Effects of an Accusump system on OCI

[KenO]

OK, so an Accusump system was recommended to me by a good automotive engineer friend for my car for a couple reasons. I have a '95 Volvo 960 wagon with a 5.3l LS based engine. Due to modifications, the oilpan sump capacity had to be reduced to ~4 quarts. Overall, I'm really not comfortable with such a small oilpan sump, and would like additional capacity. It's a DD, so a dry sump system is a bit out of the question. Also, the ilpan is shallow and without baffling, so chances of oil starvation during hard corning, especially at an autox event or if I DO decide to take it to the track someday, is a real possibility that the Accusump can account for.


However, when related to OCI's, whats the deal? How often is the oil in the Accusump system exchanged? If for example, I were to end up with ~2-3 quart sin the Accusump, is that oil constantly being exchanged with that in the engine, or ONLY when it's needed?

 

[Donald]

I am curious as to what mods you did to reduce the oil capacity?

 

[KenO]

Originally Posted By: Donald
I am curious as to what mods you did to reduce the oil capacity?

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.

 

[Lead Shoes]

Get creative again with the welder and make the pan bigger if room permits.

 

[A_Harman]

The Accusump "breathes" oil in and out in response to changing oil pressure in the engine main gallery. If you are idling with an oil gallery pressure of 30 psi, then increase engine speed so that oil pressure increases to 50 psi, the Accusump will take in some oil from the engine. Then when you decrease engine speed so that oil pressure goes back down to 30 psi, the Accusump will put oil back into the engine. Once the Accusump "inhales" oil, there is not much internal flow in its reservoir to actually mix the new oil with what was already there, so if the Accusump has to immediately "exhale", I suppose that what goes back out would be mostly the "new" oil. But over hundreds of "inhale" and "exhale" cycles as oil pressure fluctuates, the oil would mix pretty well with what was in the reservoir. When you do an oil change, I recommend that you also drain the Accusump.

 

[SteveSRT8]

I use an accumulator on my street toy, it has a small solenoid on it so when you shut the engine down I can hold 2 quarts of oil under pressure in it for the next startup.

If it didn't have the solenoid valve it would simply drain into the sump. Oil changes remain the same.

 

[dailydriver]

Originally Posted By: KenO
Originally Posted By: Donald
I am curious as to what mods you did to reduce the oil capacity?

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.


YIKES!!!!!

Except for the cost involved, I personally would have gone with a dry sump instead of that.

But yes, by all means, at the very least get the MAX capacity Accusump you can fit ANYWHERE in that thing.

 

[KenO]

Originally Posted By: dailydriver
Originally Posted By: KenO
Originally Posted By: Donald
I am curious as to what mods you did to reduce the oil capacity?

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.


YIKES!!!!!

Except for the cost involved, I personally would have gone with a dry sump instead of that.

But yes, by all means, at the very least get the MAX capacity Accusump you can fit ANYWHERE in that thing.



Why though? What is your reasoning for this? And dry sump, besides being cost prohibitive, isn't happening on a daily driver.

 

[Mitch Alsup]

Accusump can deal with the short durations of potential oil starvation, but essentially does nothing for OCI.

BTW one of my (almost) DD already has has a dry sump (from the factory).

 

[mechtech2]

I'd simply change the oil a bit more frequently.

If you DO some hard cornering, then the Accusump is wise.

 

[dailydriver]

Originally Posted By: KenO
Originally Posted By: dailydriver
Originally Posted By: KenO
Originally Posted By: Donald
I am curious as to what mods you did to reduce the oil capacity?

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.


YIKES!!!!!

Except for the cost involved, I personally would have gone with a dry sump instead of that.

But yes, by all means, at the very least get the MAX capacity Accusump you can fit ANYWHERE in that thing.



Why though? What is your reasoning for this? And dry sump, besides being cost prohibitive, isn't happening on a daily driver.


Mainly because the WHOLE bottom of the dry sump would be on the same plain as the front of that pan, giving you more room with NO worries about oil pressure (in hard, high-g corners or elsewhere).

But YES, if you do not have too much vested in this Gen 3, then this setup with an Accusump will do fine.

