Post Swap Impressions and Ideas
As of this writing, it's been a little over three weeks since the project started. The car is running very well, and save for some as of yet unresolved issues with electrics, the job is a complete success.
My immediate impressions upon driving the car for the first time was that, even with my AVC-R disconnected, it was very fast. Keep in mind that i had been driving on an automatic that was on it's death bed. It was so dreadful to drive that i avoided it conciously. 6.6PSI made the car accelerate very smoothly, without the obvious increase in boost now present with 11PSI. It was so linear that it could have been an N/A car, save for a slightly weak low end, and the turbo sounds. One thing i did notice quite early is that my pathetic transmission mount was worse than what was on the 4EAT. Now i really needed replacements.
Shifting worked very well, even with the stock linkage missing the centering spring. The center console was one made for the 4EAT assembly, and instead of even putting the MT boot on, i just chose to put the light grey knob on the stock shifter and call it good. It doesn't look pretty, but it's not hideous. In fact, i think it's kind of funny looking.
One problem that turned out not to be a problem at all was related to the speedometer. It turns out that the speedo cable was simply in need of better contact, so a bit more twisting and pushing netted me a working speedo. This also seemed to satisfy the ECU, as my AVC-R now showed the speed. This also tells me that the ECU gets its speed info from the speedometer, not some extra sensor on the transmission. The two plugs on the transmission are for neutral-sense and the reverse lights.
I still haven't hooked either up, but i do look quite carefully before backing up, and the neutral switch isn't as important as it might seem. Sure, you could theoretically start it in gear, but chances are i won't. There is, however, a companion to this function on the AT side. The shifter must be in Park or Neutral in order for the key to be released. If the key is inserted, and the car isn't sure what gear it's in, the key is trapped. This is easily defeated by jumpering two of the wires that come from the center console. The problem is that this will fool the car into thinking it's in park, but also defeat the Cruise Control, because that will not engage while in Park. A solution involving a relay has been used by Alex, and i'll eventually impliment it.
There is also a wire that supposedly tells the ECU to work as an MT version instead of the AT. Al is working on finding me this exact wire, and until i know for sure, i'm not snipping anything. This might help the high idle and set the timing a bit more in advance instead of retarding it for the AT.
In retrospect, i'm pleased that i got to stay with the 3.9 gears. 1st and 2nd are short enough, and i can barely hit 55 in 2nd as it is. I'm sure 4.11 would have me shifting a bit more often. This, and the fuel mileage benefit i'm seeing, are good enough reasons to stay with 3.9. If you're looking for a drag car, gearing is very important, but i wanted a compromise.
On the subject of that 55MPH limit, and the ECU, i'm also limited by the 6250RPM redline that is strictly imposed by my ECU. The 5MT should have at least a 6500RPM limit. I would like to defeat this altogether, and use my DIS-2 for rev control, as it has a very nice system to impose it's rev limit, and is adjustable. I've spoken to several people who feel the SOHC can take up to 7250RPM before the valvetrain has problems. While i'm don't want to be that adventurous, i would like to get at least 6750 and see what it feels like.
A week and a half ago, i ordered a set of STi engine and transmission mounts to replace my pathetic stock ones. These are about $169 for the package of 3. They're smaller, but much stiffer than even the OE versions. Installation was done by Charlie, as he's got the tools to do the job much easier and with much less pain than if i were to do it myself. I'd rather pay for the job to be done right in this case, but that is just my opinion.
The engine and trans mounts made a HUGE, difference. It's hard to explain in words really, but it's very different. Before, it was as if the engine and transmission were just barely attached to the car, flopping around with their own inertia. Now, the car feels solid, as if it's one large unit instead of one inside of another. I cannot stress how impressed i am. Shifting is very crisp, with none of the shuddering caused by the loose mounts and the drivetrain bucking around.
On a cautious note, however, i have noticed a bit more NVH in the cabin. This is to be expected, as the notoriously lumpy Subaru engine is now attached by a very hard mount to the frame of the car. The car is also reinforced with a front strut mount brace and lower arm bar. This combination is rewarding however, driving the car fast over bumps and through corners is much more confidence inspiring now than before.
About the same time i ordered my mounts, i also ordered a short shifter from Kartboy. They offer a very nicely TIG welded unit that's shorter than the stock unit, but also raises the pivot point of the shifter, imporving the feel by bringing the angle of the rod to the transmission shaft closer to 180 degrees.version of this shifter, one for the RS and another for the WRX. Apparently the WRX uses a slightly wider assembly, for some reason.
Unfortunately, the stock unit i had is much narrower than the Kartboy RS assembly, so after getting two of them, we figured that perhaps the STi assembly was a more complete solution.
I then ordered the STi assembly from Richard Buckner, the same that sold me my pressure plate and clutch. The STi part is a complete linkage, which includes everything but the boot and knob. It has a harder bushing on the lower connecting rod, the shifter is shorter, and the pivot is raised from the stock angle. The unit bolted right in, but we soon found that i was missing an important part. There is a linkage on the top rod that compensates for a drop in the angle of the linkage on the top of the transmission. The stock part is different than the newer models, and requires a replacement piece in order to work properly. This part was supposed to be included, but was unfortunately not present in the box. I'll update when i get it installed.