BlkSnake

What boost do the stock turbos run at? Combined? Each? Im just curious. Also how much can the engines handle easily w/o any real threat to them?

Singletrack

The manifold seems to handle the added pressure without issues, it's the turbos that die : )

-st

AndrewWK

based on my experience you can only boost up to .8 bar using the overboost feature otherwise .6 bar

GIACUser

is that the stock turbos are tiny. Tiny limits their ability to flow efficiently as the pressure rises. As you raise pressure you raise charge temperature as a byproduct of trying achieve a certain level of flow. I believe the turbos will be far outside their efficiency range before they pose a major threat to the engine. Assuming cooling and fueling are appropriate. It seems that some of the stock tubing and connectors on the intake side can be problematic. I think if you were to move to larger more efficient turbos you could then get the power up to a level that may pose some threat to longevity..... but would be incredible fun. while it lasted.

FlyBry2.7T

some chip make a little more, some may make a little less. These are safe levels of boost for this engine. It is engineered/designed/built of very good quality components. But, and this applies to a stock boost engine as well, a lot of longevity is dependent on how you operate and maintain the engine. They are only at full boost, whatever it may be, for a few seconds per gear. Being electronically monitored (sensors), the turbos should last their expected lifetime with proper care and maintenance. I love 1 BAR of boost, if you are considering a chip, by all mean do it!!

2.7tDallas

and almost only on the S4, not A6..might be becuase we disapate the heat better

captainbilly

The biggest problem with increasing the boost on these engines, assuming the chipping was well done, is turbo damage not engine damage. If you use the correctly sized turbo and properly designed chip (with correctly sized injectors, TBB that won't tear, etc.) the engine can probably run much more than 1 bar. But, if the chip allows some detonation (knock) at high boost pressures than the whole thing could blow up in your face in a few miles of full power use.

On the other hand, I am very nervous about these 100 octane chips due to the fact that they may be pushing the stock turbos to the ragged edge. Maybe I am wrong, maybe they are getting the extra power by not retarding the ignition due to less tendancy to detonate but, if the power comes from more boost, I fear for the turbos.

Singletrack

Overboost feature?

AndrewWK

that it's for use while passing. I'd really like to see the difference after chipping on the boost gauge.

AndrewWK

Singletrack

I'm not sure where it starts to become inneficient, but I don't think it's long after that...maybe 18PSI or so.

I've never heard that refered to as an overboost feature, is that from audi docs or something? I always think of max boost in terms of being in a specific gear at WOT.

-st