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So I am just sitting there responding to some NASIOC posts, and I get the call...... "Your 2008 STI is here!!!" our good buddy at our dealer tells me. This was a huge surprise to us as we had all been told they would be in by the end of January! It's December, and we already got our car. Time to get to work!

tech_car_08stisidefront2 When ever we get a new car, the first thing we do is go over all the new things, and changes done from the previous models, and in this case from the WRX. For us, getting a new model of a car, is like opening Christmas presents. First off, from the WRX, this car is very different. They may share a few of the same parts, like the chassis, and dash, but that is where similarities end. With our STI came a very "Mini Cooper" type of media pack. Magazines, brochures, tattoo, kill markers, listing of all Subaru clubs....... tech_cars_08stimediapack


The obvious changes are the flares. 2007 and previous model WRX's had the very distinguished wheel well bulges. So when the 2008 WRX came out with little to no bulge, I was a little disappointed. One of the more distinguishing features of the WRX/STI was taken away. Anyone else who feels the same, should go look at a 2008 STI, you will not be disappointed! tech_cars_08stifront4 Subaru took their race-car-like bulge to the next level. There is roughly 2" more fender flare on the STI vs. the WRX. When looking them both side by side, this is very noticeable and makes the WRX look more "relaxed" and more of a grocery getter! tech_cars_08stiside2 To incorporate the flairs into the rest of the body, Subaru beefed up the front bumper and left the flair open where it meets the door. The open vent at the door really adds to the race car look, and makes is much more aggressive. tech_cars_08stisideairflow The front bumpers are wider and the lower intake is much more open looking. I say looking because of the black colored part of the plastic. The black part is just asking for us to cut it out for a front mounted intercooler. This contrasting black plastic is carried around to the fog light area to an even more aggressive look to the car. If you have seen the pics of the prototype WRC STI, you will see similar type styling. tech_cars_08stifronthoodopen tech_cars_08stisidevent tech_cars_08stifront3 Other than the flares the STI has a larger wing than the WRX. It's rather the same shape just longer and with some raised sides. This is better looking than the WRX, but still could use some improvements. We have a few things up our sleeve that should bring this part of the car back to life! tech_cars_08stiwing Right below the wing is that really bad looking, or normally bad looking Chrome panel. On the STI this part is not chrome, but color matched to the body, a huge improvement over the WRX hatch. This removal of chrome was continued to the front grill. This was one of the biggest things people complained about when the 08 WRX debuted. tech_cars_08stirear tech_cars_08stireartwintips The scoop for the STI model is unchanged from the WRX. In the past Subaru has always stuck a larger scoop on the STI to go with the larger intercoolers that came on them. But the last couple models have kept the same size scoop. The scoop is actually very large, but it's a little deceiving until you get right down and look at it. When we show customers our WRX or STI, its one of the things people talk about. No more snow shovel to try to look over while driving, just a nice bulge. tech_cars_08stifronttop One thing that I didn't pick up on right away is the badges. STI has always been pink, but on the 08, they are red! I didn't notice this at first because our car is white, and from far away, red and white make pink. tech_cars_08stipasssiderear Again, Subaru is making it more appealing to more people. But they still kept the STI pink in some places. tech_cars_08stistiboot


