Hey RK,

A couple comments:

- I'm using a remote oil filter with the Canton Racing racing filter. It is supposed to flow 15 gpm and is full flow.
- If you look at the data I posted a while back comparing the Canton and the 1042 filters, there was not much difference between the 2 for pressure drop. So that was interesting.
- The Accusump (and pressure switch) is located post oil filter so it sees approx. a 10 psi drop compared to the pump pressure pre-filter (sometimes more under load).

- So if you look at the PCA 3rd session, the Min pump pressure was 52 psi. That would mean about 42 psi at the pressure switch, which is not low enough (35 psi) to open the Accusump. That's why it did not open during the entire session. Why? Not sure, but maybe the fresh oil made a difference, and also the increased air pre-load could be a part of it as well, contributing to an increase in oil sump level. If you look at the NASA session 3rd data, the Accusump opened 16 times during those 3 laps...
- No I did not see any evidence of oil depletion that would be shown by a substantial air pressure drop in the Accusump. It did not go below 51 psi, indicating about 2/3 of a quart remaining at worse.
- I think that if you're going to put an Accusump, you need a check valve AND/OR an oil filter that has an anti-drainback valve. With the racing filter, it does not have one, but my system does have a check valve to reduce back flow to the pump.

ah, sorry - you are already on that and i missed your filter comparison post. my bad. ok, so flow looks like ...

oil pump - avg 64 - remote filter - accusump insertion avg 58 - way down the line to the heads avg 34

so actually not much drop across the filter then. and it is tiny (8 micron) filter w/o bypass so no issues there.

i agree i am seeing little need for the pressure switch. my triumph gt6 race car has an accusump with just manual valve and seems to work fine. also, a caveat to those installing an accusump without a remote filter - with just a sandwich plate to add the accusump, i think it inserts before the filter (pls correct if i am wrong) so average pressures would be in the 60's and not the 50's which might affect choise of pressure switch if going in that direction?

The moroso sandwich puts the accusump after the filter but the canton and others i have seen put it before the filter. I thought after would be better to get any possible benefit from the anti drain feature of the filter, if it had one.

Yes, it looks like the Canton Racing sandwich plate feeds the Accusump (or oil cooler) pre-filter, so the pressures would be higher and you might need a higher setting pressure switch. When I talked to Canton, he mentioned that it would be better to have filtered oil going into the Accusump accumulator. Not to mention what Steved0x said about the benefits of the anti-drainback if you don't use a check valve. The issue I had when deciding to go with a remote filter base was two-fold: not enough room for a 1042 with a sandwich plate (too low), and more ports available to install pressure sensors with remote base (more flexibility). I think TuneRS now has a really nice remote take off plate that is low profile that integrates a backflow preventer.

This is an interesting discussion. I took my Accusump out a couple years ago. If anyone is interested in a setup, I'll let it go cheap. Just pm me.

Just sent you a PM.

Gang,

I was at NASA Bondurant last weekend and I logged the oil pressure data while using the Accusump pressure switch bypass, effectively running the valve open all the time when bypass is ON.

It is a very short 1 mile track with almost constant turns, and pretty slow overall. Last time I was there, the Accusump was triggering often.

Here's an updated summary:

http://986forum.com/forums/uploads02...1543200197.jpg

For session 1, I did not engage the bypass switch, just leaving it in standard pressure switch mode. It only triggered once. For sessions 2 and 3, I turned ON the bypass switch, keeping the valve open. Although the temps were warmer than session 1, I did not see any significant difference on the Valve Cover oil pressure minimums, with a 4 psi difference (31-27) between sessions 1 and 3 with bypass ON being better. This comes at the expense of a somewhat higher oil volume depletion in the Accusump, indicated by lower minimums/maximums air side pressures when the bypass is ON. This means there is more oil in the sump/in circulation in the engine. This setup is working well for me so far, but I can't yet conclude that the bypass switch ON has a significant effect on reducing oil pressure dips (starvation). Will need more data.

What I will do for the next event is reduce the total oil volume so that, at 80 psi air side pressure, the dash level indicator shows full and not 1 bar above as I had setup for the previous events. My suspicion is that the extra volume is contributing for the Accusump not triggering as often, as well as possibly the air temps being cooler. I also believe that the higher air side preload (15 psi vs 7 psi originally) is helping.

Another update with the most recent data from AMP with PCA this last Saturday.
It was a spectacular day to be at the track, great weather, air temp 65-70F, only a few cars in DE4, so a lot of open track!

