Porsche 996.1 cab

Disclaimer, not my hands:

In reply to Dammit :

There seems to be a difference in price for things mailed to residences vs. business addresses.  My wife mailed a quilt to a colleague in England and it cost $75 for a 4-5 pound package.  Looking at UPS and FedEx pricing for the same package, that seems like a bargain.

Charley

Interesting, thanks Charley.

BBI have yet to ship my seat base, apparently (I had to chase them to get this update) they haven't actually made it yet, so can't post it (for obvious reasons). They have given me no estimate as to when it will ship, apart from "soon".

Awesome.

Just get Recaro stuff and be done with it.  Recaro sliders and side brackets will bolt right into the floor of your car as well as the seat.  That's what I used on my old Recaro SPG XL's and it worked perfectly.

I've got some Recaro side-mounts, but I was advised that they'd position the seat high in comparison to the BBI mount.

Of course, if the BBI mount never arrives, it's moot.

Did you get the Recaro double-locking sliders?

I've not got the seat with me, but these dimensions are what I've found online:

Runners on the outer row of mounting holes:

Too far apart to mount the seat:

Flip the base, look at the mounting holes:

I moved the runners to the middle position, so they're inline with the mounting holes in the car:

At this point the seats would mount using the supplied 5mm spacers:

Or I can move the side mounts inward, which would mount the seat to the side-mounts with no spacers (which does strike me as better).

However, what I'm struggling with is what this gives me over mounting the Recaro side-mounts on the OEM sliders.

The BBI side mounts do have more mounting holes:

Than the Recaro:

Which as long as the seat doesn't hit the base suggests that ultimate mounting could be lower, but I have to count the thickness of the base plate in the total stack height.

Still very unsure, with that said.

In reply to Dammit :

Yes, the Recaro double locking sliders.  While the Recaro side plates have less holes,I didn't have an issue.  I'm also all torso, so tend to sit really high in seats, I was able to get very comfortable with the Recaro side plates.  Plenty of space in the car, even with my helmet on.

Bit of a pause for research- the 3.6 heads run 40mm intake valves, the 3.4 runs 37mm intakes. We had intended on going to 38 as they’d work with the existing valve seat. But- 40mm would flow a lot more. What we need to know is the valve centres for the 3.6- if they’re comparable to the 3.4 then it means Porsche was happy that the head was (is) strong enough to have larger valve seats fitted, and we’ll go that route. If Porsche spaced the 3.6 valves further apart by an appreciable amount then that suggests this might lead to (a fairly exciting) failure mode. 

Problem is we are going to have to purchase a 3.6 head as no one seems to have this knowledge. 

Therefore if anyone either has a 3.6/3.8 head, or has access to one I’d be hugely in your debt if you’d measure the valve centre separation. 

Seat arrives:

And is instantly turned into a cat basket:

Those shoulder harness holes gonna be high enough for you?  I fit fine in that seat but the harness holes are way too low for me...

They're just above my shoulder, which I assume (!) makes them high enough?

Not that I intend on using a six point harness with these, but of course it'd be nice for them to be high enough if I ever change my mind.

Here's a question that I'm sure most people on here should be able to answer and which I cannot - is there a specific type of bolt for attaching a seat belt receiver to a chair frame?

You should be able to reuse the stock bolt. 

Yes, as long as the holes are higher than your shoulder you're all set

My partner in the engine project has installed our billet tappet chest in his engine to test it (it's otherwise stock):

We're sticking with the stock seats as, when we measured the 3.6 head, Porsche did space the (larger) valves further apart, so we don't want to risk there being insufficient material in the 3.4 head to support the larger seat and associated 40mm valve, so 38's it is. That's 1mm larger than stock, and allows some very useful re-profling of the seat.

Dammit said:

Seat arrives:

 

And is instantly turned into a cat basket:

Furball approved seating.

She was a huge fan of the seat - which has now (after a very thorough hoovering) gone back to Recaro for a QC issue.

More from my partner in crime, all bolts torqued down:

Camshafts and VarioCam actuator in:

Waiting for the sealant to turn up in order to install the cover:

Looking pretty awesome.

Would anyone know where I could source custom-wound beehive valve springs? Totally struck out from all the normal places one might think to look here (UK).

I'd call Comp Cams here in the USA

Who can guess what this is?

Here's a clue - it's not directly related to these parts, the completion of which means we now just need to ascertain the precise rod length we need, have the rods made, and then put the bottom ends together.

No idea what that part is, but the seat, pistons, and block look great! I have a roll bar for a 996 cab. I wish you were in the states so I could donate it to the cause.

The mystery part has a  7/16th UNF thread - that's a huge clue.

Thanks for the kind offer on the roll-bar, I will be in the States at the end of August but I suspect it wouldn't (easily) fit in my suitcase!

Pumps- would it be madness to use the current oil pump as a single stage scavenge pump for the main sump, whilst introducing another pump to pressurise the oil system?

i.e. are pressure and scavenge pumps physically different as one will see air whilst the other should see only oil, or is a pump a pump?

Here's the oil circuit for the M96:

What's going on there is that the engine has three sumps - one per head (as this is a flat/boxer engine) and one central/crankcase sump.

Each head has a scavenge pump that feeds back to the central sump via a swirl pot.

The central sump has the oil pickup, drawn on by the engines oil pump, which is driven by the (infamous) IMS (intermediate shaft).

Porsche, for the X51 performance version of the X51 introduced a dual stage head scavenge pump - literally stacking another stage on top of the standard one, with both driven by a common shaft, itself driven by the exhaust cam. The second stage scavenges the other end of the head from the first stage, in order to prevent oil pooling under braking that is not returned to the central sump.

The X51 package also has a higher gated baffle in the central sump to (try!) to keep the oil pickup submerged during high-G.

Despite this, the M96 can still encounter oil starvation on the track - the pickup is uncovered and oil supply stutters, and whilst this may not be immediately fatal it dramatically shortens the life of the engine.

I am considering the following:

If you'll forgive the deeply amateur diagram, what is going on is:

Each head has a dual-stage scavenge, evacuating oil from either end of the heads. The oil is not being returned to the central sump - it's going to the dry sump tank, which features a centrifugal de-foaming path for the oil.

The original oil pump is now drawing oil from the central sump which is going straight into the dry sump tank. It's been turned into a scavenge pump, basically - hence my question earlier today.

A new oil pump is stacked on top of the original oil pump, both driven by the IMS. I'd need to make a new cover plate for the oil pump for this. This new pump takes de-foamed oil from the dry-sump tank and routes it into the oil filter, and thence the block/existing oil galleries.

The engine would have five scavenge pumps, four in the heads and one in the central sump for the main bearings and piston oil squirters.

It would have one pressure pump/oil pump, added by modifying the standard oil pump to add a second stage.

What say you GRM - insanity? Or would this work?