In a quick glance, nothing has change. Take a second look and you will find all the little things that are different. Starting from left to right the first thing is the intake system. The intake has the newer smaller Denso MAF sensor, and Legacy type intake air box. Both these items were the same as found on the WRX, but the difference is in the silencer. When we first pulled apart the 2008 WRX, I noticed the air box was the same as the Legacy, but no silencer. In fact it had the place to snap one in, but the hole was blocked off. The STI has the silencer! Not sure why but I guess to make the engine quieter. Just like the Legacy platform, the power steering reservoir, and ABS is moved back to the shock tower. Subaru relocated the boost control solenoid from the shock tower to the top of the intake manifold. This is a very distinguishing part of the 2008 STI. The solenoid is covered by/held on by a nicely formed steel shroud. tech_cars_08stienginebay The intercooler looks to be similar to ones found on the older STI's but with no STI logo painted on the face. Actually it's quite a bit larger than the previous STI IC. The new STI intercooler has a bracket that now bolts to the head, instead of the block, which allows the IC to stretch further over the turbo. This newer wider IC fits the wider opening of the hood scoop and definitely makes better use (compared to the WRX) of the air traveling through the scoop. While the PERRIN WRX TMIC fits right now, this gives us some more freedom to make an even Bigger Intercooler! The turbo that this new TMIC covers up is not labeled like other turbos. Is it a VF40, 39, 43, who knows, we will have to pull it off to discover the exact size. But base on our initial dyno numbers we saw, its not much different than the previous STI turbo. Just like the 2008 WRX, the STI engine has the secondary air pump installed. Some may be thinking that has to go! This is a great way for Subaru to keep their engines within the emissions guidelines with out having to cut back on power. So be happy its there and that your engine makes 305HP! The Other strange thing is the fuel system. Its looks pretty similar, but the fuel pressure regulator has moved to the shock tower. Not only that, but the feed and return line feed into the regulator. It's sort of a balanced fuel system. I am sure Subaru did this to make it close to a return less system but not a return less system. This setup will minimize fuel traveling through the rail and heating up, then traveling back to the tank. Hot fuel is bad for a couple reasons, and anyone who has been on the dyno with no gas in the tank can contest how hot fuel gets, and how it hurts power. tech_cars_08stifuelpressure After that there is nothing else really visible under the hood. But wait there is something you can't see, and this is a very annoying part to be missing. The AC belt has no tensioner on it! What? I discovered this on the WRX when I went to throw on a PERRIN crank pulley on the engine. Then I noticed there was No AC tensioner. There must be something we can do about this, but it will have to wait. Other than that that is all the visible things in the engine bay. Well there is something you can kind of see..... tech_cars_08stiactensioner The one thing about the 2008 STI that will either make this engine the best engine Subaru has ever made, or make it the 2ndmost complicated (behind the Ez30R) is the Dual AVCS. Not only does the ECU change the timing of the intake cam depending on load, but now it can change the exhaust cam! This could be very cool! I am sure Subaru says they did it for emissions, and blah, blah, blah, but what will it do for tuning? We have seen what varying the cams can do for turbo spool up (decrease the lag time), but what can changing the Exhaust cam timing do? This is something we will have to wait and see. From our initial dyno testing, and data logging using the DeltaDash, the Exhaust cam is being retarded. Which when teamed with an advancing intake cam, this can create more valve overlap. Normally this is good in NA high revving engines, and bad for boosted engines. But who knows what it will do for power or spool, we will just have to wait until we can tune the ECU. tech_tune_apflash2 If anyone has looked at the last few STI engines Subaru has made, they have seen the lower part of the head, with the blanked out fittings for a sensor to go. Well now there is finally something filling the hole! And now both the top and bottom of the cam covers have bulges! A small but interesting difference from the WRX to the STI is the STI has an oil cooler/warmer where the WRX did away with this. The 2008 WRX is the first turbo Subaru engine to not use an oil cooler in a very long time. Obvious, this was a way to cut some cost out of the car on the WRX. tech_cars_08stiavcs The HP specs on the engine are a little different than previous STI's. The past STI models (2004-2006) were rated at 300 engine HP and 300ft-lbs of torque. The 2008 is rated at 305 engine HP and 290 ft-lbs of torque. So why the change? This has to do with the SAE ratings that changed a while back. The 2007 STI was rated at 293HP and 290ft-lbs of torque. So Subaru has added some power, and kept the same peak torque but lower the RPM at which it hits 290ft-lbs. But I think there is a little more to the story. I think Subaru underrated the 2007 STI with the new SAE specs in place. In late 2005 a new SAE HP correction was put in place and while this caused some cars manufactures engine HP ratings to drop, some increased. Subaru's HP numbers stayed the same, but when the 2007 model year STI, (first batch of Subaru's affected by this change) the numbers dropped, to the 293/290. What is strange, is that many people were finding the 2007 STI was making more power than before! Not a lot but 10-20 more HP than previous cars, and with a lower HP, that seems kind of strange?? Hmmm, now for 2008 they claim more HP and same torque at a lower RPM, but with less working RPM? Seems like they might have kept the same power, as the previous year and cut back the Redline. Who, knows, but it is strange. dyno_tune_08stibasestiruns The Exhaust is again similar but different than the WRX exhaust. Similar in that it's a tube that goes from the front of the car to back, and bolts to flange on the muffler. They both have transverse mounted mufflers, but that is where things start to change. The STI steps up the diameter of the exhaust, and gets rid of the funny shaped center mounted resonator for a normal round type. The muffler is similar to the WRX, but the obvious change is the tips. The STI has a new distinct look, kind of Euro, kind of BMW like dual twin tips. tech_cars_08stimcoupe08sti The muffler is about the same size, but with the different tip configuration. The larger piping, different resonator, and tip configuration make for a nice change in the exhaust note. tech_cars_08stimufflerrear


