Remove the metal intake dividers or keep them in ??

[GolfRS]

Hey all, here is a thread that you might be interested in concerning Piston Types used in these cars....


http://www.audizine.com/forum/showth...lver-T-threads



vizi

Cars mentioned in the thread seem to be all pre 2006 and that is when production of the AXX engine ceased, to be replace by the BWA engine in Europe.

AFAIK the first A3 models were imported in the U.S. long before the launch of the GTI, and hence
probably had the AXX engine (or equivalent of) that had the crowned pistons.

And to respond to one of the comments in the thread, as discussed previously, the crown pistons are
considered to be fully forged as opposed to the dome pistons that are cast (that could explain the piston failures)....

[loudgli]

little late to the party, but...

I noticed a pretty significant difference in cold starts when I (forgot) to put the dividers back in.

Only change along with that was a slightly thicker headgasket.

But the cold starts got quite abit worse without the dividers.

Now maybe its possibly RS4's injectors multiply this, I dunno.

Next time my intake is off Im gonna take the rest of the flappers out. I cant imagine the cold starts getting any worse. I dont drive the car in the winter anyway so its mostly a non issue for me.

Just putin' my info out there.

[crew219]

I think what you mean is that the "cold start" is bad when the engine is in dual injection mode for catalyst heating. After that 10-20 second period, the car is 100% smooth even if it is still at the elevated cold idle of 1200rpms.

Dave

[loudgli]

I think what you mean is that the "cold start" is bad when the engine is in dual injection mode for catalyst heating. After that 10-20 second period, the car is 100% smooth even if it is still at the elevated cold idle of 1200rpms.

Dave

well yeah I guess.

The car hard starts worse than it used to and it almost cant be driven until the "dual injection mode" as you call it turns off. This was always there with the rs4's but definitely more pronounced now.

[crew219]

well yeah I guess.

The car hard starts worse than it used to and it almost cant be driven until the "dual injection mode" as you call it turns off. This was always there with the rs4's but definitely more pronounced now.

You should see if your tuner can delete the dual injection mode.

[loudgli]

You should see if your tuner can delete the dual injection mode.

switching to maestro in the coming weeks, so ill research that then. thx

[RaraK69]

AFAIK double injection would only take place in a stratified mode, correct me if im wrong.

No cars run stratified mode in USA after 2006 for SURE. The more i looked at some maps in these
ecu's the more i realized that the mode isnt supporte due to the ecu not even having some of the
stratified mode maps anymore after 2006.



More info i kinda pieced together over some reading and stuff lately.
Lighting the fire on the fuel injector debate.


RS4 pistons, and early 2.0tfsi pistons = crown type, right?

RS4 injectors + crown type pistons make more sense to me. Why?
After seeing RS4 injector spray pattern from the AWE bench test it makes sense. Crown is
To enhance "tumble" and "swirl". RS4 injector is of a design to create a swirl when
it is injected(design of tip) Spray angle must be proper of course, and the crown design
may play part of this to help "center it up" with its high crown to the center of combustion.

Stock/S3 injector debate, with domed pistons works great. Why?
This is becuase the injector does not create a swirl in itself, its a cone shape, cone shape
is relying on the dome of the piston and airflow to "tumble" the fuel and keep it into a centralized
cloud. This style injector should work fine with either piston in my mind.

TSI injectors, newer generation AFAIK, uses a ~6 hole spray pattern.
More efficient spray pattern, more fuel can be delivered, better design overall and most DI motor
utilize an injector like this in production now, not just VAG. These injectors require a higher
potential fuel pressure, hence why TSI's run much higher fuel pressure and utilize a different HPFP
setup.


Ok, dead horse got kicked again. but figured i would throw this out there and hope someone has something to
contribute to my totally made up in my own mind point of view. I did do some research on DI above an beyond
VAG to contribute to the statements i have made though

[GolfRS]

AFAIK double injection would only take place in a stratified mode, correct me if im wrong.

