I was wondering if there is a mechanical difference between the LS3 motor in the upcoming GXP and the current Corvette that will explain the 28 horsepower difference? Is it marketing, electronic or mechanical? If someone could shed light on this I would appreciate it. Thanks.

more restrictive intake and exhaust...

By intake you mean before the throttle body not the intake manifold right?

By intake you mean before the throttle body not the intake manifold right?
I think there is some sort of acoustic muffler on the intake so that it isn't as loud as it would be unrestricted (as is the case in most cars, I think). GM doesn't think that Pontiacs should be as loud as Corvettes. That's at least the reason I've heard.

The way I read this post it seems like the Corvette get the acoustic muffler too.

"Higher flow intake manifold with acoustic shell
Intake ports revised to match new cylinder head. The new composite intake manifold is manufactured with a lost core process to improve runner to runner variation and to reduce flow losses. Acoustic foam is sandwiched between the outside top of the intake manifold and an additional “skull cap” acoustic shell to reduce radiated engine noise. Structural enhancements have been added to the manifold bosses. "

Here is the thread.

http://www.camaro5.com/forums/showthread.php?t=1977

Intake tract before the throttle body/exhaust and subsequent calibration.

Different intake manifold from the corvette for packaging concerns, different exhaust. tune.. etc....

I was wondering if there is a mechanical difference between the LS3 motor in the upcoming GXP and the current Corvette that will explain the 28 horsepower difference? Is it marketing, electronic or mechanical? If someone could shed light on this I would appreciate it. Thanks.

because the decision makers are GAY

because the decision makers are GAY

correct.:wink2:

I was wondering if there is a mechanical difference between the LS3 motor in the upcoming GXP and the current Corvette that will explain the 28 horsepower difference? Is it marketing, electronic or mechanical? If someone could shed light on this I would appreciate it. Thanks.
Intake tract before the throttle body/exhaust and subsequent calibration.

Does that answer your question '99?

because the decision makers are GAY

:gr_jest:

generally the tune and supporting hardware like everyone else has stated. the camaro will not get the c6 tune either if that helps.

this engine is a 450hp crank motor. its nice to know that all you need is a tune to get it there! the camaro with the ls3 is running 12.7 at 113. and it weights near 4000lbs. the camaro z28 with the lsa put down 520 rwhp in one of gms test. and the zr1 put down 663rwhp in one of their tests.

just saying the power will be there in the end regardless if its a stock tune or not. gm has done their homework.

The extra length of the exhaust is one of the main reasons for the restriction, same for the side intake. The ZR1 put down 663 bhp you mean, not rwhp. I've had the chance to look at and get a ride in test Zr1 #9 in phx az, and it's a great car. However, you'll need more than a tune for 50 more hp. These cars come with a light state of tune for emissions and mpg regs. A simple tune and CAI on the GXP and you're at abot 450 bhp and a solid upper 12 quarter at around 111+ mph. The intake is all LS3 on this car, no different than on the vett just like in the GTO's. A good head, cam and bolt-ons with a good tune in the GXP and you've got a stout 540 bhp all motor car that'll run with or beat the 550bhp LSx CTS-v. In fact final testing at GM has officially comfirmed that the CTS-v will be at 560 bhp and the ZR1 around 635-640 bhp.

I just hope this big over weight sedan has at least a 3.55 rear or better (3.73) in it so the baby will hustle.

The Reason the HSV's LS3 makes less power is due to the other components which wouldn't be as durable with the extra torque so the power was restricted somewhat until they update the components which will occur in 2010 i believe

The Reason the HSV's LS3 makes less power is due to the other components which wouldn't be as durable with the extra torque so the power was restricted somewhat until they update the components which will occur in 2010 i believe

Sounds like a dog & pony show to me. :bs:

Pontiac is missing the boat here. The competition, LS-F, M3, are over 403. I believe GM is limiting the HP because they don't want another car in Corvette territory. GM should bring this out with at least 420 HP to be class competitive.

Pontiac is missing the boat here. The competition, LS-F, M3, are over 403. I believe GM is limiting the HP because they don't want another car in Corvette territory. GM should bring this out with at least 420 HP to be class competitive.

That old "rule" has long since passed, hence the 04 GTO coming with 350 HP and the 06 GTO coming with 400 :)

Different intake manifold from the corvette for packaging concerns, different exhaust. tune.. etc....

Actually its the exact same intake manifold, the L76 in the G8 already utilizes a LS3 intake manifold; it fits perfectly ;)

That old "rule" has long since passed, hence the 04 GTO coming with 350 HP and the 06 GTO coming with 400 :)

So, if it wasn't an intake or exhaust change for packaging reasons, why wouldn't the LS3 make the same 430 HP as the 'Vette?

