RS4 Airbox

Took another step toward completing a transition over to a Bosch RS4 MAF sensor by acquiring an RS4 Airbox top.  The lower half of the RS4 and S4 airboxes are nearly identical with the RS4 airbox just having a port that opens to allow more air in.  The darintake modification, cutting openings in the lower half of the stock S4 airbox accomplishes the same function so that the only needed piece of the intake is the top half of the airbox that attaches to the 83mm RS4 MAF housing.

Another benefit to having the RS4 airbox on hand will be to flow test it versus the stock airbox.

Audi B5 RS4 Airbox and MAF
Audi B5 RS4 Airbox and RS4 MAF with Bosch Sensor

More Thermal Spacers

A while back I purchased a set of Phenolic spacers from Autospeed Performance to use on my car.  A well read visitor will note that I have thoroughly documented how the similar phenolic thermal spacers from 034 failed to impress me.  So why would I purchase another set of these?  It wasn’t to try and prove or disprove Autospeed’s claims that:

  • Proven to reduce intake air temps as much as 10%
  • Reduced intake air temperatures result in better throttle response
  • Maximizes spark advance
  • Reducing the influence of detonation
  • Overall increased torque and power

Though it would be great if these phenolic spacers managed to do all that for my S4.  No, I bought the Autospeed spacers because I had sold off the 034 spacers only to discover a while later that my RS4 Y-pipe did not fit on top of the stock S4 manifold as well without them.  I simply bought the phenolic thermal spacers to raise the intake manifold slightly.

As a side bonus I do plan on subjecting the Autospeed product to a similar rigorous evaluation as I did with the 034 product, who knows, maybe the phenolic material Autospeed uses in their thermal spacers is capable of delivering the results claimed.

Autospeed Phenolic Thermal Spacers
Autospeed Phenolic Thermal Spacers


Silicone RS4 MAF Hose

Adding to the inventory of products to test out on the flow bench I’ve acquired a Silicone RS4 MAF accordion hose from 034 Motorsports.  I didn’t pick this up just to test 034’s claim – “Features a larger inside diameter and smoother surface for better flow” but I will be able to put it to use on my car as well.

RS4 MAF Accordion Hose