p1prodrive

iTrader: (3)

iam interested to see the outcome on monday

Alan Jeffery

We'll take a look first thing...

jd5217

thanks Alan, hope the outcome is the right one.

David_Wallis

Thats worrying!

Alan Jeffery

I wouldn't let it worry you too much, unless you have one fitted, in which case what's your experience with it?

jd5217

i may pop down tomorrow Alan, if that is ok.

Alan Jeffery

JD, you can move in Mate!

jd5217

got my own mug yet?

Alan Jeffery

I'll organise it. Please don't let your hairy dog sleep in my office, although your missus would be just fine!

jd5217

I will pass the message on to her.

dynamix

iTrader: (3)

I wonder who will be on the phone to Cosworth first

Area 52 Autosport

The work/research on this product was done by Cosworth USA, once they wake up they will be informed of our findings.

Will up date in due course.


Jase.

p1prodrive

iTrader: (3)

waiting....lazy those yanks lol !

Alan Jeffery

Well, we would have had JD's car equipped by now, although as it transpires, you can't drop the sump with the RC headers on! Hot damn. It looks like it would fall off until you realise it won't. Normally of course, there's no reason to remove the sump at all, unless the motor's out. No matter, we'll have it done by tomorrow morning, and go from there.

jd5217

thanks for the update Alan.

Cosericworth

Hi Jase,

This is Eric Hsu from Cosworth USA where the baffle plate was designed and developed. A colleague of mine in the UK brought this thread to my attention. I gave you a call at around 6:10pm (Uk time) and the number just rang and rang. I did not have an opportunity to leave a message.

To answer some questions, the baffle plate was developed out of necessity when some of the more serious club racers and time attack cars complained of excessive blow by, worn/spun rod bearings, pump cavitation, etc. The multiple catch can/drainback configuration certainly helps to keep oil in the sump, but the answer was to prevent oil from sloshing into the heads and pumping out in the first place. This is where the Cosworth baffle comes into play. Our baffle plate was developed in conjunction with two of our serious Subaru customers here in the US who compete in Time Attack. Using our 32 years of race engine experience (32 in the USA) and field testing at the tracks, we developed the current baffle plate design that has significantly reduced the blow by problem and keeps the oil in the sump in all but the fastest cars (which need a dry sump).

Enough of the baffle's background. As for your/Dynamix's problem: I cannot imagine what the trouble would be. The pickup bolts directly to the block and the baffle does not interfere with this connection. The only way for there to be low oil pressure would be if there were no oil in the pan. All of the oil would have to be pumped out of the sump and not enough oil draining back into the sump. Since this baffle has been proven on multiple time attack cars and numerous street cars, I find it hard to believe that the baffle would be causing such a problem. Perhaps it is some other coincidence? We have sold over 50 units in the past 10 weeks and have not received a single complaint to date.

Reading Dynamix's blog, I see that he reports 10psi oil pressure at idle. Jase, you mention it was 6psi with the Cosworth baffle. Just so we are clear, could you please specify? Just as a reference, the factory specifications are 14psi @ idle and 43psi @ 5,000rpm (direct from the service manual). Any additional data we can get would be helpful. We would like to ensure that our product is trouble free for everybody. If we can learn from this particular situation, then we can perhaps make our product easier to install and then everybody wins.

I just had one of our test cars look at their datalogs for some pressure information. This engine uses the Cosworth high volume big rotor oil pump, and Mobil 1 15W-50 oil. Here's what was reported:

Idle = 37psi
3k rpm = 106psi
5k rpm = 115psi
7k rpm = 106psi

The team shimmed the pressure relief valve spring on their own (this is why the oil pressure is so high), but the point is that there are no oil pressure issues at idle and above (and no drainage issues).

The other development car has raced at Laguna Seca, Thunder Hill, and a couple others without any oiling issues. Laguna Seca has severe elevation changes, off camber turns, high speed sweepers, etc. and they have not had any oil return problems. It is currently the fastest TA Subaru in the states.



Mike Warfield and the GST team is building a second TA Subaru and they are going to be using the Cosworth baffle plate again.

I will attempt to give you a call tomorrow morning again. Hopefully, I can help you/Dynamix to resolve this problem.

Thanks,
Eric Hsu
Cosworth USA

johnfelstead

Hi Erik, Just to be acurate, the factory spec is 14psi @ 600rpm, not idle. Idle is set at 700rpm (+/-100) on the US spec car, the UK spec cars are set to idle at 750rpm (+/-100) so you would expect to see closer to 25psi as a worst case scenario in reality at idle in the UK. (the manual figures are very conservative too IMHO)

Those specs are with the oil at 80 degrees, so fully up to temperature, you should see significantly more presure when the oil is cold (probably 35psi or so at cold idle on 10W/60 oil) as was the case when the initial tests were carried out and the 6psi reading was taken i would expect.

Based on what you say though, i think it's well worth them refiting this baffle plate for a second test, just incase there was a problem with the o-ring seal on the pickup pipe, which would have been disturbed when they removed the baffle plate for the second test. It may be that the pick up pipe was catching the baffle plate so not sitting flat (i am not saying that it was, just that it's posible for that to happen so worth eliminating). That's what i would do anyway.

frayz

iTrader: (7)

Interesting, this thread could well determine wether or not i buy one of these baffles.

dynamix

iTrader: (3)

Thank you for taking the time to respond Eric.

