golfman

I believe the new LS2 motor is 400 HP because chevy didn't want to lose market with current LS6 buyers. I have two vettes a black 02 LS1 and an 03 Ls6 Z06. I personally like the engine bump for the normal vette, but I would be unhappy if it were faster than the current Z06.

Many people on this forum where mad when the HP of the Z06 went from 385 HP to 405 Hp in a year. I think that is what is happening hear. GM knows that most vette customers are loyal and the LS1 buyers will buy again with a 50 HP bump. The ls6 guys and gals arent upset either. I think the delay on the LS6 proves this to be correct.

The new Zo6 will probably be about 450 to 460 HP same size bump we see here. The car will run close to 12.0 seconds and maybe 3.8s to 3.9s 0 to 60 times. It will be hard to get much better than that with the gears the way they are. The viper and Ford GT have times like this but they dont have to shift before 60 miles per hour making it easier to acheive.


I will wait for the new Z06 and see what happens. I also have to say GM better get the new Z06 better than the current Viper or I think they will lose alot of market share.





[Modified by golfman, 6:43 PM 1/14/2004]


[Modified by golfman, 6:45 PM 1/14/2004]


[Modified by golfman, 6:46 PM 1/14/2004]


[Modified by golfman, 10:07 PM 1/17/2004]

night feeder

but i thought it was pretty much confirmed that the c6 z06 would be at 500hp

scorp508

5hp more makes the Z06 look nice on paper. Come real world watch out for the new baby on the block.

Dsob15

I also think 0-60 in 3.8s should come pretty easy if the new Z gets 450-460hp.

WhiteDiamond

I agree with the marketing concern, but I also believe the C6 Z-51 will be faster than the current Z06. I think the wording used in the press introduction and the confirmed "improvements" to the LS2 pretty much say underrated 400/400 LS2. I also believe the availability of the C6 in the 3rd quarter of this year almost gurantees that most '04 Z06s will be sold with the incentives and below invoice pricing that has allready started. This makes sure the Z06 doesn't compete against the faster Z-51 equipped C6, IMO.

Todd

Evil-Twin

Iwas just reading in the pipe line.... SAE (Society of Automotive Engineers) Dodge is building a carbon fiber Viper... 150 lbs lighter than the C6... with 650 HP...


[Modified by Evil-Twin, 1:27 PM 1/15/2004]

bhamvett

Dave Hill stated that the next Z06 will be a BIGGER jump in power than
the current Z06! It will be at least 500hp!

WhiteDiamond

I think this is where this conversation gets into trouble, as I believe the new Z06 will probably still cost lest that the current Viper. If you throw a carbon fiber suit on the Viper, what kinda price are we looking at? GM will still own their claim of best performance per dollar with the C6 Z06. Also, if the new Z06 does in fact get the aluminum frame that has been debated so much, it could easily be 150lb to 250lbs lighter than the C6. Maybe the ZL-1 or Blue Devil will be produced and be more of a price "contender" with a carbon fiber Viper.

Todd

Low Flight

[QUOTE

Iwas just reading in the pipe line.... SAE (Society of Automotive Engineers) Dodge is building a carbon fiber Viper... 150 lbs lighter than the C6... with 650 HP...


[Modified by Evil-Twin, 1:27 PM 1/15/2004][/QUOTE]

I think that we may as well just accept that GM will not beat DC with a production car, even if they build the "Blue Devil". I believe this is simply because DC is of a different mindset than GM. DC will not allow themselves to be beaten in HP numbers and will go to whatever length neccessary to have the highest HP rating of large American automotive manufacturers. DC is big on HP for the mere sake of HP no matter how outrageous, take for example the Dodge Tomahawk. GM thus far has not elected to take such an approach and is instead aiming for larger production volume and sales and a reputation of most performance for the dollar rather than most performance period. Another example is that while we are hearing rumors of the 665 HP Blue Devil , DC is already showing the 850 HP ME 412. Whether or not the 412 goes to production remains to be seen, although it would not surprise me.

I for one don't care. 400 HP for the C6 is more than I currently have in my C5. If I buy the C6 Z06 then I will have even more HP. I also already have a car that has some pretty incredible all around performance compared to the majority of production cars currently on the road. It's somewhat rare that I even see a Viper on the road. I am willing to bet also that a Viper is not a car I would enjoy driving every day around town , let alone on a long road trip. I think I've got a great package with the Corvette, great performance, comfort and ease of driving and it's a damn fine looking car. I'll be able to say exactly the same thing about the C6 too. I'm content to leave p*ssing contests to teenagers. If the biggest thing I can brag about in my life is how much HP my car has, then I'm in deep poopie.

