Learn me dry sumps....

In reply to Knurled. :

Depends on the track!  Eklhart Lake has 3 corners that I would slow from 160mph to around 40 then bop around a corner with your foot flat to the floor.  

Without a dry sump system Oil pressure disappears on braking and doesn’t come back until the oil goes back around the oil pickup. On a long engine like a inline six or V12  where oil can disappear out of the pan and go up into the timing chain area. that can be several seconds the engine is working without oil.

Cornering,  depending on baffles, depth of oil pan, windage tray,  oil level, etc.  oil may be kept around the pickup tube  for a while before air is drawn into the pump. 

An accusump would run out of pressure under braking and doesn’t start filling back up until further down the next straight. Pressure  needs to build up for both bearing surfaces  and the sump before it’s back to normal.  

An accusump is OK for momentary pressure drops as long as the sump doesn’t completely run out of pressure. If it does filling the sump back up delays getting full pressure until it does.  

Vigo said:

Other than Porsche 911s, the Z06 LS7 and some exotics, I can't think of another OEM dry sump system.

Well, that's the kind of stuff i was thinking of. I still think there are more factory applications than aftermarket  on race cars (could be wrong!!), but if you spend a lot of time at tracks you'll run into all the aftermarket ones. I can't remember the last time I saw one in person that wasn't on a corvette. 

Thanks.  Isn't interesting how one's experiences so color one's perception?  I guess I really have no idea if there are more factory applications than race car applications (it probably depends on how you count them) and when it comes to the point you were making it really doesn't matter. 

I installed an Accusump in my old E30 track car after losing two M20 engines to oil starvation. I plumbed it into the oil filter housing just ahead of the oil cooler return line using a T-adapter and a check-valve. I also had a windage tray to reduce the potential foaming problem from oil overfill.

But the tech support people at Canton Racing warned me that this wasn’t optimal. They recommended drilling/tapping a port right on top of the oil pickup so that when the unit discharges, the oil shoots directly into the pickup. This way, it works faster and keeps the extra oil volume to a minimum.

They also recommended a simple mechanical valve instead of one of their electronic valves. They said the electronic valves were convenient and good for pre-oiling, but not appropriate for race use because they slightly slowed discharge. 

I didn’t have the system in the car for very long before I sold it, but I do think it has some value if installed and used as recommended. I bought another Accusump setup for my current race car, but never bothered to install it as the Cosworth engine doesn’t seem to have any oil starvation issues. 

In reply to LanEvo :

If you're modding the block to have an oil feed in front of the oil pump, and you have a tank anyway, in a way you are only a larger tank and a scavenge pump away from having a dry sump.

Might be useful if the stock pump isn't a liability.

Also:  Toyota Previas.  What the heck was going on with the underhood oil tank?  There was a tank up high and also a dipstick on the engine and I never looked into what sorcery was going on.

The motor in the Previa was based on the T block, that is, indestructible, but stroked and mounted sideways so that the "pan" is on one side and the head is on the other.  I never looked at their oiling system, but I imagine it would be interesting, set up like that.

In reply to Dr. Hess :

It turns out to not be all that interesting.  There is an electric motor on the underhood tank and a low oil level sensor in the pan.  When you turn the key on, if the low oil level sensor is tripped, the electric motor runs for a few seconds to add oil to the engine.

Kind of a nice feature on a vehicle where you have to move some seats to check the dipstick, but apparently the switches tend to fail after a couple decades.

Huh.  An attempt to be soccer mom resistant.  I've read that the Puerto Ricans would use those blocks in their monster Rolla drag cars, mounted vertically, of course.  I doubt there are many T blocks left, much less racing.

You can spend a lot of money on a dry sump system and may not need to.

An Accusump combined with some work on the baffling in the sump does pretty much the same thing for a fraction of the cost.  And it keeps the main gallery filled under pressure for the full sweep of even a long corner if implemented properly.

BTW, one thing people seem to ignore or be unaware of is that air in the gauge tube damps response.  remove the line from the back of the gauge and run the engine (with a little cup under it) to bleed the air out, and then reconnect it. You will get faster readings, which you really want if there is a drop in pressure.....

In reply to wspohn :

If you size and install an Accusump in the way that Canton recommends, I think you can get most of the protection of a dry sump for under $500 all-in. Especially if you already have a baffled pan +/- windage tray.

From what I’ve read, a dry sump has many other benefits besides just oil starvation for a true race engine. The Accusump is only going to cover that one area, so it will never be a replacement for a true dry sump setup.

wspohn said:

You can spend a lot of money on a dry sump system and may not need to.

An Accusump combined with some work on the baffling in the sump does pretty much the same thing for a fraction of the cost.  And it keeps the main gallery filled under pressure for the full sweep of even a long corner if implemented properly.

BTW, one thing people seem to ignore or be unaware of is that air in the gauge tube damps response.  remove the line from the back of the gauge and run the engine (with a little cup under it) to bleed the air out, and then reconnect it. You will get faster readings, which you really want if there is a drop in pressure.....

No!! An accusump will not work as well as a dry sump.!  In fact in some aspects it’s worse than the stock system.   Assuming the oil pan is correctly baffled to always keep a head of oil at the pickup an accusump is not needed.  

The reason is if you starve the engine of oil due to braking or cornering with an accusump  the accusump needs to be recharged.  

So as soon as the oil pump starts to pick up oil again some of that oil and pressure goes to recharging the Accusump. Until the accusump is fully filled and recharged you won’t have full oil pressure.  The  size of the accusump  will determine how long it takes to get back to original pressure. But until that is full and pressurized the oil will be running on less than full pressure. 

A dry sump on the other hand never runs out of pressure. The system is designed to always have a head of oil.  In addition if you use a de-airiation tank  you will always have straight air free oil to the system. That will help in cooling the  oil as well as  providing better lubrication.  

In addition a dry sump evacuates all the oil that would normally be in the oil pan.  That’s why they are called dry sump.  A dry sump system might have 2-3-4 sections of pump just used to evacuate waste oil. And only one section to pressurize  the engine.  

That lack of oil benefits in several ways under hard braking or cornering even a well baffled pan will have oil up around the crankshaft.  Whipping the oil froth around by the crankshaft will cost horsepower.  

An oil accumulator will never be as reliable as a dry sump in every situation, but it can help in transient situations if it's connected and plumbed correctly.  I run one even though I've paid attention to the baffling and run crank scrapers if they'll fit. 

 Here's how I do it. 

1. I use a 12v solenoid that's activated from the ignition circuit.
2. I use a bullet style check valve after the solenoid with a small hole drilled in the check.  That allows the oil to leave the accumulator quickly, but refills slowly so as not to starve the motor when the oil pressure comes back.