Cupcar

Below is a diagram of the oiling system in the new A91 engine scheduled to replace the GT3's Metzger engine in the next generation GT3. The A91 is an "integrated dry sump" engine.

I added the text and pointers showing how I think the system works based on my examination of this diagram and pictures of the new oil pump shown in Car and Driver recently.

There appears to be a central scavenge/pressure oil pump with 4 scavenge pumps in a row that suck oil from 4 long galleries leading from the 4 cam boxes. There appear to be no camshaft driven scavenge pumps as in the Metzger engine.

Porsche says the central oil pump is driven at a variable speed via an electronically controlled chain drive from the crankshaft. The variable speed eliminates the usual over pumping and "popping off" with bypass valves of oil at high engine speed that occurs in the Metzger engine and this saves 3 wasted horsepower according to Porsche.

There are two brown colored cylindrical bodies that appear parallel to the crankshaft, could these be oil storage points for a crankcase scavenge pump if there is a crankcase scavenge pump?

Anybody have thoughts or information?

C.J. Ichiban

wow- great diagram

GT3 Chuck

yeah..."integrated dry sump"...aka wet sump

btw...think those are galleys not galleries

wilfred

I am still in disbelieve stage that the 997 GT3 MkII will use regular engine. So the difference between them will be better suspension and little bit in horsepower? Anyways, I guess the bottomline is to wait and see how the new motor holds up by those who track theirs regularly. And I don't mean the ones on professional race teams that can afford to rebuild the motor every season...

TT Surgeon

I for one have no interest in the new engine, might as well just get the base carrera.
Keepin' the turbo!

mooty

stop worrying what is NEXT.
enjoy the CURRENT car.

Cupcar

"Gallery" is a common term used to describe an oil system's internal crankcase drillings. For example note this sentence:

"The outlet of the oil pump connects to a main oil feed which supplies oil to a main bearing gallery and a hydraulically actuated device such as a cam phaser or switching lifters."

in this patent application here: http://www.patentstorm.us/patents/68...scription.html

GT3 Chuck

hey, you learn something new everyday...thanks...

OldGuy

Are those mini tanks in the sump area sort mini sump? they might hold enough oil to
keep starvation at bay till the induced G situation is resolved and the car is back at
horizontal?

Cupcar

I think they may be, they could even be Accusump type devices or something like that http://www.accusump.com/accusump.pdf/instructions.pdf

Sure seems like a lot of work to eliminate a dry sump tank doesn't it, especially when Porsche did a tank so easily on the Metzger engine.

OldGuy

Yea the complications seem more than the old dry sump. There has to be a reason. We will find out next racing year. We should really give this a chance. I remember in the old days of aviation we thought the
propeller was the only proven method of propulsion.

prg

My suspicion is the racing variants will be dry sumped.

OldGuy

I dont think they can be. typically they dont let Porsche cheat. For homologation reasons they
have to be the same dont they?

prg

I don't know. Were the ALMS corvettes dry sumped prior to the C6Z06 getting a dry sumped motor?

911rox

If I'm not mistaken, the two main benefits of a dry sump over a wet or the proposed integrated sump (other than continuous oil supply under load) are:

i) added oil cooling, ie the oil can discipate heat much faster in an external tank due to the reduce thermal mass of the container housing it, as opposed to being encased in an aluminium engine block running at substantially higher temps and relying purely on the coolant system to provide cooling, and

ii) greater oil volume (11+ lts for dry sump as opposed to 5-6 ltrs for internal sump) to ensure cooler running, less oil deterioration and breakdown due to extreme heat and increased protection from oil starvation under extreme load.

This engine is likely to run alot hotter than a dry sump unless external coolers are used for race applications and then you've defeated the purpose of removing external lines (and thus possible leaks) as well as weight (cooler instead of tank?). No???