Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

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

Link to comment
Share on other sites

  • Moderators

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.

Link to comment
Share on other sites

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.....

Link to comment
Share on other sites

  • 4 weeks later...
  • 5 months later...

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?

Link to comment
Share on other sites

  • 2 months later...

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 :)

Link to comment
Share on other sites

  • 3 weeks later...

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.

Link to comment
Share on other sites

  • Moderators

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.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.