jd5217

as long as i get to put my cosworth sticker on the car I am happy LOL

dynamix

iTrader: (3)

You are a big kid mate

I'm gutted I dont get one

But hey, its xmas eve - I am in a good mood

David_Wallis

Classic

Alan Jeffery

Dynamix - I can't ignore a plea like that mate.
Send me an SAE, and a sticker will be winging its way to you.

johnfelstead

I can if the flaps are being sucked shut.

As an example, you have a similar surface area for drainback on something like a small block chevy for the oil returns from the heads and above the camshaft/lifters, and when you run those on a racetrack one of the bigest problems is getting the oil back into the sump, they tend to fill the heads and lifter valley up dropping the sump level dramatically. To get over this you have to do a lot of internal work to polish the returns, take out any rough casting and open up the return paths as much as posible.

There is a huge amount of oil flow going on inside any engine, it's recirculated at a stagering rate. The stock STi oil pump flows 47 litres a minute at 5000rpm, that means it would take less than 6 seconds to completely empty the sump if the return drainage was restricted.

This is why the proper baffled sumps have direct feed to the pickup from above and use a surge tube around the pickup, so you always have a columb of oil above and around the pickup. The cosworth item may stop oil surge out of the block breather, but it is also introducing an extra restriction for the oil to overcome in getting to the oil pickup. Below is what a proper baffled sump looks like, a lot of attention is payed to getting oil to the pickup pipe with no restriction.

banny sti

iTrader: (68)

Where do I get me one of them, looks soooo lurverly lol

Banny

frayz

iTrader: (7)

Interested too. Where from and how much please

Andy.F

The relief valve is opening from around 2000 rpm though so at least 50% of that flow you quote at 5000rpm is simply recirculating and not being drawn from the sump.

Can you explain how you think the flaps are being sucked shut at idle speed

johnfelstead

Unfortunately i dont have a perspex block and sump to hand, so cant tell you at what point, if at all, the flaps are being sucked shut. Why do you think it cant be sucked shut at idle though, if you think it might be at higher rpm? From what Mike posted we do know that one of the flaps was sucked shut and in fact sucked through the plate, that will take a fair suction force to achieve. The crank is still rotating 12.5 times a second at idle, which will be generating some airflow over the top of that plate.

What hasnt been answered so far which i asked earlier is should the OEM windage tray be used in conjunction with this plate?

You can make your own baffled sump or buy them from a few supliers off the shelf, this thread isnt really the place for listing them.

Andy.F

I would put money on it that the flap can't be sucked through the hole by windage forces alone. Don't you think Cosworth may have tested these trays before selling them ?

Unlike many V8's the scoob crank is quite far above the sump pan, on a V8 as you know ideally you need a windage or scraper tray, not sure this applies to the subaru in the same way.

dynamix

iTrader: (3)

No Andy, they havent tested them on a std sump let alone a narrow 06 EDM or JDM sump.

Andy.F

johnfelstead

A windage tray is stock fit on the Subaru engine Andy, i would think mainly to prevent oil being thrown up the bores more than anything else.

I haven't seen Cosworth come back with any testing on stock sumps yet.

Andy.F

Yes I know, I have a modified version and a custom baffle on my own car which works well. I was however genuinely interested in the Cosworth one and wasn't willing to accept that it just doesn't work !

How are the flaps controlled on that sump you posted a pic of ?

Alan Jeffery

The standard windage tray doesn't fit with the baffle plate.

johnfelstead

My sump uses two styles of flaps and a surge tube.

The top two flaps are alloy that forms a double padle with a central hinge, under no cornering G or surge load the flap is open, when cornering left the right flap closes and the left stays open, cornering right it works in the oposite direction.

What you cant see well from the pictures is that at the rear the large apature behind where the alloy plate stops has a vertical wall, with two rubber flaps similar to the cosworth items. You get oil down that chamber, under normal load these flaps open as the oil pools at the bottom and flows into the main chamber, under hard acceleration those flaps close so oil cant get out of the main chamber.

The most important part of the design is the surge tube that surounds the pickup. This has a small gap at the bottom similar in height to the distance between the oil pickup entry port and the sump floor, to allow oil to flow from the main baffled chambers to the pickup. The way the surge tube works is pretty simple, it gets a feed directly from the top (which is why it has sloped feeds into the tube) and also from the bottom via the main baffled chamber. Under cornering G or accel G you efectively get two anti surge effects, firstly the oil being fed from the bottom cant surge away enough to uncover the bottom feed to the tube because of the baffling, secondly the oil has to climb back up the surge tube in order to uncover the pickup.

Surge tubes like this are often used in aplications with low viscosity fluids like fuel because of their efectiveness in resisting being uncovered at the bottom under high G. I used to run my lift fuel pumps on my cossie westfield using the same design in the fuel tank for the same reasons.

Cosericworth

I spoke to several customers (shops) who have used the baffle plate both with the factory twin scroll sump and the 2004 non-twin scroll factory sump. They report no problems.

The Cosworth "big" sump is 1.5L larger than the factory sump. If in fact the oil was not draining back into the sump and staying above the baffle plate, all the large pan would do is delay the oil pump from sucking air for a short time. Stock sump or big sump, this drop in oil pressure has not occurred with any of our customers.

As for the vacuum sucking up the flaps - this just isn't possible without some kind of unusual coincidence. There are holes and slots in the baffle plate that are permanently open (not covered by rubber flaps). The top side of the baffle and the bottom side of the baffle are not individually sealed chambers. Therefore any vacuum present on top of the baffle plate is also present below the baffle plate. This also applies to any "vacuum" caused by windage of the crankshaft.

