One of the problems I have with running a small business is that it's hard to set limits on how much time you spend on it. There's always more work to do! I say that because I've been finding it hard to make time to put my own project car on the dyno when I have a steady stream of customers asking for tuning. (It's a good problem to have.) So we've seen a lot of cars on the dyno lately, but my white car hasn't been one. On the plus side, the weather has been cooler, so when it finally does get back on there the ambient temps should be a little lower.

I can't make a post without a photo, so here's one of the car with a new Subaru World Rally Team sunshade I got from my online friend Subie Gal.

Tuning Half-Done...

Cobb Tuning looked at our slightly funky ECU (see previous blog post), did a collective shrug ("Weird, we've never seen that before."), and reflashed it back to its initial state. Then when the ECU came back I realized that my AccessPort was still "married" to the ECU in its previous state -- so I couldn't use the AccessPort until THAT was also reflashed. Anyway, a couple of weeks and several postal shipments later, the electronics were all ready to go, and we strapped the car to the dyno on a very hot and humid July day. Initial results were promising, but I was having some trouble making the car reach my desired boost level. I realized that the newest Subaru ECUs have several temperature compensation tables related to boost levels.

Basically, after the intake temperature exceeds 104 degrees F, the boost targets and duty cycles are all reduced, and the hotter the intake temps get, the lower the boost targets get. According to my logs the ambient temperature at the dyno was 102 F, and the intake temperature on our car was exceeding 135 degrees F -- that would explain why the car was seeking 19 psi instead of 21 psi. The only way I could keep tuning at my target boost levels was to zero out all the temperature-triggered safety features, but I felt it best to leave those in place. I decided to continue the tuning process in the morning when the ambient temperature was below 102.

Here are my initial results from the first half of the tuning process. Since the turbo is larger than stock, there is some spool penalty -- note how the red power line is above the blue line between 2600 and around 3500. But where the stock turbo is reaching its peak torque, the larger Tomei turbo is just getting started, and the torque and power exceed the stock numbers from that point on.

Once the air temps are cooler and I can depend on the car making the boost pressures I specify, I'll get back to work -- I hope to be able to show some additional power on my next update.

Summer Progress

We successfully installed the TurboXS FMIC kit, the Tomei turbo, and a TurboXS turbo-back exhaust. I hooked up the laptop computer to the ECU for some dyno tuning, and found that I could not reflash the ECU, although other tuning functions were working normally. Weird. We parked the STI in the Mach V showroom and sent the ECU off for some diagnostic investigation.

While the bumper was off I swapped in some blue-er HID bulbs for the headlamps -- the stock ones always looked a little to yellow to me. And then to round out the HID blue lighting up front, we also popped in an HID 9006 kit for the fogs.

Surgery Underway

I finally managed to push the paying customers aside (sorry, everybody!) to get the Mach V STI on the lift for some extensive surgery. The tasks include replacement of the turbocharger with the Tomei ARMS model; installation of the TurboXS FMIC kit (see previous post); removal of the stock exhaust system in favor of a full TurboXS turbo-back exhaust; and replacement of the fog lamp bulbs with HID units.

So far the turbo is in place, and the bumper is off in preparation for fitting of the FMIC plumbing and core. The core is a generously-sized bar-and-plate unit. Bar-and-plate is known for efficient heat transfer and low pressure drop compared to cheaper tube-and-fin designs.

The exhaust is a full 3" mandrel-bent system. Although the STI has a dual-outlet muffler in stock form, this new system is only a single-outlet. If I was in full-on marketing mode, I'd say that was for weight savings. The truth is that TurboXS hasn't yet relased their dual-outlet STI system, so for now we're going to make do with the single-outlet that fits the WRX hatchback. But hey, we are saving weight...

I also popped in some cool color-changing turn signal bulbs for the front corners of the car. The stock turn signals double as side markers. I wanted those to be pure white, but you can't have white turn signals. These bulbs solve that by being pure LED-white while they're behaving as marker lights, but when they do their blinking turn-singal duty, they turn orange! It's very cool. I took a video:

FMIC and Harness Bar In the STIzzle

FMIC stands for "Front Mounted Intercooler," for those not in the know. All turbo Subaru models have their intercoolers up on the top of the engine -- that's why there's the big hood scoop. That top-mounted location means a very short pipe routing for the charge air, but it's not ideal for cooling. For that, the front of the car is perfect. Cooler intake temperatures mean more horsepower, and that's what we're after.

