991 engine now a good design?

[Andyuk911]

Based on all the prior IMS/RMS bore scoring/ poor cooling of cyl 5 & 6, etc etc issues are these ALL now fixed in the 991?

The only item that I could possibly see as an issue is the carbon build up due to the direct injection, so a 50k miles decoke...

Thanks

[JFP in PA]

The 9A1 is a much better design than what it replaced, having addressed many of the issues of the M96/97. That said, only time will reveal any new potential flaws. You are correct on the DFI/carbon deposit issue, but the DFI also shortens oil life (much higher fuel intrusion) and introduces 1700+ psig fuel pressures that have shown some pump failure related issues. Unfortuantely, because any of these problems would be covered under warranty, little information has leaked out to the aftermarket to date.

[logray]

The 9A1 was introdcued on the 911's in 2009 (997 mk2), for sale late 2008.

[Andyuk911]

Has anybody decoked a DFI 997.2 engine yet ?

I wonder if it suffers as bad as an Audi FSI engine.

Maybe the oil seperation is bettter on the Porsche.

[Andyuk911]

bump :D

[wvicary]

Has anybody decoked a DFI 997.2 engine yet ?

I wonder if it suffers as bad as an Audi FSI engine.

Maybe the oil seperation is bettter on the Porsche.

No issues yet that I'm aware of. There were some failures of the early high pressure pumps but I think they were within a certain VIN range so a limited number of vehicle were affected.

The sky isn't falling yet.....

[Andyuk911]

ok - thanks

[perryinva]

The 997.2 doesn't have an IMS?

Edited June 29, 2012 by perryinva

[phillipj]

No it does not...

[Dus10R]

We'll know how good the 9A1 motor is when the new GT3 comes out. If the GT3 uses the same motor then its probably a good engine. If it uses a different engine with a true dry sump like all of its predecessors than its up in the air still whether or not the 9A1 is good.

Whatever motor the GT3 versions use, are usually the best engines. Its sad, but since the 996, Porsche has created two types of 911's, what I call the: Dumbed-down, Cost-over-Quality version, normal 911 & then the Money-no-Object, Quality-over-Cost version, GT3 (and Turbo (up to 2011).

Example? New 997 M97 motor cost $18k to $20k. New 9A1 motor costs $22k to $25k

GT3 motor cost: $50k to $63k

Think there is some quality differences between the three?

[Brad Roberts]

All Turbo's since 2010 have the new 9A1 engine. The engine is FAR supperior to anything they have produced outside the 962 based 4cam Metzger engines. Based on what they have done with the AOS (it still has one) I'm doubting we will continue to see coking issues. They smartened up. The breather line from each head? It dumps back into the the oil filler neck... which means the AOS cannot fill up with oil and therefore does not allow oil vapor into the intake system like the M96/M97 engines.

I'm very impressed, and VERY happy to be dealing with the new engines :)

[Andyuk911]

Since the new GT3 DFI engine is now out ... perhaps people will revise their thoughts on the benefits of direct injection.

This is a mini turbo engine with Direct Injection.

I would expect no difference in Porsche DFI engine.

[RFM]

Audi is struggling with the same problem, so they have a new 4 cylinder turbo engine released in this country which use both injection systems in the same engine, DI at starting and on full load, IDI at partial load. They claim allows the carbon build up problem as solved. Wait and see.