nwc6

1920 miles, MN6, Z51, Base Exhaust, 92 octane, 396hp/383tq on a mustang dyno..

JSB LS3

Ok, fair enough...I stand corrected. If thats the case then, the C6 certainly has a more efficient drivetrain than my LS2 GTO did....

jschindler

The GTO was not rated at the new system. I read what you said - that GM was voluntarily using the old system before. Where did you get that information? What we know is that the LS2 in the C6 Corvette would have been rated at around 395 under the old system.

I have no idea what the LS2 GTO's dyno's at, so I don't know whether the Corvette is more efficient or not. I just know how the new rating system works, what the LS3 is rated at, and what the LS3 dyno's at. And for what its worth, I also know that dyno measurements from dynos around the country are not some sort of official measure. I've dyno'd at MTI in Houston several times and I have a lot of confidence in the consistency of their results. But I also know they are not certified in what they do, and it's possible that on any given day they (and others) could make a run without the dyno being properly set up.

I take the results that are being posted here just like I look at any information I read on a forum. I look for a pattern. If 25 people post results, and 20 of them are between 388 and 392 I consider that to be good information and the rest outliers (or just plain liars).

'06 Quicksilver Z06

I've gone a step further and don't look at chassis dyno numbers anymore at all.

Dyno numbers from off not only different dynos, but different brands of dynos, and comparing dyno results across different dynos and brands of dyno yeilds very limited information.

Talon 90 has already pointed this out and I agree with him.

At the end of the day, when it all shakes out, really, what do dyno numbers represent other than "potential" for the car to do something?

The power still has to be gotten to the ground effectively.

Track results show what the car and driver have actually "done", regardless of "dyno numbers".

LS2-Zomb!e

LOL!!

03 Z-oh-6

I still don't quite understand how SAE certified can be accurate unless they test EVERY motor that's developed. There's many tolerances in building an engine, even with the same parts, hence, some may be stronger than others.

'06 Quicksilver Z06

If GM were either deliberately or inadvertantly producing LS3 or LS7 engines with a wide degree of variability in power output, it would defeat the purpose of them having gone to the trouble to obtain the privilage to call their engines SAE Certified.

That designation is supposed to give the purchaser the assurance that his car produces within one percent , up or down, of what GM says it does. It is a significant selling point and will continue to become even more of a selling point. Especially in light of some manufacturers engines either

A. Being re rated lower after submission for the testing.

B.. Some manufacturers avoiding the testing leaving the purchaser to perhaps ask "Why?"

The engines for the testing are tested randomly. Thats the key. For the certification process, they are production engines simply grabbed at random from off the line.

Look at the link I gave you with the remarks about the Dodge Viper.
http://www.caranddriver.com/columns/...esolution.html
http://www.motortrend.com/features/e...8_technologue/

Also look at the notes from the LS7 engine builder and the folks at Katech who do a significant amount of work for GM as well. Katech has dynoed hundreds of their LS7engines and found these SAE Certified engines to all be within a few horses of one another. Thats no accident.

Since they (GM) are going to have to supply a random engine for the SAE certification testing, then GM has to know approximately what any of their engines are going to dyno during that testing.

What if a grossly "weak" one were to be pulled from the shelf for submission for the testing?

GM knows ahead of time, that no matter which of their LS3 engines is chosen at random for the SAE certification testing, that it is going to produce within a 2 percent range of what any of the other ones on the shelf is going to produce.

And thats really all you need to know.

They are not about to run the risk of having a weak one pulled from the shelf at random for testing.

http://forums.corvetteforum.com/show...post1562787163
http://forums.corvetteforum.com/show...&postcount=356
http://forums.corvetteforum.com/show...&postcount=371.

If GM were knowingly producing 460hp LS3 engines, and the independent observer witnessed this, then GM would have to call it 455 horsepower or 465 horsepower or something in between. 1% down or 1% up of what the observer saw.

They could not call it 430.

But aside from that, what if GM were knowingly or inadvertantly, producing some 460 hp LS3s and it turned out that a 430hp one was randomly selected for the testing???

What good would that do them??? What allow them to call it 430 when it was really 460?? Why would they want that scenario. Makes no sense.

Seems that they would want the 460hp one pulled for testing in the first place. Especially since this was "Certified" and the "Certified" status being used as a marketing tool.

What would be the best way for them to insure that happend????

Thats right.......Make sure that they all were making 460 or thereabouts.

No, GM knows going into the testing, approximately and to within 2%, (1% down or 1% over what the independent observer is going to see) what any of those engines is going to dyno should it be randomly pulled from the shelf for testing.

Also do a bit of research and look at what that SAE Certification LOGO means.

http://www.sae.org/certifiedpower/
http://media.gm.com/us/powertrain/en...2008/08car.htm

03 Z-oh-6

Ya know, I really appreciate people like yourself who thoroughly answer questions.

1974Pantera

Excellent post and write up, very informative!

C6 DVL

I had a feeling this thread was going to turn into this.....all we are missing is the cat in the hat (C6 Tech inside joke)

JSB LS3

Well it's WELL documented that the LS1 F-body was underrated between 1998-2002.

the '02 Z28 for example, was rated at 310 flywheel HP, yet there are more than a few cases of stock LS1 cars making 320 REAR WHEEL horsepower.

GM took an LS1, that, while not totally identical to the one in the C5 corvette, was nearly identical in horsepower production, stuck it in the Camaro and Firebird and then chopped about 30 horsepower off the rating in order to keep the corvette flagship looking as attractive as possible.

