MeOughtta

Why manual valve:

1) Super simple instead of relatively complex
2) Much cheaper
3) The electric valve sometimes sticks closed. Very frustrating.
4) Unaffected by shorts, and opens, or a blown fuse.
5) No problem with it draining your pre-oiling charge just because you moved the key to "Run" so you could put up an electric window or ACC to listen to the radio or whatever.
6) Don't have to find a wire that is hot during both crank and run to power the valve.

Where to mount it:

My idea is to run the line along the tunnel and put the manual valve right on the tunnel next the the shifter. Then, all you have to remember is to open the valve before START and close it before OFF. Super simple.


M.

bbundy

This place makes a Dry Sump pan for a Miata

http://www.drysump.com/mazda.htm

interesting that it doesn’t have attachment to the transmission like the stock pan.

Also I thinking a Dry sump system will end up costing more like $2,500 by the time it is all pieced together. It would also require a lot of custom fabrication work to mount the pump in my case I think.

Bob

dc2696

iTrader: (2)

@$600 for an oil pan, ya I can see it costing $2,500

If I can get the pump for a decent price everythig else should be cheap enough to build/find

ZX-Tex

iTrader: (15)

Good points

I am guessing you mean running the hose through the OUTSIDE of the cabin, underneath the car, and using a bulkhead mount style valve. Running the line through the cabin makes me nervous. One it could fail (unlikely, but it could happen) and two, it could rupture in a crash. Either way, you have a scalding hot, toxic, combustible fluid spraying all around you and the cabin.

wildo

iTrader: (1)

Both are good questions.

I have enough experience with both electronic and mechanical devices not operating as advertised, that I've learned to trust neither.

For a Miata, at least given the data I've logged, it depends. One of my engines would idle at 35 PSI fully warmed-up, another idled at 22-25 PSI. I suppose that since the oil pressure ramped up as soon as I moved off idle, the pressure at idle doesn't matter. I'd go with 35-40 PSI. 55-60 is too high and I'd bet that the valve would be constantly open.


Thinking about this a bit more, how does it matter where the warning pressure sensor is? As soon as the Accusump valve opens, won't the oil pressure in the system equalize? Likewise, if the valve sticks or isn't flipped open, and the pressure warning sensor is on the Accsump side, the engine's oil pressure could drop to zero, and the warning would never go off. Unless I'm missing something, I think it would be best to put the warning sensor where you are concerned about actually having low oil pressure (on the engine block).

In addition to a warning light, routing the pressure warning signal to an ECU input and having it cut spark could be a nice upgrade, too.

Good points about powering the electronic valve and having issues with it sticking, but I'm not a fan of running fuel or pressurized hot oil lines through the cockpit. I'd rather risk my engine than my skin. Perhaps a manual valve with remote activation is the way to go.

ScottFW

iTrader: (4)

http://www.accusump.com/accusump.pdf..._cable_kit.pdf

ZX-Tex

iTrader: (15)

^^ Yeah I think that is what Hustler was referring to.

MeOughtta

For *certain* I would have a gauge and alarm on the actual oil pressure. I was describing a *supplementary* low pressure alarm which would go off while there is still sufficient oil left to keep the engine alive.

As for placement, it goes on the air pressure side of the Accusump's internal piston. That pressure will decrease as the pressure behind the piston drives oil out of the Accusump and into the engine. It is, in effect, a way to measure how much oil is left in the Accusump and activate an alarm when the Accusump is down to 1/3 (or whatever fraction you like) of it's capacity.

You're right about routing the line outside the cockpit and that is how it's currently routed.

I've thought about that, but decided against it. Imagine taking a fast turn at the limits of adhesion when a sensor failure or loose connection causes to ECU to cut spark and send you into the wall. In trying to save the engine, you could lose the whole car! I'm just using an extremely loud buzzer.

M.

Builder

I have an Accusump and 35psi electronic valve that I am going to install in the '97 I purchased on Thursday. It's my first Miata adventure and I am looking forward to learning about the cars. The goal is a barely street-legal track weapon. Probably headed for turbo setup, then a V8 swap.

