Monday, March 30, 2009

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. 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.

Monday, March 9, 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:

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...