Going through some old files I came across this picture:

The first vendor claim that I tested, AWE’s S-Flo intake.

The product is a cone style air filter that was purported by AWE to have increased air flow rates through the MAF sensor by 25 grams-per-second.  That is an astonishing increase in airflow rate simply by changing from the stock airbox and flat panel filter to an open element cone type filter.  At the time of the AWE S-Flo’s introduction in the 2000 time period I hadn’t yet grasped that with the stock MAF sensor a grams/second change resulted in nearly a 1 for 1 wheel horsepower change.  That would have meant the S-Flo should have resulted in close to 25 additional wheel horsepower if it in fact did increase airflow rates by 25 g/s.

I had been reluctant to try the AWE S-Flo, a prior test performed by another Audiworld forum member on a K&N panel filter had shown no improvement over the stock air intake system.  Still, I was hopeful AWE was accurate in their claims for the product and when a Group Buy was started to give a discount price on the S-Flo I decided to give one a try.

As the buy group members began to receive their products I was slow to get around to installing mine.  Another forum member with a car setup just like mine had recorded some measurements of airflow.  An important point to remember is that back in the mid-2001 time frame all of the B5 S4’s were relatively uniform in terms of modifications, there simply was not all that much that could be done to the motor outside of a Stage 1 tune, exhaust muffler system, and intake filter.

The other forum member, “Black BiTurbo”, had his car setup just like mine, and he provided me with the VAG-COM readings from his car with the AWE S-Flo installed.  I recorded my car and compared our data.

The results shown above were a small surprise and a big disappointment with AWE Tuning.  There was no difference, using the S-Flo was no better than the stock air intake system.

I began to bring this point up with AWE representatives on the forum.  They said they would be dyno-ing an S4 with their S-Flo intake to prove the performance gains.  Months passed with no dyno test being conducted, then years went by, still nothing.  Eventually after making the same claims for over a decade AWE stopped selling the product, never having backed up their claims as they had stated they would.

If you look around you can still find other vendors peddling the AWE S-Flo with the same unsubstantiated claims, 

I ended up sending my unused AWE S-Flo intake back to the vendor for a refund.