eriksmartt.com/blog

subaru links

- Impreza S203
Subaru has announced an update to the Impreza S202, called the S203. Think of it as an upgraded STi with the power of a Spec C. The site’s in Japanese, but it still has some nice pics.

- http://www.superhonda.com/photopost/data/516/559Suparu-med.jpg
I don’t really know what to make of this, other then hoping it isn’t true. I can’t read the page to know what this is, although it looks to be an example of how Subaru’s latest styling cues might be applied to the Impreza:

[update 2004-12-28]
- Subdriven: S203
Found another article about the S203 — this time in English.

Cold weather fuel leak

We were out running errands the other night when the smell of fuel started filling the cabin of my 2002 Subaru Impreza. At first I thought it might be another car in traffic, but quickly realized that the obnoxious odor was coming from my engine bay. One of the Service Managers at a Subaru dealer had warned me about this a few months prior, but I didn’t realize that it was related to the cold weather. Apparently when it’s cold enough outside (which it has been here), one of the fuel hoses contracts and fuel leaks out onto the passenger side of the engine (near the turbo.) Subaru of America has acknowledged this design flaw with a service bulletin, but it’s not considered a recall or warranty work (which I guess means it’s little more than a warning that it happens, and that some re-designed parts are available to solve the problem at the owner’s expense.)

Before doing anything with the car I searched through NASIOC (North American Subaru Impreza Owner’s Club) to learn more about the problem. Interestingly enough, there have been over 10 other local owners in the past couple days that have posted about the exact same problem. (It’s unusually cold right now.)

The next day I stopped by a local Subaru dealer only to be sadly disappointed with their interpretation of “customer service”. Since I recently moved, I don’t know where the best places in town are for this kind of thing, but I can tell you that this particular dealer won’t be getting any of my business. They were terrible, which was particularly bad since the local dealer in my old town was amazing. So instead of giving my business to these guys, I’ve order the parts from an out-of-state dealer who’s always been pleasant. I also made a point to post to some of the boards about the poor service at this dealer.

I bring all this up for a couple reasons: (1) If you have a 2002 WRX getting up near 50k miles, there’s a known issue with the fuel line on the passenger’s side of the engine (under the intake manifold.) If you’re still under warranty, I’d go in and complain about a fuel smell just to get the work done. (2) Subaru is aware that this first batch of WRX’s leak fuel when cold, but haven’t recalled it. And finally, (3) I love my car, and everyone I know who owns one loves it too — but all it takes is one jackass (actually two) at a dealer to make potential customers post bad things to their blogs and discussion boards ;-)

[Update: 2007-03-20]

I’ve noticed that this post (and my Texas heat and a coolant leak post) still get quite a few hits, so I thought I’d add some extra info (and turn comments on, which they should be now.) First, the fuel leak is caused by a short section of rubber fuel line that connects two sections of hard line under the intake manifold. When cold, everything contracts, and there’s a possibility for fuel to spray out from the connection.

When I took my car to the dealer, I was slightly over 50k miles, and they refused to do the service under warranty. Instead of paying the (rather large) fee to have the dealer swap in new stock lines, I decided to go ahead and install some after-market steel-braided lines myself. Doing this yourself is a pretty big job — you’ll be pulling A LOT of parts out of the engine bay. I’ve included a few photos below to illustrate:

The engine bay pulled apart. This is what you’re getting into if you decide to do this yourself. Just about everything above the engine has to come off:

Don’t forget that once you pull all those parts off, you’ll need a lot of new gaskets and hoses to put it back together. If you have any other mods or maintenance you were thinking of doing, now’s the time. (Ex., fuel filter, spark plugs, coolant hoses…)

The intake manifold getting the new fuel lines installed:

Back together:

Note that “back together” means assembled, but with a number of changes. The Perrin doc’s didn’t mention it, but there are a few parts that will no longer fit once the larger, Perrin fuel rails are installed. Most notably are some parts known lovingly as the Green Brackets of Death. The GBD’s are heavy steel pieces that cover the fuel injectors to protect them in the event of an accident. (Breaking off a fuel injector during a crash is a great way to start an engine fire.) The GBD’s will no longer fit once the Perrin rails are on. Once you’ve come to accept this, the next thing you’ll notice is that the left GBD also features some crankcase ventilation hard-line welded to it. By not re-using the GBD’s, you lose this as well, and now you need a new solution for your crankcase breather hose on that side.

Testing fuel pressure with the new fuel rails:

Don’t try this at home, but with a little painter’s tape, even a test gauge can be visible from the cabin:

[Update: 2008-08-13]
Here’s the Subaru Service Bulletin (#09-36-03):

Found it on this thread: http://forums.nasioc.com/forums/showthread.php?t=1421635

Googl’ing for http://www.google.com/search?hl=en&q=subaru%20service%20bulletin%20fuel%20leak also brings up a lot of info.

An evening with COBB Tuning

Last thursday, Subaru of Dallas hosted what they called a “High Performance Tuning” session, with keynote speaker Trey Cobb of COBB Tuning.

The event started with the obligatory pizza and beer, then moved to an introduction of the staff, some history of the new dealership, and a hint at where the dealership is heading. The most notable new information is that Subaru of Dallas is expanding to add an STi showroom, which will stock the entire line of STi parts. This will be the first STi showroom in the Americas.

