I thought pontiac claimed the lower HP numbers were due to corvettes being optimized for airflow, and pontiacs not. How does the 2008 VXR8 (and the clubsport, I presume) get the full 432HP out of the LS3? It's not just the top-end, either, the torque is down 20 lb-fts as well.

sorry if this has been beaten to death, haven't found this exact question answered...

That could easily be explained by tuning, but they could have also opened up the exhaust a little bit. Magnaflow said the G8's 2.25" exhaust tubing had crush bends in it, which certainly doesn't help matters.

I could just be advertising.

The GXP's hp rating has not been finalized yet- I would think it will be right around the 422 hp quoted for the LS3 Camaro. Also, GM is using the new SAE certification procedures for hp ratings in the US. I do not know if the VXR8's rating is SAE certified.

British HP are smaller than US hp... ok not really but horsepower in the UK is measeaured using Gross horsepower like back in the 1960s. It does not include parasitic losses from pumps and comressors etc. SAE does that easily would account for a 20 HP difference.

Three Words:

Environmental
Protection
Agency

I could just be advertising.

right, and I did read about the fear of pontiac eclipsing the corvette HP ratings, at least while C7 is not out...

and perhaps it's too early to tell before we hear all the official announcements. Thanks for answers, guys, here's to hoping I can get one under MSRP, and that I get that promotion to pay for all the gas!!

It's the metric system, duh!


:wink2:

right, and I did read about the fear of pontiac eclipsing the corvette HP ratings, at least while C7 is not out...




They did not worry about that when the LS2 GTO came out in 2005 with the same 400 hp rating as the C6.

Besides, with SAE certified numbers, GM no longer has any say in what the rating is. That's also why we are seeing such goofy numbers. For example, the 400 hp LS2 was not SAE certified, while the 361 hp L76 is SAE certified. Just a guess, but I bet the LS2 would come in at say 397hp certified.

They did not worry about that when the LS2 GTO came out in 2005 with the same 400 hp rating as the C6.

Besides, with SAE certified numbers, GM no longer has any say in what the rating is. That's also why we are seeing such goofy numbers. For example, the 400 hp LS2 was not SAE certified, while the 361 hp L76 is SAE certified. Just a guess, but I bet the LS2 would come in at say 397hp certified.

actually, i think i read somewhere that the LS2 would have been ~402 with the new SAE certification.

I thought pontiac claimed the lower HP numbers were due to corvettes being optimized for airflow, and pontiacs not. How does the 2008 VXR8 (and the clubsport, I presume) get the full 432HP out of the LS3? It's not just the top-end, either, the torque is down 20 lb-fts as well.

sorry if this has been beaten to death, haven't found this exact question answered...

Probably because the Clubsport has to compete with the power output of the GT and Turbo 6 Falcons.

it's because we use horsepower and they use horsepowers.....

ok, not really, but someone said it already, EPA, plus, you can't have a 4 door car with more power than your new Camaro!

Probably because the Clubsport has to compete with the power output of the GT and Turbo 6 Falcons.

strange thing is, holden normally claim "average" figures while ford go for the best possible result

Guys,

I'm pretty sure GM pulled back on the tuning of the GXP to try and avoid as much of the G.G.T. as possible. By applying a less-aggressive tuning map to this car, they can squeek a few more MPG out of it and avoid a much larger fee... this will attract customers.

IF the Holden makes 432hp, and the corvette makes 430hp, then we ALL know the GXP can EASILY make this much hp if not a whole bunch more.

Hunt around and you'll find MANY folks are getting almost 500hp from this engine with a tune/headers/intake/exhaust (and sometimes the GMPP Hot CAM). This engine has TONS of potential... don't worry so much!

~LSx

Guys,

I'm pretty sure GM pulled back on the tuning of the GXP to try and avoid as much of the G.G.T. as possible. By applying a less-aggressive tuning map to this car, they can squeek a few more MPG out of it and avoid a much larger fee... this will attract customers.

IF the Holden makes 432hp, and the corvette makes 430hp, then we ALL know the GXP can EASILY make this much hp if not a whole bunch more.

Hunt around and you'll find MANY folks are getting almost 500hp from this engine with a tune/headers/intake/exhaust (and sometimes the GMPP Hot CAM). This engine has TONS of potential... don't worry so much!

~LSx

yes 497 hp with tune headers and otr :)

right, and I did read about the fear of pontiac eclipsing the corvette HP ratings, at least while C7 is not out...


It was the same game back when the Buick Grand National was in the showroom. It was quicker in the 1/4 and more more powerfull than the C4, but GM would not let the literature show it.

I thought pontiac claimed the lower HP numbers were due to corvettes being optimized for airflow, and pontiacs not. How does the 2008 VXR8 (and the clubsport, I presume) get the full 432HP out of the LS3? It's not just the top-end, either, the torque is down 20 lb-fts as well.

sorry if this has been beaten to death, haven't found this exact question answered...

Airflow has absolutely zilch to do with the hp cert. In fact normally they test an engine on a stand, not in the car. Connected to full exhaust and all accessories - but no tranny. That's why it is referred to as flywheel hp. (and brake hp has nothing to do with brakes)

Three Words:

Environmental
Protection
Agency

damn tree huggers :whine:

Airflow has absolutely zilch to do with the hp cert. In fact normally they test an engine on a stand, not in the car. Connected to full exhaust and all accessories - but no tranny. That's why it is referred to as flywheel hp. (and brake hp has nothing to do with brakes)

Hmm....so the throttle body is simply open to the air, with no filter element on it? Am I getting you right? Still, even if this were the case, the intake would be a factor. The throttle body needs to be mounted to something, right? :)

Even on the same engine, if an intake is of a different design because of space constraints (e.g. lower hood), then air flow would be different.

Guys,

I'm pretty sure GM pulled back on the tuning of the GXP to try and avoid as much of the G.G.T. as possible. By applying a less-aggressive tuning map to this car, they can squeek a few more MPG out of it and avoid a much larger fee... this will attract customers.

IF the Holden makes 432hp, and the corvette makes 430hp, then we ALL know the GXP can EASILY make this much hp if not a whole bunch more.

Hunt around and you'll find MANY folks are getting almost 500hp from this engine with a tune/headers/intake/exhaust (and sometimes the GMPP Hot CAM). This engine has TONS of potential... don't worry so much!

~LSx

That sounds about right.

The countries where the clubsport, and the commodore & lumina for that matter, are sold have a high demand for high powered vehicles, even though gas is at least 75% higher in those countries. That demand for america has dropped dramatically, i hate to say, so america isnt one of these countries anymore. The only vehicles america is focused on are the gas-sipping kinds. And of course, pontiac is going to do whatever it takes to put the MPG as high as possible, even if it means decreasing the HP a little. Hell, dont be suprised to see the L99 V8 in the G8 GXPs with the automatic. Im pretty sure that the info given on the GXP so far isnt quite final.

The lumina is for the SWA market... last time I was over here they were bitching because gas was 50c a gallon...

I thought the VXR8 had 414 hp and I thought that was with a 6.0 V8 like the L76 (L96 in the VXR8 right?). Isn't the Ls3 a 6.3 V8?

I thought the VXR8 had 414 hp and I thought that was with a 6.0 V8 like the L76 (L96 in the VXR8 right?). Isn't the Ls3 a 6.3 V8?

LS3 is 6.2L, and the newest VXR switches from the 6.0L LS2 to the new 6.2L LS3