... that they tuned the GXP to 400hp to escape the Gas Guzzler Tax!

Think about it! The car comes with much shorter gearing, and has more HP as well. To offset these they simply detuned it a bit to get better highway mileage to ease up on what GGT there will be.

I'm almost positive that with a mild retune, intake, exhaust, this engine will easily make the 30hp back, and then some!

~LSx

... that they tuned the GXP to 400hp to escape the Gas Guzzler Tax!

Think about it! The car comes with much shorter gearing, and has more HP as well. To offset these they simply detuned it a bit to get better highway mileage to ease up on what GGT there will be.

I'm almost positive that with a mild retune, intake, exhaust, this engine will easily make the 30hp back, and then some!

~LSx

I think you're exactly right on that.
The LS2 in the HSV range came standard with 411hp
The LS3 in the updated HSV range now comes standard with 425hp.

Would seem to me that the only difference between the AU LS3 and the US LS3 is the tune, and only that for fuel comsumption fgures.

The LS3 in standard form in AU is currently being shown to have VERY VERY conservative tunes, specifically in the timing, to ensure driveline longevity and also to allow for a bit more of a safety margin for the UK export model which comes with a Harrop HH112 supercharger option.

i think gm reduce the hp to keep the ls3 corvette quiker than the g8 GXP

of course its the only supercar that gm had , so they wont made a car has the same power of corvette

check

So, if it wasn't an intake or exhaust change for packaging reasons, why wouldn't the LS3 make the same 430 HP as the 'Vette?

It is, just like I said but someone said intake MANIFOLD which is the one we already have; its the same ;)

i think gm reduce the hp to keep the ls3 corvette quiker than the g8 GXP

of course its the only supercar that gm had , so they wont made a car has the same power of corvette

You have no argument. My 2006 GTO has the same amount of HP as a 2006 Corvette, 400hp. Is it as fast? No, b/c it weighs a ton more, but does it piss off Corvette die hards, HELL YEAH.

Also, the 2009 CTS-V will have 556hp which surpasses both the base Corvette and the Z06 in HP.

i think gm reduce the hp to keep the ls3 corvette quiker than the g8 GXP

of course its the only supercar that gm had , so they wont made a car has the same power of corvetteThey could rate it the same and the Vette would still be faster so that doesn't matter. Very big weight difference between the two.

The 89 TTA was "rated" 5hp higher than the Vette that year. But it was also a second faster... :)

Shhhhhhhhh!!! My turn to talk!!!

I believe GM is limiting the HP because they don't want another car in Corvette territory.

Duh! :iagree:

That old "rule" has long since passed, hence the 04 GTO coming with 350 HP and the 06 GTO coming with 400

When did it pass??? A corvette was faster than a GTO then!!!

... that they tuned the GXP to 400hp to escape the Gas Guzzler Tax!

Think about it! The car comes with much shorter gearing, and has more HP as well. To offset these they simply detuned it a bit to get better highway mileage to ease up on what GGT there will be.

I'm almost positive that with a mild retune, intake, exhaust, this engine will easily make the 30hp back, and then some!


Sounds very logical. Face it people, i know the musclecar crowd, let alone the crowd on this site, are suckers for high powered RWD vehicles, but gas is always going to be an issue from now on. Most of you are repeatedly using this statement, "People who are purchasing this vehicle doesnt care about the price of gas.". That statement is the biggest load of bull**** i have ever heard. No matter what anyone says, in the back of everyone's head, there is a care for gas mileage and a fear that it wont stop going up. So for those of you who think that you are so manly that you could give a damn about gas while driving a heavy RWD gas guzzler, one day, your pride ballon will burst.

Dont get me wrong, the GXP is an awesome vehicle. Hell I want one. Im just tired of hearin that statement and i just wanted to point out the truth, thats all.

i think gm reduce the hp to keep the ls3 corvette quiker than the g8 GXP

of course its the only supercar that gm had , so they wont made a car has the same power of corvette

Again, DUH!!!

Also, the 2009 CTS-V will have 556hp which surpasses both the base Corvette and the Z06 in HP.

Hold it right there pal!!! Red Light!!! Brick wall!!! Pay attention bra!!! The new CTS-V has the same supercharged powerplant as the corvette ZR1, just detuned, proportional(so to speak) to the GXP and the regular corvette. It has moved up from being on par with the regular corvette and became on par with the "blue devil". Smart idea. If it would have stayed on par with the regular corvette, it would have been HIGHLY overshadowed by the G8 GXP.

