Best Upgrades for Audi B8 and B8.5 S4

You just bought that awesome Audi S4 and have been driving it around the last couple of weeks.  When you first got it sure felt fast, but now you feel it leaving you a bit dissatisfied because you can never be happy with a stock car.  If this describes you then I understand, and we should be friends.

The Audi B8 S4 is an amazing car and the 3.0T engine responds very well to tuning and still maintains fantastic reliability.  Some of your upgrade options include:

  1. 1. ECU Tune
  2. 2. TCU Tune
  3. 3. Intake
  4. 4. Supercharger/Crank Pulleys
  5. 5. Upgraded Cooling System
  6. 6. Larger Throttle Body
  7. 7. Exhaust
  8. 8. Water Methanol Injection
  9. 9. Brakes
  10. 10. Suspension
  11. 11. Upgraded Driver

Let’s review each of these in a little bit more depth:

ECU Tune

Tuning your ECU is by far one of the most popular upgrades out there.  It is going to remap your ECU with an emphasis on performance.  Audi tuned your car with a lot of compromises due to conflicting goals of fuel economy, neglect from owners, emissions, etc.  Well, you are an enthusiast and you are going to put good fuel in your car and keep it maintained so we can tune it for maximum safe power.  We can do a flash tune from provider like APR or we can get you on the dyno and perform a custom tune.  Bang for your buck this is one of the best power upgrades out there.  You can expect to pick up over 100 horsepower with this upgrade and get other perks like the top speed limiter removed.

TCU Tune

With the introduction of the DSG transmission this is becoming a very popular upgrade.  Your factory software has a shift strategy that is not built for performance, but built for all the compromises that a mass market needs just like the ECU.  An upgraded transmission control unit, or TCU, tune can help you go faster by improving shift speeds, having higher clutch pressure to handle more power, and give you quicker acceleration.  Your transmission has a lot of impact on your driving experience and have a software strategy programmed that is geared towards performance makes for a more exciting and sporting ride.  The APR tune even includes removal of the auto up/down shift and user selectable launch control.


Upgraded intakes are another upgrade that can open up your engine up.  We typically see 15-20 horespower improvement with an upgraded intake.  While the power jump isn’t as significant as the tune it still allows a larger volume of air into the engine and also allows you to hear the supercharger whine better as well.  Depending on the intake you choose it can dress up your engine bay as well.  There are some great carbon fiber options that really fit the look of your S4.

Supercharger and Crank Pulley Upgrades

The 3.0T uses an Eaton TVS style centrifugal supercharger.  This supercharger builds boost pressure by the use of engine pulleys.  One way to make more boost pressure is to spin the supercharger faster.  This can be done by installing a smaller diameter supercharger pulley and/or a larger diameter crank pulley.  When done together we can spin the supercharger at its peak safe speed and maximum boost pressures.  The ECU will need to be retuned with these installed as the car will bypass any excess boost pressure if not calibrated for this upgrade.

Upgraded Cooling System

APR CPS Intercooler

The Audi 3.0T engine uses 1 coolant intercooler per bank of cylinders.  It allows for a compact design, but does make It difficult to upgrade.  The best way is to add a larger intercooler radiator at the front of the car to get those air intake temperatures down.  We have found APR’s CPS system functions very well and helps increase intercooler efficiency when we are turning up the boost.

Larger Throttle Body

APR vs Stock throttle body comparison

The next bottle neck on this car is the intake throttle body.  As we push the limits on this car it is necessary to upgrade to a larger diameter throttle body.  APR refers to their product as the Ultracharger Throttle Body System.  It is 28% larger than the stock throttle body and 5% larger than the supercharger inlet.  This eliminates the throttle body as a point of restriction in the system.  This is an important upgrade to consider if you drive your car aggressively as the stock throttle body is a significant restriction at higher supercharger speeds.


Exhaust upgrades on the 3.0T range from something as simple as upgraded tips to high-flow cats.  On this particular platform most folks stick with just doing the exhaust after the catted manifolds.  This is primarily due to the cost of doing upgraded catalytic converters on these cars, but also because the performance gains just aren’t there to justify the cost.  My recommendation is that you pick an exhaust you like the sound of and go from there.  Sure, you might pick up 8-10 horsepower, but you probably won’t feel it.  Unless you are dealing with blown out catalytic converters that need to be replaced anyway, I would put your upgrade funds elsewhere.

Water Methanol Injection

Water methanol is a fun upgrade as it allows you to run a more aggressive tune designed for higher octane fuel while only using pump gas.  Water methanol works by utilizing a jet of a water/methanol mixture injected into the intake (jet placement can have multiple configurations depending how extreme you want to get) to lower the intake air temperature substantially and increase your effective octane to help reduce detonation and knock.  You can see up to a 25 point octane increase with water meth set up on your vehicle.  This increase of octane rating of your fuel means more power by being able to run high boost and more advanced timing.  There are a wide range of systems and controllers depending on how complex you want the system to be, but it is something to consider on your upgrade wish list.


EBC Brakes

Now you have added all that power but sill rolling around on stock brakes.  This may not be a good idea.  There are a lot of options from simple pad and rotor upgrades, to full big brake systems with larger calipers.  You will want to be careful in picking your upgrades as some pad/rotor combinations are not appropriate for the street due to their effective heat range, but there are some really great upgrades that will keep you safe and make you look good at the same time.  Remember, slow is fast so braking is important.  You want to be able to brake as quickly as possible so you can mash that right pedal as quickly as possible.  I have had really good luck with EBC and StopTech products if you are looking for recommendations.


Suspension is another area that you can upgrade to make you faster.  Items such as coilovers, swaybars and mounts will help keep your car planted allowing you to corner and brake faster.  Just like brakes the upgrades you will want to consider are dependent on vehicle use.  If this is a daily driver a lower ride height may not be for you.  The options for suspension can be overwhelming at times, but give us a call at the shop and we can walk through all of your options and what will work best for your driving style and habits.

Upgraded Driver

This one should really be first, but we are saving it for the last because it is really the most important.  Often, we see guys at the track in 600+ horsepower cars getting schooled by old men in stock 200 horsepower cars.  This happens when the driver thinks that power is the only answer to going faster.  However, the cliché slow is fast exists for a reason.  A smooth consistent driver taking the right line and braking at the right points is key.  You can improve your skill cheaply by joining the SCCA and doing autocross in a parking lot.  There are also various driving schools and open track days to explore.  These off-road driving options will allow you to truly test you and your vehicles limits in a safe environment.

While this list has lots of goodies it is by no means comprehensive.  We would recommend that you give us a call and we can help you find the most efficient upgrade path.  Hopefully your budget and goals align, but we will do our best to get you the most for every dollar you spend with us.  We are enthusiasts and we know how a bad combination of upgrades can ruin the fun of a car.  We can help you avoid that and actually enjoy the finished project.  Call us at (801) 566-6115 and the team at Alex’s Autohaus would be delighted to talk about your project car.

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