Carrera2kid

Guys,
This is a fairly basic question, I know, but I figure some of you will know and won't mind sharing with the class: what are the differences (beyond displacement and horsepower) between the GT3 engine in the 997 GT3 and GT3RS and the 997 Carrera S (or even the Carrera S with the powerkit)?
I have read on this forum that the Carrera S engine is a $10,000 engine, while the GT3 engine is a $40,000 engine, but never read the backup as to why. Is that really true? If so, why?
Much obliged for sharing on this topic.
Regards,
Ray
'07 RS

Flying Finn

In short, arguably the biggest different in principle between the Carrera S & GT3 engine is that GT3 has a different, a true dry sump crankcase (which looseli is based on the old 964 crankcase).

OldGuy

As finn says the GT3 is a hand assembled race motor based on the current Cup motor that go to Cup cars and is built in the race division. Its based on the 1998 GT1 dry sump racing motor that has roots in the the 964 motor. In fact early 04 GT3s had 964 part #s on the case.
The 997 Carrera motor is a mass produced motor that uses a lot cheaper parts and its a wet sump design. It evolved from the 996 carrera motor which for Porsche was its first mass produced motor thats cheaper to replace than fix. Its not worth fixing for major stuff like RMS failures so Porsche R & Rs the motors and sends the bad motor back the factory.
The GT3 motor has all the trick racing stuff like titanium rods hollow valves balanced everything agressive cams etc etc.

YA911Fan

But, to reaffirm the genetic link with lowly 997 engines, Porsche makes sure that a few painstakingly-hand-assembled-by-Dieter-in-blue-overalls 997 GT3 engines have RMS problems.

997gt3north

my leaky 997gt3 rms is getting replaced today while they put in the rs lwfw

Bob Rouleau

The 996/997 engine is a more modern design with fewer parts and less assembly time. Early production had problems with poor casting (porous) - a supplier problem. Porsche replaced them without hesitation. Some of the defective castings were rebuilt with sleeves - a bad idea since the sleeves themselves wee failure prone. In subsequent years some cases were poory cast resulting in an ecentric hole for the Rear Main Seal. This caused leaks and Porsche replaced the engines - not because it s cheaper to replace than repair but because no repair could fix the improper alignment of the casting.

That being said Porsche has also replaced 997 and 997 Turbo engines which are also based on the dry sump GT1 race engine. Any engine can have an RMS problem and they are showing up on current GT3 and RS models too. Not a deal breaker.

Best,

krC2S

biggest difference technically is that GT3 is a high revving engine..it's typically cheaper and easier to get power by using bigger displacement as opposed to a high revving engine

NAvyC4S

Well Porsche is known for having perfectly balanced engines.

TT Gasman

First, I would suggest reading The 911 Story by Paul Frere and Excellence was Expected by karl Ludvigsen, these books have everything you ever wanted to know. Excellent resources for any p car nut!
To your question, as others have said the 996/997s have a water cooled "integrated dry sump", which has more in common with a wet sump than a true dry sump. A true dry sump engines feature a seperate oil tank. both have a series of scavenger pumps to maintain oil pressure, but the cheaper M96 is a mirror image casting, hence it lacks an equal oil scavenging. This can be a disaster in certain high G situations, causing oil starvation. This is addressed in the X51 powerkit which gets an additional scavenging pump on the "bad side".
Having said all this, the M96 has a high specific output and uses high quality components, compared to it's competition...They are actually very reliable, I know from personal experience. Though I still believe Porsche cheated the 996 buyers by not giving us a true dry sump engine. For the sake of a bigger profit margin, we got a souped up boxster motor...
The real problem/ difference is the transmission in the 996 cars. ( I'm not sure about the asian derived 997 6 speed). These things were designed to be non-servicable. They can't be repaired and are replaced en bloc. Although there are a few race shops repairing them now. The GT3 and Turbos get a G50 derived 6 speed trransmission.....

spr10r

my rms has not looked after it's oil properly and let out a few drops. What does the lwfw cost if it's fitted as part of warranty?

OldGuy

Spr if I recall correctly I paid about $1500 for the LWFW and RS clutch for my 996 GT3. The parts were installed at no cost as they had the motor out for the RMS repair.

Gasman Great explanation-One more thing about the GT3 tranny - its designed to be easily removed at the track to change gear sets. Uh I dont have the money laying around for different gear sets but still, its nice to know its possible. Plus I really like the new gearing in the 7 compared to the 6 GT3

flash1034

Huh?

OldGuy

Flash
SPR said that his RMS has leaked some oil. He wants to know how much it will cost to have the LWFW and clutch put in if the motor has to be out for the RMS repair under warranty.

JasonAndreas

The G96.00 & .03, etc. were most definitely designed to be serviceable. The gearbox internals were not available outside/from Porsche up until the summer of '06 because of a warranty contract with Getrag and not because of some design issue.

997gt3north

i'm having a race shop do the lwfw install
it was they that commented on the rms (i had seen oil stains on the garage floor so i knew it was likely bad)
i'm not a really big fan of dealerships for work on cars if i can find a really good shop that only works on porsche race cars so all the work is being done on my own tab
they are charging me 700 CDN$ for the lwfw install