Accusump Valve Question
Discussion
I am going to fit an accusump to my Sport and was wondering which valve is normally specified for the unit.
I will be tracking the car and thought the EPC (electric pressure sensing valve) would be appropriate as opposed to the basic electric valve.
Is the EPC valve the one to go with and if so, which pressure range is appropriate?(there are three choices I think). I will have the 3 quart capacity tank.
Cheers.
I will be tracking the car and thought the EPC (electric pressure sensing valve) would be appropriate as opposed to the basic electric valve.
Is the EPC valve the one to go with and if so, which pressure range is appropriate?(there are three choices I think). I will have the 3 quart capacity tank.
Cheers.
Fast BMW 7 said:
I am going to fit an accusump to my Sport and was wondering which valve is normally specified for the unit.
I will be tracking the car and thought the EPC (electric pressure sensing valve) would be appropriate as opposed to the basic electric valve.
Is the EPC valve the one to go with and if so, which pressure range is appropriate?(there are three choices I think). I will have the 3 quart capacity tank.
Cheers.
Don't understand why/how you would use a pressure sensing valve. The basic electric valve is all you need. It opens when you turn on the ignition and closes when you turn off. At all other times it is open and allows the Accusump to vary in pressure with the engine. It's function is to deal with a sudden drop in pressure (Surge) in which case you don't want to wait for a switch and valve to make a decision.
Steve
Just a thought: nobody could yet explain to me what exactly the Accusump does under all driving conditions (hard acceleration, deceleration, high g-force turns). Don´t think it is extremely plausible but we had some discussions over here whether the Accusump is not pushing oil back into the engine when you need it least, eg. with hard braking when you release throttle and oil pressure drops suddenly (which is normal). In these cases there is anyway too much oil in some areas of the pan and the Accusump could make this even worse, meaning that the crankshaft gets into the oil... In this case an electric pressure sensing valve would be better because it would not release oil immediately, only when the pressure drops below (for example) 1 bar.
Reason for these thoughts is that all Ultimas around here suffer from high oil consumption, and all have Accusump with the basic electric valve. One reason for high oil consumption could be too much oil in the pan, either by overfilling or maybe by the Accusump flooding under certain conditions?
We have not yet decided whether we will replace the valve but it is on a list of potential improvements.
Reason for these thoughts is that all Ultimas around here suffer from high oil consumption, and all have Accusump with the basic electric valve. One reason for high oil consumption could be too much oil in the pan, either by overfilling or maybe by the Accusump flooding under certain conditions?
We have not yet decided whether we will replace the valve but it is on a list of potential improvements.
Some good points about the oil consumption connection.
Of cause you can vary the pressure at which the accusump starts to flow oil back into the engine... it does effect the amount of oil it holds but IMO if your engine is needing large volumes of oil from the accsump under braking, cornering etc... then its a band-aid for a problem rather than a solution.
I agree with Steve, a switch could prevent the accsump doing what its supposed to do, which is react quickly when needed....
Of cause you can vary the pressure at which the accusump starts to flow oil back into the engine... it does effect the amount of oil it holds but IMO if your engine is needing large volumes of oil from the accsump under braking, cornering etc... then its a band-aid for a problem rather than a solution.
I agree with Steve, a switch could prevent the accsump doing what its supposed to do, which is react quickly when needed....
The reason why I asked about the EPC valve is that Accusump recommend that the plain electric valve would not be quick enough to re-fill the cylinder under track use conditions. Here is their note from their website:
"Note: The refill rates on the electric valves are suitable and recommended for Street and Drag Strip use. On Circle Track and Road Course applications where quick refill rates are required, we recommend our E.P.C valve or our manual valve "
Does anyone find problems with their electric valve-equipped accusump not "keeping up" on a road course with lots of turns and lots of heavy braking?
Thanks for the opinions!
"Note: The refill rates on the electric valves are suitable and recommended for Street and Drag Strip use. On Circle Track and Road Course applications where quick refill rates are required, we recommend our E.P.C valve or our manual valve "
Does anyone find problems with their electric valve-equipped accusump not "keeping up" on a road course with lots of turns and lots of heavy braking?
Thanks for the opinions!
Having been swayed by the accusump argument, I am on point of fitting one. Have a question maybe relevant to this thread - do you need to apply an air pre-charge to the Accusump and is this variable? Pressure in the air side presumably dictates how much and what pressure oil you get in and out of the accumulator - I would imaging for most purposes, you don't want the thing to discharge until pressure drops below normal idle oil pressure, although may be different for serious track work.
