Sorry for being a novice, but I have a quick question . If anyone can answer for me, It'll be much appreciated. I was wondering if the 2006 S4 B7 comes stock with a single or double fuel rail feed system. Just ask this question because I was interested in the Hyperflow Air induction system, which apparently may cause overfuleing if there is only a single fuel rail system. Thanks S4 rulz

 

I hate it when newbies ask such stupid questions....j/k...

I'll ask all the stupid quesitons around here! What is the difference between a double and single fuel rail system? (other than the obvious). I've never heard of either term.

 

As far as I know, all Audis are using the common rail system (all cylinders are located on a single high-pressure rail). 2006 models are using the latest piezo injectors. The injector, located on the intake side in the cylinder head, is served by a high-pressure pump driven by the camshaft and a pressure reservoir shared by all cylinders: thus, the "common rail" system.