Upgrade your B9 or B9.5 Audi A4, A5, Allroad or Q5 2.0T to support ethanol and gain some more power with this easy to follow guide
You've upgraded your intake, intercooler, freed up your exhaust flow and installed Stage 2 tuning. You love the power, but now you want more. If this is where you're at, you may be interested in installing ethanol (E85) tuning to your Audi B9/B9.5 2.0T vehicle. If you find that you're in this situation, this guide will hopefully help you to understand what is required to make the jump to using ethanol in your car.
How Does Ethanol Make More Power?
Ethanol is able to make more power simply because it is a much more stable fuel than most gasoline. In E85 form (85% ethanol content), its octane rating is 108. This is several points above 100 or even 104 octane racing gasoline. Because of this, it is incredibly knock resistant, which means that tuners can advance timing and boost pressure to much higher levels than your typical 91 or 93 octane pump gasoline. Ethanol also tends to run a bit cooler than gasoline, which is also great for more performance.
Vehicle Models Covered in this Guide
If you have an Audi B9 or B9.5 model (in the US) equipped with the 2.0T Gen 3 TSI engine, this guide is for you. Please note that in 2021, Audi switched B9.5 models to the Gen 4 TSI engine, which are not covered in this guide. If you are unsure about which engine you have, please feel free to contact us.
- 2017-2020 Audi A4 Quattro 2.0T
- 2017-2020 Audi A4 Allroad 2.0T
- 2018-2020 Audi A5 Quattro 2.0T
- 2018-2020 Audi Q5 Quattro 2.0T
Software Hardware Requirements
Regardless of which model you have, the requirements to use ethanol in your B9/B9.5 2.0T vehicle are the same. You'll need to install an ECU tune designed to work with ethanol and a few upgrades to the fuel system as well. Read on to learn more about the required tuning and hardware below.
ECU Tuning
At the moment, Audi B9/B9.5 2.0T ethanol tuning is available from both 034Motorsport and Integrated Engineering (IE). The software from either tuner will allow you to take advantage of using ethanol, but the options available to you are slightly different.
With 034Motorsport's E85 tuning, you can simply flash your ECU to an E85 tune and drive it as long as you have filled your tank with E85. You'll just need to make sure that you run as much gasoline out of your tank before flashing to the E85 tune. If you plan on switching back and forth between gasoline and E85 tunes, you'll also need to purchase an 034Motorsport Dynamic+ Flashing Kit.
With IE, you have two choices. You can flash your car to their E85 tune whenever you have E85 in your tank. Once again, you'll have to make sure that you've run as much gasoline as possible out of the tank before flashing to E85. If you don't plan on getting the TrueFlex kit below and want to switch between gasoline and E85 tunes, you'll also need to purchase an IE Powerlink Flashing Interface.
Alternatively, IE also offers their TrueFlex Sensor Kit. This kit includes an ethanol content sensor and all of the parts necessary to splice it into your factory wiring and fuel system. Once this kit has been installed and you've flashed to their TrueFlex tune, the sensor will tell your ECU the level of ethanol content being fed to your engine and adjust the tuning to compensate.
Fuel System Hardware Upgrades Required
While ethanol can make more power than normal pump gasoline, it also burns very quickly. This means that no matter which tune you end up going with, you'll need to upgrade your fuel system to keep up with the increased fueling demand.
The main restriction in the fuel system of B9/B9.5 2.0T vehicles is the high pressure fuel pump (HPFP). Unfortunately, all B9/B9.5 vehicles equipped with the Gen 3 TSI engine use a HPFP that is laser welded shut. This prevents you from taking it apart and upgrading it's internals for increased fueling capabilities. Fortunately, there are several other versions of the Gen 3 TSI engine that have a HPFP that can be opened up and upgraded. In this case, the HPFP from the 2.0T engine found in the VW Mk7/Mk7.5 GTI, Golf R, Audi 8V A3/S3 and 8S TT/TTS can also be swapped over to Audi B9/B9.5 models.
Another part is required to perform this swap: a new vacuum pump. This is simply because the new HPFP is not physically compatible with the existing vacuum pump on your B9/B9.5 Audi.
Finally, you'll also need a larger fuel piston for your new HPFP. This upgraded piston is larger to allow the HPFP to keep up with the increased demands of ethanol. Installation of this part is fairly simple with either the 034Motorsport or IE tool (both available as an option in our kit), a bench vise and some basic hand tools.
Alternatively, if you don't want to do all of the disassembly work yourself, 034Motorsport also offers an already upgraded HPFP that is assembled and ready to install.
One Kit to Rule Them All
Since we realize not everyone wants to piece together all of these parts, we've put together an upgrade kit. This kit is complete and includes everything required for this upgrade. Even the mounting hardware and gasket is included. In addition, you may choose which brand of internals you'd like to use to upgrade the pump. You can find the kit here. The parts included in this kit are the same ones that we use when upgrading the HPFP on an Audi B9/B9.5 2.0T vehicle in one of our shops.
I hope that this guide has made it a bit more clear on what is required to run ethanol in your Audi B9/B9.5 A4, A5, Allroad or Q5 2.0T. If you have any further questions, please feel free to contact us.