As for the 400 HP rating on the C6, I tend to agree that it was done so as not to slap current Z06 owners in the face. I am certain though that we will see a slightly higher HP number on the base model in 2006. I also expect that we may see more engine changes in the life of the C6 generation than what we saw with the C5. With the C4 it started off in 1984 with the 205 HP L83, the next year saw the introduction of the L98 at 230 HP which gained another 10 HP in 1987, 5 more HP in 1988 and had 250 HP by its end in 1991. In 1992 the LT-1 was introduced with 300 HP. Of course in the period between 1990 and 1995 we also had the ZR-1 only LT-5 engine which began it's run with 375 Hp and finished with 405 HP. There was also the limited run of the 330 HP LT-4 in 1996. There are so many new engine technologies on the horizon ( thanks to Runge_Kutta for keeping us up to date on many of them) that I am very excited to see what the C6 generation will bring us.

Sorry for the long winded post.

LittleBoyBlu99

MC TORCH RED

if its anywhere near 500 hp, i will wait on the new z.

I Bin Therbefor

Be ready to be unhappy. Given equal tires the C6 will take your Z06. Even will the run flats it will come within a second of the Z06 lap times according to Hill. Actually he said something like, if there was a four second lap time difference between the C5 and the C5 Z06, now there will be a 1 second lap time difference between the C6 and the C5 Z06. I don't even know if he was talking about the Z51 package when he made that statement.
To further add to your gloom, I strongly suspect that the rwhp is going to go in favor of the C6.

golfman

I think that the Z06 C5 will still win on the track over the C6. The C5 is about a 100 pounds lighter than the new C6. Should help with a 10th of a second on the 1/4 Mile runs. If you believe the C6 is underrated in HP. I would think LS1 and the LS6 are underrated as well. IMO

Question?

I have heard that if a engine is making equaL amounts of Torque and HP isnt that engine about at it's max performance. That being said why is the LS2 already spent on HP and TQ. Can someone please answer this question.

My answer is GM wont change the motor for 5 more years. Since 1997 to date the LS1 is only improved 5 HP. Same thing will happen with LS2. IMO


[Modified by golfman, 10:07 PM 1/17/2004]

bdavies

The reason I believe the LS2 is underrated at 400/400 is because of the specs. It is larger in displacement, has a larger throttlebody and intake track, has 10.9:1 compression and supposedly close to the same valve lift as the LS6. There are also statements about reduced exhaust backpressure. To me this suggests > 405bhp. Also, the weight of the C6 coupe and C5 Z06 seem to be within 50 lbs of each other from what I've read. With the Z51 gearing and tires I would think it will be about even - or possibly even a slight advantage to the C6 in a straight line.

And close to equal HP & tq numbers does not mean it is at it's peak. In fact, it usually means just the opposite. Engines that are at an extremely high state of tune typically produce much higher hp numbers than tq numbers. Look at the E46 M3, Honda S2000 and other similar engines.

SWCDuke

[QUOTE]Question?

I have heard that if a engine is making equaL amounts of Torque and HP isnt that engine about at it's max performance. That being said why is the LS2 already spent on HP and TQ. Can someone please answer this question.
[QUOTE]

What you heard is an oversimplification that masks the actual process of power production.

There are two key points here. First, peak torque is basically a function of displacement and compression ratio and represents a force acting through an angle.

Horsepower is the rate of energy (or work) per unit time and is the product of torque and engine rotational speed. If torque is expressed as lb-ft and engine speed in RPM then (making all the unit conversions):

Horsepower = Torque X RPM/5252

The working rev range of the engine is a big factor, which is a function of stroke, valve timing, runner length tuning, internal engine friction, and other contributing variables.

An extreme case is a Formula 1 engine. At three liters with a high CR, low internal friction (practically no piston skirt, dry sump, etc.) wild valve timing, excellent inlet and exhaust tuning to achieve well in excess of 100 percent volumetric efficiency in the upper rev range, it might produce peak torque of something over 200 lb-ft, which isn't much by Corvette standards, but with a bore/stroke ratio of about 2:1 and 10 cylinders, it can rev very high until it reaches the current limiting mean piston speed (about 5000 feet per minute) at which even the highest output engines are choked, so it produces about 750 HP at 18,000, which corresponds to a torque of 218 lb-ft at 18,000. The tradeoff here is that the power band of these engines only extends from about 15000-18000, so gear ratio spreads have to be kept to about 10 percent to keep them on a boil. Below 10,000 revs they barely run!

