And the answer is: scavenge pumps use Gerotor or Roots type rotating pumps, whilst the pressure pump uses gears. So my original plan needs modifying, which means doing more with the oil pump assembly than I had planned, but less with the oil filter- but overall will result in a better solution. I’m tempted to use a fifth Gerotor as then they’ll all be the same wheel.
This whole project is so far beyond my level of comprehension, but man, I'm excited to see the results!
You and me both. We are, I promise, getting there slowly.
Ok, plan C, with context:
The M96 in Porsche language (which is not quite marketing, but not far from it) has an "integrated dry-sump". What they mean is that being a flat engine it has a sump in each head, with a scavenge pump in each head driven from the exhaust cam that returns oil to the central wet sump.
The central sump has a traditional oil pickup in the centre that feeds the block mounted oil pump, which takes its drive from the Intermediate Shaft (of IMS bearing fame).
There are a couple of problems with this - under heavy braking the oil pools at the front of the engine, and the sump for head 2 is at the back of the block, so the scavenge pump will suck air at this point, which can lead to the tappet carrier fracturing from hydraulic pressure as the oil builds up.
Under cornering loads a more traditional wet-sump failure mode can occur - the pickup is uncovered, sucks air, and all bearings suddenly have no oil pressure.
Porsche did address this with the X51 "powerkit" upgrade, which added an additional scavenge stage to head 2, the pickup of which is at the front of the head and is ideally placed to remove oil that is pooling there whilst under braking. It also had higher baffles in the sump, with less willing doors to try to keep the pickup submerged. It was better, but not perfect.
Current plan: add a second scavenge stage to the scavenge pump on bank 1, add a third stage to the pump on bank 2, these scavenge the sump.
The existing pumps return oil to the sump, in the new design they'd return oil directly to the dry sump tank.
The output line from the dry sump runs directly to the opening in the block to which the oil pickup bolts in usual circumstances (either through the sump plate, or through a hole drilled in the side of the sump, which on the M96 is part of the engine case).
This gives 3 scavenge stages, one pressure stage - said pressure stage is the original oil pump, being fed through what was the oil pickup tube from the dry sump tank, so the only things that are altered are the head mounted scavenge pumps and the sump closing plate.
Every time I get this out of the back of the garage I'm impressed with how well thought out it is:
And it just fits back in the garage with it on:
Sadly you need to remove the rack to cycle the roof:
Thing that gets me is that the very chassis of the car was designed to allow this, it must have been designed at the same time as the rack.
Thanks, anonymous Porsche engineer who wanted to take their skis/canoe/bike with them.
Success!
Looks good, nice bit of engineering on the roof rack. I tried a roof rack again recently but the fact that my bike has a thru axle that's boost sized complicates matters. I have to run an adapter for the fork and the bike basically doesn't fit on the tray.
So back to hitch mounted racks for me, I'll keep the roof racks for my skis.
Thule provide adapters for their racks, you can swap between 100mm QR/12mm bolt-thru/15mm bolt-thru/15mm boost bolt-thru/20mm bolt-thru in ~30 seconds.
Sadly you need to purchase the adapter for each variation, but that's a momentary annoyance and then you've got pretty much everything covered.
However, the wheel carrier is a bit more of a pain -that's 100mm QR, with a 15mm bolt-thru boost wheel in there, but actually (with additional high-tech toe-strap retention mechanism) it's passed static testing with flying colours.
We'll see if it's there when I get to the bike park tomorrow.
Yeah, I didn't feel like buying new bike trays, so I got the adapter instead. In retrospect new bike trays would've been a better way to go but I also already have a Kuat NV2 sitting in my garage, so I elected to just buy a tow hitch and use it instead.
Continuing on the bike theme, sometimes things just don't work out:
And whip it apart:
Offered it up and I'd have to pull the cranks, which I didn't have time for:
So in conclusion, if I was prepared to break it down a little more, no problem - but not quite as simple as I'd hoped.
Early morning in a French field, about to head from Rambouillet to Morzine taking in the D996, D959, D928 and a host of others.
Slowly making progress:
We have clearance with the stock rods, but we're not getting the squish that we want, and we need to check CR as we need to raise it half a point or so from stock - so longer rods are in the future. This does mean that we can use 300M, and aim for the rods to be as light as possible. Pistons will also either need to be heavily machined or we will need to start from scratch in order to reduce the weight as far as we can.
In other news I got to play on an airfield a few days ago, which was a lot of fun - it's always a great moment when you recalibrate your sense of what the car will do in terms of lateral grip before starting to move around as the speed rises.
I also finally gave in and ordered a set of BBS LM's, they're being made to order in (which surprised me) Japan, and will be with me in the New Year.
BBS LM's are so awesome looking! I'm slumming it with BBS RS-GT's. ha!
Forgot about this, 2,000 miles from London to the French alps and back:
Rapid prototyped parts arrive for checking:
Bolting things up ahead of running in.
It'll go in the car after Christmas. Somewhat nervous, bolting our own parts into an engine, but nothing beats empirical testing.
Also got a test segment of the sandwhich plate printed, and it plus the ITB clears in the areas that we were most concerned about - we'll get full three cylinder plates printed now for a final test, then have the final item machined.
Getting close now!
Bit more development on the E46 ITB adapter plate:
We'll get these machined from aluminium now that we've confirmed the fit - and we're onto the much more involved topic of trumpet length and plenum volume.
very cool, thanks for keeping this thread alive!
Dammit said:I also finally gave in and ordered a set of BBS LM's, they're being made to order in (which surprised me) Japan, and will be with me in the New Year.
I'm slumming with factory refurbished HRE 547s.
I've always loved the look of the E88 on a 911 race-car, so it had to be the LM for my road-car.
The sun has (finally, intermittently) put his hat on and we can see the first signs of spring here in blighty.
What makes this type of clear but chilly driving better? Heated seats. What do Recaro SPG buckets lack? Heating elements. TIme to fix that.
Soon:
$2,000 of valves arrive:
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