I have been on a trackday at Hockenheimring 2 weeks ago and in lefthanders my oilpressure goes down. In the attached picture you can see this pretty good (blue means no oil pressure):
Engine is bone stock, but pretty worn (150hp on clutch). At the moment I am rebuilding another 2.5, and want to prevent oil surge on the new engine. Any tips (including pictures) what to change on the oilsump to get rid of this problem?
By the way, here a video of our fastest lap:
[youtube][/youtube]
Wasn't that bad for our very first time on the track.
Thanks for your advice!
Cheers,
Philip
Last edited by kyuss on Sat Nov 21, 2009 4:28 pm, edited 1 time in total.
Accusump sounds interesting, but it only fights the symptoms, not the cause of the problem. I read the other thread, I don't think a bigger oil pump will help significantly, baffled sump will be the way to go first.
Does anyone have pictures of his baffled oilsump? Just need an idea how to rework ours... I am thinking of welding some aluminium sheets in at the right places, but am not exactly shure where the right places are.
When the sumpmods don't help us with the oil pressure we surely have to go for the Accusump.
Our car is a '86 325i 2door, prepared for DMSB Group G (we mainly do slalom races, something like this:
[youtube][/youtube]
Group G means, that everything has to stay stock, only mods allowed are suspension, and safety stuff like seats, cage, harness.
Tires are Toyo P888 (although Bridgestone RE55S have proven to be better, but are much more expensive as well )
Suspension consists of H&R Group N Springs on stock mounts (140N/mm or 800lb/in on Front, 180N/mm or 1000lb/in on rear) with bilstein shocks, this is the Group N Nordschleife wet setup, which works very good with semis. For real slicks it would be a little bit too soft.
Great stuff, seems like a quick little car. Have a look at trap door sump modifications too. Heard good things, not too sure how they work though lol. Yes accusump isn't a remedy to the problem. But should act as good insurance after the improved baffling.
I have had issues in the past with oil surge and oil pressure followed by engine failure
A windage tray between the sump and the block seems to be the best solution that works from experience for me. (I run in PBMW so am limited to what I can do with the sump/pump)
That's a different idea. Do they really work?? I understand the principal that less oil on the un-lubricated parts of the crank means more in the sump, but I really didn't think that a great deal of oil would hold on to the surface?
RPM wrote:Very nice Uwe, you can do very similar on an M20 sump
Didn't realise the rubber flaps were BMW items, part number noted- thanks!
I am not sure if these are the best design. But better than nothing.
In some Grp A oil pans I noticed that they make the flaps out of metal and hinge them on a wire instead of plastic molded part.
Looks like a piano hinge if that makes sense. Can imagine the action of something like this is better than the (possibly) slow opening rubber flap.
Hi guys,
thanks to your ideas I am now just working on an horizontal aluminum baffle to keep the oil in the pan on lefthanders, I don't think that I will need a flap since gravity should bring the oil down again (contrary to vertical baffles in an S14, but the M20 sump looks a little bit different, don't think I will need vertical baffles there). Whats your opinion?
I will post some pictures as soon as I am done (I have already made a prototype out of steel, since I didn't have any aluminum sheets left... )
Also thinking about ordering a crank scraper, as every little helps, and one scraper is still cheaper than a set of conrod bearings.
rix313 wrote:What's the advantage of having the extra capcity then? Sorry if that sounds stupid but I want to know rather than guess
I've just taken the sump off of my M40 to make a baffle for that.
e21Jason wrote:More capacity means a bigger reservoir of oil for the pump to suck from, so it takes longer for starvation to set in.
Also raises the heat capacity of the total sump. That is to say, it takes more Joules of heat to raise the temperature of the oil by a unit amount. While it will take slightly longer to bring the oil to operating temperature (from a cold start) the temperature of the oil will not rise as quickly during sustained peak power output. Although, depending upon your cooling arrangements, it can also take longer to cool down as well.
"It is amazing how many drivers, even at the Formula-1 level, think that brakes are for slowing the car down." - Mario Andretti
UweM3 wrote:In some Grp A oil pans I noticed that they make the flaps out of metal and hinge them on a wire instead of plastic molded part.
Looks like a piano hinge if that makes sense. Can imagine the action of something like this is better than the (possibly) slow opening rubber flap.
For what it may be worth, the attached images are of the baffles in our M20B25 sump.
I have wedged a brush into one of the trap doors to try to show it more clearly.
The sump is a steel one, off of an ETA, I think and modified to suit. Extended resevoir section, too although this sits low and TBH looks very exposed and liable to damage. For this reason, we may be changing the sump again.
We run a IE crack scraper in our otherwise unmodified sump with good effect. Had to shave the profile a little to accomodate the bigger crack, but other than that, no worries.
)