Pontiac is missing the boat here. The competition, LS-F, M3, are over 403. I believe GM is limiting the HP because they don't want another car in Corvette territory. GM should bring this out with at least 420 HP to be class competitive.

Sounds like the late 80's when the GN was whooping the Corvette. Suddenly the GN was no more, wonder why.

Shhhhhhhhh!!! My turn to talk!!!



Duh! :iagree:



When did it pass??? A corvette was faster than a GTO then!!!



Again you missed the point, even IF the GXP came with all 436HP it would STILL be slower than the vette due to its weight. Same thing with the GTO, the old rule of nothing having the same (or more) HP than the Corvette is dead. GM did NOT reduce the HP to keep it slower than the vette, the G8 weighs almost 800 lbs more!

Also your statement about the CTS-V having the same "powerplant" as the ZR1 is false. The LSA (NOT the LS9) in the CTS-V is similar in architecture but uses a different blower, inlet and a host of other parts; its NOT the same engine.

Again you missed the point, even IF the GXP came with all 436HP it would STILL be slower than the vette due to its weight. Same thing with the GTO, the old rule of nothing having the same (or more) HP than the Corvette is dead. GM did NOT reduce the HP to keep it slower than the vette, the G8 weighs almost 800 lbs more!

Also your statement about the CTS-V having the same "powerplant" as the ZR1 is false. The LSA (NOT the LS9) in the CTS-V is similar in architecture but uses a different blower, inlet and a host of other parts; its NOT the same engine.

Geez, Chris, always ruining the discussion with those pesky little fact things.

:rofl:

I know I know... sorry :( LOL :D

http://menacingmorons.tripod.com/sitebuildercontent/sitebuilderpictures/owned.jpg

Again you missed the point, even IF the GXP came with all 436HP it would STILL be slower than the vette due to its weight. Same thing with the GTO, the old rule of nothing having the same (or more) HP than the Corvette is dead. GM did NOT reduce the HP to keep it slower than the vette, the G8 weighs almost 800 lbs more!

Also your statement about the CTS-V having the same "powerplant" as the ZR1 is false. The LSA (NOT the LS9) in the CTS-V is similar in architecture but uses a different blower, inlet and a host of other parts; its NOT the same engine.


The Vette has the advantage that no other platform in GM has - They are allowed to be loud, and there is much more willingness to compromise on air induction and exhaust routing.

That being said, I would guess one of the largest differences is in the exhaust backpressure, and in induction restriction. The vette runs an air cleaner on the front of a straight piece of pipe that feeds the intake manifold directly. The exhaust is large (larger than the G8) and straight, and flows very well.

The G8 is still intended to be a touring/sports sedan. If you want a horsepower machine thats bred for that only, then the Corvette is for you. The G8's competition has a higher level of smoothness and refinement than Corvette owners demand. A more restrictive exhaust, along with an induction system that must fit and bend to fit under the hood will easily make up the 30hp difference.

Geez, Chris, always ruining the discussion with those pesky little fact things.

:rofl:

He's bad about that, isn't he. :gr_jest:

Don't look past the 800 lb gorilla in the room folks.
You start with more, you end up with more. We're talking cubes.
It's not that difficult to get power from 6.2 liters. How or why
it makes less is really a useless discussion.
Pick up a wrench, learn how an engine works and have fun. This can
be a real wolf in sheep's clothing like the ol LT1 Impalas back in the day.
It's no sports car but a sedan with some real potential. Depending on
pricing it could be a heck of a deal.

Just my 2 cents,
Carry on.

The G8 is still intended to be a touring/sports sedan. If you want a horsepower machine thats bred for that only, then the Corvette is for you. The G8's competition has a higher level of smoothness and refinement than Corvette owners demand. A more restrictive exhaust, along with an induction system that must fit and bend to fit under the hood will easily make up the 30hp difference.

Smoothness, maybe. With navigation, HUD, Dual zone auto climate controls, seatwarmers, paddle shifters, etc., the corvette is pretty refined. Its a LOT better than a certain halo car in the chrysler family....

the gxp g8 will be running very similar to what the old cts v did. 400hp in a 4000lb car. it will also be just as easy to tune....however the tune and mods should have a significant increase in power compared to the 6.0. which is very cool! :driving:

the only question remaining is will gm keep the 6060 tranny as an option! if gm can kill the z28, and the optional stick in the g8 gt, i would not put any dumb move past them!!!!:(

i think gm reduce the hp to keep the ls3 corvette quiker than the g8 GXP


Yup the 800lbs they added was for better handling too ;)


of course its the only supercar that gm had , so they wont made a car has the same power of corvette

Yeah, except for those pesky 04-06 GTO's that had the same power rating ;)

I believe gas guzzler is a factor, fer shure.

