Yep, those mopars are pretty quick. I had no intention of modding my drive train until I ran into a black jeep SRT8 at a stop light one day. The guy just about knocked my socks off. The next day I called Tom Wong and told him to pencil me in a cam and head job because there was no way a jeep was gonna kick my butt. Now with that and a few other mods including a 4.10 rear end I have no trouble from soccer mom. However, these days they seem to be putting 400 hp in a friggin Honda so I'm either going to the Z or adding FI just to stay on top of the curve. We'll see how the economy goes this spring. No point in FI this time of year with 10 inches of snow on the ground. With that said, I will be lurking in parts section looking for a bargain.

Actually, the LS3 drivetrain has 4.3 gigawatts of additional frictional losses.

You’re wrong about the argument being based on that quote. That quote was in the latest edition of Corvette Quarterly magazine. My argument was developed in March http://forums.corvetteforum.com/c6-c...e-for-ls3.html and then added into this thread in September and the “quote” was just added in as support a few days ago.

You seem to criticize individual details rather than looking at the evidence as a whole, which is what supports my case for a stronger than advertised LS2. The thing is, statements from GM personnel in a position to know the truth preceded evidence.

I’m sure you will not be satisfied with anything I say short of producing a dyno sheet from GM so we’ll leave it at that.

I think this what is called "a standoff". I believe you though. ;)

To say that your "evidence" is weak would acknowledge that you actually have any evidence, which by any engineering standard you clearly do not. You seem obsessed with an idea you have formed, and have grasped at any straw you can find to support your argument.

For example:

...You claim the LS3 has less frictional losses thru the drivetrain because the LS3 peak hp is 100 hp rpm less than the LS2, and therefore the LS2 is getting rated artificially lower because it must struggle to make power 100 rpm higher. You then assigned a percentage loss which you derived from thin air.

...You also make a claim that some of the wheel options for the LS3 are lighter, and that explains some of the power difference between the two engines (despite any chassis dyno numbers to the contrary).

Yes, I am critical of the individual details you proffer here, and with good reason as your "big picture" collapses when the details are put under any kind of scrutiny. Substituting opinion and disguising it as fact is basically what you have presented. No offense and nothing personal.

If GM didn't test the LS2 under the new standard, then no one knows the answer.

Percent
 

5 hp as a percent of 400 equals just a little over 1%. Not too sure I get this issue.:)

the issue here is obvious. i want to be "right" and you are "wrong" no matter how much data you have. :D

I could bury you in data and it wouldn't mean anything if the data isn't real or relevant.

My evidence began with information from a key employee in Corvette powertrain assembly at the Bowling Green Assembly Plant, which was later supported by information from within GM Corvette engineering. You characterize that as "grasping at any straw." You are the one who is "grasping" by throwing out numerous accusations without much thought, hoping one will stick.

It is easy to find supporting evidence when beginning with facts about true LS2 power. As far as your criticism of my evidence is concerned, the content of your own allegations is lacking. Let's take a look at the two you mention here.

1. That percentage loss was not from thin air but from a calculation based on what percent 100 is of 6,000 rpm. Friction loss based on rpm is close enough to linear so that your statement makes no sense at all. Before you ask, I am not a mechanical engineer, but got verification of this from a well respected forum member who is a mechanical engineer. I then multiplied 1.67% times a 50 horsepower drivetrain loss but probably should have used 61 horsepower, the difference between 411 certified and 350 rwhp. That would have resulted in LS2 having 1.0187 more horsepower lost to friction than LS3. These are small figures, but they do adequately represent power lost to friction due to peak power in LS2 occurring at a higher rpm.

Once again you are making assumptions that you seem to be pulling out of thin air, just like you did when you stated I was basing my case for a more efficient LS3 drivetrain on a couple of sentences in a Corvette Quarterly magazine article.

2. As far as forged wheels are concerned, I said they were reportedly lighter in weight and listed links to posts from two forum members who weighed these wheels. Their findings were that they weighed less than the cast wheels. Two to four pounds of weight in the rear wheels would not make a great difference on a chassis dyno, but will contribute to the combined difference when included with the other factors I mentioned.