Here's a link to the first 15 minutes of session 3, with data overlay showing the oil and accusump pressures. I had the by-pass switch turned ON for this session. This basically bypassed the pressure switch and kept the solenoid valve open.

https://youtu.be/-pKNVFNYCgE

Here's the updated data summary that includes the 4 sessions last Saturday:
Something went wrong for session 2 as indicated by negative pressures.

http://986forum.com/forums/uploads02...1543981522.jpg

The oil pressure during session 3 was rock solid. I am sold on the Accusump by-pass mod. I think this is a configuration that can be used for pre-oiling as well as open valve for track usage. I also believe the 15 psi Accusump air side preload is more effective than the recommended 7-10 psi. One other thing I'm doing is keeping the oil level slightly above the max line on both the dip stick and the electronic gauge. No issues with AOS.

I think you have a good combo:

Electronic pressure switch, which can hold the oil and then be released for pre-oiling, and also a way to bypass that, so it is always open, for when you are on the track. Combined with the higher starting air pressure, the accusump has more "power" to buffer the pressure fluctuations.

What Pre Pressure are you using in your Accusump? Gauge pressure.

Hey there, if you mean air preload pressure, then I use 15 psi now. Used to go with 7 psi but found that 15 psi works better.

This is all very helpful! Im considering adding Accusump to my 986S for track duty.

Also trying to reduce weight at the same time. Do you have any data to suggest that the 2qt is the best size, or would the 1qt system also cover the vast majority of the needs?

The charts are low enough resolution that I cannot tell if it appears the Accusump is running near the end of its capacity when discharging.

Thanks for any insights you can offer!

why does the voltage across the solenoid drop slowly?? I would assume it is in either an on or off position. (high volt or low volt)

Insights appreciated.

Great data above AZ986S. I installed of the accusump on my '01 986 S, in the tunnel, it fits well and seems to be the most logical location.

Here is a video of the results on the track with track tires. I run my oil level about half way between low and full, with this set up I get an accusump dump on almost every corner and even under heavy breaking. Based on the video there are even a few longer corners where the accusump runs dry. Running Mobil 1 0W-40, BTW. Accusump has a 35PSI valve with 10 psi of pre-pressure in the air chamber.

I also run into very low oil pressure at idle post track sessions, i.e 5-7 PSI at idle and 250 F oil temp.

Conclusion: If you're tracking a 986 or 996, strongly consider an Accusump or deeper oil pan, you'll need it.

Video Link - https://youtu.be/lp-PJr1aPtA

I autocross my car, and am trying to decide if I need a Deep Sump, an Accusump, or both!

I am leaning toward Yes Accusump, no deep sump, but would love to get the input of others. If both presents a large advantage, I am definitely open to that configuration. I already have the X-51 baffle setup with the stock oil pan.

Silber

Another question that occurs to me, is if you run the accusump all the time, without a pressure switch, how do you prevent the crankcase from overflowing into the AOS and intake at idle?

Hey Silber,

It's been a while since I've posted here, but rest assured all is well!

To answer your question, there is a one-way valve (check valve) that allows the engine oil coming from the oil pump to enter the accusump, but ONLY when this engine oil pressure is greater than the oil pressure on the oil side in the accusump. So when you run with the accusump with the standard pressure switch mode (with electronic valve), the oil will release from the accusump into the engine oil path when the engine oil pressure is lower than the accusump oil pressure. This is only usually momentary (up to a few seconds), but then the engine oil pressure will recover and become greater than the accusump oil pressure as the engine RPMs increase, in effect "recharging" the accusump for the next corner. This is what SAVES your engine from oil starvation... So, in this case, the worst case scenario is coming off the track after a session, hot engine oil, low oil pressure at idle (lower than 35 psi) and so that would dump maybe 1 quart at most into the engine and into the sump. Hence why you need to set you normal oil level lower than max. I also just switch the Accusump Electronic valve to OFF coming off the track after a session so that the accusump is fully recharged, and I only turn it ON when I am on my way onto the track, not at idle.

OK, so what I found with data over a couple years now is this is still not a perfect setup to prevent oil starvation (but better than no protection). There is a time lag when using the pressure switch and electronic solenoid valve, and that lag even if it is 500 milliseconds, can still add up to some engine damage over time. So what I did in my car was add a switch to "bypass" the pressure switch and effectively turn ON and keep ON the solenoid valve when on the track. What this does is it simulates a mechanical valve and virtually eliminates any time lag. I've had this setup for 3 years now and 40+ events driven hard on the same engine, using Mobil1 15W50. Stock AOS with X-51 baffle system. No oil consumption. The engine gets run hard, but I rarely redline it, preferring to shift around 6,500-6,800 RPM.

So I would say it has had a positive impact on reducing oil starvation and extending the life on this 3.2 engine, considering that I had the previous engine for only 14 events prior to it failing.

Anyone want to buy a complete, ready to install Accusump setup for a Boxster? Was mounted in the trunk in my car by the PO, was only used for about 1 year and 1-2 races, then removed. Includes custom hoses, oil filter adapter, electronic valve, mounting brackets, and all wiring needed. Asking $500 shipped to CONUS - OBO. PM me if interested.

Here is a pic.

http://986forum.com/forums/uploads02...1638798400.jpg