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Old 08-03-2010, 11:39 AM   #21
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My two cents... The other reason IMO for accusump over baffling is ease of installation, and maybe even expense.

If you are building an engine that is not in the car yet then a baffle can be added easily, and should be. The cost of a baffled oil pan is another issue, but can be DIYed (as demonstrated here and elsewhere) to save money.

If the engine is in the car already then the accusump may take less time. This is especially true if there is already an oil cooler in the system.

In my case, I have this LS1 Miata track car with the engine already in. The oil cooler is also already in. So, adding an accusump is easier than pulling the engine to swap oil pans. I have been told that the add-a-quart-over-full system works for the track LS1 cars. But I like the idea of having the accusump as insurance.

Good thread, good sticky.
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Old 08-03-2010, 01:32 PM   #22
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Originally Posted by baron340 View Post
If this is true.. then what is the real benefit of an accusump system? It seems that some well thought out baffling would solve the problems. Or are you all doing this just for the safety net?
I think the problem is high G braking. A downshift in the braking zone putting the engine at high revs with some engine braking while the oil pressure drops to zero can be real bad. I’m looking at my engine bearings now that I have my engine apart and I see signs of what looks like oil starvation. Sombody posted some data collected in the oil pan baffling thread I started showing that baffling may not do the trick.

We are getting into a different realm of performance than spec Miata, or most other forms of Miata racing, More mechanical grip + aero downforce + much higher speeds entering the braking + much more braking required + more gears needed to pass through for downshifting.

As for the LS1 cars I think they have a different problem. I thought they have starvation issues cornering.

Bob

Last edited by bbundy; 08-03-2010 at 01:45 PM.
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Old 08-03-2010, 02:55 PM   #23
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As for the LS1 cars I think they have a different problem. I thought they have starvation issues cornering.
Yes I believe that is correct.
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Old 08-03-2010, 09:11 PM   #24
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Okay, under braking then, I stand corrected. On a rally car, that's not an issue, as you always want to leave a bit of margin for the unexpected when compared to driving the same dozen corners repeatedly. So again, it wasn't part of the plan for the Targa car.

The F-body pan used on the LS conversions is known for having starvation problems in long corners. The baffled one from V8 Roadsters should solve that problem.
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Old 08-03-2010, 09:26 PM   #25
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Okay, under braking then, I stand corrected. On a rally car, that's not an issue, as you always want to leave a bit of margin for the unexpected when compared to driving the same dozen corners repeatedly. So again, it wasn't part of the plan for the Targa car.

The F-body pan used on the LS conversions is known for having starvation problems in long corners. The baffled one from V8 Roadsters should solve that problem.
I agree that in a Miata motor it's not really a required thing. When I saw that light blink it was only for a split second, never under load. It's on my list of things to add to my race car, but it's not high up on that list.

Knowing what I know about the LS motors and the failures that SCCA T1 guys see, though, I would never track an LS block without an Accusump installed, ESPECIALLY any motor based around the LS3 block/heads. There's a California guy with a baffled pan (Improved Racing made the baffle) running an LS1 car in SCCA ITE, and he still sees oil pressure drop to 20psi in long sweepers (20psi is where his Accusump kicks in). The V8R pan may solve the issue, but I have no interest in gambling a $3000 LS longblock in order to find out. The Accusumps work, they are reasonably inexpensive, and they are basically foolproof if you use an automatic valve.
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Old 08-04-2010, 01:37 AM   #26
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Mine is mounted diagonally behind the passenger seat. That puts the ball valve withing easy reach of the driver for pre-start oiling. The gauge is on the lower side, but still visible behind the seat. The check valve is installed per the install instructions immediately next to the T on the return line from the oil cooler. The idea (at least in my mind) was that if pressure drops, the accusump feeds into the motor, not back toward the cooler.

I don't know that it is 100% necessary, but the last rebuild on my motor was caused by an undiagnosed oiling issue. CHEAP INSURANCE is never a bad thing.
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Old 08-04-2010, 09:20 AM   #27
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I was just thinking that one of the smaller accusump tanks might fit in the tray where the wiper assembly goes for those of us who dont have a wiper assembly, this would defiantly keep the lines short.
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Old 08-04-2010, 01:17 PM   #28
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Quote:
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I was just thinking that one of the smaller accusump tanks might fit in the tray where the wiper assembly goes for those of us who dont have a wiper assembly, this would defiantly keep the lines short.
I though about this too but need to move weight away from the front. How much does all this stuff weigh? I think this peace of mind will remove another worry from my mind mid-corner...which is a problem for Mr. Negativity.
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Old 08-04-2010, 02:46 PM   #29
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You'll be looking at around 20 pounds gained, mostly over the rear end with the 3 quarts of oil and the accumulator.
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Old 08-05-2010, 07:46 PM   #30
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Quote:
Originally Posted by bbundy View Post
Sombody posted some data collected in the oil pan baffling thread I started showing that baffling may not do the trick.
That was me, and here is the data plot I posted in this thread: Extra baffling for the oil pan.
The black trace is a recent datalog of my stock non-baffled, non-crank scraper engine. The red trace is a datalog from last year of my baffled & crank-scraped high-revving N/A engine.