I'm followin this thred with interest. But im new here socan I put in a few comments go easy blokes my english is not good. accusump oil supply is pumpd into engin through oilways and bearings when the oil pressure sags so it does not all dump into the sump in one hit. So I cant see the oil level maxing out as someone rote. When oil covers the picup it starts to refil the acccussump and supply the oilways and bearings as well. Cz thought the overfilling of the sump was cause of oil burning in all the ultima engines. is it true all burn oil? if this was hapening the oil woould be sent out the back burnt as oil smoke . do you all see smoke when breaking heavy or cornerin fast?
ultimacz said:
Just a thought: nobody could yet explain to me what exactly the Accusump does under all driving conditions (hard acceleration, deceleration, high g-force turns). Don´t think it is extremely plausible but we had some discussions over here whether the Accusump is not pushing oil back into the engine when you need it least, eg. with hard braking when you release throttle and oil pressure drops suddenly (which is normal). In these cases there is anyway too much oil in some areas of the pan and the Accusump could make this even worse, meaning that the crankshaft gets into the oil... In this case an electric pressure sensing valve would be better because it would not release oil immediately, only when the pressure drops below (for example) 1 bar.
Reason for these thoughts is that all Ultimas around here suffer from high oil consumption, and all have Accusump with the basic electric valve. One reason for high oil consumption could be too much oil in the pan, either by overfilling or maybe by the Accusump flooding under certain conditions?
We have not yet decided whether we will replace the valve but it is on a list of potential improvements.
Have done some rudimentary calculations (Boyles Law P1V1=P2V2)on the assumption you start with an empty 6 pint Accusump, no precharge, ie 6 pints of air at 15 psi absolute pressure. Your engine idles hot at 25psi gauge= 40 psi absolute. The air is now compressed to 2.25 pints so the Accusump has taken 3.75 pints oil out of the sump. At max revs the oil pressure is 70 psi gauge = 85 psi absolute so air volume drops to 1.06 pints, oil volume now 4.94 pints. ie another 1.19 pints taken out of the sump to Accusump. So between max and min operating pressures, change in volume of oil in sump is only 1.19 pints.
I could never understand why people spend £500 on an accusump system when they could spend £800 on a dry sump system. It never loses any pressure and as good as guarantees the oil pressure at what ever driving demands the car is subjected too.
The extra £300 is negligable against a £10k price of the engine I would think. Sorry for the OT post, and I know it doesn't help to those that have them, but for those that are 'pricing up' it was the best option I took, the guage does not move!
The extra £300 is negligable against a £10k price of the engine I would think. Sorry for the OT post, and I know it doesn't help to those that have them, but for those that are 'pricing up' it was the best option I took, the guage does not move!
Reasons for Accusump Vs. Dry sump:
Simplicity which translates to reliability
Price. I think the difference si greater tahn stated. This is certainly the case in the States.
No place to put the sump tank on a center shift car.
Both systems have great points to argue. However, after driving a car with an aftermarket drysump system on the street I knew it was way beyond needed and a pain in the neck to maintain.
ken
Simplicity which translates to reliability
Price. I think the difference si greater tahn stated. This is certainly the case in the States.
No place to put the sump tank on a center shift car.
Both systems have great points to argue. However, after driving a car with an aftermarket drysump system on the street I knew it was way beyond needed and a pain in the neck to maintain.
ken
Excuse my numptyism, it is a while since I played with the big bpys! But, my understanding of how an Accusump performed was that it only pushed oil into the system whem oil pressure dropped to a critical low. IE when the oil warning light came on, then the the valve opened, being on the same wiring circuit. This also being when oil would be needed the most.
More of an engine saver than a eutopian solution.
This would of also happen on start up because the oil pressure was zero, the light would be on so the accusump would then release its charge, pre-pressurised. Once started the oil pressure would rise and the system would then rebalance with a volume of oil returning to the Accusump after which the valve would close.
I could be talking the usual bollox of course!!!!
Paul.B
More of an engine saver than a eutopian solution.
This would of also happen on start up because the oil pressure was zero, the light would be on so the accusump would then release its charge, pre-pressurised. Once started the oil pressure would rise and the system would then rebalance with a volume of oil returning to the Accusump after which the valve would close.
I could be talking the usual bollox of course!!!!
Paul.B
Paul.B said:
More of an engine saver than a eutopian solution.
Paul.B
Agree with this completely.
on the 'how it works'.
I thought the accsump worked on pressure, so when the idnition on the valve is opened and the accusmp is then pressurised by the oil pump... the more pressure the pump deliveres the more oil goes into the accsump.
The accusump pressure can be varied by the air valve at the rear of it.
One think I do know is that if I turned the reved the car for a few seconds and then turned the ignition off(thus closing the electronic valve) it had a lot more pressure on the dial than if I turned it off at idle.
As for dry sump cost difference... I thought a complete dry sump system is around £1,400, won't the quivalant wet sump accusump system be around £1,000 (by the time you have bought a pump and canton sump pan)?.
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