“Ubuntu 7.10 will be the first Ubuntu release to offer a complete mobile and embedded edition built with the Hildon user interface components” (developed by Nokia for the Maemo platform.)

Now that’s interesting. Could it be that we’ll see Ubuntu Mobile booting on Nokia N800′s? It’s certainly a possibility — and one that could bring a larger breadth of software to Nokia’s mobile Linux tablets.

However, as interesting as it may be if Nokia adopts Ubuntu, the possibilities for wider Hildon support didn’t hit me until my drive home today. It was one of those obvious moments. I had been using my Nokia N800 while walking to my car, so the touch- and small-screen friendly UI was fresh in my mind. Then I started thinking about my Car PC. It uses a 7″ touch screen and runs Ubuntu (a full distribution, with a UI designed for full-size monitors.) Running Gnome on my cheap, in-car 7″ monitor makes for a pretty lousy experience. Text is hard to read, and everything is too small to click on. However, if this news is right, Ubuntu 7.10 will change all of that. I’ll be able to run Hildon on my Car PC! That’s killer. Imagine having Canola running in-car, sitting on 100GB of multimedia…

Audi RS4 Hillclimb (A record-breaking run, from what I gather): http://video.google.com/videoplay?docid=1806221753710392507

Audi R8 Hillclimb: http://video.google.com/videoplay?docid=6184680728064832823

(Via Autoblog)

Expecting the worst, I waited for the car to cool down, then popped the hood to have a look around. Puddles of coolant stood in every nook of the front-right corner of the engine bay, though the source of the leak eluded me. I was at least expecting to see a blown hose, but unfortunately, everything looked just fine. Since I knew that more probing was needed, I pushed the car into the garage to let it completely cool overnight.

The next morning it was time to call in reinforcements. In this case, they came in the form of a Snap-on Cooling System Tester. It’s not uncommon for a coolant leak to only happen under pressure, so a cooling system tester can be used to pressurize the system. The device is pretty simple — it’s just a hand pump, but it’s crucial for testing hoses and fittings. (Thanks for letting me borrow the tester Rob!)

The pictures below show the process:

Step 1: Pop the radiator cap from a completely cooled engine:

Step 2: Attach the right adapter…

Step 3: Attach the pump, and pump it. Watch the pressure gauge and don’t exceed the pressure your system is likely to run. In my case, I didn’t want to exceed 15 psi (~1.1 bar.)

Step 4: Watch the coolant spray out the pin-hole leak like a fountain!

As you can see in the pictures, the leak was pretty easy to find with the right tools, but would have been extremely difficult without them. Fixing it was even easier, and it gave me a nice excuse to flush the system and replace the other hoses as well (I went with higher-strength hoses for the replacements.) Also of note, you may have noticed in the pictures that I’m running a high-pressure radiator cap. (The STi cap is rated 1.3 bar.) This may have caused the blown hose, so do be aware of this when swapping caps.

If you’d like to replicate this at home, remember that automotive coolant is considered toxic once it’s been run in an engine. Always wear protective gloves when working with automotive fluids, and recycle them appropriately. (See the EPA page on Antifreeze for more on this.)

[Update]
Since this repair, the radiator lasted another year before also developing a crack and blowing coolant all over the engine bay. The stock WRX radiator features a plastic top, which was the failure point for mine. Since all the coolant hoses were replaced with high-strength lines, that plastic top may have simply been the next weakest link in an over-pressurized coolant system. Now that the car has an all-aluminum radiator, I’m curious where the next weakest link might turn up (hoping that it’s not catastrophic!)

There were a few alternatives available to make it all go back together, but I’m one of those “If you’re gonna do it, you might as well do it right” people, and to do it right meant ordering some different fasteners (that no one in town had.)

At the same time that the car was apart, I also noticed that it might be about time for a compression and leak-down test.. as it seems I may have some bad rings. Arrg… Not what I wanted to see, but then again, I didn’t really expect the motor to last as long as it did. Hopefully I can still buy some time with it though, as building a new motor isn’t exactly in the budget.

So just like last year, the holidays are over and the car’s still on jack stands (and it will continue to be there for at least a few more days.) However, I did go ahead and order one of these ATC style fuseblocks for the in-progress rewiring project. I went with the small, 6-fuse unit. Once it arrives, I can finish wiring up the new relays so that I’ll have some fresh 12v to tap. It’s a bit overkill, I know, but I’ve got another project up my sleeves that will require power (and code :-) More details to come…

So what am I up to? Mostly general maintenance. The car’s developed a slight exhaust leak from a variety of places in the exhaust manifold so I ordered new gaskets and cleaned and re-sealed it. It was about time to give everything a once-over with the torque wrench anyway, so it didn’t bother me that much and it’s easy enough to do.