But, I want to repeat the second part of my earlier statement here: to be class competitive, the G8 GXP needs to bring at least 420 large to the party. The M3, LS-F and whatever the Mercedes is bringing to the table (450? 460?) are all above 400. GM should not detune this car. Hell, pump this puppy to 450 and start kicking some A..

But the GXP will be SOOO much cheaper than all those you mentioned. You mention class, so mention cars in the same class.

Don't look past the 800 lb gorilla in the room folks.
You start with more, you end up with more. We're talking cubes.
It's not that difficult to get power from 6.2 liters. How or why
it makes less is really a useless discussion.
Pick up a wrench, learn how an engine works and have fun. This can
be a real wolf in sheep's clothing like the ol LT1 Impalas back in the day.
It's no sports car but a sedan with some real potential. Depending on
pricing it could be a heck of a deal.

Just my 2 cents,
Carry on.

Junior...

The GXP and the base corvette have the same motor. This is what the debate is about.

But the GXP will be SOOO much cheaper than all those you mentioned. You mention class, so mention cars in the same class.

I vehemently disagree with you. GM is positioning the G8 GXP as a competitor to these cars at half the price, which is a great strategy. If you are playing in this performance field, then fully play. It shouldn't be that difficult to deliver the G8 GXP with 420 HP.

Ignoring the price factor kinda invalidates any class comparison. How many are going to cross-shop the G8 with the IS-F, M3, and such?

Car classes are a combination of price, size, intended use, etc. You can't really pick and choose. Well, you can, but then it's just a comparison between performance, not class. And then a lot of people will say, upon reading the comparison... "it's not a fair comparison, the G8 costs half as much."

I would like to think it will be a pretty close match Performance wise and spend a little of the money on mods that you saved when buying the G8 GXP over the say M3 and you have yourself a M3/M5/IS-F/C-63 eater.

The new M3 sedan specs
weight = 3726 1lbs
414 @ 8,300 rpm
295 lb.-ft. @ 3,900 rpm

The New IS-F Specs
weight = 3,780 lbs
416 @ 6,600 rpm
371 lb.-ft. @ 5,200 rpm

I would like to think it will be a pretty close match Performance wise and spend a little of the money on mods that you saved when buying the G8 GXP over the say M3 and you have yourself a M3/M5/IS-F/C-63 eater.

The new M3 sedan specs
weight = 3726 1lbs
414 @ 8,300 rpm
295 lb.-ft. @ 3,900 rpm

The New IS-F Specs
weight = 3,780 lbs
416 @ 6,600 rpm
371 lb.-ft. @ 5,200 rpm

Don't forget to factor in vehicle weights.

Don't forget to factor in vehicle weights.

I'm not, I know what will win but between the GXP and the M3 I think it will be close, very close. Allthough I love the AMG C-63 I sure as hell dont have 60-65 grand to spend on a car, so the G8 GXP with some mods is as close as I can get.

Ignoring the price factor kinda invalidates any class comparison. How many are going to cross-shop the G8 with the IS-F, M3, and such?

Car classes are a combination of price, size, intended use, etc. You can't really pick and choose. Well, you can, but then it's just a comparison between performance, not class. And then a lot of people will say, upon reading the comparison... "it's not a fair comparison, the G8 costs half as much."

This is exactly what GM wants. The mantra for the latest CSV was 5 series quality for 3 series money. GM will position the G8 GXP as the affordable American alternative to the IS-F and M3. The rags will write that the quality isn't the same but the performance yada, yada, which is what they're doing now with the G8 GT.

My point is this: GM will be the price/performance leader here. But if you're going to make the stretch, why stop 20 HP shy of the mark when, given that the same drivetrain in the Corvette puts down 430 HP, you should be able to deliver the same goods?

This is exactly what GM wants. The mantra for the latest CSV was 5 series quality for 3 series money. GM will position the G8 GXP as the affordable American alternative to the IS-F and M3. The rags will write that the quality isn't the same but the performance yada, yada, which is what they're doing now with the G8 GT.

My point is this: GM will be the price/performance leader here. But if you're going to make the stretch, why stop 20 HP shy of the mark when, given that the same drivetrain in the Corvette puts down 430 HP, you should be able to deliver the same goods?

GM said in a MT article on the GXP is that the air flow to the engine is less optiminzed to the GXP than the Vette. That's the only difference.

GM said in a MT article on the GXP is that the air flow to the engine is less optiminzed to the GXP than the Vette. That's the only difference.

Right. I'm calling BS here. Roughly 10 percent drivetrain loss from air flow? C'mon GM. Get the 30 HP back.

