Edmunds Follow-Up Test - LS3 Pontiac G8 GXP

Discussion in 'OT Driven' started by TriShield, Nov 23, 2008.

  1. TriShield

    TriShield Super Moderator® Super Moderator

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    Corvette Power, Mad Max Mojo

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    A GXP doesn't look that much different from the G8 GT, but the unique front fascia with a broad air slot and isolated foglights is your first clue.

    By Dan Edmunds, Director of Vehicle Testing
    Date posted: 11-20-2008

    6.2-liter LS3 V8 415 hp and 415 lb-ft of torque - Optional six-speed manual transmission - 245/40R19 tires on forged alloy wheels

    About 19 months ago, we sent operatives with a briefcase bristling with test equipment to Australia. The mission: Get an early peek at the 2008 Pontiac G8 GT by test-driving its stablemate, the then-new 2007 Holden Commodore SS.

    The residual jet lag was magically wiped away by the Commodore SS's thrilling combination of rear-wheel drive, independent rear suspension, a six-speed manual transmission and a 6.0-liter V8. Or maybe it was the Mad Max flashbacks and the Vegemite.

    Yet even though we loved the 2008 Pontiac G8 when it hit the streets in the U.S. eight months ago, we knew that the Aussie mojo from the Commodore SS hadn't made the trip from the Land of Oz.

    Turns out that Pontiac was holding a few aces up its sleeve, and now the 2009 Pontiac G8 GXP puts them all on the table.

    The Most Powerful Production Pontiac...Ever?

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    A 6.2-liter LS3 V8 engine with the power to light up the rear Bridgestones at will is your second clue. These reworked exhaust tips may look the same, but they're about a half-inch larger in diameter.

    Ace No. 1 is the 2009 Pontiac GXP's LS3 V8, the base engine found under the hood of the 2008 Corvette. Displacing 6.2 liters (376 cubic inches), the G8 GXP version makes 415 horsepower and 415 pound-feet of torque, some 54 hp and 30 lb-ft more than the G8 GT's V8 engine.

    The 2009 Pontiac G8 GXP is the most powerful production Pontiac built to date. Really.

    You could argue that the 1970 Pontiac Trans Am could be equipped with a 400-cubic-inch Ram Air V, which was rated at 500 hp. But this special-order engine was a dealer-installed item, and it would never withstand a grocery run on 91 octane gasoline or live long enough to meet a 100,000-mile powertrain warranty, and hooking one up for a 2008 smog test would be, um, futile.

    Moreover, the 2009 Pontiac G8 GXP's 415-hp rating is certified as an SAE net output, which means it was produced under tightly controlled test procedures that include the presence of an independent observer.

    Twisting the key brings this engine to life with a burbling idle that the 6.0-liter V8 of our 2008 Pontiac G8 GT long-term test car can't match. There's plenty of life under the throttle pedal, as the GXP responds with the kind of healthy shove to the backside you'd get if someone put a sign on the back of your jacket that said, "Kick me."

    The exhaust note that comes from the GXP's low-restriction exhaust system contains just enough of that high-school rock-and-roll soundtrack to make us want to stand on the power pedal whenever possible, yet it's not offensive enough that the old guy down the street will shake his cane at us. And did we mention the off-throttle burble?

    But there is a dark side. The GXP's fuel consumption figures are expected to settle near those of the ZR1 Corvette, which are 14 mpg city and 20 mpg highway. Plus the Corvette gets slapped with a $1,700 gas-guzzler tax, so it's likely the GXP will, too.

    Shift Change

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    Firmer FE3-specification dampers and a few rear suspension tweaks improve steering precision and turn-in, and we think the extra control improves the ride, too. Whomp on the loud pedal with the stability control turned off and the GXP gets rowdy, but never scary.

    When it comes time to grab the next gear, we actually can. Ace No. 2 in Pontiac's program for the GXP is the same Tremec TR6060 six-speed manual transmission we experienced in the Holden Commodore SS. Except here the shift lever is under our right hand, where it belongs.

    There is one little catch, however. In a reversal of usual practice, the same Hydra-matic six-speed automatic found in our G8 GT is the GXP's standard offering. You have to fork over $695 extra to get the six-speed manual.

    At least it's a good one. The lever action is sure and the gates are well-defined. And having full command of the transmission makes the LS3 much more of a willing partner, especially when corners are thrown into the mix.

    We're not as convinced about the clutch, however. The engagement point is easy enough to detect, but the pedal effort is too light. The Luk single-disc clutch and single-mass flywheel are the same found in the bell housing of the 361-hp Holden Commodore SS, but we're assured there's more than enough capacity to deal with the LS3.

    The same limited-slip rear end found in the G8 GT and Commodore SS is fitted to the GXP, but with a couple of important changes. The GXP's final-drive ratio is shorter, as the Holden's 3.45:1 rear end is changed to 3.70 here when the manual transmission is in place. The automatic variant enjoys a 3.27 rear end instead of the G8 GT's 2.92 gears. And the GXP's ring-and-pinion gears are shot-peened and phosphate-coated for enhanced wear and durability, something that can't be said of the rear ends of some other high-output cars.

    Rubber Meets the Track

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    Red seat inserts are paired with red steering wheel accents; if you choose all-black seats, you'll get an all-black wheel, too. That's right, the G8 GXP can be equipped with a six-speed manual transmission.

    Our instrumented acceleration test runs peg the performance of the 2009 Pontiac G8 GXP with its six-speed manual transmission at 5.2 seconds to 60 mph (4.9 with 1 foot of rollout like on a drag strip) and 13.4 seconds at 105.9 mph in the quarter-mile. That's about 0.4 to 0.6 second quicker than the G8 GT and Commodore SS. Pontiac points out that the automatic-equipped GXP will do 0.2 second quicker still.

    The most obvious change to the chassis is the fitment of larger 14-inch ventilated brake rotors with Brembo four-piston fixed calipers in front. Bigger brakes mean the 19-inch tires are now standard, and they're the same 245/40R19 Bridgestone Potenza RE050A summer performance tires that are optional for the GT. Here they're mounted on unique forged-aluminum wheels that weigh about 1 pound less apiece than the GT's optional wheels.

    The GXP's stopping distance from 60 mph comes in at 110 feet — the same result as the G8 GT with the same tires, but smaller brakes. The benefit from the new brake package expresses itself as increased fade resistance after numerous hard stops, and excellent pedal feel.

    The GXP carries the so-called FE3 suspension package with sport-tuned struts and shocks that feature firmer damping rates, which replaces the FE2 setup found in the GT. No further changes apply to the front suspension, but the rear gets a 2mm-larger stabilizer bar (from 18mm to 20), a lower control arm with an outer ball joint instead of a rubber bushing, and a revised toe link.

    There are no specific steering system changes, but these mods alone give the GXP better turn-in response and precision along with a reduced tendency toward understeer. The car's ride quality doesn't suffer much at all from the extra damping control, either. In fact, we like the way the GXP deals with uneven asphalt better than the sometimes soggy feel of our G8 GT.

    None of this adds up to a measurable benefit at our test track, presumably because our G8 GT features identical tires. The GXP's 0.84g effort on the skid pad is on par with our GT, but its slalom time of 63.6 mph is actually slightly slower. Our test pilot theorizes that the GXP's stiffer rear stabilizer bar that helps reduce understeer in corners might be making this 4,010-pound sedan a little pendulous through the slalom as the tires heat up after four or five consecutive cones with the stability control shut off.

    Visually Similar

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    Two things: There's no redline, and the dreaded (and electronically enforced) 1-to-4 skip shift with 2nd-gear lockout sometimes rears its ugly head when tooling around lazily in 1st gear. Almost no one liked the pong-style digital gauges that used to sit here in 2008; now they're gone and replaced by...nothing.

    Perhaps the most unexpected aspect of the 2009 Pontiac G8 GXP is its visual similarity to the G8 GT. Apart from the wheel differences between the two cars, the GXP's handsome front and rear fascias aren't distinctive enough to get your attention unless you park a GT alongside. And you have to brandish a ruler to confirm that the quad exhaust tips are, in fact, a half-inch bigger.

