1.8T Tuning Guide

1.8T Tuning GuideEverything You need to know about Tuning your EA888.3 1.8TOver the last 18 months, we've gathered a lot of information about these stout EA888.3 engines. Here's what you need to know before building and tuning your EA888.3 1.8T and what to expect.Let's get started!
The 1.8T is a little powerhouse hidden in sheep's clothing. Simply flashing your 1.8T with a Stage 1 tune removes that fluffy white coat and brings the EA888.3 to life. The real problem with this powerplant is the transmission that VW decided to mate it with. In some models, the 1.8T is paired with a lethargic and under equipped Automatic 09G slush box. If you're one of the unfortunate ones stuck with this transmission in your Golf or Jetta, you won't be able to read past this point without some sense of regret and frustration. Since our Stage 2 tune will require a DSG tune or clutch upgrade to control the torque, the 09G optioned vehicles are unfortunately not able to handle any more power than Stage 1 without causing drivability issues. However, the Stage 1 gains are still very impressive and will reignite your love of driving and make any milk run fun.Stage 1 Dyno graph showing crank horsepower and torque with 93 Octane (98RON)Bitten by the Tuning Bug.If you are one of the lucky ones with a manual transmission, or a DQ250 DSG transmission, you'll be able to scratch that unwavering itch for even more power. Once the butterflies subside after enough seat time in your new and improved Stage 1 tuned 1.8T, you'll be browsing for your next upgrade to squeeze even more power out of your grocery getter. Downpipe, intercooler, and maybe a clutch upgrade will be topics that you research day and night making sure you buy the right parts to get the most bang for buck. I'm here to tell you not to worry too much about the brand of hardware that you choose. Without getting into the nuances of every manufacturers different pitch or fancy product descriptions, here's what you need to consider for your hardware upgrades.Downpipe:The main requirement for an upgraded downpipe is that it increases exhaust flow from the turbocharger. Catted downpipes help reduce smell and in most cases also help with sound. Catless downpipes essentially remove all exhaust restriction with the downside (or upside depending what side of 1999 you were born on) of increased exhaust fumes, and sound. You can also pair it with a matched catback system to improve sound and maybe see a few more horsepower as well. The important thing to know about the EA888.3 engine is that it requires the function of the O2 sensors. Do not try to "trick" your O2 sensor by shoving it in an "O2 spacer" or a "J-Pipe", your lambda readings will be incorrect and your ECU will try to adjust for it not knowing that you've tricked the reading mechanically. During our development, we chose the HPA catted downpipe. Our beta test vehicles had other brands and all performed similarly.Intercooler:Keeping your Intake temperatures low and efficient is another key part of making safe and consistent power. The factory intercooler is quite small, and with the increase in power also comes an increase in heat. To manage this heat, your intercooler should be upgraded. A larger front mount intercooler can help reduce Intake Temps. With a larger surface area, a larger core, and being mounted directly in front of your radiator can help bring your intake temps down, make them consistent, and combat heat soak. For our development vehicle, we used a front mount intercooler kit from eBay, but if you've got money to burn, anything with a name brand stamped into the end tanks will do just fine. Remember, you just need cooler air. The car doesn't care what brand you picked.Intake:Don't be fooled by a fancy cone filter clamped onto a mild steel tube with some fancy powder coating that claims to increase horsepower by 5-10%. In most cases, aftermarket intakes are a gimmick. There are some that will improve performance, but do your research if you are actually interested in increasing performance. If you've read this far, I assume you are interested in increasing performance without wasting money. Food for thought, the power figures that are published on our product catalog were realized using the factory airbox with only a K&N filter panel upgrade. In most cases, the factory plastic (polypropylene) intake system will perform better than a steel pipe and heat shield because it is inherently resistant to heat. Many aftermarket intakes actually increase Intake Air temps and reduce overall performance. But this article isn't a case study on thermal dynamics, so let's move on without breaking the bank on a fancy cone filter with pretty colours.
MoAR PoWAr!Now that you've exhausted yourself researching the best parts to buy for your build, got them installed, and flashed your ECU with the Stage 2 tune from your favourite tuner, it's time to enjoy your little boost in power. But then, a few months later you're back here reading the rest of this article wondering what the next step is in your new found quest for horsepower gains. So let's dive into what Stage 3 looks like for your 1.8T.Traditionally, in our little VW world Stage 1 is a simple ECU tune upgrade requiring no hardware modifications. A simple flash and away you go. Stage 2 typically means you've done basic hardware upgrades such as a downpipe upgrade and maybe some other various hardware upgrades to improve cooling, such as intercooler, intake. Generally just bolt on upgrades that replace factory parts with upgraded or improved versions. Once you've tapped out your bolt on options, it's time to start looking deeper into the major components like turbocharger upgrades and fuelling upgrades. Bigger fuel pumps, larger turbo, but leaving the internals alone... for now.For the 1.8T, Stage 3 looks a little bit different. We have many turbo upgrade options to choose from. The factory equipped IHI IS12 Turbocharger comes stock on the 1.8T and runs out of steam for higher horsepower goals. A direct bolt on replacement is available by using the IHI IS20 commonly found on the VW GTI 2.0T, and the even bigger IHI IS38 found under the hood of the VW Golf R. And then there are aftermarket turbo upgrades that also suit this engine, but we'll get in to those later. The most common upgrade path for most 1.8T owners is an OEM IS20 or IS38 turbocharger. Because they are so common, they can be found on the used market for quite cheap, but even a brand new one is not going to burn an enormous hole in your wallet. Fitment is spot on, and calibration is easy. It's a perfect upgrade to push your 1.8T into Stage 3. But which turbo is better? The short answer is both. For the long answer, continue on.We tested both of the popular turbo upgrades to compare them for you. Because the IS38 is quite a bit larger, it will come with the downsides of a slower spool in favour of more top end power, whereas the IS20 will spool up quick and strong, but taps out before the IS38 is out of breath.Comparison dyno graph showing power figures for IS12, IS20, and IS38 turbochargers.In the above graph, we can see where the IS20 helps bump the entire powerband up almost evenly across the board, keeping similar driving characteristics as the IS12, just amplified. When we look at how the IS38 behaves we see a much slower ramp up in power until around 3500rpm where it starts to pull away from the smaller options. The nice thing about these turbo options is that these power figures are realized with the factory fuelling. But there are still benefits to upgrading your fuel system with MPI (multi port injection).What is MPI and why should I get it?MPI, or Multi Port Injection is not new. In fact, it's the old way of doing things. With tighter regulations and consumers wanting more fuel efficiency, DI (Direct Injection) was introduced into newer vehicles as a better way to control the combustion process and make a more fuel efficient vehicle and reduce emissions. So why do we want to introduce an MPI system back into our vehicles?With a Multi Port Injection system, your fuel is injected into the intake ports, just upstream of the intake valve. Each cylinder has its own injector, and fuel is mixed with air before entering the combustion chamber. This indirect method can result in a more homogeneous mixture, aiding combustion stability. An added benefit is that port injection also cleans your intake from carbon deposits as the corrosive fuel mixture goes through the intake ports and not directly into the cylinder where it bypasses the intake manifold.How does this improve power?Comparison dyno graph showing the power increase between stock fuelling system and an MPI fuelling systemBy adding MPI, we are able to add more fuel and generate more power. Above, is a comparison of an IS38 equipped 1.8T with and without MPI. You can see where the MPI helps generate more peak torque, and sooner in the RPM range than without. There's also a noticeable bump in Horsepower across the entire RPM range. In the end, it's a peak gain of over 25ftlb and over 10hp.What you need to be able to run MPI on your 1.8TWith so many options for MPI upgrades available, we have developed flex fuel tuning for several combinations of hardware upgrades.