BTW, here's the GM line on the G8 GT...

http://wwww23.pontiac.com/g8/compare/

...wherein, they compare the G8 GT to the 550i. Not the same class, at all, and yet there it is.

How cool would it be to go to the G8 GXP comparison site and see:

G8 GXP - more HP than the BMW M3 and the Lexus IS-F

GM will position the G8 GXP as the affordable American alternative to the IS-F and M3.

No they won't. The G8's size, especially in the back seat area, makes it more suited to a 550i or LS460 comparison.

Sure, but a performance comparison doesn't mean much to the market when the prices are so different. Yay for bragging rights... but it's not the same class.

Or M5... which it might not get totally stomped by... they are both heavy cars and the gxp makes more torque...

I am kind of over HP numbers... it is an artificial scale anyway... I am willing to bt that onc it shows up a well driven GXP will be within a few tenths of a well driven M5

LOL. I find this whole thread kind of funny. Here I am, driving a BMW, arguing that Pontiac should have the balls to step up, win this HP war, and say it competes in the same class as world class performance cars and here are most of you, the Pontiac faithful I presume, kicking the dirt, heads bowed, "we don't really compete." C'mon folks! Grow a pair.

LOL. I find this whole thread kind of funny. Here I am, driving a BMW, arguing that Pontiac should have the balls to step up, win this HP war, and say it competes in the same class as world class performance cars and here are most of you, the Pontiac faithful I presume, kicking the dirt, heads bowed, "we don't really compete." C'mon folks! Grow a pair.

You must be reading a different thread than I am.

LOL. I find this whole thread kind of funny. Here I am, driving a BMW, arguing that Pontiac should have the balls to step up, win this HP war, and say it competes in the same class as world class performance cars and here are most of you, the Pontiac faithful I presume, kicking the dirt, heads bowed, "we don't really compete." C'mon folks! Grow a pair.

When they can get the M5 to put out the torque of even a base v8 G8 come back and talk...

When they can get the M5 to put out the torque of even a base v8 G8 come back and talk...

That wont take too long when the GXP starts selling like hotcakes. Wait for it......wait for it...... :oldfogey:

dollar reread my post... I was saying a GT puts out more torque stock than a M5

I was working for a chevy dealer when they discontinued the camero.

One of the reasons rumoured was the amount of complaints from corvette owners because the camero was getting so close to the corvette in hp and drive train...as well as luxury..(Stereo, Leather interior etc...) and at less cost.

This could very well be the reason for the detune with these engines.

To keep them separated.

Right. I'm calling BS here. Roughly 10 percent drivetrain loss from air flow? C'mon GM. Get the 30 HP back.

BTW, here's the GM line on the G8 GT...

http://wwww23.pontiac.com/g8/compare/

...wherein, they compare the G8 GT to the 550i. Not the same class, at all, and yet there it is.

How cool would it be to go to the G8 GXP comparison site and see:

G8 GXP - more HP than the BMW M3 and the Lexus IS-F


An engine is an air pump. I've stated it before, so I apologize for sounding like a broken record. The greater colume of air you can pump through the engine, the more power it will make. The G8 LS3 makes less power than the vette because of a much more restrictive induction and exhaust. Worth every bit of 30hp. Put a high-flowing induction, and open up the exhaust a bit, and you'll get right back there.

intake, tune and exhaust will all be different on the c6 and the camaro when compared to the gxp. it will not be hard to get the ls3 that comes in the gxp up to 450(or about 380rwhp) with basic bolt ons. add cams and heads and your at the next level!

camaro was canned because of low sales! vette owners may have complained but they did not switch over.

camaro was canned because the Mustang outsold it and the Firebird combined!

intake, tune and exhaust will all be different on the c6 and the camaro when compared to the gxp. it will not be hard to get the ls3 that comes in the gxp up to 450(or about 380rwhp) with basic bolt ons. add cams and heads and your at the next level!

camaro was canned because of low sales! vette owners may have complained but they did not switch over.

the 430-436 hp vette puts down 380-390 rwhp. That 430-436 hp rating they have is the SAE certified rating, meaning the engine makes within +-1% of the rated HP. Thats it. nothing more, nothing less. this 450 hp your talking about is absurd.

the 430-436 hp vette puts down 380-390 rwhp. That 430-436 hp rating they have is the SAE certified rating, meaning the engine makes within +-1% of the rated HP. Thats it. nothing more, nothing less. this 450 hp your talking about is absurd.