    But perhaps that's the point after decades of Pontiac scoop-and-cladding excess. Still, we think the ready-made stand-up wing from the 2007 Holden Commodore SS is just the thing for this car if you can get one, as the GXP's spoiler seems a flaccid carry-over from the GT.

    Inside the cabin, you'll find that the optional leather-upholstered seats are now standard, but with large GXP logos embroidered into them. A heavily sculpted steering wheel from the Holden Commodore SS-V makes its first appearance. We'd rather it didn't, because its cartoonish contours don't fit our hands. Everything else inside is pure GT fare, including new-for-2009 Bluetooth connectivity.

    Now How Much Would You Pay?

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    One of the best and most precise sunroof actuation controls this side of an Audi; twist to your chosen detent on the right to slide open or to the left to tilt.

    The 2009 Pontiac G8 GXP is expected to start at just over $39,000, including destination and the compulsory gas-guzzler tax. Our test car has the two most significant options, the six-speed manual and a $900 sunroof. We figure the as-tested price of our particular GXP settles just below the $41,000 mark.

    If this holds true, the 2009 Pontiac G8 GXP will be cheaper than the similarly optioned SRT8 versions of the Chrysler 300 and Dodge Charger. And you can't opt for a manual in either one of those cars at any price.

    Pontiac has been building up to the GXP for a long time and this time it's got some serious wide-track excitement to sell. You could argue that the 2009 Pontiac G8 GXP is more like a four-door Trans Am than a regular G8.

    But the question is, has Pontiac held onto its best cards too long? Can the GXP show everyone that the G8 is good enough to make Pontiac a brand to be proud of?

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    The 2009 Pontiac G8 GXP wears unique 19-by-8-inch forged-alloy wheels that contain four-piston Brembo brake calipers in front.

    What Works: 6.2-liter LS3 V8 producing 415 horsepower; rollicking exhaust note; optional six-speed manual; communicative chassis tuning.

    What Needs Work: Light-effort clutch action; comically over-contoured steering wheel; too similar visually to the G8 GT.

    Bottom Line: Never mind the Firebird or the GTO, because the 2009 Pontiac G8 GXP is Pontiac's best car ever.


    Performance

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    0 - 30 (sec): 2.3
    0 - 45 (sec): 3.5
    0 - 60 (sec): 5.2
    0 - 75 (sec): 7.4
    1/4 Mile (sec @ mph): 13.4 @ 105.9
    0-60 with 1-ft Rollout (sec): 4.9
    30 - 0 (ft): 28
    60 - 0 (ft): 110
    Braking Rating (Excellent, Good, Average, Poor or Very Poor): Excellent
    Slalom (mph): 63.6
    Skid Pad Lateral acceleration (g): 0.84
    Handling Rating (Excellent, Good, Average, Poor or Very Poor): Good
    Db @ Idle: 50.3
    Db @ Full Throttle: 81.3
    Db @ 70 mph Cruise: 66.3

    Acceleration Comments: Unfortunately, the most effective launch is the ugliest and most abusive, with lots of axle hop from a lowish 2,500 rpm. Higher rpm with smoother tire spin felt better, but was slower. The clutch took some getting used to, with low effort and a high engagement point. Also it feels as if there is a damper in it, slowing and smoothing aggressive shifts. The shifter is slick and accurate, however. Also, why no painted redline on the tach -- especially as this slow-reacting tachometer often is 500 rpm behind?

    Handling Comments: Skid pad: There's a noticeable "tipping point" where the GXP can go from benign understeer into a very slight oversteer attitude. Good balance here and a sideways drift is a piece of cake. Slalom: Unfortunately, that slight oversteer tendency we liked on the skid pad is more pronounced in the slalom, and it builds up as the cones pass. Entering with any kind of quick pace is paid off with a pendulumlike, increasingly tail-happy run. The best run was earned by entering slowly and finishing strong, feeding throttle to keep the rear planted.

    Braking Comments: Very solid, fade-free braking performance. Moderate pedal effort, but so-so feedback. Still, this is a very good overall setup.

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  2. TriShield

    TriShield Super Moderator® Super Moderator

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    GM also lent AutoBlog the same silver GXP to drive.

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  3. Formula-95

    Formula-95 2:32 PM 5-13-09 Never Forget, Hamburglar OT Supporter

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    i ALMOST want to trade in my GTO for that car...almost.


    same with the Camaro
     
  4. Gai

    Gai New Member

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    Awesome but I'm going for the GT. Just can't see the value in the GXP over the GT price wise.
     
  5. PanzerAce

    PanzerAce Active Member

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    Pontiac makes the only US cars that I would DD :cool:

    cliffs on this 1->4 shift thing? And more importantly, is there any way to disable it?
     
  6. you know me

    you know me OT where the douchbags play

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    it started on the 90 vette as a way to get around the gas guzzler tax...why this car has it since you have to pay the tax anyway is beyond me. yes it can be disabled...least it always has been. the deal is that you have to go from 1-4 (the computer locks out 2-3) under low rpm shifts
     
    Last edited: Nov 23, 2008
  7. 396Hawk

    396Hawk Active Member

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    I'm sure someone has or will have a SSE out for the G8.

    Decent numbers and I like the interior but IMHO the exterior styling of the car is awful.
     
    Last edited: Nov 23, 2008
  8. amill94

    amill94 OT Supporter

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    I've been waiting since the G8 launch for the specifics on this car, most importantly price...and at the price of $40k I'm gonna say meh. It's definitely a good offering and I love they took the Holden steering wheel too. However, I was looking between this and the Camaro SS, and I'm leaning toward the SS at this point.
     
  9. art_VW_shark

    art_VW_shark OT Supporter

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    how does the manual force you to skip shift? is there an mechanism that blocks the fork from enters 2 and 3?
     
  10. TriShield

    TriShield Super Moderator® Super Moderator

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    Yes, it also blocks you from going into reverse if the car is moving forward.
     
  11. CJPA

    CJPA New Member

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    Fucking reviewers. :rofl:

    First Pontiac is just too fucking wild with the styling.

    Now it's not wild enough :ugh:

    I think the GXP is great. I won't be buying one because I'm not in the market, but it's a good car for sure, a nice improvement over the GT. I think the styling is agressive but subtle, definitely a competitor in the 5-series area that Pontiac wanted to create.
     
  12. BigT

    BigT LSX Crew

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    I wish the camaro had that interior. :hsugh:
     
  13. Mitchj

    Mitchj OT Supporter

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    i have to say, i'd rather a camaro :o

    the gt is still an excellent buy, and i'm not going to bitch about the auto like everyone else.
     
  14. Original

    Original OT Supporter

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    maybe it's the wheels.. but i swear the GT looks better :o

    fast car for sure though. if the price is right i just might get a GT in a few years
     
  15. art_VW_shark

    art_VW_shark OT Supporter

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    even teh 6MT vette has that restrictive shit? :barf:
     
  16. Mitchj

    Mitchj OT Supporter

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    not being able to go into reverse is a good thing
     
  17. CJPA

    CJPA New Member

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    Shit's been around for more than a decade, man.

    Skip-Shift Eliminators are like $30.

    Or you could just apply more throttle :)
     
  18. TriShield

    TriShield Super Moderator® Super Moderator

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    That's what I do, mine rarely ever comes on.
     
  19. CJPA

    CJPA New Member

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    But you're missing out on some substantial engine-braking (pun intended) :mamoru:
     
  20. z284pwr

    z284pwr OT Supporter

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    It'll be interesting to see how these hold value :noes:
    If they fall into what I'm willing to part, I'll get my ass reamed if I go get one, but it's tempting :naughty:
     
  21. art_VW_shark

    art_VW_shark OT Supporter

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    That's ridiculous.
     
  22. CJPA

    CJPA New Member

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    In for depreciation buy of G8GT in a couple years
     
  23. Bernout

    Bernout OT Supporter

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    Too bad about the shitty mileage :(
     
  24. Mitchj

    Mitchj OT Supporter

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    the milage is the same as the GT.
     
  25. you know me

    you know me OT where the douchbags play

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    :ugh:
     

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