The big suspension change was done with the release of the 2008 WRX and now the STI takes it a step further. Like the Engine if you take a quick glance under the car and it doesn't look a whole lot different, but in fact there are a few very important differences to note. Starting from the front of car, the STI suspension is laid out just like the 08 WRX, and previous Legacy models. No lower subframe and the vertical control arm bushings are there. The control arms are the forge aluminum type similar to what was installed on the Legacy Spec-B. The front swaybar is just like every other Subaru out there, 20mm. tech_cars_08sticontrolarm Nothing other than that to take note of, other than some funny looking engine mounts. Subaru claimed that the 2008 WRX engine and tranny were lowered roughly .5" over older Impreza's. While this might be true on the WRX, it is very noticeable on the STI. The front engine motor mounts are noticeably flatter, looking as though they had been smashed in a 100 ton press. Also gone are the cheap, rubbery plastic engine mounts. Moving back toward the tranny, we find the same thing. The tranny mount was also shorter than before. Besides lowering the center of gravity the lower mounts make the engine and tranny stiffer, providing a better transmission of power from the engine to the wheels. And like the other STI tranny mounts, its solid across the middle of it. tech_cars_08stimotormout Just like the 2007 STI the 2008 STI has taller gear ratios for the 2nd, 3rd, and 4th gears. In the 2007 STI this was a noticeable change and made for a better delivery of the power across the entire speed range of the car. The clutch is the same nice and smoother engaging clutch of the past. We will soon find out how much torque it can hold! The shifter seems shorter than I remember, but this could be because I was used to the longer stock WRX SS I had been driving lately. Still in my opinion, the height of the knob seems too short, but I am tall guy, so shorter shifters are not something i have ever liked. Shorter throw, now that is a different story. Since the WRX came out, I always thought that it needed to be a couple inches taller. One strange thing with the tranny is the dipstick is gone! Now in its place is a Socket cap screw plugging the hole. So where did it go? The dip stick altogether is gone, and now has the more normal side fill plug. For those of us who do our own service, this is not going to be as easy as it once was to change the tranny oil. As we get to the back of the car, again the suspension is similar to the WRX, but a couple things are different. One is the differential cradle. The cradle on the WRX is a steel formed piece, and like other STI parts, its aluminum and a bit lighter. The other thing about the rear suspension is the swaybar is bigger. The WRX uses a 15mm and the STI has an 18mm. Overall this seems small compared to the older cars, but because of the way the swaybar, is designed, this has a greater overall stiffness than the 19mm bars of the past. tech_cars_08stidiffandbrace The Suspension bushing and rear subframe bushings seem a little stiffer, but it will take some part number cross referencing to figure this out. Last but not least, the wheel and tires. The wheels are huge for the STI. Wheels are 18x8.5" with a 55 offset. The older STI wheels were 17x7.5, and later changed to 17x8. The largest tire that came on previous STI's was a 235, and now they have monster wide 245! Like other changes to the STI, Subaru picked a more subdued tire. Gone is the super sticky Potneza for a Dunlop with a tread wear rating of 300. Some magazines have done some skid pad tests and shown a slight drop in lateral G's on the 08, which is most likely from change in tires. While the 08 STI has a lower lateral G rating, it has shown to be faster in the slalom and faster around the track. To us and others reading this article, I am sure we are thinking the same thing. Who cares what it comes with, how big of a tire can we go! With stock 8.5 wheels, 265 should be no problem, but what about a 295? With the right width and offset, I think 295s will be common. Imagine the grip the STI will have with some 295 Yoko Advan A048's. That will be scary!


