High oil and coolant temps, low oil pressure - new Rad and Accusump

[AndyW]

Did my hottest track day yet...95F at The Ridge in Shelton WA. Finally experienced the coolant temp power reduction that others have mentioned. Saw over 280F oil temp, 250F coolant temp, and IAT's to 170F. Trans temp also got to 250F. Caused me to install a CSF radiator yesterday. Next track day is Thursday...hope it's hot again so I can get a good comparison. May need to upgrade my dual oil cooler setup as well.

https://datazap.me/u/andyw/very-hot-...ata=5-12-14-19

https://datazap.me/u/andyw/very-hot-...a=5-7-12-14-19

[what have i got into]

Is the vented hood helping at all?

[AndyW]

Originally Posted by what have i got into

Is the vented hood helping at all?

Yes. On a previous track day I had indications the vents were definitely helping.

[mKilgore]

Really interesting to see your logging over a whole session. I plan to do the same at the end of the month for a track day.

I am interested in your oil pressure logging. It looks like you dipped below 30 psi at the same point on the track for each lap. From your logs, it looks like this was a heavy braking section into a slow part of the track, maybe the downhill switchbacks toward the end of the lap? It's pretty low pressure, but you're also at low rpms, so maybe nothing to worry about? Any thoughts?

[bbnks2]

Originally Posted by mKilgore

Really interesting to see your logging over a whole session. I plan to do the same at the end of the month for a track day.

I am interested in your oil pressure logging. It looks like you dipped below 30 psi at the same point on the track for each lap. From your logs, it looks like this was a heavy braking section into a slow part of the track, maybe the downhill switchbacks toward the end of the lap? It's pretty low pressure, but you're also at low rpms, so maybe nothing to worry about? Any thoughts?

I actually see him down as low at 25psi at 3400 rpms and rolling back into the throttle (accelerator position is at 54%). That is pretty bad. Anything over 3,000rpm should be above 60psi. Especially if you're already rolling back into the throttle.

See timestamp 865.47. He is at 0% pedal input, 2400rpm, 48psi (sounds about right since 40psi is idle). The next two data points he is accelerating and oil pressure is dropping. Not a good sign.

As for the overheating, seems like a really slow course that you're dropping to the bottom of 2nd gear. Radiator should help a lot since you're an automatic. if you do a comparison log, make sure it's at the same track because that can have a huge influence on temps.

[AndyW]

Sigh...now I'm worried about oil pressure...lol. I had been considering an Accusump. Maybe I need to pull the trigger. Which turn is worse for oil...left IIRC. There is a large left sweeper on that track where my VIRB data indicates 1.3-1.4 g's. There is also the "thumb" turn which is a short, tight left hander.

Which pressure switch should I get with the Accusump? 35-40 seems optimal to prevent discharge at idle...

[AndyW]

Originally Posted by bbnks2

I actually see him down as low at 25psi at 3400 rpms and rolling back into the throttle (accelerator position is at 54%). That is pretty bad. Anything over 3,000rpm should be above 60psi. Especially if you're already rolling back into the throttle.

See timestamp 865.47. He is at 0% pedal input, 2400rpm, 48psi (sounds about right since 40psi is idle). The next two data points he is accelerating and oil pressure is dropping. Not a good sign.

As for the overheating, seems like a really slow course that you're dropping to the bottom of 2nd gear. Radiator should help a lot since you're an automatic. if you do a comparison log, make sure it's at the same track because that can have a huge influence on temps.

Do you have a link to how your Accusump is mounted and plumbed? I remember reading a thread about oil starvation last year but can't find it. Thx!

[AndyW]

Nevermind...found it on the other site..forgot some of the discussion there.

Pulled this interesting data from the log (removing idle time at start and finish)

% Time less than 40 psi 5%
Longest time less than 40 psi 4 Sec
% Time less than 60 psi 18%

These are very different than my numbers from last fall.

Low pressure points are definitely in the slowest left hand corner.

So, what is the concensus on need for a check valve?...I plan to tee in to the return line from my driver side oil cooler.

