Project Gen 3 STi:
Testing the COBB AccessPORT.
By Wes Dumalski
As it turns out owning a project car is not easy! First and foremost these are real cars owned by real people that pay for them with their own money. Life as well as well as vehicle practicality and reliability have ways of getting in the way of project car progress and/or completion. Take our Gen 3 GR STi project for example… We had had the car repainted, put back to stock all just so we could start fresh… OK so that is a total lie, the real story is that the previous project car was sold by the owner after blowing up it's totally stock motor on more than one occasion. While I personally do not have all of the gory details the demise of the previous test vehicle put a complete HALT on our build and left unfinished business under our project car tab. As luck would have it I was looking for a new all around practical car in January of this year and that practical car turned out to be a 2008 STi.
Rather than re-hash the juicy details that Mike already covered in the first two installments HERE and HERE let's get right down to business. That business is the stock tune. It for lack of a better term SUCKS! The power band is horrible with peaks and valleys that you can not only see on a dyno. graph but also feel under power delivery. Honestly I wonder how the car ever left the factory with this being acceptable. As I began to research the platform more (yes I started by reading Mike's previous articles) I realized I was not the only one that noticed this. Apparently MANY of the cars that had reliability problems were linked in MANY cases to the STOCK TUNE. Apparently in the name of emissions Subaru decided to do some funky things! The OEM tuning strategy was to lean the car out low in the RPM band between the crossover from closed to open loop. This lean condition was good at reducing emissions but bad for piston rings, especially if the car was modified in any way without a re-tune. Like many other cars there are always horror stories and while I would not consider the EJ25 the most durable of engines, if things are done correctly and conservatively it should hold moderate power just fine. In many cases the start of this project reminds me of Project 200SX where we were dealing with an engine that nearly everyone had written off and plenty of people lined up to tell us what was not possible, and in the end we proved just how much reliable power it could make! Also similar I am sure there are going to be S.P.E.'s who will tell us we can make more power by running more boost, running a more aggressive timing map or AF ratio, but alas that shit will fall on deaf ears. Just like our other projects our goal is reliable USABLE power and the FIRST step towards that goal was, believe it or not, getting RID of the factory tune.
|This sweet little handheld number is the key to your dreams…|
Enter COBB AccessPORT. Chances are you have suffered head trauma or been marooned on an island and only recently returned to civilization if this is the first time you are hearing about the Cobb AccessPORT. But in the spirit of giving you the benefit of the doubt we will offer some fundamentals. The AccessPORT (hereinafter referred to as the AP) is a handheld module that allows you to interface with the OEM ECU through the OBD II port. The primary goal is to allow re-flashing of the OEM ECU calibration to achieve a desired goal. Notice that I carefully chose my words in the previous sentence, OF COURSE the primary goal is to make more power through more aggressive parameters, but one can also choose to flash a Fuel Economy or Valet map in addition to the numerous performance maps. That's right folks, in less than a minute you can cripple your car's performance to prevent a re-creation of the airborne Ferrari scene from Ferris Bueller's Day Off. In our case, the main goal of using the AP was not just to make more power, it was to keep our motor from shitting itself. I find it rather ironic that to avoid reliability problems we actually used a product that INCREASES PERFORMANCE but alas we will just have to suffer that side effect.
Not being someone who qualifies themselves as ECU tuning savvy I was reluctant to mess with it until I could get on the dyno but upon receipt of the COBB AP I cracked open the package to see what it was all about. After reading the simple instruction manual (yes I really read it) I thought to myself 'hell even I can't screw this up”. I connected the provided cord to the OBD II port, snapped the other end in to the AP and turned the key to ON. After a few seconds the AccessPORT identified the vehicle and presented some options. It comes pre-loaded with different MAP choices for various stages of modifications. In my case the car was box stock so I chose the 93 Octane Stage 1 MAP. After backing up the existing ecu data it installed the stage 1 map. I turned the key off to finalize the install and that was it. Seriously I did nothing else and guess what that few minutes resulted in?
An increase of 53 lb ft of torque to the wheels. HP was also up across the entire power band with MUCH more usable power in the area under the curve despite a peak difference of 15HP. In addition to the large increase in power we also gained much needed reliability through less time spent at Stoichiometric due to zeroing out the Closed Loop/Open Loop delay. All of this assessment performed by my rear end diagnostic sampler on the street outside my house… OK OK so we used a real dyno with real numbers but we will get to those in a second…
I did not install the AP at the dyno. It was done one evening in my garage when I had about 20 minutes to spare between work and family time. After doing the install I went for a drive and the first thing I noticed was that it was a completely different car. Gone were the flat spots and choppy power delivery and in their place was stump pulling torque that was instantly available and fell off much less as the revs climbed. In the week and a half I drove the car before I had the chance to dyno, I also noticed increased fuel economy by an average of 2 MPG. And this was on the Stage 1 MAP NOT the fuel economy map. Honestly I was amazed by the change and my posterior dynamometer told no lies, the power was real.
|The AMS facility is MUCH nicer than our posterior dynamometer!|