More refinements on found on the insides of the STI. The first thing you will notice is the seats and carpet, are not blue anymore, but a better grey color. Subaru is again, trying to make their cars more appealing to everyone, and getting away from the blue is one to get the older crowd interested in the car. The seats also get better bolsters than the older STI. I as well as many others hated the past STI seats. They were too flat, too hard, no bolsters. The WRX seats were better than the STI seats! tech_cars_08stiinterior The next most noticeable item is the center console. It's more Legacy like, with nicer buttons, trim and the cool sliding door that covers up the cup holders. Located on the center console is the buttons for the center diff control and I-drive functions. The Diff control of the past was simple. There was an auto mode, and a knob to put more power to the back or front, which also allowed you to lock the diff, or leave it open. The 08 STI has all these same features, but adds a DIFF plus and DIFF Minus setting for gravel specific, and tarmac specific settings. And instead of the Radio Shack type roller switch, it's a silver, luxury car type of switch. Taking the similar styling note from the older STI, the new one has a more drastic approach to the shifter trim ring. Previous STI's simply took the WRX console and bolted on a ring. Now its whole different plastic console piece compared to the WRX. Also right above it a perfect Cell phone holder. The WRX has a similar spot, but no rubber mat. So your phone or garage door opener just slides around, and annoys the hell out of you! tech_cars_08sticenterconsole Onto the dash. I had been driving the 08 WRX for a long time, and come to love the layout of the dash, the quality of the gauges and seating postion. Again, the STI goes a step further with the gauges, and HVAC controls. The lighting of the dash I a little different, as is the HVAC controls. The small bits of silver add to a nicer, more quality look to the interior. To the left of the dash are the mirror controls, headlight leveling system, and the DSC button. This is all similar to the WRX, except that the DSC has 2 modes. Normally it controls both traction, and yaw or rotation of the car. Traction control is handled by closing the throttle, and the yaw is controlled by applying the brakes. Hit it once and both are turned off, and the DSC light turns orange. But hold it down the DSC light turns green. This second mode does away with the traction control and keeps the yaw control in place. This mode is what most likely will be preferred for track or auto crossing. So now if the tires slip, the ABS unit will start to apply force to the brakes, and not cut power to the engine. tech_cars_08stidash2 The rest of the interior is about the same, but with the new grey Alcantara patched in here and there. The seating room is the same, the trunk room is the same, speaking of the trunk, gone is the Intercooler sprayer tank. Subaru didn't include this in the 08 STI, which is a bummer, but it just gives us another reason to create our own tank for our water injection system. There is a little more plastic on the doors than I would like but its Subaru not a Porsche!


Many people are complaining about how expensive the STI is this year. The price for the base STI did go up $1000, but there is more than a $1000 in parts. 18 wheels, 245 wide tires, 2 stage DSC, New Center diff settings, Lower engine and drive train, more powerful engine, nicer interior, better seating position, telescoping steering wheel, wider track, shorter body, cool hatchback shape, and the flares all make it worth way more than $1000. Not to mention than this STI has the most potential for power and handling compared to previous STI's. Subaru did leave some things to be desired, but of course, no car is perfect. That is why the term "aftermarket parts" exist!

What are our plans for the STI?

We have 2 big tricks up our sleeve, things that no one else has ever done before! Besides that, there are the normal things to expect. Turbo back exhausts, intakes, intercoolers, shifters, bushings, swaybars, endlinks, PSRS, and the most important item we plan on offering is Custom AccessPORT maps for all stages of tune. As you are reading this, we are the first to have, and are already tuning our STI. We are the first, and we are the ones leading the pack. There are many exciting things in the next few months you will see from us! tech_cars_08stifunstiexhaust build_exhaust_08sti_proto build_exhaust_08sti_proto1 build_exhaust_08sti_proto2

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