JMB

Tadge, with all of the heroic engineering that went into the LS7 where you had to claw for every last ounce of HP to crack the 500 mark (e.g., vented block bay windows, exotic exhaust manifolds, etc) why did the engineers choose to leave at least 50+ free HP on the table for the LT4 that would have easily allowed the LT4 to be rated at 700+ HP and not just beat the competition but destroy it? Surely your engineers have seen what the aftermarket guys have done with a simple low restriction intake tube/filter mod? I understand emissions and noise requirements, however, I also understand mitigation options to counter these?

Couldn't it have been just as simple to once again lead the Industry today like Chevrolet did 45+ years ago when they put Headers from the factory in the trunk as an option on the 1969 Z28 for the dealer to install "for offroad use" and today offer a high flow air intake option for the 2015 Z06 that fits in the back hatch for installation "for offroad use only" that wouldn't negate the warranty?

jvp

I'm not sure you do. It's a simple case of fuel econ, emissions, and longevity. None of the aftermarket guys have to worry about any of those things. GM does.

atljar

The vast majority of CAI systems I have seen, INCREASE fuel economy. My one and only guess would be noise concerns.

JMB

I agree and once again, a muffler (Helmholtz resonator) can be designed for this!

98vert6spd

The answer very easily could be we need to be able to have a horsepower gain in year two and three to boost sales or maybe in year three and four or who knows looks like you just figured them out

JMB

I am fearful that you hit the finish sized nail on the head with a frickin' sledgehammer

jvp

The C5 Z06 had 1 HP bump and that was due to making the exhaust more efficient.

At no other point in the recent Corvette line-up has the HP bumped when the engine model has stayed the same. I think you guys are dreaming. I'll bet a paycheck that the C7 Z06, as it stands, sees no HP increase.

383vett

What??? The 2001 C5Z06 was rated at 385 hp. The next year it went up to 405 hp. These were both LS6 motors.

JMB

jvp.....while I appreciate everything that you have done to get Tadge on board there really are a few more details behind the C5Z power increase from '01 to '02! There were actually several VERY significant changes from the 2001 C5Z06 to the 2002 C5Z06 that brought about the HP difference, not one as you have cited. The highlights include a combination of:

• Improved lower restriction exhaust system
• Revised higher lift/more aggressive camshaft for more airflow
• Revised MAF to screen-less for more airlflow
• And guess what....A REVISED AIR INTAKE TRACT for more airflow!

Sounds to me like GM dumped the guy that came up with the low restriction air intake for the 2002 C5Z and went back to their "good ole boy" who was clueless when designing the 2001 C5Z intake and hired him back as a contractor to design the C7Z intake based on his previous "expertise" sorry, I couldn't resist

With the dropped 100K mile warranty for 2016 & on I wouldn't be so sure and I just make have to take you up on your generous offer!

jvp

Re-read my post. I quoted it here and added some emphasis:

It's possible you misread my "1" HP bump where perhaps I should have used "a" in its place.

Glenn Quagmire

I'm curious about how Tadge would answer the OP's question.

383vett

Gotcha

ivanjo11

I also think that 650 hp is about the limit for this chassis because of traction issues. More power more mean less traction.

I think that they are still leaving tenths of a seconds on the table with just the gearing. Z06 M7 has a tall gearing in comparison with the 911 Turbo S and the GTR and the Stage 3 A8 runs out of steam from 130 mph to 150 mph but i think that is mainly because of the conservative 2.41 rear axle.

Tonylmiller

It is amazing to me that anyone would think that GM would "leave 50+ Free HP on the table". It just makes absolutely zero sense to think that they would do that on such a high performance car.

JMB

Do you live in a cave? Haven't you seen the results?

Nate@VanBortelChevy

There is a lot that comes into play in final HP figures.

Output
Emissions
Federal Gov't Regulations
Engine Longevity
Usability
Practicality
Cost
Gas Guzzler Tax

Imagine if GM went with a header style exhaust manifold and were able to bump the HP +15. This cost them $500 more per car. $500 x 5000= $2,500,000 extra in costs for just 1 model year. Sure they could pass the $500 extra and raise the cost of the car, but to reach their target demand they have to keep the price down.

And what would happen if a higher flowing intake or exhaust would then cause the MPG and emissions ratings to drop? How are people going to feel about having to pay the gas guzzler tax? Yes, MPG and emissions quality will decline, more air = more fuel!

JMB

Let's get real for a minute...my personal opinion is that there isn't a soul who would care when they're dropping in the neighborhood of $100K for this car that it costs a few bucks more for a +50HP low restriction intake system and can't meet the guzzler tax just like the A8 Guzzler Tax hasn't kept a single buyer from stepping up either. The Hellcat meets emissions at 707HP and so do all of the Shelby Super Snakes that produce 850HP so people need to stop defending GM on this issue...their isn't a good excuse! If MOPAR and FORD/Shelby have better engineers than GM that can figure out how to make mega HP and pass emissions then Tadge just needs to fess up and admit that his engineers are less capable.....personally I don't think they are, that's why I am asking the question. For all of the whiners on this thread you'd think I posted this question in a "green" Forum rather than a High Performance Car Forum.

Let's face it, GM left the easiest +50HP on the table for NO GOOD reason when it comes to their premier performance car, period!

jvp

You have people who understand the technical limitations to output trying to explain to you why GM did what they did, and you insist on calling us "whiners" or other such names. I can guarantee you this isn't even going on the poll now.

Enjoy your day.

JMB

I stated in my very first post that I understand what it takes, I didn't ask for further explanations.

So much for the Democratic process....