BC

The block cradle, when removed, has some very interesting "passages" for the oil to get where it needs to go - such as to the mains on the crank, and up to the camshafts, etc.

Ich würde annehmen, daß dieser deutsche Mann entschieden hat, daß die Öldurchgänge viel umadressiert oder vergrößert werden.

- What do you say Nicole?

He is obviously making sure his solution looks like one 400 dollars would be worth it for. The passages at the cradle/block seam look VERY important, and the also look pretty complex.

I understand that the dry sump solution is the end all be all, but how much would it really cost. We would obviously use the original pump, plumbed to take oil from the oil tank, and we would need a two or so stage scavenge in the place where the air pump is.

Any thoughts on cost?

Fastest928

about $4K, if you so your own fab work.

Bob DeVore, the "DEV" in DEVEK, was the first to do use the native oil pump as the pressure side. Many 928 racers have copied the system.

A two stage pump is the minimum....

PLUS, if done right, you will pick up 5-7 hp per liter of displacement.

Marc
DEVEK

BC

With all due respect Marc, I must question your 4k number. I understand that I asked for price approximations, but:

A pump is 500 dollars with two stages.
Plumbing - ?
Tank in Pegasus is 300 for the biggest.
Pan customization - 200 bucks tops.

What say we?

Jim bailey - 928 International

dry sump cost probably about 1/2 way between the Optimist and the Capitalist ........

bcdavis

Hahahahaha!

dr bob

... and half what the cynic discovered it's worth.


Definitions:

Optimist is one who will loan his 928 to the teenage son.
Pessimist is one who won't.
Cynic is one who did.

BC

Dr. Bob - you seem to speak from experience.

Realistically, I can't see why a dry sump system, such has been described in this thread, running with the stock pump, could be more then 1500 dollars if you do your own work. That includes you doing your own scrapers for the crank, and not getting too crazy with oil tank placement.

This is the only issue - oil tank placement. Where to put it? A good sage once told me that the passenger wheel well, behind the wheel would work, but I looked in there, and it looks kind of tight. The tank needs to be close to the engine indeed, but the weight concerns me. Yes, you are simply relocating the oil from down low to somewhere else, but it SHOULD be on the passenger side at least.

Jim bailey - 928 International

Brendan once you remove the reservoir for the windshield / headlight washer (unneeded weight) there is enough space for a custom oil tank in the fender ($$) with a filler neck and cap under the hood (actually a 911 dry sump tank might just fit ). The oil lines should never be INSIDE the car especially a street car .

Nicole

Uli wrote me from Germany.

The above (red) 928 race car with the Accusump is/was owned by Reiner Kaufmann, for whom the special oiling solution was developed as well. The cross drilling of the crank did not make the engine last at rpms of 7k - that's why Uli analyzed the oiling system and found a fundamental design flaw. He worked long hours for 3 weeks to develop his solution - that's why he is so concerned about keeping it proprietary.

He says that in 1988, Porsche wanted to launch a 928 Cup, but failed because of that very problem. The factory had to scrap the 928 Cup project becaues they could not solve the oiling problem... Now, how embarassing is that? Here goes my belief in German engineering... ;-)

GlenL

I put my catch tank, maybe smaller, in the left fender where the cruise control servo was mounted. A handy bracket to mount it on. There are already some large holes in the fender to run the lines through.

Passenger side might be good for weight distribution, though.

Jim bailey - 928 International

Just to clarify one point ....drilling the crank is simply NOT CROSS DRILLING it is feeding the 2-6 journal from a DIFFERENT main bearing (modified by grooving), different flow path . Mark Anderson many years ago followed Bob Devore's dry sump design BUT continued to have 2-6 failures in the hybrid Euro / five liter engines ...yes plural . So next ran the same drysump set up BUT drilled the crank "like a Chevy"and no more such problems at 7,500 RPM . Just "drilling the crank" however has not eliminated 2-6 failures for other racers who shall go unnamed especially those who neglect to turn on the accusump . I also do not know how others who have have tried ; "cross drilled" their cranks . Stroker cranks have modified oil paths and are rarely spin much over 6,000 rpm anyway (Anderson hits 7,000 at times ) . Since Uli offers to modify JUST THE LOWER cradle ........that implies a change in the oiling path , that sounds familiar . Perhaps there are multiple solutions to the same design flaws . Our experience is that dry sump plus drilled crank works very well . Dry sump alone DID NOT at high RPM . Joe Fan runs a stroker 6.5 ( modified crank) with accusump and it has been O K as well . While we may not know exactly why there are failures we by trial and error ($$$) seem to know how to eliminate them . It would of course be interesting to know what modification is being done to the lower cradle , but like some others Uli does not seem to be talking .........

Nathan Valles

Could it really be as simple as opening up an oil passage that never got drilled? Or enlarging one that was drilled too small? Of course, having never actually had a lower cradle in my hands I am just guessing at this one.

Jim bailey - 928 International

Nathan it could even be reducing the size of one which is too large !! to force the oil to go where it is needed most . Not unusual for a racing engine turning high RPM to need to restrict the amount of oil being sent to the valve train to keep the oil pan level higher so the bearings get what they need . Like I mentioned Uli is not talking ............

Cameron

Wow. I guess I have to stop laughing at my M3 buddies about this:

http://members.roadfly.com/jason/m3engines.htm

.....Cameron
'91 Euro GT

Fastest928

Restricting oil to the head is a common method of increasing the oil in the sump pan. Porsche did this with all cup cars, and derived the solution from the 944S2...by using an oil restrictor for the heads!

Nicole: Tell Uli to say hi to Riener for us!!

Brendon: 3-4 gallon swirl tank, vents, filters, hoses, AN fittings, adel clamps, manifolds, pumps, pulleys, belts, brackets, thermostats, scavenger pump manifold, cooler, modified pans, brackets, breathers and filters, scrapers and windage trays, etc. Look at weaver, perterson, barnes 3 stage pumps.....


Marc
DEVEK