2008 STi Exhaust

First article production pieces are done. Overall, we’re extremely pleased. This past weekend we put our 2008 STi through its paces at Buttonwillow and found a few areas we can make some subtle improvements to this design. Yes, we’ll take it on the chin from those that occasionally complain of our time to market but ultimately we’re a) enthusiasts and b) picky so we like to make sure things are right rather than just sell-able. Does it mean we’re perfect because we care? No, but we’d still rather care.

Alrighty, on to some pics!

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We’ll post some SAE sound ratings soon but the good news is we’re well within legal limits, even with our high flow catted downpipe. We also drove the car from Buttonwillow to Salt Lake City and the driver and passengers reported a nice, non-droning exhaust note the entire trip. That’s important considering how ‘hatch’ models tend to amplify exhaust tones in the cabin.


12 responses to “2008 STi Exhaust”

  1. The lack of drone will make this a favorite among 08 STI owners, which seem to prefer a less aggressive exhaust tone at idle and freeway speeds. As far as I can tell, new Subaru owners want to hear the exhaust when they get on the throttle and they want it quiet all other times. Sounds like Cobb is heading in the right direction as usual. Please send us press releases when this is ready.

    -Kevin

  2. Once you’ve got this exhaust done and equal-length headers are available, this is gonna be a “Gimme, gimme, gimme!” item. I briefly had a catback on my 06 and hated the “something’s amiss” exhaust note caused by the unequal length headers.

    Replaced the 06 with an 07 last year because of the taller gearing which I knew would be better suited to the track use that’s 90+% of what my Scoobs do.

    Picked up my 08 a few weeks ago and my first time at the track was very disappointing. Not only are the tires inferior to the RE070’s previously used (new tires and wheels should arrive today), the engine simply wouldn’t act right. The only place at this particular track (MidAmericaMotorplex) that I pay attention to the speedo (the exit of turn 4), the 08 was pulling 90 mph where the 06 and 07 both would be indicating 110. Side note: The 06 would hit the rev limiter in this turn, so the 07’s gearing did prove to be better for me at least there, though my overall lap speeds were identical — there’s some positive and some negative to the taller middle gears.

    The main culprit in the 08 causing my much lower speeds (and a best lap time of 1:52.55 compared to the consistent low 1:48’s of the 06/07) was the ECU, followed distantly by the tires and softer springs. And possibly aerodynamics?

    No matter how many times I reset the ECU, just as my brakes and tires got warmed up enough, the engine would start falling on its face at 5200 rpm and stay relatively dead to redline. I ended up getting my best lap times by short-shifting it to stay below 5200.

    I ordered my AccessPort the day before yesterday and it was waiting for me when I got home yesterday. I installed it and took the car for a ride and to say that I was impressed would be quite an understatement. Though what’s left in the fuel tank is a mix of 94 I got from the track and 92 I got from a station in Iowa, I wasn’t looking to endanger the engine or really (yet) extract every last pony, so I used the 91-octane tune.

    Took it for a drive and no matter how hard I flogged it, it pulled so hard that every time I floored it in 3rd gear the engine really meant business starting from around 3300 rpm and not throwing in the towel until the low to mid 6’s. 3rd gear got used up so quickly that I ended up risking the wrath of the local constabulary by testing it in 4th.

    Thanks, Cobb. You unlocked what Subaru promised but couldn’t deliver. The car isn’t a snarling beast and I don’t want it to be, as I don’t want the fragility that goes with that since reliability and longevity are important to me, as I do anywhere from 6k to 10k track miles per year. Well, okay, it does snarl quite a bit. Just the right amount. Enough that it should be competent on the track like my old ones (and then some) but it doesn’t feel like it’s trying to break itself or wear itself out early.

    One more thing. I’ll take this with a grain of salt, due to the fact that the chip I put in an F350 diesel I used to own actually fudged the OBC’s reported economy figures (about 15% higher than calculated at the pump), but before the AccessPort, I was getting 23.3 mpg on the 10-mile roundtrip from my house to my office, and tried the Economy mode (Realtime, since it was temporary) yesterday and got a reported 29.2 mpg on the same trip.

    I’m off to the track (Heartland Park) this weekend (hope the new tires and wheels arrive today) but afterwards will run the car in Economy mode for a couple of weeks and report back here my findings of reported vs measured fuel economy.

    I have a feeling the numbers will match, as you guys roll like I do, which is why it took only a brief phone call (to ask about the effect on the 08’s 3-map setup) to decide I wanted this thing in my car.

    Oh, and you’ve sealed the 07’s fate. I kept it in case the 08 disappointed but now I’m very pleased with it and the 07’s going up for sale on eBay next week. If anyone’s in the market, it’ll be the silver one with zero options (not even boost gauge — it blocks important instruments) with just over 4k miles.

  3. Correction/qualification to previous post:

    When I reported 29.2 mpg in Economy mode for my 10-mile round trip compared to the 23.3 I usually get, I neglected an important item that occurred to me today. I usually make this trip starting with a cold engine going each direction. When I tried it out yesterday it was with a warmed-up engine, which did boost the numbers higher.

    I put 61 miles on the car today and got a reported 25.7 mpg doing about 70% highway and 30% city driving.

    My fuel economy figures tend to run toward the high side and I have yet to encounter the car whose EPA figures I couldn’t beat. I’m pretty obsessive about fuel economy (it’s like a video game to me and I’m always going for a higher score) on public roads, which is also why a couple of the Scoobs stablemates are a Civic Hybrid and a Camry Hybrid. I consistently get at least 50 mpg in the Camry with a best of 55.5 while my wife gets 38 out of it. How the car is driven makes that big a difference.

    I should also point out that my commute to work is very easy on a car. 2.5 miles of 45 mph, a stop sign, and 60 mph the other 2.5 miles.

    I’ll be driving the car to Topeka tomorrow (about 90 miles) to play on the track and will drive it in economy mode (only TO the track, of course) and report here what figures I achieve from it.

    Will also report lap times after my next trip to MAM, which I think is in a few weeks. It’s a given I’ll trounce my 1:52.55 pre-Cobb best (average was about 1:55). I just don’t know yet by how much, but I’m guessing I’ve got a low 1:47 car now. Once Cobb gets the sways and springs ready, we’re shooting for 1:45’s.

  4. Any word on a cbe from Cobb yet for the 08+ Sti? I’m really dissapointed it has taken so long for this exhaust to come out while a slew of other products are released. I miss the days when Cobb focused on Subaru!!

  5. When is the Cobb Cat back going to be released for the 08 STI? Also when is the cobb Cold air intake coming out for the 08 STI?

  6. The Catback for the 2008 STI is still in the works and should be available shortly. We will make a formal announcement when these units go on sale.

    Travis
    COBB Tuning

  7. After reading Bob’s posting, I’m relieved that I’m not the only nut job that thinks the car is flat from 5K on. I’ve been debating if it would be cured by the Access Port. I’m gonna go ahead and get it, tune it to stage 1 and wait for the catback. Once it’s out, I’ll go with the turboback and bump it to stage 2. So please, come out with the CBE soon. I’ve been running with a friend that has an ’06 STi with a few mods, and he is kicking the $#!^ out of me.

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