[mKilgore]

An accusump is high on my priority list as well. Which is why I took an interest in your data logs. From what I have seen, the 35-40 psi valve is suggested as the most common application, but I think bbnks2 did the 55-60 psi valve. This brings up an interesting question, because if you look at your datalogs, it appears like the accusump would be discharging 5-6 times per lap using the 35-40 psi valve, and possibly another 1-2 more times if you use the 55-60 psi valve. I assume that using one of the EPC electric valves kit which allows for "fast" refills of the system would be sufficient to refill the accumulator and have it ready to discharge again, but I don't really know.

I plan to take logs of the next couple of track days in which I won't have an accusump, and then hopefully can install one over the winter break and compare with new logs as the same track with an accusump.

[AndyW]

Originally Posted by mKilgore

An accusump is high on my priority list as well. Which is why I took an interest in your data logs. From what I have seen, the 35-40 psi valve is suggested as the most common application, but I think bbnks2 did the 55-60 psi valve. This brings up an interesting question, because if you look at your datalogs, it appears like the accusump would be discharging 5-6 times per lap using the 35-40 psi valve, and possibly another 1-2 more times if you use the 55-60 psi valve. I assume that using one of the EPC electric valves kit which allows for "fast" refills of the system would be sufficient to refill the accumulator and have it ready to discharge again, but I don't really know.

I plan to take logs of the next couple of track days in which I won't have an accusump, and then hopefully can install one over the winter break and compare with new logs as the same track with an accusump.

Yes, that is my dilema. 35-40 psi would be what Canton recommends...slightly below idle pressure, but bbnks2 has a point with keeping pressure higher...just something you have to manage with a manual switch. I keep going back and forth.

[AndyW]

I guess I need to understand the consequences of forgetting to turn it off and it dumps the oil to the sump...what am I risking dumping 3 extra quarts to the sump?

[mKilgore]

Originally Posted by AndyW

I guess I need to understand the consequences of forgetting to turn it off and it dumps the oil to the sump...what am I risking dumping 3 extra quarts to the sump?

If you do the wired 12V control, do you still have to manually turn it off before turning the car off? I know the benefit of the wired 12V option is that you don't have to turn it on, but maybe that doesn't work the same for turning it off?

[AndyW]

Originally Posted by mKilgore

If you do the wired 12V control, do you still have to manually turn it off before turning the car off? I know the benefit of the wired 12V option is that you don't have to turn it on, but maybe that doesn't work the same for turning it off?

Even with the ignition drive power, if the valve is the 55-60, at idle,
the system is at 40 psi so the Accusump will dump. That is why bbnks2 has a switch to turn the system on while going on the track and turning it off while leaving the track.

[bbnks2]

I have the 60psi electric valve. I wired it to a manual switch so I can turn the Accusump off for street driving. I flip the switch on as soon as I roll onto the track. My thought process was that I should never really be below 3,000rpm/60psi on track anyway so I went with the 60psi valve.

The risk is that at idle (40psi) the accusump electronic solenoid would be open. Constant open voltage on the solenoid tends to burn it out quickly. I think Accusump addressed that specific issue though many years ago when they moved to a new electronic valve. But, that is a valid risk... burning the solenoid out.

The Accuusmp doesn't just dump all of it's oil at <60psi. I have a 3qt unit. If pressure falls to 40psi it will probably only discharge 1-1.5qts. Another 1.5-2qts of oil will still be in equilibrium in the accumulator. It takes pressure dropping down to less than the 7psi air bladder pressure for it to fully discharge all 3 qts. So long as there is more than 7psi of oil pressure the accumulator will always have some level of oil in it. At 20psi pressure it might fill with 1qt... and 100psi it might even cram as much as 3.5qts in. Hope that helps conceptualize how the oil pressure drives how much oil get's pushed into the accumulator... and then the dropping pressure allows that oil to slowly feed into the system to equilibrium when the solenoid opens.

I don't think a check valve will really do anything. I think the positive displacement oil pump will prevent any backflow. My logs show the accusump feeds into the block when the car is even fully OFF (builds over 60psi) so the oil pump and oil filter is preventing backflow even when the cars not running and no oil is flowing from the oil pump.

[AndyW]

Originally Posted by bbnks2

I have the 60psi electric valve. I wired it to a manual switch so I can turn the Accusump off for street driving. I flip the switch on as soon as I roll onto the track. My thought process was that I should never really be below 3,000rpm/60psi on track anyway so I went with the 60psi valve.