The 10 psi I mention was my casual observation, the 6psi that Jase states is fact. Both were with oil at around 70-80 C although I was not watching the gauge at the time. The idle on my car is set to 800rpm hence why we were very concerned by the low pressure on idle and the characteristics of the dropping pressure when revved as if oil was being trapped above it.

Have you any cars running this tray on the standard sump?

If it is a case of oil volume in the sump that is causing the drop in pressure, which is cured by the high volume sump pan then I could see why the larger volume pans would not see the issue as there is enough total volume in the system to allow for a couple of litres to delayed in returning.

John, from what I can see of it, the pickup cant catch the tray as it fits through a nicely shaped hole to join with the block. The tray is essentially free to move about whilst in this configuration until sandwiched (and located by the bolts) between the sump and the block. The O ring was present and showed no signs of an incorrect seal when removed.

jd5217

interesting response from cosworth.

Area 52 Autosport

Hi Eric,

Thanks for the prompt reply

A little more info on Dynamix’s car:

2006 EDM STi.
2.5L built short motor (new)
Stock sump & pick up arrangement
Breather system includes a -10 return to the sump (via the oil drain plug).
OEM Oil Filter
Millers CRO 10w-40 oil

The motor is our Stage 3 unit and as such is blueprinted. Everything within this short engine is measured and measured again, we do not use Plasti-gauge to estimate tolerances. The crank is modified from the stock 79mm unit, but not to the extent were it shows a measurable difference in oil pressures (at low rpm). Our oil pumps are all also measured for rotor clearance.

Oil pressure was measured by an Autometer mechanical gauge (we always fit this gauge on first start up on new motors), we also had Dynamix’s SPA digital pressure gauge too. This gauge showed 6 PSI at circa 80c. The Autometer’s resolution at low pressures isn’t so good, but certainly displayed less than 10 PSI. At 3000 rpm it was no more than 45 PSI (warm, on both gauges). They both took the feed from the stock pressure sensor location.

Now a loss in oil pressure is usually dictated by one of the following (as I’m sure you are aware!): Worn crank bearings/journals, large clearances (as previous or from mistakes during initial assembly), major oil leak (missing gallery plug etc.), worn oil pump or blocked returns.

In this case we can discount all of the above usual suspects. The fact that oil pressure is ‘normal’ without the Cosworth plate adds weight to this. I agree with John in regard to manual figures being very conservative.

The other possibility is the pick up becoming restricted, either from foreign body material blocking the screen (not the case here) or a basic lack of oil. During this ‘test’ we used 2 filters & 3 lots of oil (not all at the same time ). Certainly the correct amount of oil was in the engine at all times, but I am suspecting not ‘enough’ in the sump while the engine was running. Each time the car was started oil pressure was higher (I forget the exact figure) for the first few seconds then would drop to the above mentioned figures, as I’m sure you would agree this points to a drainage issue.

You mention it was developed in conjunction with two of your Time Attack customers, are they running the later style stock sump & pick up? You mention one team runs your high flow pump with a shimmed relief valve, what does the other car run? (I suspect this not to be an issue though)

Yesterday was the one day we weren’t working late, sorry I missed your call. Do you have a number I can contact you on? (I’m out of the office all day today). PM if you prefer.



Jase.

Area 52 Autosport

John,

If it were one of our own cars than I would be more inclined to refit the tray. I would also like to try it without the flaps, just to see what happens. However as this is a customers car then it is not my call, and TBH, based on what we have seen so far, not something I would recommend.


Jase.

johnfelstead

I can see that would be the case Jason.

You say the presures were measured hot, does that mean you ran the engine at 6psi for 15 minutes? or was the presure higher when cold?

dynamix

iTrader: (3)

i dont think it was quite that long John but yes the pressure was falling from cold idle.

Area 52 Autosport

IIRC initial start up pressure was circa 60 psi. On first fire up we never let cars idle, revs are varied between 1500rpm and 2000rpm. The engine was initially ran for around 6-7 mins, during this time we were doing the usual checks. Over this period it dropped down to 6 psi - at that point (believing the gauge or sender to be faulty) we put our own mechanical gauge on and restarted the car, no change so we immediatly stopped the motor and started looking for the likely cause.

Jase.

jd5217

could the narrow sump be causing issues?

Area 52 Autosport

Right, rather than leaving this matter hanging in the air we decided, after much deliberation, to refit the baffle tray.

And the results are.... exactly the same.

On starting pressure was only 40 psi (as opposed to 90 psi) and after less than a minute, infact the ECU was still running the ‘cold start routine’ (and rpm was circa 1400rpm) it had fallen to 30 psi so we decided to call it quits.

It certainly looks like the Cosworth baffle plate in this application is baffling the wrong way


BTW do you need a new parts tester?


Jase.

jd5217

you been in contact with cosworth again yet?

Area 52 Autosport

jd,

No we haven't spoken to them yet.

Re: 'the narrow sump' - I don’t believe so. A capacity increase would possibly cure the issue. However in doing so (designing & fabricating a new sump) there would be less need for the baffle plate. It would be interesting to see if purposely overfilling with oil changes the results we have measured.

Duncan's already had 4 oil changes and his car has travelled less than 40 feet. Brings new meaning to the phrase "one careful owner" Must remember to stamp his service book

jd5217

hmmm will be interesting to see the results on mine then.