Next up was a fuel pressure gauge. The changes to the fuel system made last year raised the fuel pressure slightly and I’m not sure how well the stock fuel pump is keeping up. After the original fuel system changes I used a temporary gauge to smoke test it, but I decided it was about time for a permanent installation. Unfortunately, I ended up needing one more hose fitting that just so happens to be uncommon enough for the general automotive shops to not carry it.

While installing the gauge I also decided that I might as well do the wiring proper and run fresh power to a set of relays driven by various ignition-key positions and whether the headlights are on. Unfortunately, it turned out to be more complicated then I expected to source a decent fuse and power distribution block, so that’s also waiting for next week to be finished. (On a related note, I was explaining this to a friend who commented that buying a fuse box was probably a common thing to do 20 years ago. But I guess people don’t rewire their cars much anymore.)

The next bit I found particularly interesting. I decided to mount the new fuel pressure gauge in the corner of the dash by the A-pillar. Doing the installation nicely would require a few holes to be made in the factory plastic to run wires, so I went in search of a used piece to cut up instead. I figured that a part like this should be an easy find on eBay, and if not, there are always people buying wrecked Impreza’s for parts. After having no luck with eBay or craigslist, I hit up the usual Subaru discussion boards and found the part selling used for about $25. Then out of curiosity, I called the dealer… who quoted me $25 for the part new. Huh. It is certainly a peculiar market when a scarce used part sells for the same price as a readily available new part. Once the wiring is complete, I’ll start the pillar trimming — and if I’m really lucky, my new phone will be here soon and I’ll be able to photo-document the installation.

First a little background (which has to be a bit simplified or it would be a book. Sorry.) There are exceptions, but in general, modern fuel injection systems are load (typically measured by MAF or MAP) and RPM based, and the amount of fuel injected typically increases with both of those metrics. Fundamentally, it has nothing to do with vehicle speed, the AC being on, or your tires. The fuel injectors spray however much fuel is needed to hit a target AFR (air-fuel ratio) for a given engine load and RPM.

Knowing that fuel injection rates are tied to engine load (and a few more details that I’ll try to throw in), let’s go over this list and explain why:

(1) Don’t accelerate quickly.

Accelerating hard wastes uses a lot of fuel for a few reasons. First, you’ve increased engine load; Second, the car is going to richen the mixture to reduce the potential for detonation as heat and load builds; And finally (and this is where it’s going to get messy), you might have switched the fuel injection system from Closed Loop to Open Loop.

In closed loop fueling, the car’s computer (ECU) is watching the Oxygen sensor and tuning the fuel trims automagically to target a stoichiometric air-fuel ratio of approximately 14.7 parts air to fuel. This ratio is generally agreed to be the most efficient at burning all the available fuel, and it’s also the ratio for which catalytic converters are designed to operate most efficiently. However, the car doesn’t always try to be a non-polluter. In my Subaru, for example, the factory ECU switches from closed-loop fueling to open-loop fueling at approximately 60% throttle (TPS). If you press the gas pedal past this cut-over point, the car no longer targets a 14.7 AFR, but instead switches fueling for maximum power (which in a Turbo car is anywhere from 12.5 AFR to 10.5 AFR depending on the quality of fuel — and yes, the better the fuel, the less you need.)

(2) Let your car brake itself.

It’s arguable whether or not engine braking is a good idea mechanically, but it’s generally true that the car needs less fuel under this condition. The reason, once again, is because of reduced engine load (ie., the engine is no longer working to push the vehicle, thus it’s no longer sucking in a large volume of air, thus it no longer needs to spray a lot of fuel to keep that large volume of air at a particular AFR.) The engine may even use less fuel under engine braking then it does when coasting in neutral. That said, the brakes are designed to slow car, not the engine, and the brakes are cheaper to replace, so this isn’t always a good idea.

(3) Drive at the speed limit on highways and freeways.

Speed has nothing to do with fuel consumption. It’s load vs. RPM. The simplified reason your car uses less fuel at 55 MPH then it does at 60 MPH is because if you stay in the same gear, RPM’s increase with speed (as does aerodynamic drag, which increases load.)

Of course, this rule doesn’t always hold true. If you can draft another vehicle, you’ll reduce engine load. Furthermore, gear selection plays a role. 55 MPH in 4th gear will run at a higher RPM and should use more fuel then 60 MPH in 5th; But 55 MPH in 5th gear might not produce enough torque to climb a hill, thus increasing load when you try to maintain that speed without downshifting. You can also sometimes run the car leaner at high RPM’s after you’ve past peak torque output, so increases in RPM don’t always linearly add fuel.