The risk is that at idle (40psi) the accusump electronic solenoid would be open. Constant open voltage on the solenoid tends to burn it out quickly. I think Accusump addressed that specific issue though many years ago when they moved to a new electronic valve. But, that is a valid risk... burning the solenoid out.

The Accuusmp doesn't just dump all of it's oil at <60psi. I have a 3qt unit. If pressure falls to 40psi it will probably only discharge 1-1.5qts. Another 1.5-2qts of oil will still be in equilibrium in the accumulator. It takes pressure dropping down to less than the 7psi air bladder pressure for it to fully discharge all 3 qts. So long as there is more than 7psi of oil pressure the accumulator will always have some level of oil in it. At 20psi pressure it might fill with 1qt... and 100psi it might even cram as much as 3.5qts in. Hope that helps conceptualize how the oil pressure drives how much oil get's pushed into the accumulator... and then the dropping pressure allows that oil to slowly feed into the system to equilibrium when the solenoid opens.

I don't think a check valve will really do anything. I think the positive displacement oil pump will prevent any backflow. My logs show the accusump feeds into the block when the car is even fully OFF (builds over 60psi) so the oil pump and oil filter is preventing backflow even when the cars not running and no oil is flowing from the oil pump.

THx for the detailed explanation. I read the Canton docs and now understand it much better. This is what I think will happen. Pls correct me if I am wrong...

- Accumulator has a 7-10# bladder pressure..the air pressure that will vacate all the oil. For this to happen, system pressure would have to go to essentially zero. So full discharge is not realistic in an operating (vice prelube) scenario.

- The control valve will always let system pressure push oil into the accumulator as long as system pressure is above the EPC valve setpoint. It functions as a check valve when the EPC is below it's setpoint. So oil will fill the accumulator to 90# (basically max out put pressure) and somewhere between 2 and 3 quarts.

- When pressure falls below the EPC setpoint, the EPC allows flow toward the system and flow rate will be based on the D/P. So, if the setpoint is 60#, that is a 20# D/P initially, with a reducing flow rate as D/P goes down due to the Accusump piston moving due to the D/P. Assuming system pressure continued to head toward 40# the Accusump will keep emptying until it equalizes with the system with some remaining volume in the tank (the only way the tank empties if if system pressure gets to 7-10#, which would be "Game over" while moving).

This leads me to believe the earlier the oil starts flowing as you move toward a minimum system pressure, the better - you have more time to push oil into the system before a critical point is reached (lets pick 40# as the red line since that is around idle pressure, as that seems to be the concensus). If we picked the 35-40# EPC valve, the initial pressure between the tank and the system is greater when the valve opens, so the flow rate will be higher than if you were using the 55-60# EPC valve, but the discharge for the 35-40# EPC is much closer to danger when it starts helping. I need to see if Canton has any flow rate vs D/P graphs. It may be moot. All of my events are less than 4 seconds. i.e. If the Accusump discharges from 80# to 40# in 2 sec and 80#-60# in 3 seconds, I think it's a wash.

I am going to see if there is any data or graphs on the rate at which the Accusump discharges. Once site I looked at said the 3Qt gives "15-60 sec" which seems extremely optimistic. Without knowing flow rates it is difficult to know.

[AndyW]

This guy doesn't even use a valve... http://www.billavista.com/Tech/Artic...ing/index.html

This guy uses it on an airplane and gets 6-8 seconds https://vansairforce.com/community/s....php?p=1098370

[AndyW]

Ordered my Accusump stuff. Hope to install next week. got the 55-60# EPC. Am going to go wireless for the power switch. https://smile.amazon.com/gp/product/...29BIB8JL&psc=1

[mKilgore]

Great stuff, thank you both for the explanations. Please keep us updated AndyW. I'll be following suit within the next few months.

[bbnks2]

Originally Posted by AndyW

- Accumulator has a 7-10# bladder pressure..the air pressure that will vacate all the oil. For this to happen, system pressure would have to go to essentially zero. So full discharge is not realistic in an operating (vice prelube) scenario.

sounds correct

Originally Posted by AndyW

- The control valve will always let system pressure push oil into the accumulator as long as system pressure is above the EPC valve setpoint. It functions as a check valve when the EPC is below it's setpoint. So oil will fill the accumulator to 90# (basically max out put pressure) and somewhere between 2 and 3 quarts.

yes, I usually see mine sitting at around 120psi. cold starts produce lots of pressure. Also, 1st and 2nd gear the oil control isn't as good since the acceleration is so fast. You can sometimes see over 100psi oil pressure in 2nd gear. Normal pressure under full load is ~80psi or so.

