World One Performance Blog

Continuing from the other day’s blog, you can see we’re obviously a day behind. But, let’s continue without delay!

The UTEC quickly became the go-to form of engine management between 2003 and 2004, but soon Cobb released their own AccessPort to compete with the UTEC. The AccessPort was a reflashing device instead of a piggyback ECU, which offered several advantages. Being a reflashing device, nothing needed to be installed between the stock ECU and the car (like how piggybacks are installed), and since it reflashed the stock ECU, it was similar to the ECUtek in terms of tuning resolution. Since this reflashing was done through the car’s OBD-II port under the steering wheel, the AccessPort could also be used to log and/or display types of data, such as RPM, throttle position, and more. The AccessPort also included pre-made basemaps for specific engine mods, which made it just as easy, if not easier to use, than the UTEC for those who are not interested in doing their own tuning. Cobb eventually released their own AccessTuner to allow users to do their own tuning, but it was a separate option and not included as part of the standard AccessPort package. For those who didn’t care to tune their own car, Cobb gave their dealers with AWD dynos the option to do “Protunes,” which allowed for professional tuning via the AccessPort at a shop. These Protunes could also be saved and distributed, so many Protuners released their own maps to match specific modifications as well. Despite some initial hiccups to get all of the basemaps working properly and safely for all vehicles, the AccessPort went on to become a huge success for Cobb Tuning, and it eventually overthrew the UTEC for the king of the hill in affordable engine management.

However, the basemaps that both TurboXS and Cobb supplied did have their disadvantages. In order to maintain safety, these maps were tuned for the lowest common denominator and were specific per octane level as well, to ensure that customers would not blow up their motors. While they still improved performance over being untuned and they kept the motor healthy, there was still always going to be room for improvement with a custom tune for each specific car. This still remains true today, although the margin for improvement has been able to shrink with some new engine management options available. The other problem (although not a problem for most people) is that you typically have to follow a specific mod path for the basemaps, and if you stray away from that, you have to get a custom tune for your car no matter what. While for big horsepower applications a custom map is a given, simply changing your intake away from the stock airbox is enough to warrant a custom tune, except for intakes specifically developed by TurboXS and Cobb Tuning respectively. As mentioned in the previous blog, the stock airbox is rather efficient so this may not be a big deal, but not being able to change the intake without a custom tune does put limits on your freedom of modification. Striving for more freedom of modification, other companies sought out to create another option for those people who wanted to not only wanted more freedom than he UTEC and AccessPort offered, but also get away from the limits of the stock ECU itself.

Enter the Element Tuning Hydra EMS. In 2005, Element Tuning entered the fray with their version of the Hydra EMS. The Hydra is a standalone ECU that completely replaces the stock unit. While standalone ECUs of the past required the user to tune every aspect of the car’s behavior from simply idling all the way up to wide-open throttle, Element Tuning took this difficult and time-consuming process out of the equation by taking care of all this programming already, as well as shipping the Hydra with basemaps specific to each car’s modifications, much like the UTEC and AccessPort. Moreover, Element also had maps available for a wide variety of different sized turbos, water/alcohol injection, and different sized intercoolers and intakes. The Hydra also had equal or better tuning resolution than the stock ECU, thus a basemap from a Hydra would typically be more accurate than that of a UTEC or AccessPort. This lowered the amount of custom tuning that would need to be done, but of course a custom tune per vehicle would also bring out the full potential of the car’s setup, which of course was easily possible with the provided software. On top of all this, the Hydra was also very adaptable to different environmental conditions, so the problem of having a map tuned for sea level and then needing a completely different map for mountain passes was effectively eliminated. Our own World One STI back in 2004 actually had a prototype Hydra EMS that helped it finish 2nd in its class and 6th place overall at the very first Primedia Time Attack. However, as good as this system is for tuning and adaptability, it also had its disadvantages, especially for daily drivers. The main issue is that because it’s a replacement to the stock ECU, it does not support OBD-II, and thus it will not pass emissions in just about every state in the country. The other issue, although it may be a very minor issue to some, is that you also lose your cruise control, however this is problem is apparently being fixed for the 08-09 STI. AEM soon followed up with their own plug-n-play Hydra EMS, but not until just in the past year, so support and available tuners aren’t quite as available at this time currently.

Since the release of the Hydra, both TurboXS and Cobb Tuning have updated their UTECs and AccessPorts respectively to add more features, but yet another option was introduced in 2006 that has since thrown the engine management market on its head. A group of computer-minded enthusiasts put their minds together and were able to connect to the stock ECU and then go on to start programming it. It took awhile to get things reliable and easier to use, but as it stands today, this Open Source style of tuning using the OpenECU software has become an easy entry point for customers to start tuning their own vehicles, especially since the software itself is free to download. The only purchase necessary is the Tactrix cable, that allows you to connect your laptop to your car’s OBD-II port (much like how the AccessPort connects). While OpenECU is always in a state of development, many tuners have embraced the software and use it as their primary form of tuning, allowing them to tune to the same levels as that of the AccessPort and ECUtek. Of course, the drawback is that you have to rely on user support rather than having any guarantees or formal support from a company, so in many cases, you’re on your own.

Overall, Subaru owners should be thankful that they have so many choices available to them. This isn’t the case with other makes such as Mitsubishi and Nissan. No matter what form of engine management you choose, it’s always important to understand that how well your car performs is going to depend on how the car is tuned, whether that’s strictly from a basemap or from a custom tune. If you go with a custom tune, be sure the you go to a reputable tuner that has experience tuning the type of setup that you have. After all, just because someone can tune a 300 whp car doesn’t mean that they won’t have any problems tuning a 600 whp car. As always, if you have any questions, please feel free to contact us or post a comment here. For our next part in this series, we’ll be talking about intercoolers, both top mount and front mount, and how they can affect your car’s behavior.

