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Whenever a new performance car hits the market, a quick trip to the dyno always seems to be the first priority. This phenomenon again holds true for the new Pontiac G8 GT. After having driven the sport sedan, we remarked that the sedan's 6.0-liter small block V8 engine provided "a glorious combination of aural assault and potent propulsion." We do love us some alliteration! Getting back to the dyno, the good people over at PCMforless have already put their new G8 GT on a Dynojet for a few pulls. The first pull yielded 286.62 ponies and the second, after a bit of tuning, wrung the bell at 310.37 galloping horses. Factoring in drivetrain loss of about 15%, those numbers are (surprise!) right in line with the 361 horsepower that Pontiac is claiming for the G8 GT.

While over 300 horsepower is mighty impressive for a 30K-ish sport sedan, we'd be remiss if we didn't at least mention that the 2009 G8 GXP will be packing another 40 horsies underhood. Oh yeah... and a clutch. Check out a video of the full-pull after the jump, where you'll no doubt enjoy some of that glorious aural assault.
Thanks for the tip, Nick!




[Source: G8GT.com] Video:


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    • 1 Second Ago
  • 54 Comments
      • 7 Years Ago
      what do they exactly mean by tuning?
        • 7 Years Ago
        RJ: the 6sp auto has no direct gear. More important though is being able to get the torque converter locked at low rpm and high throttle (which the controller tends not to do) so you see what the engine makes, not the extra torque multiplication in the converter.
        • 7 Years Ago
        A couple ECU changes to adjust air/fuel ratio and timing, probably.

        They need to let the engine loosen up a bit; it'l too new to show its true hp potential.

        the 286hp they got is pretty poor considering LS1 F-bodies in the late 90's did over 300 on teh dyno. A manual would also help, as autos don't reproduce accurate readings on inertia based dynos (unless they can lock into the direct gear at low rpm).
      • 7 Years Ago
      seriously a holdo, if you don't have anything more to add to a discussion than "2 valves bad, 4 valves good" and expect people to take you seriously, then please stop, the adults are trying to talk and you clearly have failed to reach that level of discourse yet.
      • 7 Years Ago
      I have a 2007 car, one of the vag concerns golf gti engined ones. 200 hp with 2 litres. A nice car, but I'd get the G8 in a heartbeat if it was similarly priced in europe.

      hp / litre is just useless rices math; what matters is the input (consumption) and output (hp & torque) of the engine and its mass. These are all very good numbers in the G8 - the engines internal displacement doesn't matter. It's just a good engine however you look at it.

      • 7 Years Ago
      a_holdo

      First stop taking reply advice from our your 12 yr old son, go gas up your 2.0L, drive 400 miles on one tank somewhere, so we don't have to read posts from someone that has no idea what a V-8 is.
      • 7 Years Ago
      [sorry computer spazzed] This 6L makes tq at all RPMs and will still get 30mpg on real world highway driving, your 2.5 sti and 2.0 wrx will not do that. And I know this because i own both a 2.0 turbo and an ls-x car.
      • 7 Years Ago
      All this preaching "torque torque torque!" Hopefully some day people will realize that torque at the crank is meaningless. Force (or torque) at the wheels is what moves the car, and that is engine torque through gearing. As long as both cars are geared properly and have usable powerbands, the car with more power will always beat a wimpy "torque monster".

      They advertised 361hp and they got 310hp after "tuning"? Pathetic. I don't care if quoting crank numbers is common; that doesn't make it right. If I'm buying an engine, I want crank numbers. If I'm buying the whole car, I want wheel numbers. Giving numbers at the crank is like me saying "my car can put out over 1000hp at the fuel pump!" (It can, by the way. I bet you're jealous.)
        • 7 Years Ago
        m, this is a street car. I agree that given the proper gearing a smaller, higher revving engine can have the same wheel torque as a larger engine, but driving around at 5000+ rpm all the time is bad for fuel economy, engine life and is just plain annoying for anyone in or near your car.
        • 7 Years Ago
        Why are you so upset? Every manufacturer has done and is doing this. It's not like it is exclusive to GM.

        A 15% drivetrain loss means that has the HP goes up, the overall loss will increase, but relative. The ratio remains the same.

        crankHP/whp ~ 0.15
        • 7 Years Ago
        So you're saying that it dynos within 3% of what it's quoted, and they're not quoting wheel power? It sure sounds to me like they are. Or perhaps you think they're just completely incompetent at measuring power and were way off? Then just by pure coincidence the number they ended up with was nearly dead on the number the power the car actually puts out at the wheels? I guess their luck makes up for their incompetence.