Trey’s presentation focused entirely on their R&D process and the new parts they are offering for the Impreza and Legacy. While this wasn’t quite what I was hoping for, it was rather informative. Trey spent a significant percentage of time discussing their new downpipe and the thinking behind it’s fabrication. His first point was about the casting process for the bellmouth housing. It’s two notable features are a taper design that doesn’t interrupt flow coming from the turbo exhaust port (the taper is on the waste-gate side), and a casting made from stainless steel instead of iron (using an investment cast instead of a sand cast for a smoother surface.) The bellmouth housing is then slipped over a 304 stainless steel pipe (with a small internal gap to leave room for metal expansion), which is joined in a zig-zag patterned fusion weld (a TIG weld with no filler metal.) The odd shaped joint was designed for increased strength, which should allow this section to hold up to exhaust heat abuse better then a traditional pipe weld. The bellmouth also features a top-mounted O2 bung, which is conveniently located if you’re not using heat shields.

The new Cobb downpipe also features a very small catalytic converter. Trey wouldn’t disclose the brand, but emphasized that this is a modern catalytic converter design more popular in Europe then North America. The device is more expensive then traditional high-flow cats, but more efficient and features a lower profile. The downpipe bolts to the factory mid-pipe using the same donut flex joint used by Subaru.

After addressing audience questions about the downpipe, Trey moved on to the new Cobb uppipe. An uppipe is a pretty simple part, so instead of simply copying the factory design and removing the cat, Cobb focused on optimizing air flow through this section with extensive CAD and fluid-dynamics modeling. The end result is a 100% investment cast stainless steel part. As a fully-cast part, the piece requires no welding, thus avoiding the common joint failure seen in other uppipes. The uppipe is available in 304 stainless, or Inconel 625. Inconel is a more exotic metal that is stronger and more heat resistant then regular stainless. The qualities of Inconel make it a great choice for exhaust headers, but also make it very expensive to tool. Given the higher manufacturing costs, the Inconel part is about $150 more then the stainless piece.

Trey also pointed out the use of non-stainless, coated studs in their uppipe. He claimed that stainless studs combined with non-stainless nuts are a recipe for seized bolts. Cobb also uses a custom made stud that properly matches the factory bolt lengths, to ease installation and reduce the chance of the studs hitting an after-market downpipe.

After discussing fluctuations in the raw metals market, Trey moved to the highly controversial (in the WRX world) topic of after-market intakes. After holding out for many years, Cobb will soon introduce a short pod intake for the Impreza. While Trey is still a strong believer in keeping the stock air-box unless pushing over 400hp, he’s recognized that customers want the sound of a pod intake and are willing to purchase a part just for that.

The common problem with after-market intakes for the WRX is a disruption in airflow over the Mass Airflow Sensor, which then requires extensive ECU tuning to correct. To avoid this, Cobb designed a short intake featuring internal air stabilization channels. While describing the design, Trey mentioned that the new Subaru Legacy GT uses a very similar design in it’s factory intake. Trey only had a 3D printed model of the intake to show, but indicated that the final parts are in production.

While running short on time, Trey quickly introduced the Access Port. The Access Port is a simple ECU map storage device, which connects to the factory OBDII port, capable of storing and selecting alternate ECU maps for the stock ECU. After this short explanation, Trey quickly moved to a demonstration of his upcoming StreetTuner software. StreetTuner is an engine management solution which enables end users to modify every data point in the factory ECU — in real time. Unlike piggyback or replacement ECU’s, using StreetTuner with an AccessPort gives direct control over the existing ECU, and the ability to modify every tuning aspect available in the factory ECU (ex., low-det and high-det timing maps, the boost map, OLF cutover point, MAF correction, target air/fuel ratios, etc.) The modifications to the ECU are undetectable by the Subaru diagnostic tools used at dealers and don’t require any rewiring.

The event wrapped up with a door-prize raffle that unfortunately didn’t include any actual car parts. However, I won a Hot Subaru T-Shirt, which was pretty cool. Hot Subaru also has a short blurb about the event.

Thanks to Trey Cobb, COBB Tuning, and Subaru of Dallas for hosting the event!

A Python script to calculate UTEC map checksums

I had a sudden burst of inspiration the other night and wrote a Python script that can read/write map files for the TurboXS UTEC, along with generating or inserting the proper checksum value into the map. For Mac OS X users, I also wrote a BBEdit filter that will stick the checksum into maps you are editing with that text editor.

If you don’t know what a UTEC is, it’s probably safe to stop reading here. For those that are curious, the UTEC, which stands for “User Tunable Engine Computer”, is a programmable ECU for the Subaru WRX. Until now, there were no Open Source utilities to compute the checksums necessary to upload self-edited ECU maps, nor were there any tools for OS X users at all.

You can find the readme and pylibutec.tgz file here: pylibutec

pylibutec.tgz contains some unit testing code, sample maps to validate, the bbedit filter, a readme, and the ‘utec’ module, which contains a script called ‘maputil.py’

The code was written and tested with Python 2.3 on Mac OS X (Panther) for the 4.1 UTEC firmware. I have not tested on any other platforms, but I would appreciate any feedback, patches, etc., so I can improve the code.

Mad props go to Pete at TurboXS for explaining the checksum process. His explanation is included in the source code.

pylibutec is Open Source, licensed under the Creative Commons Attribution 2.0