We chose the TurboXS front-mounted intercooler kit because we like the guys at TurboXS and we've done business with them for a long time. They make nice intercooler kits, with proper high-strength T-bolt clamps, multi-layer silicone couplers, and polished aluminum tubing. The extra-huge intercooler core should work nicely with the larger turbo we'll be fitting.

One interesting note about this kit is that it includes TWO different piping options, so it'll fit both the 2008+ WRX as well as the 2008+ WRX STI. The STI still uses the old-style aluminum manifold, with the turbo and stock intercooler separated by some piping. The WRX uses the newer plastic intake manifold, with the turbo outlet dumping directly into the stock intercooler. You'd need different plumbing for either option, so TurboXS thoughtfully included both with the kit.

Our kit is in a box in the showroom in front of our car. As soon as we can get some spare shop hours we'll be fitting it up. Stay tuned. In the mean time, I took one last picture of the car before the surgery...

In other news, we developed a harness bar for the 2008+ WRX/STI. This will allow you to mount four- and five-point harnesses in your car without having a full roll cage. We built and delivered the prototype bar to a happy customer during our Mother's Day Meltdown Spring Open House event, and should be building some production bars in the next couple of weeks. This isn't some slapped-together kludge part, either. Just to name one detail of this thing, we machined custom spacers to allow the proper freedom of movement of the factory shoulder belt even with the harness bar installed. Sure, it might have been easier to just throw some washers in there, but that's not the way we do things. Check our web site soon for pricing and availability.

Mwah Hah Hah! The Power Mods Begin

Okay, it's a small start, but we installed some Deatschwerks 750cc fuel injectors on the STI. These are a new type that use an OEM-style Denso core. I expected that they'd act a lot like stock injectors, but larger, and I wasn't disappointed. I plugged the laptop computer in and drove around the neighborhood with the computer data logging for me. A few adjustments to the "injector scale" constant, and the car was behaving just like it did before, just with lower injector duty cycles. The car is now ready for a bigger turbo.

Sharp-eyed blog readers will notice that previously I said I'd use 850cc injectors. Well...my relatively mild power plans don't really merit that large of a fuel injector, and I'm always preaching to MY customers how they should use only as much fuel injector as their power goals require, and not larger. So I thought I'd practice what I preach.

In general, the larger the fuel injector, the tougher it is to tune low-load and idle fueling. Cars equipped with very large injectors sometimes can't trim the injector flow low enough at idle, so they'll idle very rich, smelling of extra fuel out the tailpipe.

While I'm going back on previous blog promises, you know when I said the exterior of the car was done? Well...maybe not. Besides a front lip, which I wrote about before, I think I'm going to up-size the rear wing. Stay tuned.

The photo above doesn't really have anything to do with today's topic, but I liked it. I took it at sunset back on January 28, 2009.

Power Plans, and MPG

At this point our STI is pretty nicely set up in the handling department, what with the upgraded wheels and tires, Cusco coilovers, and Whiteline sway bars. And the car is looking pretty good, too. But the horsepower is still pretty close to stock -- the only power modification we've done is a Cobb AccessPort.

Part of the reason I haven't bolted a bunch of power-increasing parts on the car has to do with the engine failures we've witnessed among our customer base. (See my notes and pics below regarding that subject.) I confess I'm not very excited to think about having to pull the block out of the car to replace the pistons. Even if the likelihood of a failure is low, the expense (in both money and time) is pretty high.

Another contributing factor is that our service business has been growing and it's been a little hard to schedule work on our own car when we're full up with paying work. (That's not a bad problem to have!) The final factor is that like many of us considering the economic downturn, I'm a little leery of spending cash that I might need if the economic climate continues to worsen.

That said, I didn't buy this car to keep in bone-stock. The reason for having is to showcase what we sell and provide some first-hand insights about the parts and how they work. So here is our plan for power production on the car:

• Mitsubishi 20G turbo or equivalent (maybe a Tomei ARMS turbo)
• Deatschwerks 850cc fuel injectors
• Walbro 255 lph fuel pump
• Turbo-back exhaust system (with cat)
• TurboXS front-mounted intercooler
• Upgraded turbo induction pipe
• TurboXS intake

This should give a healthy amount of power (figure around 350 awhp on our Dynojet dyno) but still leave the car relatively civilized for daily-driver duties.

On a completely different note, I've been noticing that the STI's miles per gallon is still improving. I noticed this looking at me from the dash the other day...