I've been considering an Accusump as well. Just like Savington, I'm seeing pressures as low as ~20PSI in heavy braking zones.

For those of us with lots of room on the exhaust side of the engine bay (no turbo, no power steering, no A/C), I believe a 1 or 2 QT Accusump would fit nicely on the frame rail. Another option would be the cowl, depending on your windshield wiper situation. The 1 QT is really small and could fit anywhere, but is it enough?

According to Canton, their systems supply between 15 - 45 seconds of pressurized oil. Since the low pressure issue is specific to heavy braking zones, "15 seconds" of pressurized oil would be plenty, as the system would only discharge for a few seconds, and then quickly recoup. That said, if you are looking for the Accusump to save your engine in the event of a bigger problem, 2 quarts would buy you more time.

- Will
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Old 08-05-2010, 10:14 PM   #31
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One thing I would absolutely want is a light that engages when the Accusump valve opens. If you see that light trigger under load at any time, shut the car down ASAP.
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Old 08-06-2010, 12:44 AM   #32
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Link to trackspeed group buy on lightened, inconel, Swain-tech coated low-pressure light set-up?
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Old 08-06-2010, 01:48 AM   #33
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Link to trackspeed group buy on lightened, inconel, Swain-tech coated low-pressure light set-up?
I'm going to group buy an Inconel train on your girlfriend.
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Old 08-06-2010, 02:17 AM   #34
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I haven't lol'd that hard from a post in a long time Sav.

Can someone write a small shopping list for us lazy/ignorant folk as to what you'd all need to run one of these systems on a miata? It'd be great to have in this thread anyways. I'm seeing kits like this for about $360 everywhere, what else?

http://treperformance.com/i-133436-c...usump-kit.html
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Old 08-09-2010, 12:25 PM   #35
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There's an article in the current issue of Modified Magazine on an accusump install. It didn't go -that- deep but it might be a useful reference. I would scan it but I got the magazine all wet...
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Old 08-29-2010, 02:18 PM   #36
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i am running a 1qt accusump in my car for pre oiling. i run with a remote filter and a oil cooler.

i will put a nice thread together tonight when i have more times with details and pics. im running a manual ball valve and i have it mounted on the passenger side of the tranny tunnel. you have to have a check valve in your system to stop the accusump from back feeding. you want it to go straight to the engine, not have to pressurize your filter. it dosnt take long to loose a qt @ 60psi through a -8 line. so you want the route to be as direct as possible
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Old 08-29-2010, 07:12 PM   #37
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I got a look at a 3 qt accusump on somone's track car (not a Miata) the other day. The 3 qt is really, really big.
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Old 10-28-2010, 04:09 AM   #38
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I just got in a bunch of parts and starting to plan out my install. Iím liking the Idea of coming up with some brackets to mount the accumulator back by the location of the fuel filter, looks like it will work good.

The problem Iím having is for the life of me I canít figure out how to hook everything up correctly with the system I have now. I have a Mocal sandwich thermostat and oil cooler and I previously ditched the remote mount oil filter to clean things up.

After thinking it through it seems this configuration isnít quite compatible with the Accusump.

It seems to make use of the check valve you need to use a Block off adapter and remotely mount both the thermostat for the oil cooler and also oil filter.

The number of fittings, adapters, filter mounts, and block off plates needed to do this along with a different style thermostat just went through the roof.

The other option seems to be to not use the check valve and just stack a single port Accusump sandwich plate underneath the thermostat sandwich plate.

Bob
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Old 10-28-2010, 12:09 PM   #39
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Damn it, I hate it when my response gets wiped out...OK let's try this again.

From what I have read there are mixed opinions as to whether or not the check valve is really needed. Just to be clear I am not talking about the valve that opens up flow to and from the accumulator tank, manual or electric. I am talking about a check valve that is upstream of the tee-in point for the accusump; it is shown in the Canton installation diagrams.

The purpose of it as you know is to keep the accumulator from dumping its flow upstream into the oil pump instead of downstream into the engine. Some have argued however that there is not a need for the check valve since the backflow into the oil pump is actually beneficial. It helps keep the pump primed for when the oil makes its way back into the pickup tube portion of the oil pan. This makes sense to me. And IIRC there are people road-racing accusumps without a check valve.

As long as the accusump has enough capacity to feed oil upstream and downstream of the tee point during the pressure drop event, then why not get rid of the check valve? Though it would be dependent on the engine and oil plumbing system configuration, I would expect that most of the flow would still travel downstream compared to the 'backflow' into the pump.

Bob can you not just tee the accusump into the feed line for the oil cooler?
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Old 10-28-2010, 01:32 PM   #40
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Quote:
Originally Posted by ZX-Tex View Post

Bob can you not just tee the accusump into the feed line for the oil cooler?

With a Mocal sandwich style thermostat it seems like that would feed oil to the engine only when its warmed up and the thermostat is open. Probably wouldnít pre oil very well in that configuration Iím guessing, might work fine once up to temp.

Seems like if I keep the mocal sandwich thermostat the slickest solution is to install one of these
http://www.racerpartswholesale.com/p.../316/Accusumps
Install it stacked underneath the mocal thermostat and hook the accumulator to it. The only issue is their would be no check valve if that was a required or important element of the system.

Bob
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