I cannot find a dual evacuation/scavenge oil pump for a 996 Carrera mk2 engine. I mean the oil pump on the right cylinder head of the engine from the x51 kit with an extra oil line from the front of the head.

what is the difference between the mk1 and mk2 x51 engines that make the extra oil line unnecessary?

Robert

 

The internal oil drain back passages were re-designed in the 996.2 and the x51 kit for them doesn't include the tandem scavenge pump or external line.

 

Porschetech3- Which brings me to the question: Can the dual scavenge be theoretically fitted without ginormous amounts of pain and expense? If, say, Charles still had a kit laying on the shelf, would it be something to experimentally install to try out this winter before the summer heat tests on the oil? I’ve been thinking about changing to the 997 swirl pots and seeing about the different scavenge paths and methods to increase reliability.

 

Theoretically it can't hurt and can only help, but the dual scavenge pump kits were expensive and were not popular enough, and the reason LN stopped making them.

 

Yeah, but I’m a 996 owner, so I have deep pockets (but T-Rex arms, ha!) and love to medicate my motor paranoia. Well, I can’t be paranoid if my M96 is really out to get me. I think I’ll give LN a shout to see if they have one. Thanks, Skip.

 

Have you seen oil pressure dips ?

What were the scenarios ?

I have seen dips on track despite LN deep sump and baffle and XP9 oil.

Too much oil in the heads not enough in the sump is my theory.

 

Focus on keeping your oil temps in check, and you'll be just fine without any of this. The primary fault these engines see come in the form of oil that is so hot, that it becomes impossible to control in regard to G force aggravations, along with a loss of viscosity that comes with the temperatures. This his a double negative for the engine. Once shear is induced, the engine is doomed.

 

Exactly! Temp control is key. What’s such an *** pain is each M96/M97 engine has it’s own special way of killing oil. My DT40 fill works fine for wear characteristics per UOA trend, but I get 0.5 to 0.7 indicated when oil temp gets above 98C. My engine temp does fine with same hot operating conditions. The formula I haven’t discovered is how to reduce aeration and shear, and maintaining adequate oil introduction to entire block during high rpm evolutions. My hot oil pressure indications at idle are not comforting because I’m missing some pieces to this puzzle.

I’ve already tried a 1 part DT50 to 7 parts DT40 for last 300 miles with a small positive pressure effect. I’ve toyed with upgrading to CSF rads, internal AOS to 997, Accusump possible mounting locations, dual element scavenge, etc, because this is my keeper 911. If there’s practical data to support a solution, I’m game to try anything. I just love the challenge too much!

I remembered a thread here from a couple of years back discussing M96 3.4 and 3.6 scavenge, so I’m glad this came back up to see if any new info can be added to the knowledge base.

 

We have one bank 1 and one bank 2 pump left:

http://www.ebay.com/itm/183804677679

http://www.ebay.com/itm/173898091156

They aren't an easy install and extra work is required on a 996/997. Engines with the camshaft driven vacuum pump also require fitting a Hella on-demand vacuum pump for the brake booster.

The 2 quart deep sump paired with race oil has proven to be a satisfactory alternative to these expensive tandem scavenge pumps and why we decided to not offer them anymore. Once the sets on eBay are gone, there will be no more left.

 

Thanks Charles! And, yes, those pumps are much more pricey than the deep sump.

 

That's great to hear. What sort of tests were done and results were seen?

 

One of my engineers had previously posted the Aim data on one of the multiple threads discussing deep sumps. I can't seem to find the post or the data itself to share again, but I did find the corresponding email from Racers Edge in 2012 with their feedback when running our two quart deep sump on a 996 race car:

"Charles,

Here is the data from Sebring I promised you. It is from the AIM system I have installed in my 996. Also included is data from the last time I ran there in 2009 when I did not have any additional sump capacity. All data is on Hoosier R6’s as I did not have to run slicks this past weekend. You can see in the new data from this weekend that there are some dips in pressure but they correspond exactly to low RPM. And the 2009 data shows many dips into the 2 bar range due to braking cornering. Looks like you have yourself a good product.

I tried to E-mail it but it wouldn't go due to its size."

The link obviously doesn't work anymore and although I have the email, data was not attached, as mentioned in the email. I know he was running Millers Nano as he was importing the oil back then.

Just to recap, oil aeration is a big issue as are high oil temperatures. Once the oil gets hot, say 240F or higher, the problem gets considerably worse, so it's probably a good idea to run XP6 (20w50) in those instances over XP9. This would be in addition to running a 2 quart deep sump.

For what it is worth, Jake has always recommended using XP6 for his builds when tracked.

Some choose to run an Accusump alone or in addition to a deep sump, but the argument against this is once the valve dumps the oil, it has to rob oil to re-fill the Accusump, which then is robbing oil that would otherwise go to the engine. I personally used to run an Accusump on my track car before I replaced it with a 2 quart deep sump, but the tandem scavenge pumps, cost aside, make perfect sense as we know the oil gets stuck in the heads under sustained g-force loads. The scavenge pumps do aerate the oil, but running a race oil helps to overcome this over using an A40 oil or any street oil for that matter.

Skip's UIDS and UAOS with drain back are also available to address these issues, but again the thicker oil at higher oil temperatures is still a good idea. Skip has seen improved oil pressure running higher oil levels when using his UAOS than we would normally recommend when using a stock AOS.

We are revisiting the whole tandem scavenge pump situation now that we have 5 axis machining capabilities in house (originally to allow us to move to CNC porting from hand porting to support our Porsche cylinder head rebuilding program), so we can make a pump that will fit 996 and 997 models without the interference issues our previous and other designs out there have had with the suspension uprights.