You refer to chassis dyno numbers as evidence to the contrary. The difference between morning and afternoon air pressure in the tires can cause a change in chassis dyno readings. Why do you mention these numbers as support for your cause when they vary by 25 or more horsepower between different dynos? If rwhp numbers are so unreliable that a decent comparison between chassis dynos can't be made, how in the world can they be used to accurately determine the effect of a small difference in wheel weight?

Scientific scrutiny is a tough taskmaster. Your chassis dyno numbers and arguments do not stand up to that type of inspection either. You say my big picture collapses with scrutiny. The collective information presented builds a strong case for my conclusion about LS2 Certified horsepower. Your case gets weaker with each specific criticism.

You mention "LS2 under the new standard." I only have one source that said they did such a rating, so I admit to not being 100% sure myself--maybe 95% considering the supporting evidence (Crush1's post; calculations in "The effect of horsepower and weight on quarter-mile trap speeds for C6 Corvettes"; all existing GM engines gaining power when re-rated under the new standard; analysis of GM's performance numbers). You failed to mention the "old standard", which LS2 certainly was tested at and truthfully revealed by more than one GM employee positioned to know. Of course you don't believe that either.

You don't agree with much of anything I have presented here and have made your contentions known in a very negative fashion. Further discussion is pointless, especially when I have to correct continuing statements characterized by a lack of understanding.

you've already made that point long ago. what else is new?

No need to take this personally, I'm not trying to hurt your feelings. However, this is an open forum and I'll post when I feel it appropriate.;)

why would you thing that i have taken anything that you said personally? :crazy: why would you think that you hurt my feelings?:crazy: just so you understand my position, this is an open forum and i'll post when i fell appripriate also. ;);) you didn't answer my question, what else is new? :lolg:

Good, it seemed like you were upset that I was scrutinizing some of this so called data and exposing how flawed it is.

What's new? Not much, just sitting around waiting to be called out for a flight. What's new with you?

The only numbers I pay any attention to are the ones at the end of the quarter mile. As for the old cars, I put close to 200K miles on a COPO 427 Chevelle. I've also had two L78 396 375 hp Chevelles with over 50K miles between them. Although I have little faith in the seat of the pants dyno, I would put our 2005 LS2 in between the L78 and L72 but awfully close to the 427. From the factory, these old cars came with #68 primary (very lean) and #76 secondary jets and retarded timing in the name of emissions standards. Add to that little F70-14 tires for traction and they went nowhere fast. Getting the jetting and ignition curve right, along with headers, made a HUGE difference. To start with the F70s were half decent traction. After tuning, they were useless and the car got the biggest available at the time. In the computer age, that is all looked after. You have to remember that those old engines were on the drawing boards around 1960 and were at Daytona in 1963. With 50 plus years of development since then, the cars should run better and they do. Still, a well prepared 425 hp 427 can run run 12.2s. Not too shabby. Anecdotal, yes and that's no worse that talking numbers when you can be at the track proving the numbers. There are some pretty good formulas for calculating hp based on et, mph and weight. Those are numbers you can take to the bank.

As long as you have resurrected a four year old thread (that will get closed because of that) I'll take the bait. The problem with using 1/4 mile times to back into hp is that you have no idea how good the driver is. A dyno takes no talent to floor the gas pedal in fourth gear and see what the computer spits out.

Ibtl.....:)

I just spent X amount of time reading this thread. Knowledge gain is is equal to 0. I have realized that some people cant do math......lol

So all those together mean we dont have an answer to how much variation in HP there is, right?

Since when does 396 at the wheels = 462 at the crank with 16.8% driveline loss? Oh yeah, when you multiply 396 by 1.168 instead of doing it correctly. No math wizard here but crank hp = 100% and the at the wheels is 100% less the 16.8%.

Wow, bottom line is that I can now order that 409 billet aluminum badge for my LS2 that I've always wanted to!:thumbs::thumbs:

No point in even going down that road. There is way too much information out there since this thread started in 2008.

Thread started in 08, simple math has been around a lot longer. If they dont get either by now I guess they wont. :)

LS2s have plenty of pep, if the 12s came with one that is what I would have. :thumbs: