J-Mod Revealed

Performance Nirvana

You’ve heard about the J-Mod.  You’ve wondered, ‘how can I get the J-Mod?’  Now, finally the J-Mod is available.

When performance at all costs is your goal, J-Mod can help get you there.

Everyone knows that air flow to your motor is what makes POWER!  What few realize is that pressure losses before the turbo impact performance two and a half times as much a post-turbo losses.  The money you were saving for those big honking side mount IC’s, forget it, pre-turbo pressure losses are where it’s at, and that’s precisely what the J-Mod targets like a fat guy going for the Chocolate fountain at Golden Corral.

Extensive R&D

Born out of flow bench testing, the J-Mod delivers measurable gains in intake airflow.  Did we mention that air flow is what makes POWER!

The Secret

The J-Mod development effort involved multiple specialized tools operated by dedicated craftsmen tirelessly working to uncork more POWER from your motor.

J-Mod transforms your car’s intake system from mild to wild and unleashes all of the ground pounding POWER you’ve dreamed about.

Achieving intake bliss

The cost for this service is reasonable for all of the POWER your S4 will gain.  Contact us directly to discuss installment payment plans.


While not recommended, the following Do-It-Yourself section will give guidance to those desiring to try this at home.


Begin with your stock air box upper.

Audi B5 S4 stock airbox intake
Unmodified Stock Airbox

Got a steak?  Get a fork ’cause you could cut it on that edge.  Air doesn’t like sharp edges, and neither does the J-Mod.  After the J-Mod your intake will look like this, smooth as a babies bottom.

Modified Audi B5 S4 Airbox intake
Post J-Mod

The entire turbulence generating edge is wiped out, leaving behind a smooth curve that guides airflow along to your awaiting turbocharger.

From the inside of the airbox you can see how thoroughly the J-Mod addresses intake deficiencies.

Intake Pre-Mod
Intake Pre-Mod

The sharp edges above are wiped out, leaving behind a smooth path for the air to adhere allowing the airflow to remain laminar, minimizing intake losses and resulting in more POWER.  Look below at the finished product.

After J-Mod view of inside the airbox.
After J-Mod view of inside the airbox.

 The Real Deal

Out of curiosity I thought I’d smooth the inside edges of the airbox up near where the MAF housing fits.  Smoother is better than sharp in this location so I took a file and sandpaper to the plastic and smoothed the edge out.  As the flow bench testing showed, it did make a difference, but is so small (about 3/100’s of a psi) I doubt it matters – but hey it improves airflow and that’s a good enough claim for most after market performance products.

Airbox pressure loss chart
Airbox pressure loss various configurations