        My daily driver started as a 2004 Dodge SRT-4. Dodge quoted it at 230hp, and stock examples dyno very consistently at 230hp. You probably think this was another coincidence, but I think it was on purpose.
        • 7 Years Ago
        Pharmed Gator, thanks for bringing this to personal attacks. It really helps conversation along. Perhaps you can't see all the conversation above where specific examples of vehicles rated at the wheels are pointed out? Maybe the premier race series only exist in my tiny little sheltered mind. Formula 1 and MotoGP are merely figments of my imagination. Out in the real world with you, I would see the fastest race vehicles spinning 3000rpm all the time. Maybe you haven't heard of those series. You might want to look them up. They're kind of interesting.

        Also, you might want to do a little research on the effects of weed. I think you might be a little confused on just what the "good stuff" can do.

        Way to bring this old conversation back from the dead with such a meaningful comment.
        • 7 Years Ago
        I see what you're saying, I wish wheel numbers were advertised as well. But guess what?? they aren't. By ANYONE. So while you say you'll only buy cars that advertise wheel numbers, not a single company does that, so have fun walking.
        • 7 Years Ago
        I realize that this makes me an unusual consumer, but I value honesty in advertising. The fact that my car made the advertised power at the wheels played a part in my decision to purchase it.

        I actually think a decent advertising campaign could be built off of showing that your company's advertised numbers are what the customer can actually use and the competitors are less. I'm picturing two cars next to each other on dynamometers. Both brand X and brand Y have advertisements posted in front of them showing that they claim 300hp. Then they're both fired up and brand X makes 300hp and brand Y makes 255hp.

        Maybe I'm crazy, and real, useful numbers wouldn't appeal to anyone but me.
        • 7 Years Ago
        the torque at the crank of a 6L is eleventy billion times more than that at the crank of a 2L

        My point was that those low displacement motors even if they have 300 at full potential are stil lacking torque.

        No Replacement for Displacement.

        U feel it on the on ramps, while merging on the freeways..

        torque
        torque
        torque
        torque
        torque
        • 7 Years Ago
        m... you sad little person. I think you need to sit down and go read some car magazines or car brochures because every car manufacture puts the crank horse power down on their website/brochure. And if for some reason in that tiny little sheltered mind you think that torque does not matter, please let all of us know where you get your weed because you are smoking some good stuff.
        • 7 Years Ago
        ^^
        Winner!

        Dumbest. Post. Evar.
        • 7 Years Ago
        How about the 2004 model that I currently drive? Check your facts. Some cars were advertised with useful information.

        I said the fact that they advertised truthfully played a part in my decision to buy it. I didn't limit myself to those vehicles only. Performance, functionality, and economy are the major decision drivers. But keeping in mind what kind of people and what kind of ideas your money is supporting always factors in too.
        • 7 Years Ago
        The SRT is another car that has a reputation for being grossly underrated. You could be right that those ratings could have been intentional, but OFFICIALLY, everyone rates at the crank.
      • 7 Years Ago
      361 crank hp is weak as hell. The stock SRT-8s have had much more hp with about the same CID, for a long time now.
      • 7 Years Ago
      My car has 227hp at the crank out of a 2 liter. 310 out of a 6 liter? Seems unimpressive at best.
        • 7 Years Ago
        consider a few things:

        assuming your 2.0 is running ~15psi boost, it is intaking closer to 4.0L at full throttle if you want to compare to a naturally aspirated engine.

        217lb*ft from your turbo doesn't look so hot up against 385lb*ft from the LS3.

        The LS3 also gets to peak hp 700rpm lower than Subaru. Stick in a larger cam to put the V8's peak hp up at 6000rpm and you're easily over 400hp. (430hp in Corvette)

        18/25 EPA mpg (adjusted for 2008+ testing - http://www.fueleconomy.gov/feg/sbs.htm) isn't exceptional either and likely on par with the G8.
        • 7 Years Ago
        Want to compare Apples to Apples? GM's very own 2.0 turbo four makes 260hp, 260 torque(with a wide, usable powerband), is rock solid reliable, and uses less fuel doing it than your engine.

        Don't get me wrong, I LOVE subies(I wanted a WRX myself untill they uglied it up so bad), but youe engine isn't the be all end all.
          • 7 Years Ago
          Are you stoned? Compairing a 6.0L V8 with a 2.0 that must be driven at the redline to pump out 100 less horses then the V8. The car can also be power steered (rwd) if all the power does get you into trouble... The 4 cyls may be right for some situations, I think GM did a nice job droping a 4 cyl into the Aura and G6. Nice ride and good gas milage for under 20K. However real cars like the G8 and Dodge srt8 can criuse at 70mph and only 1500 (mine sometimes less) rpm! Thank you Detroit (and Austrilia) for building real cars again. I own a G8 GT and my wife will buy the new Camaro if it arrives before we must retire her 75K Saturn...
        • 7 Years Ago
        Say it with me - T-U-R-B-O. Your 2.0 has one, this engine does not.
        • 7 Years Ago
        this car has something called torque. and lots of it.

        unless that 2.0L is FI'd, it won't have anywhere near as much torque or the same torque curve.
        • 7 Years Ago
        I agree, you can get 300whp+ out of 2.5L subarus, you'd think a 6L would do much better. On top of that, how much does this car weigh?
        • 7 Years Ago
        310 at the rear wheels...