In reality, LS1 corvettes and LS1 f-bodies basically all produce somewhere between 290 and 320 RWHP, despite the fact that the f-body is "rated" at somewhere between 305-345 (depending on options and model) and the Corvette was always said to make 345-350.

Now the thought of doing this on the LS3 is not totally out of this world when you consider it. granted the Z06 is another level of fast, but given the price tag you can see why people might suspect the 20 grand-cheaper LS3's "on paper" rating might be reduced just a little .

That said, apparantly it isn't....but I hope this answers your question about a possible theory behind it.

03 Z-oh-6

Then again, the LS3 is SAE certified, the LS1 was not.

jschindler

You've answered your own question, but you still don't get it. I won't dissagree that the Camaros were under rated. That was BEFORE the new SAE CERTIFIED rating system. The LS3 is AFTER the new rating system. What part of that are you having trouble with?

'06 Quicksilver Z06

Precisely.

The LS7 was the first engine GM submitted for SAE Certification. This was in 2005 in preparation for the release of the Z06.

The LS3 is currently another GM engine which is also SAE Certified.

The LS1 was never SAE Certified under SAE J1349 Certified Power which is how the LS7 and the LS3 are certified. So yes it may have been underrated.

http://media.gm.com/us/powertrain/en...2008/08car.htm

Sheesh, I'm not just posting these links for my health.

Listen to me real close.

GM cannot grossly underrate the LS3 or the LS7 and still stick the label you see in This Link on that product. That label belongs to the SAE. And in order to get it, you have to follow their guidelines for certification. I have already gone over those guidelines.

JSB LS3

guys relax...I'm not having trouble with any of it....

'06 Quicksilver asked what the POINT would be to underrating a motor. All I did was explain THAT. I'm not arguing with you guys about whether the LS3 is ACTUALLY underrated or not.

'06 Quicksilver Z06

I see exactly what you are saying. And GM may indeed have played the game that you point to with the Camaro vs the Vette during the C5 era.

But that game is over and done with now that they have elected to have This stamp put on some of their engines.

Here is some more food for thought.

Remeber I said that GM first started this in 2005 with the LS7.

They did not subject the '05, '06 or '07 LS2 to this testing so none of those engines receive that logo.

Why????? Because they were overrated. By about 5 horsepower or so. And that testing for certification under J 1349 would have shown it.

And this is why, even though the testing was available GM elected not to subject the LS2 based C6s to that testing, but kept right along subjecting the LS7 in the Z06 to it during '06 and '07.

Had the LS2 been subjected to http://www.sae.org/images/logos/j134...fied-power.gif

It would have been tough for GM to call the car a 400hp car and still be within the 2% range required to receive that http://www.sae.org/images/logos/j134...fied-power.gif label. It would probably come in at around 398-399 CERTIFIED horsepower. And would have been a marketing disaster. Especially with 405 horsepower C5 Z06s still on dealer lots.

So what did they do???? They went right along building those cars.......but hiding them from the test. As such, non of them receive that logo.

This is, I believe at least part of the reason why you see the significant gap between the bone stock chassis dyno numbers of an LS2 based C6 and an LS3 based C6. That "30hp bump" over the '07 which we see in the '08, is really more than a 30 hp bump because a different yardstick is being used.

I'd be livid if I had bought an '07 LS2 based C6.

There are no more shenanigans.

jschindler

Okay, we're good now, right? You're turn to buy, or mine?

OregonC6

VERY interesting. I agree with you. Any mass produced engine will vary but not by much. It depends on variances in parts ( tolerances ).

But let's take your statement: "There are no ringers, strong ones, weak ones or underrated ones."

And compare it to the almost mythological belief that has apparently grown up among some Z06 owners that certain engine "builders" at Wixom produce better engines than others.

I've believed this to be completely bogus from day one because all the engines are assembled ( more accurate I think than built ) using identical standardized work procedures and inspection methods. In other words every assembler is required to follow identical assembly methods using parts supplied ( and not checked by the assembler prior to assembly as might be done in a custom engine build ).

If any particular Wixom "builder" was using his/her own special assembly or inspection/verification techniques they would be in gross violation of their work instructions. Anyone who has knowledge of modern manufacturing control understands all this btw.

So, I am glad to read your statement above and I completely agree with you. Variation among LS7s is very small to nonexistent as is variation among LS3s. Your statement negates the idea that any particular Wixom "builder" is doing anything unique that results in his/her engines being more or less powerful than those of other builders.

Do you agree? It seems to me that this conclusion is inescapable if your statement regarding variance is true.

'06 Quicksilver Z06

Indeed I do agree.

I feel that a lot of the talk amongst Z06 owners with regard to who built their engines is more friendly banter, "competition" if you will.

I for one, certainly do not take it seriously having read the posts from one of the Wixom engine plant engine builders who frequently posts over in the Z06 section. As well as reading the information from Katech. A company which knows as much about the LS7 engine as anyone.

I don't see how anyone can take seriously, the notion that one particular builder at the Wixom plant, builds more powerful engines than another when they are all using calibrated tools, the same assembly procedures, and parts from out of the same bin.

BTW, my engine was built by Chuck Witmer. Its fun to know that, but I don't take it that my LS7 is built any better or worse than anyone else's.

siffert

I bought a 2007 C6 A6 LS2 and currently am not livid...could you please explain why I should be? Also, how about the '05-'06 LS2 owners-should they be hot under the brow and collar too? Actually, there is about a 2/10's difference on the track between my bone stock LS2 and an '08 LS3. That's what +36hp w/NPP and a 2.73 will do for you. Upset a tiny bit perhaps, but not livid...yet...cuz perhaps in 2009 we'll see a 450hp LS3! Will the '08'ers then be livid too?