Yesterday, we discussed the choosing of an aftermarket catback system to the WRX or STI, not only for additional power, but also for aesthetic purposes. However, as much as we all love the boxer sound, in terms of actual measurable power, the catback alone really doesn’t do much. Thus, after the catback, the next power mod most people consider is an aftermarket downpipe. The downpipe is where the true power starts to be made, since as you can see from the photo to the right, the stock downpipe has 2 power-robbing catalytic converters, or “cats” for short. In this photo, the downpipe on the bottom is the stock downpipe, whereas the downpipe on the top is an Invidia catless downpipe. In comparing the two downpipes, you’ll also notice a few differences other than the cats: the stock downpipe is split into two pieces (some people and manufacturers only refer to the top-most section as the downpipe, and the second section as the midpipe), and the flange at the top that connects to your turbo has a flat plate. These two differences are clear examples of how different companies prefer to approach creating an aftermarket downpipe.

Before we go further however, we must make a disclaimer: removal of the stock catalytic converters is for off-road use only, and if caught using a catless system on the street, you may be cited and fined. In other words, you do have to pay to play, so make sure you’re well aware of this, especially in states like California where emissions laws are very strict and may involve impounding your car if violated. Now that that’s out of the way, most aftermarket downpipes have the following features that are geared as improvements over the stock downpipe:

• Removal of all cats or replacing 1 or 2 cats with high-flow performance cats
• Replace the flat flange at the turbo side with a “bellmouth” or “divorced wastegate” flange
• Change from a 2-piece pipe to a 1-piece pipe

Of course, just the same as with catbacks, not every downpipe is equal, and this is even more clear with the different designs out there. No matter the design though, the main thing that really should be considered is fitment. Some downpipe have problems fitting due to hanger location, but others simply have issues with fitting because they’re made to mate to their own proprietary exhaust system, so they might require a separate pipe for it to connect to the aftermarket catback of your choice. On top of this, most aftermarket downpipes will not bolt on directly to the stock catback for 02-07 WRXs and STIs, however this is completely the opposite for 08-09 WRXs and STIs, which don’t have any problem bolting to the stock catback. Why would you want to bolt onto the stock catback you might ask? Well, although you do sacrifice power by sticking with the stock catback (since it creates a bottleneck), you do get a significant power increase over stock and you don’t attract any unneeded attention from the authorities.

Once you’ve sorted out fitment issues, the next thing to consider is going catless or staying green-friendly with a high-flow cat. It has been argued that a good high-flow cat will not hamper power at levels below 400 whp, but in our experience, this has not been the case whatsoever. Moreover, running catless helps with throttle response and faster turbo spool since there’s no back pressure in the exhaust system to slow down the exhaust flow. It has also been argued that running catless creates a bad exhaust smell in the cabin, but while this may be the case when a catless downpipe is initially installed, the smell does go away over time, so long as the downpipe was installed properly with no leaks. And, since catted downpipes are typically almost twice as expensive as catless downpipes, unless you absolutely need a catted downpipe for emissions or racing restrictions, we always recommend a catless downpipe. Catless? But what about the check engine light? Well, certain forms of engine management will turn off this check engine light for you, but we will get into that when we talk about engine management in a future part of this blog series.

After deciding on whether to go catless or catted, the next big decision is in regards to the downpipe’s flange at the turbo side. Here are a few examples of the available options, other than stock downpipe’s flat plate design. First up is the “bellmouth” design, which looks like this on the TiTek downpipe:

Next up are two variations of the “divorced wastegate” design. The idea behind the divorced wastegate is that a stock style turbo has exhaust gases the escape from the turbo’s internal wastegate, and since that might cause turbulence when mixed in with the ordinary exhaust gases that exit the turbo, it’s better for these gases to exit out separately so that the exhaust flow is not interrupted. The first one is Invidia’s version, which is essentially just a flat divider plate that diverts the gases, but the gases still go down the same exact pipe further along:

In contrast, here is Element Tuning’s take on the divorced wastegate design. This downpipe actually features a completely separate pipe for the wastegate gases, which then meets up later on with the rest of the piping. The theory behind this is that it’s a true divorced wastegate and the extra smaller piping creates a venturi effect which makes the wastegate gases not only flow faster, but also create a suction effect that makes the rest of the exhaust gases flow faster as well:

In our experience, we definitely recommend either of the above styles. It’s best to stay away from the stock downpipe’s flat plate style, which can be found on a few downpipe brands out there. However, between a bellmouth and Invidia’s divorced wastegate style, we have not seen or felt a significant difference in power. On the other hand, Element Tuning’s divorced wastegate style has proven to produce more power over the other styles.

Finally, you’ll notice that Element Tuning’s downpipe is a 2-piece design, whereas the Invidia design is a 1-piece. Generally speaking, a 1-piece tends to be better when avoid exhaust leaks, but a 2-piece design gives the option to change from a catless race pipe to a catted pipe at your discretion. Not every 2-piece downpipe has an option for a catted downpipe however, so it’s best to do your research (as always) before purchasing. Nevertheless, if you have any further questions, again please don’t hesitate to contact us. For the next blogs, we’ll change gears a little bit and highlight some products and feature a customer car, but next week we’ll come back to the power mod path with a discussion about intakes and engine management.