As a rule of thumb, a good modern production car engine should produce about 1.0-1.2 lb-ft of torque per cubic inch and the bore and stroke range of automotive engines places their maximum piston speed (about 3500 ft/min based on both aspiration efficiency and bottom end stress considerations) in the range of 5000 to 6000 RPM, so they will typically make torque and power numbers that are within about 20 percent of each other. The more highly "tuned" an engine is, the greater power it will make for a given peak torque, but torque bandwidth usually suffers, which leads to a peaky engine that is soggy down low. Examples are the engines in the Honda S2000 and Ferrari F360.

As a rule of thumb OHC engines make a higher HP number than torque in lb-ft due to better breathing efficiency. A pushrod engine will typically have a lower peak power number than peak torque, but since you can pack more CID within a given volume and mass allocation, the higher average torque will mean higher average horsepower over most of the working rev range, which is what really counts in street driving. The only place where top end power rules absolutely is Bonneville.

The LS7 engine will have higher specific output, say 500 HP, but it's peak torque will be about 450 lb-ft. Better aspiration efficiency via three valve heads and more aggressive valve timing will keep the torque curve from rolling off as much as high revs as LS2, so it will make higher peak power per cubic inch, but the 80 percent torque bandwidth will probably start higher than on LS2.

Given the high specific power output that LS2 has (equal to many DOHC designs currently in production), I don't expect to see signficant improvement over its life cycle. GM didn't leave much, if anything, on the table with the two valve heads, but the 3V heads' better aspiration efficiency will push specific power output per cubic inch higher.

Duke

SteveJ

Duke,

Taking the ratio of displacements and multiplying by 405, I come up with 426 hp that could be obtained by using the LS6 technology in the LS2. According to one of your earlier posts, the difference is largely due to the use of expensive hollow stem valves on the LS6. It looks like GM has left 26 hp on the table.

SWCDuke

Like I said previously, it required expensive, premium parts like the hollow stem valves to achieve the LS6 specfic output, but this is reflected in the higher cost of Z06. It appears that a GM objective is to keep (inflation adjusted) base coupe C6 cost same as C5, so the premium engine parts are off the table in order to keep LS2 cost the same as LS1, but for the same cost they were able to raise specific output and peak revs, which represents more value for the customer.

You can't compare LS1 to LS6 without considering the difference in cost. LS1 to LS2 is fair as will be LS6 to LS7.

I recall reading that the cost of LS1 valves is about two dollars each, and the LS6 valves are eight dollars each. (I think it was one of Hib's writeups at The Idaho Corvettes Page). That's $96, which means something on the order of over $200 at the retail level. It may not sound like much, but each system manager gets a weight and cost allocation from Dave Hill, and then Dave holds the guys' feet to the fire to keep weight and cost within budget.

If you've ever been involved with developing a complex system you learn that weight and cost tend to "creep up", and program managers must crack the whip to make the engineers get the most for the least. I've been on both ends of the whip.

Duke




[Modified by SWCDuke, 1:36 PM 1/18/2004]

SWEET LS1

I disagree here on gm will not be upping the HP for the base C6. The C5 corvette never really had any other competition until 2003 with the the 390 hp blown cobra. You need the viper to compete with the Z06. With the new 2005 mustang and cobra to follow, Ford's SVT, I believe will make it interesting to say the least. Also, you now have the Nissan 350Z wich is currently non turbocharged, but just wait, this will probably come to fruition bringing more competition to the vette. The vette cannot afford to sit still and take it for granted that it will remain america's best sport car. Just look what happened to Caddy.

SteveJ

I really don't think we are in disagreement at all, but I still think that it's more a marketing decision than an engineering one to keep the horsepower at 400. Looking at it another way, if GM were to offer a LS3 option with an extra 30 hp for a price bump of $1000, they would have a lot of takers.

WhiteDiamond

I believe the introduction of the Z06 model puts your argument to rest. GM saw that there was/is a considerable desire on the part of the consumer for a sports car in the 45 to 50K range. Instead of sitting on the idea that this is "America's Sports Car," Dave Hill and crew build the Z06 which saw substantial, but simple improvements almost every year. They continuallly tweaked the Z06 to obtain higher performance with less ill effects. Yep, there is definately a consumer out there for a Convertible or Targa coupe with Z06 performance, but I think GM and the Corvette team have definately put the time in to improve it. Plus, we must remember that much of that team has been developing a new Vette while trying to improve the current Vette.

I think the next Z06 will take Corvette performance into a new realm never seen in a Corvette before. If the 500 horse motor is truely coming and some of the engineering materials presented here are true(ie aluminum frame reduces weight even more, ect), then the next Z06 will be an exotic killer(not that the current one doesn't do a nice job here all ready).

Todd