We are in the middle of conducting our own test on a car. However, even if we do not run into an oil pressure issue, we would like to find out what is happening to Dynamix's car. Too bad we are on the other side of the world. Regardless, I'll report back with the results of our testing.

bren@apex

iTrader: (20)

Very interesting read.

How big a problem is oil surge on STi6s, specifically one running around 330bhp on a stock engine. The cars full weight and not used on the strip, just track with track tyres (R888s etc). I have no plans to run slicks but might have a go one day.

Do I need to worry and therefore start looking for prevention before I face the cure?

Do I also need to invest in a breather system at the moment or is the standard system sufficient for my needs?

Sorry for the slightly of topic questions but it is related to the thread

Alan Jeffery

I'd say there does come a point when you have to think about it, but it isn't cut and dried! The following is an attempt at keeping it simple, so I can understand what I'm saying, so please don't nit pick!
You may feel that it's a dynamics issue, (not Dynamix ! ) where the fact of a fierce acceleration in a straight line from a standing start is likely to result in oil squirting up the breather system due to gravity.
Alternatively, where cornering forces are starving the pick up of oil, also due to gravity. In that instance, the use of slicks is the factor, rather than engine power.
The other issue is crankcase pressure forcing oil out of the breather, due to blow by induced by high boost.
I'd say the trigger to action comes when it's obvious you have a problem of some kind with the breather, or when you are starting out with the intentions of competitive motor sport, in which case you are obliged to deal with breathers and catch tank systems anyway.

dynamix

iTrader: (3)

Bren is this your Time Attack scooby?

I would solve the issue before it bites you - 888's will be the reason for any surge on track.

SleeperSy

Here are some pics of my Subaru group N twin scroll baffled sump if its of any interest. I did not post IMG links, as it would fill up the thread.

http://i60.photobucket.com/albums/h2.../GrpNsump1.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump2.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump3.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump4.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump5.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump6.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump7.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump8.jpg
http://i60.photobucket.com/albums/h2.../GrpNsump9.jpg
http://i60.photobucket.com/albums/h2...GrpNsump10.jpg
http://i60.photobucket.com/albums/h2...GrpNsump11.jpg

Sleeper

johnfelstead

Hi Bren, in your aplication power wont be the deciding factor, it's how much cornering G you will be able to generate and how much oil is in the heads.

I've driven thousands of miles on track in STi5's with your power levels and had no surge issues at all with the stock sump, but i was using normal road tyres. When i started to use A048R's it started to throw a lot of oil out of the breathers which meant a recirculating system was essential.

As soon as you start to generate enough G to force the oil in the heads to cover the cam cover breathers you get oil being expelled under presure from the crankcase gases. With sustained high rpm you also get more oil staying in the heads so it's worth running slightly more oil in the sump, but only do that if you have a recirculating system, if you overfill the oil with it plumbed into the inlet you will potentially destroy the MAF sensor and fill up the boost control solonoid.

For your TA car i would sugest you sort out a proper recirculating breather system, and i think it's wise to fit a baffled sump just for long term safety, you can just about get away with the stock sump until you really start to lean on the R888's capabilities, which can generate serious cornering G once you get the car sorted.

You get a diferent problem with drag launching, which is oil out of the block breather, if you fit a recirc system that problem is fixed too. It's not going to be a big issue on your car at the moment as the sustained G once launced isnt that high.

bren@apex

iTrader: (20)

This is my TA car, the Impreza is to test and demo the Impreza coilovers and brakes that we sell We do most testing on track. As it stands I might well be using the Impreza for the first round of TA, our S14 is in the exact state as shown in the above pic and times getting on.

Ill start investigating the breather system and sump. Any recommendations for off the shelf breather systems? Our cars just destroyed its turbo so we will do a number of other upgrades whilst having that replaced. I dont need big power with this car, just reliability.

dynamix

iTrader: (3)

sorry to drag this one up again.

This seems an ideal set up unless cornering off boost (which happens a lot) and the breathed oil is then fed into the inlet.

bren@apex

iTrader: (20)

Whats a better approach if you do corner off boost? I dont know how you can avoid cornering off boost?

dynamix

iTrader: (3)

Bren - the RCM catch can has 3 inputs and I have the breathers from each head and crankcase breather attached to these without the PCV - so the vapour (and sometimes more than vapour) goes into the catch can. Any air is vented well under the car.



(excuse the filthy engine bay)

I have also fitted a drain pipe direct from the catch can to a banjo bolt replacing the sump plug.



Therefore any oil collected in one corner is fed back into the sump to replenish levels in time for the next corner.

The drain was only fitted as I was filling the catch can up that I had within 3 laps and once ending up spinning on my oil ... oops

bren@apex

iTrader: (20)

And you were filling the catch tank because the oil was pouring down the breathers, not through excessive vapour breathing because of blow by? Ive just not noticed my car smoking (until the turbo let go, its now a monster smoke generator!) nor any indication of excess oil being fed into the air intake. I dont claim to be the worlds greatest driver but I have some on track experience and do run track tyres.

Whos RCM out of interest?

jd5217

as yet not used mine on track so dont know if there will be an issue.

mainly used for drag racing at the moment.

dynamix

iTrader: (3)

Yep - the catch can would get nothing apart from a small amount of condensation on the road no matter how many liberties I took with the loud pedal. It was mainly on long right handers.

RCM = Roger Clark Motorsport

Tidgy

RCM - Rodger clarke motorsport (i presume)