Originally Posted by AndyW

- When pressure falls below the EPC setpoint, the EPC allows flow toward the system and flow rate will be based on the D/P. So, if the setpoint is 60#, that is a 20# D/P initially, with a reducing flow rate as D/P goes down due to the Accusump piston moving due to the D/P. Assuming system pressure continued to head toward 40# the Accusump will keep emptying until it equalizes with the system with some remaining volume in the tank (the only way the tank empties if if system pressure gets to 7-10#, which would be "Game over" while moving).

yes pretty much.

Originally Posted by AndyW

This leads me to believe the earlier the oil starts flowing as you move toward a minimum system pressure, the better - you have more time to push oil into the system before a critical point is reached (lets pick 40# as the red line since that is around idle pressure, as that seems to be the concensus). If we picked the 35-40# EPC valve, the initial pressure between the tank and the system is greater when the valve opens, so the flow rate will be higher than if you were using the 55-60# EPC valve, but the discharge for the 35-40# EPC is much closer to danger when it starts helping. I need to see if Canton has any flow rate vs D/P graphs. It may be moot. All of my events are less than 4 seconds. i.e. If the Accusump discharges from 80# to 40# in 2 sec and 80#-60# in 3 seconds, I think it's a wash.

Yeah that's getting more into it than I bothered. I emptied it out into a bucket once and with no pressure in the lines it only took a split second to empty. 3qts oil volume isn't much when spinning at high rpm. If you have some sort of line pressure the accumulator can help supplement you at the set-point for several seconds though. That's all I really needed to know lol. Mostly concerned with keeping the line pressure up for those 2-3 seconds moments where n54 and n55 vehicles seem to experience a drop in a oil pressure for whatever reason.

I could log oil pressure at 3,000rpm/60psi and once the light flights on to show it's dumping I can see how long the oil pressure stays up above say 50psi. Then do the same test again with no accusump. I posted a few autocross logs where you can see 25psi lows bumped up to 40-50psi lows with the Accusump and that was enough data for me lol.

How quickly it discharges is really going to be relative to how much volume the accumulator is being asked to make up for.

[AndyW]

Interestingly, if I had followed Canton's flow chart I'd have purchased a 2 qt (based on 6 cyl) and 20-25# EPC (based on idle oil pressure of >25# but <40#). I sent an email to Canton asking about this and the flow rate question.

[AndyW]

Looks like it is going to be 20F cooler (i.e. more normal) at the track tomorrow...will make it harder for a great temp comparison.

[AndyW]

So, some data from today's track time.

https://datazap.me/u/andyw/tnia-ridg...zoom=3244-8730

The good news is: No limp mode! It helped that ambient temp was 77F vice 95F --- 18F less.

Two other changes were in play.

1. I did an oil change - new oil was 5W-40 vice 5W-30 (believe this may have helped oil pressure a small bit after looking at the data)

2. I finally sealed the new vented hood from the cabin air intake area - so less backpressure for air flowing from the coolers and then up and out the vented hood.

Looking at peak temps from last time with a linear normalization for ambient temp diff in parenthesis:

Oil - 282F (264F)
Coolant - 250F (232F)
Transmission - 250F (232F)
IAT - 193F (175F)

Today
Oil - 264F
Coolant - 234F
Transmission - 234F
IAT - 170F

It seems whatever changed from the new radiator appears marginal. I really need another hot day to really compare and that's unlikely to happen this year. I think the only thing I can say for sure is that I did no harm and the new radiator definitely has more capacity than the old one - I know just driving it on the street makes oil temp 10F cooler than it was before...so it is doing something.

The good news is that oil pressure seems more under control. Interestingly, There was slightly more time less than 55# but there was a lot of traffic in this session so that may account for it (less time on max throttle).

% Time less than 35 psi <1%
Longest time less than 40 psi 3 sec
% Time less than 55 psi 15%

Will hopefully have the accusump installed before the track day next Friday and will report back.