Your absurd...

he said 450 with mods.

the 430-436 hp vette puts down 380-390 rwhp. That 430-436 hp rating they have is the SAE certified rating, meaning the engine makes within +-1% of the rated HP. Thats it. nothing more, nothing less. this 450 hp your talking about is absurd.


480 / .88 ~ 432(vette loses around 12%)
495 / .88 ~ 448(i have seen one 395 and one 393 rwhp dyno)

you think that every engine in the vette will be within a 1% tolerance ratio? and from what i understand is that every car needs to at least reach the sae certified rating. am i wrong in this? from the various readings off of various chasis dyno in various conditions it looks like the tolerance of crank horsepower numbers are within 3 to 4%.

again by adding simple mods such as a tune intake and exhaust it should be fairly easy to get 450 crank horsepower out of the ls3 motor regardless of the car it sits in.

A coworker's LS2 C6 A6 dynoed at 313 rwhp. That's almost 22% lost. Are the newer A6's that much better?

Sounds ike a bad day to me...

I was working for a chevy dealer when they discontinued the camero.

One of the reasons rumoured was the amount of complaints from corvette owners because the camero was getting so close to the corvette in hp and drive train...as well as luxury..(Stereo, Leather interior etc...) and at less cost.

This could very well be the reason for the detune with these engines.

To keep them separated.

GM seems to have gotten over this with the new Camaro...virtually the same HP as the base Corvette with the V8 expected t make 420 hp

A coworker's LS2 C6 A6 dynoed at 313 rwhp. That's almost 22% lost. Are the newer A6's that much better?

what type of dyno?

mustang dyno are noticably less than other dynos so this should be the first question. also is this sae numbers, if it was a hot day out or was run with no cool down this will significantly lower numbers.
autos will dyno less because more power is loss through an auto over the stick shift. generally i see another 5% speculation. i would assume a 16/17% loss on a auto vette would be normal.

Don't know the conditions or the dyno. But I haven't seen a G8 lose that % yet at the dyno, of those I've seen here.

dollar reread my post... I was saying a GT puts out more torque stock than a M5

Yeah but I've seen times 0-60 on the M5 of 4.3 seconds significantly below what Pontiac claims for the GXP. The M5 will soon get a twin turbo v8 anyway which will put torque through the roof (like it did for the 3.0 6 on the 335).

That said I think it's the bogey for the GXP(and I'm a Pontiac fan given that I have a GP GTP in my driveway). Surprisingly it's also getting cross shopped against STIs and EVOs since it will be in the same price range and close in performance (touch faster in straight line but slower in curves).

Don't know the conditions or the dyno. But I haven't seen a G8 lose that % yet at the dyno, of those I've seen here.

its not losing that %. either its a tight dyno, or the numbers are not corrected, or the engine is not putting out the proper power. with the info you gave us, it could be any one of those 3.

Yeah but I've seen times 0-60 on the M5 of 4.3 seconds significantly below what Pontiac claims for the GXP. The M5 will soon get a twin turbo v8 anyway which will put torque through the roof (like it did for the 3.0 6 on the 335).

That said I think it's the bogey for the GXP(and I'm a Pontiac fan given that I have a GP GTP in my driveway). Surprisingly it's also getting cross shopped against STIs and EVOs since it will be in the same price range and close in performance (touch faster in straight line but slower in curves).


the m5 is in a whole different league. rs6 which is getting a ttv10, the ctsv with the blown 6.2, the e63. the m5 has to up the ante to keep from falling behind.

i cant believe you would even campare the evo/sti to the gxp.:slap: i would even wager that on a full road course(autocross does not equal racing) the gxp would take those 2 stock vs stock.

the m5 is in a whole different league. rs6 which is getting a ttv10, the ctsv with the blown 6.2, the e63. the m5 has to up the ante to keep from falling behind.

i cant believe you would even campare the evo/sti to the gxp.:slap: i would even wager that on a full road course(autocross does not equal racing) the gxp would take those 2 stock vs stock.

Go to topgears website and compare the times of the 08 sti, 08 EVO and the 07 /08 Vauxhall VXR8 (which should be comparable to the GXP) around their track. For example, people put $1000 of mods into an STI (exhaust and tune) and get around 300 WHP (with presumably more drivetrain loss on AWD). The STI runs 4.7 0-60 and 13.3 in 1/4 stock, .90 G on the skidpad (I dont own one of those and I have a Pontiac GP GTP in case you think I'm talking my book so to speak). I'm just saying I have seen people cross shopping those cars because they all provide "cheap" performance for those who are not badge wh#res. I have never seen an M5 buyer looking at Pontiacs though I think it's a nice target for Pontiac since the aspirations for performance are similar.

