Alex (UK)

So the 997.1 Turbo+GT3+GT2 had race-grade M97 engines and the 997.2 Turbo has an 9A1 consumer-grade engine (probably with lots of strengthened engine components compared to the 997.2 Carrera engines). Right?

If so then did the 997.1 GT3/GT2/Turbo all have the same GT1 derived block? And if so is this the engine block that what has been used for racing over the last X years?

I am just trying to ascertain how bullet-proof the 997.1 Turbo/GT3/GT2 engines are or if they are only distant cousins of the race bred Metzger GT1 engines?

I personally haven't seen any threads of people with 997.1 GT3/GT2/Turbo's needing replacement engines, even those who have modified...

TB993tt

My take on it is that the GT1 "borrowed" the block from whatever the current turbo 911 was at the time.
The bottom end has been relatively unchanged going back to the 930 turbos and these are also very close in spec to the non turbo bottom ends.

The 934, 935,962, 911 Le Mans Turbo, 993GT2 and GT1 turbo racers bottom ends were all essentially the same set up as the road cars'

The cylinder heads, valve layouts, head cooling and head sealing were all different but that bottom end has been heavily tried and tested on the track.

This new A91 is completely different and not yet tested on the track.

Please someone more knowledgable correct me if I am spouting drivel

Quadcammer

I believe thats correct TB, however, I tend to believe that the heads, valves, cooling and sealing are the prime reason those cars make the power they do and are as reliable as they are.

Mad Manx

My OPC (swindon) were rebuilding a faulty 997Turbo engine earlier this year.

Don't know the fault. They said it was major work covered under warranty.

DLJ

Interesting observation. Over the years I have seen many threads outlining various problems with other PCar versions (granted, many do not indicate large-scale serious engine issues). However, the 997.1 GT3/GT2/Turbo versions with GT1 derived engines seem particularly conspicuous by the apparent lack of major issues. I hope others would volunteer more info. from their experiences.

TT Gasman

Maybe someone will chime in from their cubicle at the dealership and tell how superior the new wet sump motors are in comparision...

Quadcammer

But Doug, if they don't, that doesn't mean you can assume that the new motor is crap either.

Riz

From my understanding, the 997.1 turbo, GT2, GT3 have the true GT1 derived dry sump engine proven in endurance racing in its various forms while the 997.1 Carrera engines are not true dry sump and are not based on the GT1 racing block. Porsche creates a lot of confusion by using terms like "integrated dry sump." The true dry sump motors use a lot more oil than the "integrated" counterparts. They differ in the placement of the oil pan, oil tank, scavenger oil pumps. I'm sure there is more to it than I understand. Time will tell if the new breed of engines in all the 997.2's except the GT3/RS are as good as the older ones. We also need to see when they start using the new engines in the Cup cars.

TT Gasman

Not crap at all, I think Porsche finally got that motor right, something they should have done from the get go. Porsche and WW got cheap and decided to cut corners on the engine in the then new 996 to maximize profits. Using Lokasil instead of Nikasil, poor castings , and the dreaded out of round RMS issue to name a few. The fact Porsche never used the M96/7 in racing speaks volumes to me.
For these reasons the 9A1 motor will never be in the same league as the venerable GT1 Metzger motor IMO. They should have never put that motor in the top of the line Turbo. I hope I'm wrong , but until Porsche starts racing the 9A1 I'll pass on the kool aid and hold onto my car for a very long time. At least until BHO tries to take it from me

TT Surgeon

Agree with Doug, the 9A1 is 'probably' a good motor, even though it's completely unproven (racing), less expensive to produce, etc. However, the m96/7 boxster motors will go down in porsche racing history as the red headed step kids I'm afraid.
As soon as one wins Lemans or Daytona I'll buy one, until then BHO's gonna have to pry my cold, dead fingers off the wheel.

eclou

just wait until BHO decides to "redistribute" the hp

Macster

Word is -- in depth review of the new Turbo -- is its engine is basically the same engine as used in the lesser models with some exceptions (excluding the obvious ones) and these have to do with changes in the block casting to add extra strength where the Porsche engineers determined/deemed extra strength necessary.

Additionally some changes were made to the casting to fine tune cooling for the higher output engine's needs.

Internal parts can also be strengthened, like rods, crank, pistons, etc.

Will the new engine prove as good or better than the old one? Only time will tell.

Sincerely,

Macster.

inactiveuser1

Sounds like they are using Lokasil because of enviromental reasons and also the etching isnt needed with it.
http://www.porsche.com/australia/abo...es/principle3/
Higher mileage between oil changes,don't think anyone would want to go that many miles without an oil change more so in the turbo.
http://www.autointell.com/sports_car.../porsche25.htm

On the last page in chapter 1:
http://www.bmwseven.com/Alum_engine.pdf
It shows GALNIKAL / NIKASIL Boring the cylinder block is not
possible because of the nickel
coat ! Is that true on the NIKASIL???
With the LOKASIL
• Boring of the cylinder block is
possible

ALUSIL / SILUMAL was used on the 928 and those motors go 200,000 miles

911rox

Additionally to some of the other differences outlined, it is important to note that the M64 Metzger has a race style fully serviceable block, all be it at a price. The Nikasil liners are bolted in and therefore simply removed and replacable... thus no need to bore it out- replace and it's as good as new. The main benefit other than reliability for these engines was that they were designed to be stripped down and refreshed to new as required by race teams for competition rather than being made as a cast unit intended for a certain lifespan and subsequent trashed (modern engines).

Other differences:
- M64 true dry sump, external tank (as per race cars), 9A1- not dry sump, oil reservoir integrated into block, similar to wet sump
-M64 servicable bottom end- removable cylinder liners etc for stripping down, 9A1- traditional cast block with Lokasil, if rebuilding, it must be boredout- limited life for this reason esp in racing applications
-M64 proven race reliabilty (24hr enduros etc) and highly tunable- aftermarket tuning exceeding 1000bhp- main recent issue, some GT variants prone to RMS issue. 9A1- no race history therefore no comment. Not much aftermarket tuning available yet so tunability unkown

Whether the new motor will meet or exceed the standards set by thw Metzger, only time will tell but it won't be easy.

Alex (UK)

Thanks guys - some great answers in there!

So just to make sure I have my terminology correct:

M97 = 997.1 Carrera
M64 = 997.1 Turbo/GT3/RS/GT2, 997.2 GT3/RS
9A1 (or A91?) = 997.2 Carrera/Turbo