The way I envision this working is as follows:

The valve will open at 35 PSI. So, anytime engine pressure is less, the valve will be open and oil will be free to flow between tank and engine. True, but it doesn't mean any oil will actually flow. It depends on the pre-charge air pressure in the sump vs. the pressure in the engine. If you have 20 psi in the pre-charge and 40 psi in the engine, one or two quarts flowing into the sump might equalize the pressure. This is a variable I'll have to play with to get it right. Canton should be able to help with the baseline numbers.

Also, with the electric valve, just 'cause the ignition is on (engine off), it doesn't mean the valve is open at low pressures. The electric switch installed on the panel will arm the system...just like turning on a manual valve.

At start up, open the valve (switch on). Get pre-start oil pressure and start the engine. Turn the switch off (after recharging the sump) for general driving around town. If you get a little spirited, flick the switch on (or open the manual valve). Switch off before shut-down to capture oil pressure for next start-up.

At the track, leave it on while beating up on Corvettes. Switch off turning into pits to capture oil pressure for next start-up.

I think the trick is to log and understand the oil pressures across the RPM range to see what the engine is producing (what it needs at different RPMs). It may be necessary to modify pre-charge air pressure in the sump for track events.

As stated in this thread, the system should function when you start the engine and under heavy G-loads. Maybe the right answer is to connect the electric valve to a two-axis G-meter and timer. At 0.75G (i.e.), the valve opens for 30 seconds...or something like that.

Edited to ask: Are there no ports on the 1.8L engine block to access the pressure-side of the oil galley?

Savington

iTrader: (31)

..uh, yeah, it kind of does mean that oil will actually flow. Pressure differentials are not magic. If you hook up a 40psi oil container to a 20psi system (engine), oil will flow into the motor until the two systems equalize.

Why would you even bother with a switch? The beauty of an electronic Accusump is that you never have to even think about it - you hook it up to the ignition circuit and fuhgeddaboutit. You're way, way over-complicating it.

-At start up, you pause at "on" for a moment to pre-oil and then start the engine
-While the engine is running, the Accusump maintains charge
-If oil pressure ever goes low, the Accusump discharges for up to a minute (with a 3quart system)
-When you shut the car off, the car maintains oil pressure until just after you've shut the key off - which means that you've automatically charged the Accusump for the next time you start the car. No need to close a manual valve or hit a switch before shutting down.

This demonstrates a fundamental misunderstanding of why the Miata motor "needs" an Accusump in the first place ("needs" because IMO it doesn't need one). It has absolutely nothing to do with high G-loads - Miatas only lose oil pressure under high RPM hard braking. If I can get through turns 1 and 2 at Calspeed at 158mph in my stock-pan, no-baffles turbo car without losing oil pressure, there's no situation physically possible that will cause a Miata to lose oil pressure in a corner (unless you either don't have it in the first place, or a catastrophic failure occurs).

Hooking it up to a g-sensor also negates the major benefit of running on a BP motor (IMO): prevention against catastrophic failure. If you have it on a G-meter switch and your oil relief valve sticks open, or the pan pickup works its way loose, then your Accusump won't fire and you'll lose the motor.

I would put a 1qt Accusump somewhere near the engine bay, like in the rain gutter or in the passenger footwell or something. Hook it up to an electronic switch, and hook up some sort of pressure switch or trigger. If the Accusump fires, you see a light come on somewhere on the dash. If it comes on while under braking, fine. If it's on at any point while you are on power or on a straightaway, shut the car down ASAP and diagnose oil pressure loss.

No, not big enough to feed the entire system with pressure. Trackspeed's preferred method is to tee into the oil cooler return with a check valve.

Builder

Let's see, where to start...

Exactly what I am getting at. You missed the point. It won't flow at all, if the switch is in the off position. It will flow the wrong way, if your pre-charge is low. You might not want to activate the system, if you don't want the sump oil to dump into the oil system while you are idling and your normal pressure is 10-20 psi. And, short of the pre-oiling function, you wouldn't need a valve at all.

