Upgrade Guide: B9/B9.5 S4/S5 3.0T

 

The B9/B9.5 S4 and S5 are Audi's first venture back into a turbocharged B-platform since the B5 S4, and they did not disappoint! With a 3-litre displacement and a single turbo "hot-v" configuration, Audi modernized their S car while keeping packaging tight and allowing lots of room for improvement. 

The EA839 is an replacement for the EA837 Supercharged engine, using a single turbocharger (or twin turbos in the case of the RS4/RS5) and reverse-flow cylinder heads with integrated exhaust manifolds instead of the supercharged configuration of the previous generation. What this means for you is more efficient power, less heat, and much more potential for upgrades!

What follows is our recommendations based on hundreds of in-house builds of all shapes and sizes and years of tuning and development. These upgrades are used by us on a weekly basis and are recommended/required by almost every tuning company currently providing software for the EA839.

 

 

Stage 1 (400-490hp/460-600tq)

Requirements:

 

Stage 1 is the reason upgrades are referred to as "stages". This is the first step for most new owners, and usually offers the largest initial power increase and best bang-for-buck. Gains of 50-150hp are possible based on fuel choice, with E85-based tunes offering the largest gains for those who have access to it.

For this stage we recommend an intake and turbo inlet upgrade. While certainly not required, these simple upgrades improve power and torque over the stock airbox and offer an intoxicating spool and "blow-off" sound that will add to your car's visceral appeal.

 

 

Stage 2 (460-510hp/520-650tq)

Requirements:

 

You've flashed your car with the software of your choice, enjoyed the newfound gains, but the car is starting to feel tame, slower even. You've gotten used to the power and it's time to upgrade once again.

The next stage for your B9 is a relatively simple one, offering additional gains of 20-60hp over a Stage 1 tune alone. With the addition of a downpipe, intercooler, and charge pipes you will gain not only power and torque through airflow and cooling, but a sportier sound thanks to the upgraded downpipe. A high-pressure fuel pump (HPFP) upgrade is recommended at this point, but is not required unless you're running an ethanol blend fuel.

 

 

Stage 3 Hybrid Turbo (560-800hp/600-750tq)

Requirements:

 

Stage 3 is where "shit gets real". Stage 2 made sure that you have most of the required supporting modifications, Stage 3 is where you add the extra volume that the stock turbocharger just can't deliver. Expect gains of 250-400hp over stock depending on fueling! 

A high pressure fuel pump upgrade and RS injectors are required at this stage, as hybrid turbos can deliver more air volume than the stock fuel system can keep up with, even on pump gas.

 

 

Stage 4 Full Frame (800+hp/800+tq)

 

This Stage is what separates the boys from the men. Going with a full-frame turbo is a tough choice (especially with the various hybrid turbo options), but one that can easily slot you in the top of your class. We recommend a built engine for this stage, as chasing high power levels and removing the limits and constraints of a typical hybrid turbo setup can quickly stress your bottom end if not kept in check.

Due to the open-ended nature of going Stage 4/Full Frame, you may find the limits of certain components such as the stock plastic EA839 intake plenums (which can crack at higher boost pressures) and the low pressure fuel pump (LPFP), which can become overwhelmed when running additional port injectors and high ethanol contents.

It's important to note at this stage that the AL552 transmission can show weakness, requiring a trans build if you're prone to launching the car or racing from a dig. We are Pure Drivetrains dealers and offer an 8HP upgrade service for those in need.