If you have a Subaru WRX, chances are you also have a COBB Accessport. Everybody and their mother has already reviewed it. Even Right Foot Down reviewed it once before when Josh got one for his briefly owned WRX. So I’m going to gloss over the usual babble about what it is, what it does, and how it works, and focus on a slightly different subject – how useful is the Accessport for daily driving, as opposed to racing or squeezing as much power as possible out of the FA20 engine?
The Usual Babble
OK, I should at least give a little bit of background information in case you’ve been living under a rock. The COBB Accessport is a small smartphone sized device that plugs into the OBD2 port of your WRX (or Forester XT, or various Fords, Volkswagens, Porsches, BMWs, Mazdas, Mitsubishis, and the Nissan GT-R). It comes pre-loaded with a number of off-the-shelf tunes for various conditions or stages of tune. For example, a Stage 1 tune works with an otherwise stock car, while a Stage 2 tune for my WRX requires an aftermarket J-pipe, a popular and effective power adding mod. You can customize features like a shift light, launch control, and flat-foot shifting, run performance tests, diagnose and clear OBD2 trouble codes, and configure up to six different gauges to monitor engine parameters in real time, as well as log them. Finally, professional tuners can use the Accessport to give your car a custom tune, optimized for your particular car and combination of modifications.
At $650 it’s far from cheap. It cost me more than an entire 2003 VW Jetta. I justified the cost because I’m simply turning over the profit from selling BRZ parts into upgrades for my WRX, not investing additional project car money into it (that’s being saved for the Smyth Ute). I admit, a stretch goal of mine with this car is to one day get the same 305hp out of it as the STi while maintaining the superior daily drivability of a non-STi WRX. Seeing as how the WRX already makes 268hp from the factory, that’s only a 37hp deficit. According to several dyno charts I looked at, COBB’s Stage 1 off-the-shelf tune already gets you around halfway there. But let’s not get stuck on numbers. What’s the experience like, particularly for the commuting and spirited daily driving that I do?
As programmed from the factory, the WRX has plenty of power and is fun to drive. Even with just a little bit of throttle the car wants to take off like a rocket. And there’s the rub. Among the parameters I can look at in the center screen – even without the Accessport – is throttle position. When I push the pedal down 20%, it indicates at least 50% throttle. When I give it 20% throttle, I want 20%, not 50%. Josh made exactly the same complaint about the stock tune in his review. And when you break on through to the other side and put your right foot down to the floor, you end up not getting much more power than you did at “light” throttle. It’s quite promising and dramatic to get so much power at once, but the WRX doesn’t follow through on its promise and falls flat at higher RPMs, where it doesn’t have that much more to give. This is the exact opposite of my BRZ, which generated its normally aspirated peak horsepower at 7,000 RPM, well above the WRX’s redline despite sharing its FA20 motor minus the turbo (unfortunately). This makes the WRX difficult to drive conservatively. At lower speeds and throttle input, it always wants to go, go, go. It’s not good at just cruising along at 5-10 MPH under the limit in traffic, which is the vast majority of my daily commute.
Stage 1 OTS 93 Octane Tune
I swiped one of Josh’s screen shots here, which is why its shows the much older v1.14 tuning maps. My Accessport came with v3.01 maps already loaded. At the time I’m writing this the latest map is v3.02, but the changes only apply to the 2017 WRX, so mine is still basically the latest available for my car. Like Josh, I chose the Stage 1 off-the-shelf tune for 93 octane gas. (There is also a 91 octane tune available, which I’ll use when I travel and that’s the best gas I can get, but fortunately the sweet 93 stuff is available where I live in Massachusetts.) The Accessport install and reflash was easy. The unit walks you through it step by step.
Immediately, I found my WRX to be much easier to drive. It’s slower at low throttle inputs, but that’s actually good. Throttle response is much more linear, and 20% throttle actually means 20% throttle now. When you need to drive conservatively, it’s much easier to do. Conservative driving isn’t the reason most people get a tune. It’s not why I got one, either. But it’s a significant side effect that I feel most other reviewers overlook. As much as we’d love every road to be our own personal race track, that’s not how the real world works. In fact, between the tune and the Perrin shifter stop I already installed, I think my wife is going to have a much easier time driving the WRX now than she would have in stock form. She knows how to drive stick, but isn’t very experienced. I think it would’ve been difficult for her to find the fine line between too little and too much throttle that the stock tune provides. That line is now a grey area rather than a razor’s edge.
But don’t worry – the Stage 1 tune also delivers when you plant your right foot down. There’s a little bit of turbo lag, but not much, and the power continues to build all the way to redline rather than letting me down at higher revs like it used to. Power delivery is consistent and predictable throughout the RPM range, not all over the place like it was in the stock tune. I feel more confident in the car now, knowing what it’ll do and exactly how much power it’ll give me at any point in time. I feel like I can work with this.
One point worth noting is that my peak boost is actually lower than stock. After a fairly long drive where I played a bit on the highway, I’m only showing a peak of 17.8 PSI, much lower than the 21 PSI that the car recorded before I installed the Accessport, then reset the built-in boost gauge. That boost was only a spike, though – another result of the stock tune’s inconsistency. But this particular tune is supposed to give me a maximum boost of 19.5 PSI, and I was a bit below that. I can try the High Wastegate (HWG) version of the 93 octane Stage 1 tune to see if that helps. But now we’re talking about tweaking and optimization, which I wanted to avoid here. Let’s get back to the point.
Is It Worth It?
We know the COBB Accessport, its off-the-shelf tunes, and ability to improve your particular car’s tune even further with custom tunes is a wonderful thing to improve performance. But how well does it work in the real world, when you’re not chasing lap times or horsepower figures, but that Prius in front of you that won’t go faster than 5 MPH under the limit? Is it worth getting an Accessport if the vast majority of your driving is commuting in traffic?
Absolutely. Though I definitely notice the horsepower increase and enjoy it, I think the Stage 1 tune vastly improves the WRX at what it does best – being One Car To Rule Them All. It’s easier to drive, easier to control, and the power builds more predictably than stock. It may not make as much peak boost as stock, but again, it’s not worth chasing those kinds of numbers to get the best performance out of the car. Plus, my butt dyno tells me that peak horsepower has increased, which is what ultimately counts. COBB’s Stage 1 tune has transformed the car to drive the way I want it to drive, rather than having to work with its quirks. I don’t even feel like I need any more performance for a good long while.
Though I’d still like to chase that STi horsepower goal someday. When I’m ready, the COBB Accessport will be there to help.