MPI Option 1

MPI kit with Bosch 980CC injectors
OEM RS3 pump and controller

MPI Option 2

MPI kit with Bosch 980CC injectors
Hellcat 525 pump and stock controller

MPI Option 3

MPI kit with Bosch 925CC injectors
EQT Brushless pump Kit

Now, if your plan is to not get wild and spiral out of control with upgrades, you may not see value in the cost : horsepower ratio of adding MPI to your IS38 or IS20 equipped 1.8T. But you didn't read all the way to here just to not go deeper down the rabbit hole of 1.8T tuning, and these fuelling upgrades are required to get to the next level in your Horsepower Conquest.Flex Fuel Funhouse!That's right. To increase power even more, you can turn to the power of corn! Ethanol to be exact. A biofuel that has a different combustion characteristic than gasoline. It burns more completely and at a cooler temperature which aides in keeping your EGT (Exhaust Gas Temperatures) down while increasing power. Ethanol also contains oxygen, which can enhance the combustion of hydrocarbons in the fuel. With flex fuel tuning, your ECU adjusts to the ethanol content in your fuel system and adjusts timing and boost accordingly.Although flex fuel can help you get more power out of your vehicle, it also requires (in this application) the addition of an MPI system. The below graph illustrates how ethanol content can contribute to your peak figures.Comparison dyno graph showing the power gains from 93 oct, E40 (40% ethanol), and E65 (65% ethanol)Starting at 93 octane, we see our healthy power and torque curve. When we introduce a 40% Ethanol mixture (E40) we see the top end starts to get more head room. Even at 65% (E65) we are still seeing more power being made. With the True Flex Fuel feature, your vehicle will adapt and adjust power output on the fly based on your tanks ethanol content. No need for switching tunes or flashing a different octane file for every increment of ethanol content that is added to your fuel tank.So the only big question is, how much power is enough power for your small 1.8T?Watch a customer drag race his VW Alltrack with our Stage 3 Flex Fuel tune on his IS38 equipped 1.8TIf you've read this far and you're now ready to start the voyage of tuning your 1.8T, have a look at our product catalog. Click Here