Maybe, but I don't think so. You're not thinking of the slow vs. quick-filling electric valves. The beauty of an electric (EPC) valve is that it fills quickly and releases at a specific pressure...not just that it activates with the ignition. I don't want three extra quarts of oil dumping into my oil pan every time I pull up to a red light because my oil pressure dropped below the valve's regulator pre-set. I'll just turn the system off with the toggle switch. And, if you use the "regular" electric valve, it doesn't have a quick enough fill-rate for track use. To suggest using that valve on the track would be, well...ill-advised.

Right.
Nope, it only charges as long as the engine-side oil pressure is above your pre-charge pressure and only charges quickly if the engine-side oil pressure is above your (EPC) valve setting.

Maybe I am misunderstanding you. If your oil pressure, at idle, has dropped below the valve release point, the sump is dumping the reserve back into the engine at idle...unless you close the valve and save the pressure.

Starvation comes at high RPM and heavy G-loads, so you want to put a strong pre-charge in the sump to support the oil needs at higher RPM. I don't yet know what PSI to expect at 4k, 5k, 7k RPM. Haven't done the data logging yet.

Uh...no need to close a manual valve? So, when the engine shuts off and the oil pressure is gone from the engine, the Accusump will keep it's pressure without a closed valve? Again, I guess I don't understand. Or, yours works differently than mine. I have an Accusump and it won't keep its pressure, when the engine is shut off, unless the valve is closed (manually or electronically activated).

I'm not sure what's demonstrated here. I haven't experienced low pressure yet...just got my car last week, but... Are there not many folks that have sited loss of pressure due to G-forces in this thread? You know the old saying, "If ifs and ands were pots and pans, we'd all be in the kitchen." Anything can go wrong. If the oil line falls off a turbo, if you put antifreeze in your crank case, if your brakes fail, if, if, if... etc., etc... The chance of any system saving your engine, if the oil pickup falls out, are slim to none.

I think you are mistaking speed with G-force. You might have the fastest Miata on the planet, but I can pull "big" G-force at 30 mph. A driver may have more opportunity to extend the time frame and affect of big G-forces, when starting at 158 mph, but 1-G is 1-G is 1-G, at any speed. And, it doesn't take but a few seconds to oil-starve an engine into a damaged engine...especially at high RPM. It sounds like many here are pulling more Gs at lower speeds, possibly, than you are at higher speeds.

Now I'm thinking a pressure switch with G-sensor is appropriate...yes, that's even more complicated.

Canton The EPC valve on the Accusump IS tied to a pressure switch. Additionally, you could add an indicator light or buzzer on the pressure switch to let you know when the valve has opened...and connect it to a data logger...and a relay to activate an air horn.

hustler

iTrader: (6)

How many people are popping these motors due to oil starvation? The answer was "0" the last time I checked. Are we now suggesting $3500 for an oil system on a $2000 motor?

I look at Gary/TDR and all the locals who continually run these cars for years and years without blowing up motors.

Builder

That's good! I don't want to deal with the same crap I went through with the LT-1. Seems like a bunch of people here have issues, though. Gladly, I had not heard Miatas had oil problems.

hustler

iTrader: (6)

I don't really know what I'm talking about, but I thought the oil starvation problem came from braking. If this were occurring on the loud pedal I'd be worried.

Builder

I definitely don't know anything about Miatas. But, dynamic G-force loads affect all vehicles along vectors with components in all three axis, at all times...negative and/or positive. Braking could be considered a negative-G to us, but it's the absolute value of the forces that are of concern (to the oil pickup). If 1G under braking will uncover the oil pickup, how far from 1G, to the right or left, or in acceleration, can it handle?

It does sound like braking, or combined braking and turning, are the only major concerns, though. Having only had the car for a few days, I can't speak from experience at the track. A number of others seem to have had low-pressure experiences. Although, it sounds like others are of the opinion they have lost motors due to low pressure events.