 

[KenO]

Originally Posted By: dailydriver
Originally Posted By: KenO
Originally Posted By: dailydriver
Originally Posted By: KenO

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.





YIKES!!!!!

Except for the cost involved, I personally would have gone with a dry sump instead of that.

But yes, by all means, at the very least get the MAX capacity Accusump you can fit ANYWHERE in that thing.



Why though? What is your reasoning for this? And dry sump, besides being cost prohibitive, isn't happening on a daily driver.


Mainly because the WHOLE bottom of the dry sump would be on the same plain as the front of that pan, giving you more room with NO worries about oil pressure (in hard, high-g corners or elsewhere).

But YES, if you do not have too much vested in this Gen 3, then this setup with an Accusump will do fine.

Ill ask again then - you were adament about adding the Accusump - why? What were your reasons? Was it JUST from the possibility of starvation from oil slosh?

 

[Loobed]

Originally Posted By: KenO

Thats part of it, to fit the subframe. Also about 5k after this the bottom of the sump was shortened a few inches due to it hitting the ground and cracking (combination of just hanging too low, and a shot suspension). Was shortened to right below that level sensor.


How hard was it to TIG weld onto the cast aluminum pan. I tried TIG welding some cast aluminum Japanese motorcycle parts and found it close to impossible because of the dirt inside the cast aluminum. I am not a professional welder; I just took a class at the local college.

 

[Nyati]

Originally Posted By: KenO


Why though? What is your reasoning for this? And dry sump, besides being cost prohibitive, isn't happening on a daily driver.


all Porsche 911s are dry sumped. I had one for 12 years. 12 quart capacity. Works great on a street car.

 

[A_Harman]

With the reduced oil capacity of the sump, I recommend more frequent oil changes. Stock LS-series engines have a normal fill of 5.5 quarts, so if you are down to 4 quarts, the oil is recirculating ~28% more often. With less settling time in the pan, foaming, increased temperature, and oxidation will be more likely to occur. A high-quality synthetic oil will better than a conventional oil in this situation.

 

[A_Harman]

Originally Posted By: Brenden
Get creative again with the welder and make the pan bigger if room permits.


I agree. Do whatever you have to do to get at least 5 quarts in the sump. Can you add extensions to the sides of the pan?

 

[KenO]

Originally Posted By: A_Harman
With the reduced oil capacity of the sump, I recommend more frequent oil changes. Stock LS-series engines have a normal fill of 5.5 quarts, so if you are down to 4 quarts, the oil is recirculating ~28% more often. With less settling time in the pan, foaming, increased temperature, and oxidation will be more likely to occur. A high-quality synthetic oil will better than a conventional oil in this situation.



I've picked 5W-30 Maxlife to run in this car, and that seems to work well. I wanted something with a decent moly count, and a known good add pack, which Maxlife is known to have. Adding to the pan probably isn't an option. Maybe someday when funds aren't as limited, I'll look at one of the large-sump racer pans. Besides cost, I wanted to retain the stock filter location, that was another reason for sticking to a stock pan.


And yes, I plan to keep the OCI's now to ~4k for now. Will sample and have analysys done on the first couple 4k samples and go from there. I just don't get the push for the Accusump, as nobody has yet to explain WHY get the largest one available. I know to keep pressure up incaswe of starvation from slosh, but it seems as if a few people keep pointing out to do it simply because of the smaller sump. If you guys are talking about a reason BESIDES reduced sump capacityy to add the Accusump - spill it! Stop making me ask, or I'll just dismiss you as crazy and posting your opinions with no facts or reasoning to back it up. This is NOT a forum for opinions.

 

[A_Harman]

Maxlife, being a syn blend, is a good choice. And since you're initially doing short OCI's and UOA's, you'll be able to optimize the OCI.

The Accusump would only be there as insurance against oil starvation during an autocross or track event. I don't think you could count on it as a way to increase oil life. IIRC, there are three sizes of Accusump: 1, 2, and 3 quart. The 2-quart version is recommended for normal-sized V8 engines. That is what I put on my Corvette track car. In addition to the cost of the Accusump, by the time I had bought the hose, fittings, control valve, and mounting bracketry, I had over $700 in it. It seems to me like you could have your oil pan modified for less than that.