        361 at the crank
      • 7 Years Ago
      How exactly is a bell "wrung?" Rags are wrung out. Bells are rung.
      • 7 Years Ago
      a_holdo:

      My 1999 Golf TDI has close to 145hp and 300 lb/ft of torque at the wheels at 2500 RPM. it's 2 valves per cylinder (OHC with hydraulic lifters for that matter), has 200,000 miles on it, 1.9 liters of displacement, oh, and I get 48 MPG while doing 75 on the highway... it'll also pull a 14.5 in the quarter...

      ...and I still want this 6 liter V8.

      now about hitting your wife... might want to get counseling over your anger issues.
      • 7 Years Ago
      Funny to see all the Subaru comments on here. Just out of curiosity I compared the Legacy GT and the G8 GT, which are pretty comparable full size cars based on price:

      Subaru Legacy 2.5L GT :
      2.5L Turbocharged H4
      Requires Premium Gas (91 octane)
      243hp/ 241ft-lbs tq
      18city/ 24 highway mpg
      Starts at $28,295
      Cargo Volume: 11.4 cu. ft.
      Passenger Volume: 90.9 cu. ft.


      Now look at the G8 GT:
      6.0L N/A V8
      Runs on Regular Gas (87 octane)
      361hp/ 385ft-lbs tq
      15mpg city/ 24mpg highway
      Starts at $29,995
      Cargo Volume: 17.5 cu. ft.
      Passenger Volume: 107 cu. ft.

      Doesn't look like the Subaru is that much more efficient even though it requires premium gas, has 118hp and 144ft-lbs of torque less than the G8 GT, and is a much smaller car. In fact, it would actually cost me more to feed the Legacy GT's 2.5L H4 than the G8 GT's 6.0L V8.

      Also, it's noteworthy to mention that the G8 V6's 3.6L V6 makes 256hp and 248lb–ft of torque and gets 17mpg city and 25mpg highway. So it makes more power without the need for a turbo and gets the same gas mileage, without requiring premium gas. So much for awesome Subaru efficiency.
      • 7 Years Ago
      I would love for someone to show me any car currently produced that makes more power at the wheels than this for less money. I'll save you the time though, the only thing that comes close is a mustang GT or a charger, and inarguably this car is a nicer car than those. The G37 isn't close, RX-8 isn't anywhere's near it, STI, EVO X and Any Audi anywhere near it's price. So for all of the technology in the marketplace, there still isn't anything beating the numbers.

      And if you can't understand what useable engine trq is, and why that's different from gearing in the real world then you should probably go drive a modern V-8.
        • 7 Years Ago
        Yes actually holdums, the small block is based on an OHV design with was invented after OHC. With more modern being invented more recently in time, that would make the small block more modern. Of course newer isn't always better, but I digress. The small block engines are leaders in V8 economy, packaging size and affordability. The LS3 only costs $5,000 for a crate motor. That's nothing. The Subaru turbo boxer (which is weaker than the LS3 in every possible metric) costs well over $10,000 and its power output is over 100hp less than the LS3 and over 100 down on torque too.
        • 7 Years Ago
        holdo, the subaru 2L has been around for 20 years, so it's not a motor that anyone would call "modern" either. And last I checked, they didn't get fuel economy that anyone would consider decent for a 2L motor or for a car the size of an Impreza Basically, that motor doesn't put down power/torque OR get good fuel economy. The LS motors can do both, so really, which motor is outdated?
        • 7 Years Ago
        OHV wasn't invented.
        The lever is one of the simple machines.
        By any engineering analysis, pushrod/rocker arm engines are more complicated than camshaft/tappet.

        Anyway, the OHV came about as a cost saving measure.
        It is hard to do things right, especially WAY back when metallurgy was hit or miss.
        Timing gears, timing shaft, or timing chain for overhead camshafts were your choices 100 years ago.
        To do justice to something like that, you have to a Bugatti, not a Ford.
        • 7 Years Ago
        Modern V-8? The small block? Seriously?
        • 7 Years Ago
        holdo...

        Still buying the argument that the LS3 is anything but modern? Seriously?
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