Savington

iTrader: (31)

If your pre-charge is lower than the set point, you want to flow the "wrong" way to bring the pre-charge up for the next time you use it. If your pre-charge is wrong, then it's wrong and you should fix that. Setting precharge at 20psi completely negates the reason for having the system in the first place since it will never work correctly.

All I've ever dealt with is EPC valves, I was not even aware another type of electronic valve existed. If I refer to an electronic valve, you can safely assume that I'm referring to an EPC valve.

I meant normal running conditions. Correct oil pressure, no issues. In normal operating conditions (i.e. healthy oil pressure), an Accusump should do nothing except look pretty and refill itself.

I'm not talking about idle, I'm talking about OP loss under braking. You keep bringing up the issue of the system dumping at idle when it shouldn't be. It's a very simple issue to solve - set the EPC higher than your idle oil pressure.

My point was that there's no need to close a manual valve if it doesn't exist. This is the beauty of electronic valves - they close themselves when you shut the car off.

No, there are not many folks that have cited loss of pressure due to lateral G-force in this thread - in BP motors. Plenty of folks have documented oil pressure loss due to lateral G-force in LS motors, even with baffled pans and such, but I haven't heard anyone with an issue in Miata motors. Several people discussing oil pressure drop under braking, and one excellent graph showing how a shimmed oil pump doesn't help it, but nobody with lateral G-force starve issues.

Not at all. I mentioned the speed to quantify the g-force - 100mph around Calspeed 1/2 is a cakewalk, but 158mph in those corners is probably the most lateral g-force you'll achieve on any track in the state. The combination of banking, obscenely high speed and downforce makes for exceptionally high g-force.

Let's look at another example - Turn 2 at Willow Springs. A conservative estimate has my winged turbo car getting through that 450' radius corner at around 95mph, which is somewhere north of 1.3g. That's a sustained 1.3g, too, since the corner has over 180* of duration. 10 seconds of 1.2-1.3g cornering - and no oil pressure drop. I'm going to go ahead and say that if 10 seconds of 1.3 lateral g doesn't make it drop, you don't need to worry about it.

scottyd

What a waste of time and money. Seriously.

Wait until you stick a V8 in there and then call Trackspeed for a properly setup Accusump.

You don't need to do anything for the 1.8

If you feel the need to, do what Bob did.

Builder

Yeah, I won't jump to conclusions. But, I read every post in this thread and it sounds like it could be an issue. I'll wait and see what my data logging shows. Believe me, I'm all for not needing external oil system stuff...even though ordering the oil filter relocation kit. The less lines and fittings, the better.

bbundy

I have torn my motor apart and I have seen hammered rod and main bearings twice. I don’t have proof I am highly suspect of oil pressure loss under hard braking could be a contributor. I’m not too good at staring at my oil pressure gage while trying to drive fast but I am pretty sure I have seen my gage dip near zero under hard braking and along with high rpms seen while downshifting I don’t think this is a good thing. I have also seen the pressure flutter badly getting back on the throttle coming off a hairpin after hard braking from 110 mph into a second gear hairpin. I am theorizing the braking got all the oil to the front of the pan away from the low part of the sump and the pickup then my transition into the corner didn’t allow it to come back fast enough and re-prime the pump and get it flowing again.

This is what I want to eliminate with baffling and an Accusump. I didn’t have a problem until the car got to where it probably has about the best braking put on a Miata, 3 ½ times the stock HP, a decent amount of aero down force, and I started driving it in a manner quicker than the average track day warrior could.

Bob

Builder

I've gone through a couple of engines (Impala) due to starvation and don't want that to happen to my new baby! I figured out what happened with the first engine and subsequent rebuild. The engine had a "High Flow" pump. So, under heavier loads, it emptied the pan more quickly...even with the extra quart of goo. And, I was G-forcing the oil away from the pickup, starving the engine with higher RPM downshifts.

I've changed driving technique to exclude downshifts to more than 2500 RPM, which seems to have eliminated the problem. The Accusump was originally intended for my other car and why it's on the shelf. Glad because it's going into the Miata in a couple of week.