corner and under acceleration in another. This means that at the pressure sender you are seeing 20 lbs of oil pressure which in this setup means the Accusump has fired and whatever oil it has trapped is released to the system. How much oil under what pressure, we don't know because the events are occurring close enough to each other that we as outsiders looking in have no way to know how much oil has been moved back into the accusump. Next point the rule of thumb is you should see 10 lbs of pressure for each 1000 RPM. Now I think its safe to say that there is a point of diminishing returns on this rule by which I would suggest that probably 10 lbs at a 1000 RPM idle is to low and 70 lbs at 7000 RPM may not be needed. But looking at the tach and seeing 5000 rpm with a 20 lb light on is not giving me the warm and fussys. In the old days, 7-8 years ago on this forum we use to see a lot of complaints about American crap Chevy small blocks spitting rod and main bearings after a very few track days with a Accusump. I made the point several times here that small block Chevy's have been spinning to 7500 rpm in dirt track cars for multiple race weekends in sprint cars with no such problem. With the advent of the LS7 with its stock dry sump this issue has lessened. But I will again say to anyone building these cars with any engine. When you have a car that will generate this kind of G loading on street tires let alone slicks INSTALL A DRY SUMP ITS CHEAP INSURANCE.
Again Stu all said with due respect. Lee
Hi Lee,
I agree, a dry sump is really the way to go if someone is doing more than the very occasional track day. Someone made the comment once that unless you disassemble and clean an accusump every oil change it works as great system for injecting crud into your oil system!
I hadn't heard the 10 psi per 1000 rpm rule of thumb before, though it sound sensible. My LS7 follows this reasonably well though I'm still planing in uprating the pressure/scavenge pump over the winter as it's cheap insurance.
Could you post a link to the video?
I agree, a dry sump is really the way to go if someone is doing more than the very occasional track day. Someone made the comment once that unless you disassemble and clean an accusump every oil change it works as great system for injecting crud into your oil system!
I hadn't heard the 10 psi per 1000 rpm rule of thumb before, though it sound sensible. My LS7 follows this reasonably well though I'm still planing in uprating the pressure/scavenge pump over the winter as it's cheap insurance.
Could you post a link to the video?
Just to make it clear. In video light is on below 30 psi..... Accusump trigger is around 27 psi.
So light comes on before accusump triggered.... When light was set to 20 psi then light never came on.
..... Doesn't, however, alter the fact that a dry sump would be highly recommended for track use .
Stu
So light comes on before accusump triggered.... When light was set to 20 psi then light never came on.
..... Doesn't, however, alter the fact that a dry sump would be highly recommended for track use .
Stu
Mr Pid said:
Just to make it clear. In video light is on below 30 psi..... Accusump trigger is around 27 psi.
So light comes on before accusump triggered.... When light was set to 20 psi then light never came on.
..... Doesn't, however, alter the fact that a dry sump would be highly recommended for track use .
Stu
I have a oil warning light on a switch and a digital oil pressures gauge with the sender in the same place. The oil switch activates much lower than its rated value (20 psi). I certainly would not trust just a warning light.So light comes on before accusump triggered.... When light was set to 20 psi then light never came on.
..... Doesn't, however, alter the fact that a dry sump would be highly recommended for track use .
Stu
Video is on page 7 downloaded by Mr. Pid. Lee
I thank Stu for not shooting the messenger. I will expand my previous comment by stating that if you normally have 50 or 60 lbs of pressure at 5k to 6k RPM and during a turn or acceleration positive or negative the pressure has dropped to below 30 lbs there's only one answer and that's oil starvation at the pickup. Additionally the volume of space not made up of oil is now air. Think about it, whats the lube quality of air. and once that air is in the system its going straight to your main and rod bearings. By the way I don't own stock in a dry sump company, but I do feel a kinship with my Ultima brothers. Lee
I thank Stu for not shooting the messenger. I will expand my previous comment by stating that if you normally have 50 or 60 lbs of pressure at 5k to 6k RPM and during a turn or acceleration positive or negative the pressure has dropped to below 30 lbs there's only one answer and that's oil starvation at the pickup. Additionally the volume of space not made up of oil is now air. Think about it, whats the lube quality of air. and once that air is in the system its going straight to your main and rod bearings. By the way I don't own stock in a dry sump company, but I do feel a kinship with my Ultima brothers. Lee
Edited by ROWDYRENAULT on Friday 9th October 18:05
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