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-   -   Oil surge/starvation myth? (https://www.scoobynet.com/general-technical-10/1034004-oil-surge-starvation-myth.html)

A1AXX 18 January 2016 11:39 PM

Oil surge/starvation myth?
 
After searching a lot, all I have found are failures due to the oil pickups cracking or upgraded pumps etc

What is the myth with oil starvation from track use causing bottom end knock? I know oil starvation will cause bottom end knock, but when has it actually been caused by cornering and not some other issue?

My car has been on track with the previous owner, has the toucan, so imagine the oil pressure was fine at castle combe as it has the wee alarms etc

I know guys that have ran with no baffles/windage tray and later with rcm windage tray, with no bad results before or after. I can see the killer b setup is the best going, but may be only available from the US.

On track I am a spirited driver, running ad08rs, hsd coilovers, whiteline arbs etc etc. Use good 15w50 oil. Engine is a 2.1.

Is there real evidence that the mods to the pick up/ windage tray or sumps really make a difference to oil pressure drops? Or do the pressure drops even get to a dangerous level?!

Im just not one for wasting time and money where its not needed, think many can agree with that. So many different things you could do for track prep, where does the prep stop and the fun begin!!!

ditchmyster 19 January 2016 08:47 AM

Without sounding too obvious, it's to do with the layout of the flat four, is the way it was explained to me, the cornering forces keep and push oil to the heads / cams so causing starvation at sump/crank level as there MAY be moments when there is very little or no oil for the pick up to suck due to it's location in the sump. This isn't going to cause immediate failure but over prolonged periods of track use will cause excessive wear on the big end shells, so shortening engine life.

I'm unsure how true this is in practice, but when you think about it it seems to make sense, ultimately it's going to vary from one engine to the next dependant on use and maintenance, but if I were planing on working my engine hard on a regular basis I'd be doing everything to ensure it has the best chance of survival in a harsh environment.

A1AXX 19 January 2016 09:22 AM


Originally Posted by ditchmyster (Post 11784793)
Without sounding too obvious, it's to do with the layout of the flat four, is the way it was explained to me, the cornering forces keep and push oil to the heads / cams so causing starvation at sump/crank level as there MAY be moments when there is very little or no oil for the pick up to suck due to it's location in the sump. This isn't going to cause immediate failure but over prolonged periods of track use will cause excessive wear on the big end shells, so shortening engine life.

I'm unsure how true this is in practice, but when you think about it it seems to make sense, ultimately it's going to vary from one engine to the next dependant on use and maintenance, but if I were planing on working my engine hard on a regular basis I'd be doing everything to ensure it has the best chance of survival in a harsh environment.

Yea I see what you mean.. I can see why the rcm/cosworth tray can cause problems.. If anything I will try to get a hold of the killer b one. Dont want anything restricting the path to the sump you know.. I'd love to see comparisons of the different sumps.. Ej20 and 25 ones are different arent they. Ones flat and the other is smaller and deeper

ditchmyster 19 January 2016 09:39 AM

Spec C sump is a popular up-grade, I think they come baffled and are bigger with a slightly different shape too, but not 100% on all the details.

As for the prep thing, it's one of the many reasons some of the regular track day boys go for the the Spec C as it's built for the job out the box, with gearbox and engine oil coolers and anti surge fuel pump amongst other things, works out cheaper in the long run and the car is worth more once you've finished canning it than something like a track prepped standard STI.

A1AXX 19 January 2016 10:25 AM


Originally Posted by ditchmyster (Post 11784818)
Spec C sump is a popular up-grade, I think they come baffled and are bigger with a slightly different shape too, but not 100% on all the details.

As for the prep thing, it's one of the many reasons some of the regular track day boys go for the the Spec C as it's built for the job out the box, with gearbox and engine oil coolers and anti surge fuel pump amongst other things, works out cheaper in the long run and the car is worth more once you've finished canning it than something like a track prepped standard STI.

Ahh didnt realise they had a box cooler. Id love a spec c.. Almost spent spec c money buying the bug! Luckily as I haven't taken the hit building it, I can always break it if I wasn't going to get good money for it, about the only way I could justify it to the mrs!!

wms-racing 19 January 2016 10:49 AM

I always recommend a baffled sump for track use, I've been rallying an Impreza in the woods since 2004 and only ever used a std sump, never had a problem. But the forces on track are differn't. Speak to Alyn at AS Performance for a very cost effective modified std sump, as per Prodrive group N, but improved.

Steve Whitehorn 20 January 2016 09:07 PM

I give it death on track and I have a Prodrive Group N baffled sump for 6years now.
It has served me well and I have never had any starvation problems

A1AXX 20 January 2016 09:21 PM


Originally Posted by wms-racing (Post 11784866)
I always recommend a baffled sump for track use, I've been rallying an Impreza in the woods since 2004 and only ever used a std sump, never had a problem. But the forces on track are differn't. Speak to Alyn at AS Performance for a very cost effective modified std sump, as per Prodrive group N, but improved.


Originally Posted by Steve Whitehorn (Post 11785751)
I give it death on track and I have a Prodrive Group N baffled sump for 6years now.
It has served me well and I have never had any starvation problems


I take it the grp n is the smooth top plate and the modified sump is smoothed to copy the prodrive one?


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