Go to topgears website and compare the times of the 08 sti, 08 EVO and the 07 /08 Vauxhall VXR8 (which should be comparable to the GXP) around their track. For example, people put $1000 of mods into an STI (exhaust and tune) and get around 300 WHP (with presumably more drivetrain loss on AWD). The STI runs 4.7 0-60 and 13.3 in 1/4 stock, .90 G on the skidpad (I dont own one of those and I have a Pontiac GP GTP in case you think I'm talking my book so to speak). I'm just saying I have seen people cross shopping those cars because they all provide "cheap" performance for those who are not badge wh#res. I have never seen an M5 buyer looking at Pontiacs though I think it's a nice target for Pontiac since the aspirations for performance are similar.

top gear uses an old airfield. decent for testing but its not a track. are these the same base sti/evo that ran times similar to the live axle mustang gt on the car(the uk auto mag) test track?
the camaro which i have heard is built on the same chasis as the g8 just pulled .90g as well. would it be out of the question to see the gxp pull between .85-.90g?
just because its a heavy gm sedan does not mean it cant turn. one just needs to look at the 759 ctsv to figure that out.
with those easy mods you spoke of above the gxp should be putting down 380+rwhp(or about 450crank power out of the ls3).

if your interested in turning you might want to try one of these...1.55g is very impressive!
http://youtube.com/watch?v=64Y1xpTYXUU
its fun to run the above video with this one side by side. a very cool race so they say...
http://youtube.com/watch?v=Gvs2V4BBqI0

top gear uses an old airfield. decent for testing but its not a track. are these the same base sti/evo that ran times similar to the live axle mustang gt on the car(the uk auto mag) test track?
the camaro which i have heard is built on the same chasis as the g8 just pulled .90g as well. would it be out of the question to see the gxp pull between .85-.90g?
just because its a heavy gm sedan does not mean it cant turn. one just needs to look at the 759 ctsv to figure that out.
with those easy mods you spoke of above the gxp should be putting down 380+rwhp(or about 450crank power out of the ls3).

if your interested in turning you might want to try one of these...1.55g is very impressive!
http://youtube.com/watch?v=64Y1xpTYXUU
its fun to run the above video with this one side by side. a very cool race so they say...
http://youtube.com/watch?v=Gvs2V4BBqI0

The GXP should be above .85 for sure (btw the STI at .90 is considered to massively understeer relative to the EVO). That's interesting and exciting to note you think that the GXP should be at around 380 with exhaust and tune (I'm thinking of getting one at some point in the future so it's not entirely academic for me).

The STI and EVO were the base ones run on the most recent series(11). They came in, if I recall, around a 911 and the M3 CSL (the hard core super light one) for comparison. Edmunds compared a Shelby (new) Mustang to the STI and the STI absolutely nuked it across a range of metrics(yeah I know it's no GXP). I used the STI as an example because it's the one I dont own btw(to avoid bias).

My basic point is that I believe more people will cross shop an STI and G8 because they are similarly priced performance for value cars(with little bit different demographic : insert ricer joke here). People who can afford a 85 K M5 wont suddenly try to save 40 K on a GXP even if the 0-60 is similar or whatever. They want to be seen in the M5 and have night vision, and 10 settings for the transmission or whatever. Performance enthusiasts dont care and will go for the best car for the money. A GXP or STI owner probably takes personnal satisfaction knowing they could whoop a 550i across a range of performance for much less money.

People who can afford a 85 K M5 wont suddenly try to save 40 K on a GXP even if the 0-60 is similar or whatever. They want to be seen in the M5 and have night vision, and 10 settings for the transmission or whatever. Performance enthusiasts dont care and will go for the best car for the money. A GXP or STI owner probably takes personnal satisfaction knowing they could whoop a 550i across a range of performance for much less money.

your right. but there are some people switching to the new 550hp cts-v! we will see when audi brings the new 600hp rs6 over here?

the sti and evo are joke in my opinion. i did not respect them when they came out and now there price keeps getting higher and the performance stays the same. sure they are great for a high school kid that wants 500 a month car payments. but thats about it.
if you want all wheel drive find a year old s4! if you want more than 380 add heads and cams to the ls3. it will net you around 500rwhp if interested. i have seen vette dynos in the 520's.

your right. but there are some people switching to the new 550hp cts-v! we will see when audi brings the new 600hp rs6 over here?

the sti and evo are joke in my opinion. i did not respect them when they came out and now there price keeps getting higher and the performance stays the same. sure they are great for a high school kid that wants 500 a month car payments. but thats about it.
if you want all wheel drive find a year old s4! if you want more than 380 add heads and cams to the ls3. it will net you around 500rwhp if interested. i have seen vette dynos in the 520's.