(4) Use cruise control.

The benefit of cruise control is it’s ability to be smooth. If you can avoid sudden load, you’ll need less fuel.

(5) Don’t use the air conditioner.

First of all, don’t die of heat exhaustion just to save fuel. If it’s 120F outside, you should probably think of your immediate health first. That said, this tip is good at low speeds since running the AC compressor raises engine load. However, this tip doesn’t always hold true at highway speeds where rolling up the windows can reduce aerodynamic drag.

(6) Accelerate before hills.

Mmmm… inertia. Going uphill raises load (or climbing stairs wouldn’t be exercise.) Accelerating early may allow inertia to carry you up the hill instead of asking the engine to do all the work.

(7) Clean out your car.

The key point here is to lighten your car. It takes less power to move a lighter vehicle, and less power == less load == less fuel (or quicker acceleration on the same fuel.)

(8) Check your tire pressure.

Low pressure increases rolling resistance and increased resistance == load. Unless you’re driving in sand or rock-crawling where low pressure == traction (and you’re not going fast enough for it to matter.)

(9) Change your air filter.

If your air filter is clogged the engine will have to work harder to suck air through it. Working harder == increased load.

(10) Get a hybrid car.

Uh..

(11) Do more in one trip.

Doesn’t save fuel per mile, but miles per day, which is also a good thing.

In summary, if you really want to burn less fuel… reverse-engineer your ECU, study the fuel maps for your car, and drive accordingly ;-)

(via treehuger)

The cause? A broken exhaust mount. This mount never really fit right (which seems to be the status-quo for after-market car parts.) It’s a solid metal mount that connects to the bottom of the downpipe. It didn’t line up once the pipe was installed, but with a little re-shaping it bolted in. The part lasted about 6-8 months before snapping.

The replacement, which I don’t have a picture of off-hand, was made by modifying a left-over after-market exhaust hanger from a 4Runner that didn’t fit the truck. The new hanger is still stiff enough to keep the turbo from moving, but has a small amount of flex to avoid this problem again.

I’m not sure what motivated me to post about this, but I have a long list of draft posts in my head that all relate to after-market product quality (or lack thereof) and the apparent in-ability for some of these performance shops to understand their market and launch new products. Many of these small manufacturers miss out on the little details, like: (1) a focus on quality, (2) providing proper customer support, (3) defining a clear product strategy, and (4) properly understanding who their customer is and what need they are trying to solve. They do manage to sell parts though — which I guess is what happens when you’re market is addicted to improving performance.

Everything came back together just fine (with a few extra parts left over for good measure), but I’m still re-tuning the fueling maps. The car runs properly while in closed-loop fueling (meaning the time where output from the oxygen sensor is used to determine fueling), but goes ridiculously rich once the boost comes on (and it moves to open loop fueling.) Since I haven’t had time to debug this, I dropped the boost limiter down around 2psi, and just drive it on light throttle.

I have a couple theories as to what’s happening, and hopefully this weekend I’ll have enough time to dive into it further. The first possibility is that the injector scaling capability of the UTEC might not be working properly. The second is that several other people with similar setups have reported that in creating a better flowing fuel system, the base fuel pressure has gone up, which is why the injectors are flowing more fuel then expected. The final theory is that the stock fuel pump is no longer able to keep up with the new high-flow system. If this were true, fuel pressure would actually drop as boost comes on, and with low pressure, the injectors would be unable to properly atomize the fuel, thus causing unburnt fuel to leave the exhaust ports and be seen by the O2 sensor as running rich. This one is particularly dangerous. If true, then there is no telling how lean the engine is actually running.

Fixing the first problem involves software. Proving the second requires a fuel pressure gauge and OBD scanner capable of accessing fuel trim values (neither of which I have.) Solving it probably means an adjustable fuel pressure regulator. The third one is messy. It will also require a fuel pressure gauge, but fixing it will require an upgraded fuel pump and an adjustable fuel pressure regulator. Fortunately a buddy of mine has all the diagnostic equipment we need.

With something like 10 hours of personal time doing the labor, and another 10 to retune the car, there’s no way I’m actually saved money (if you count time as money.) But where’s the fun in just taking a car to the shop? Besides, I can now tell you what every hose under the hood goes to ;-)

If you’re interested in taking a wrench to your own Subaru, I’d suggest starting with the following discussion board sites first:

– NASIOC
– i-club
– WRX Hackers
– ScoobyMods

The second is a three-wheel motorcycle concept called the Aprila Magnet. More information can be found on the student designers’ project page, which includes a 3D rendered fly-by video and a link to his dissertation, “Energy which animates the soul; the unique relationship between the motorbike and the rider.”

I’ll take either for xmas ;-)