No cars run stratified mode in USA after 2006 for SURE. The more i looked at some maps in these
ecu's the more i realized that the mode isnt supporte due to the ecu not even having some of the
stratified mode maps anymore after 2006.



More info i kinda pieced together over some reading and stuff lately.
Lighting the fire on the fuel injector debate.


RS4 pistons, and early 2.0tfsi pistons = crown type, right?

RS4 injectors + crown type pistons make more sense to me. Why?
After seeing RS4 injector spray pattern from the AWE bench test it makes sense. Crown is
To enhance "tumble" and "swirl". RS4 injector is of a design to create a swirl when
it is injected(design of tip) Spray angle must be proper of course, and the crown design
may play part of this to help "center it up" with its high crown to the center of combustion.

Stock/S3 injector debate, with domed pistons works great. Why?
This is becuase the injector does not create a swirl in itself, its a cone shape, cone shape
is relying on the dome of the piston and airflow to "tumble" the fuel and keep it into a centralized
cloud. This style injector should work fine with either piston in my mind.

TSI injectors, newer generation AFAIK, uses a ~6 hole spray pattern.
More efficient spray pattern, more fuel can be delivered, better design overall and most DI motor
utilize an injector like this in production now, not just VAG. These injectors require a higher
potential fuel pressure, hence why TSI's run much higher fuel pressure and utilize a different HPFP
setup.


Ok, dead horse got kicked again. but figured i would throw this out there and hope someone has something to
contribute to my totally made up in my own mind point of view. I did do some research on DI above an beyond
VAG to contribute to the statements i have made though

As i already mentioned (and CoNGLoMeRaTeGTi who just likes to hate bashed me in the "other" forum) the AXX engine was terminated late 2005.Mine is an Aug 2005 production and was one of the last.So i will stick with my idea about the difference in combustion even if it is not that attractive to some....

Now for the piston/injector debate...my idea was also like yours that a more "linear" spray pattern would hit the crown piston in a way that would cause it to swirl hence enhancing combustion.
The only problem with "our" idea is the fact my engine came from the factory with the same "A" version injectors (for the factory K03) that were also later used in the BWA version of the engine that
had the dome pistons....So i don't really know what is going on there....

[iGen3]

ALL US spec. 2.0FSI engines I've been into to re-ring have had the flap-top pistons in them. All have been engine code BPY and I've done lots varying from 2005-production up until 2009. And you had dome-top from the factory in your GTI? What engine code?

As for the flaps, I have a 2006 GLI(built in 2005), so it's one of the EARLY BPY engines. I took the dividers out in the head with my last cleaning about 1.5 months ago. I've since put 8K or so miles on the car and have seen no adverse effects. No true gains, but no running conditions that effected engine either. The only reason I did it was to see what the buildup would look like(if different after 20K) when I tear it back down. Seems all the engines I tear down have TONS of buildup mainly on the top section of the ports since that is what gets the airflow all the time. So if by distributing the airflow over the entire port will reduce the buildup some, it'll benefit. Yet at the same time, I left the flaps in the manifold and left the IMRC hooked up properly, so the flaps will still create turbulence for the airflow coming in.

I'm not looking for any power gains, just seeing what happens. And as stated, I'm REVO STG 3 K04 file with RS4 injectors. So I have stumbling when it's really cold out, but that's my damn injectors, not the flaps. It's always done that!!!
-J. Hines

any update on divider delete? I forgot to put mine back just now....wondering if OK to wait till winter and any cold issues if there are any...

[jhines_06gli]

any update on divider delete? I forgot to put mine back just now....wondering if OK to wait till winter and any cold issues if there are any...

Still not running mine. And still no negative change. They may/may not go back in at next cleaning. WE shall see what my tuning route is by then.

[iGen3]

great, thanks. I'm at 190,000 miles of OEM tune. I guess I should chip it one of these days..

[Mk620T]

Removed these and my car runs fine. I'm not sure but I think the flappers have something to do with cold startups and tumbling air to get a better mix. I'm in Houston - never really gets cold.