Well I've taken this off topic enough I'll conclude by saying a for an adult that can pay cash for their car an EVO is to an S4 what a GXP will be to a 550i; wow that's like a college boards question. It's will be way better in every measurable/performance respect other than some intangible that a magazine editor can site such as fit and finish to justify the massive price difference.

Anyway, what are upgrades that you suspect would unleash the power of a vette engine in the GXP ; CAI and exhaust alone?.

Well I've taken this off topic enough I'll conclude by saying a for an adult that can pay cash for their car an EVO is to an S4 what a GXP will be to a 550i; wow that's like a college boards question. It's will be way better in every measurable/performance respect other than some intangible that a magazine editor can site such as fit and finish to justify the massive price difference.

Anyway, what are upgrades that you suspect would unleash the power of a vette engine in the GXP ; CAI and exhaust alone?.

That should more than do it.

Anyway, what are upgrades that you suspect would unleash the power of a vette engine in the GXP ; CAI and exhaust alone?.

the vette is hitting up to 390rwhp stock. for the gxp to get to 380rwhp+ it will take intake, tune, and exhaust i believe. some vette guys are hitting 520rwhp with stage 3 cams, ported heads, long tubes, intake, and tune. this stuff is not cheap, and will void any engine warranty.

i believe i saw an 6.0 cts v hit 480rwhp on the dyno with the above mods.

the vette is hitting up to 390rwhp stock. for the gxp to get to 380rwhp+ it will take intake, tune, and exhaust i believe. some vette guys are hitting 520rwhp with stage 3 cams, ported heads, long tubes, intake, and tune. this stuff is not cheap, and will void any engine warranty.

i believe i saw an 6.0 cts v hit 480rwhp on the dyno with the above mods.

as I didnt modify my last pontiac, I'm not up to speed on what would void the warranty exhaust and cai? , or any change that modifies stock hp. For DD driving it would seem there are diminishing returns beyond cai, intake and tune on most cars.

I think that the furthest i am going is a mild cam... looks like Vector and New Era are both working on that little mod for me. Hopefully they have it out for when i gt back and i can in one day go from a very litely modded GT to a car that will annihilate a GXP...

as I didnt modify my last pontiac, I'm not up to speed on what would void the warranty exhaust and cai? , or any change that modifies stock hp. For DD driving it would seem there are diminishing returns beyond cai, intake and tune on most cars.

warranty issues are tricky. some dealers are very very strict, some are not. however once the computer gets word of a voided warranty it does not matter. the law states the manufacturer has to prove the modification caused the defect. but in all honesty if you want your warranty back you have to prove to the manufacturer that the mod had nothing to do with the defect. this is the battle that can get far more expensive than the repair itself so few ever take it this far.

generally, intakes and exhaust, new springs and or shocks dont void warranties.
however changing the tune(generally anything having to do with the computer), taking out or modifying sensors, changing parts within the motor(cam, heads, piston, rods, etc), changing suspension geometry will be an automatic void of warranty.

I think that the furthest i am going is a mild cam... looks like Vector and New Era are both working on that little mod for me. Hopefully they have it out for when i gt back and i can in one day go from a very litely modded GT to a car that will annihilate a GXP...

cams are available mild to wild for the ls3 already. the vette forums have a bunch of info all the aftermarket engine mods.

I have an L76

^^^ do you know if gm will put the l76 in any other cars? it seems to be a very solid engine that puts out good power.

It is in the silverado vortecmax...

Don't think it is going to go into anything else...

are they the same engine? i have looked long and hard at a new sierra 6.0. great trucks from what i have heard.

No they are not... the truck one is better.. but they have the same RPO code... weird huh?

The truck L76 has VVT (no AFM) and the truck intake manifold.

The car L76 has AFM (no VVT) and the car intake manifold.

I believe other than the cam and the above components, they are pretty much the same engine.

Chip

Chevrolet's website says that the truck has AFM...

Chevrolet's website says that the truck has AFM...

Actually, you are right. I had substituted the L92 for the L76 in my head. L92 or L9H picked up AFM this year in addition to the VVT it originally had. Truck L76 had both all along.

You might have been thinking LY6 that has no AFM... L92 is the vortec version (but with AFM) of an LS3. L9H has no AFM. I imagine the L92 and L99 will be similar in the way the truck L76 and car L76 are.

Sorry had some RPO lookups handy.

Just as well. I'm saying uncle on RPOs right now. It appears to me that the L92 goes away or basically turns into the L9H which gets VVT and E85 capability (and you said no AFM). I am assume the L92 is going away based on the fact it is not listed in the GM powertrain guide for 2009.

Chip