Marina Blue

Jim Schindler,

The following is from a thread I mentioned before. I can understand not reading through it as it is time consuming, so I copied clips I thought you might find interesting. There are three here, each separated by a solid line. All of them begin with a quote from another post and then KaTech's answer.
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Katech
Supporting Tuner




Member Since: Oct 2005
Location: Clinton Township MI


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Quote:
Originally Posted by BLU-BY-U
once again, I really don't give a damn about crank hp. What counts is the power to the ground and what the end user makes of it. Katech, that other thread was very interesting. Thanks for all the research and testing that you and your company do. And thanks for posting on this forum.

KaTech Answer:
I think you should give a damn since the crankshaft number is the most accurate. If the rwhp numbers vary from place to place up to 50hp then how can you use that as a fair comparison between cars? Here is an example: There is a modified C6Z06 on a tuner's chassis dyno across the street. They called me up and said "Jason, this thing is still making power to 7100rpm. How high do you want us to rev this thing?" I thought for a second and pulled the engine dyno. Power started dropping off at 6400rpm on the engine dyno. Now, if frictional parasitics increase exponentially with speed, how is it continuing to make power at the wheels past 6400rpm? Its not. Even well calibrated chassis dynos are still not as trustworthy as a water brake engine dyno.
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Katech
Supporting Tuner




Member Since: Oct 2005
Location: Clinton Township MI


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Quote:
Originally Posted by BLU-BY-U
why should I worry about crank hp when the percentage possibility of my motor ever being outside of my engine bay is so remote? how many of the 12,000 z06 owners over '06 and '07 actually pull their motor to have it engine dynoed? for better or worse, the VAST, and I mean 99.99% of 427 engines are going to be dynoed on a chassis dyno.

katech, are you suggesting that you engine dyno every production ls7 engine? is there a database where I can retrieve engine dyno information about my own ls7? through serial numbers or other? or is the only way possible to know my actual ls7 crank hp by pulling the engine?

KaTech Answer:
now you see where I'm going with this. the typical user is going to end up getting a chassis dyno locally. With that said, if we can at least ballpark the friction loss from crank to wheel by "guestimating" the loss by the different type of chassis dyno used (like we've already discussed - around 10% for 248c dynojet and maybe 17% for a mustang dyno). OBVIOUSLY, shops can have exact model dynos that can for whatever reason be higher or lower than another shop around the corner. Since an engine dyno isn't feasible for 99.99% of the owners, this is just a crude guestimate to begin with, and should be considered accordingly....

thanks


It's not really a matter of your engine being out of the vehicle or not. Getting a rwhp number baseline for your car and comparing that to the same chassis dyno after some modifications is exacltly what chassis dynos are for. What they are not for is comparing two different vehicles extrapolated engine horsepower numbers from 2 different chassis dynos. The subject of this thread being the real crankshaft LS7 horsepower numbers and people trying argue those by extrapolating from chassis dyno numbers is the reason for my arguement.

No, we do not dyno LS7 engines built at Wixom. We have dyno tested many many LS7s for GM though, but are not part of the production pipeline.
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Katech
Supporting Tuner




Member Since: Oct 2005
Location: Clinton Township MI


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Quote:
Originally Posted by bernrex
Alright .... I thought they had corrected for Both factors in final # given out ... But, Katech once again comes to the rescue.

If we subtract 15Hp for cats/exhausts ... its 507 HP (for this particular engine).

Still it would fall within a 95% confidence interval of 525-505 HP. So my 'theory' may still have validity.

Katech .... feel free to give us the facts ....

KaTech Answer:
I can agree with your 15hp for cats/exhaust. 507hp is dead on within 2hp of repeatability. I rest my case.
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Jim, I realize this info does not help with how much power the LS3 will have, but it is relevent in determining where to get accurate information on crankshaft horsepower.

Phil

ssj4

Damn, am I living in the past or what, i could have sworn it was only January 2007.

Bad Kitty

Damn, am I living in the past or what, i could have sworn it was only January 2007.



Its actually that old Deja Vu all over again......

TTRotary

Wow, 8 pages of conjecture on something that's not going to happen.

If Z06 owners are incredibly lucky, GM may actually find the valvespring defects and solve the oiling problems in the LS7, because that motor is costing them a ton of warranty money.

As far as HP, my 02 Z06 dynoed 355 and my 05 C6 dynoed 360, both on the same dyno (248C). So much for underrated Z06s. The C6 runs a wee tad slower because it weighs 85 lb more. No great mystery there.

'06 Quicksilver Z06

360 is the higherst I have ever heard of. Is that SAE corrected?

TTRotary

Yes. And I'm not the only one. Someone else (forgot name) got 363. I noticed both his and my car had over 10K when dynoed, so they are at the point of being perfectly broken in without any wear yet.

My 02 Z had 4200 on the clock when I dynoed it.

bunk22

The extra weight still doens't make up for the 2-3 mph advantage the C5Z has against the C6......thats if we compare the best runs. Did you dyno your cars on the same day? I've seen on my cars, as much as 20hp difference on the same dyno on different days. The correction factor can only correct for so much.

TTRotary

NO, they were 2 years apart. However, the atmospheric conditions were very similar both times. Of course, you are right, there can be that much difference. When I bought the C6, I was pretty sure it was noticeably slower than my Z. Since I still had it, I got a friend to drive and we did some highway pulls from 45 or so. To my surprise, the C6 was right there with the Z through 120. It was interesting, the C6 would pull on the Z at the low end of each gear and the Z06 would catch it back on the top end of the gear. The C6 was Z51 so same gearset.

As an experiment, we swapped rear wheels. The Z could no longer pull. So I'd conclude that the 6.0L is a pretty stout motor if it can move a heavier car that well despite have same HP. Also, the C6 tune, as you know, is a dog. After Shawn's tune, my LS2 has that same razor-sharp response the LS6 had.

Did you get your spring issue resolved?

C6Speed

Man...I hope the '08 has 450 HP - I'll be the first in line to buy an '07 and save a chunk of change.

Lightning Coyote

I'm happy with the 400 horses in my C6. I will wait until the C7's come out.

JVM225

AP

v8ls2ca

I am waiting for the official info from GM sometime in April or June. If the new Vette for 2008 is gonna have 450HP I'll wait but if its only 25-35HP more then no need to wait, I can buy the 07 this summer and just add an Air Box, Long Tube Headers and Exhaust. That's should be plenty to make it up. .

jschindler

Maybe I'm weird to think like this, so bear with me. If you can add air box, headers and exhaust to meet the '08 hp, then what would happen if you bought an '08 and added the same mods? Wouldn't the '08 then have more hp?

ZPirate

In the MT Confidential section (p 17) of the March 2007 issue of Motor Trend, MT says the hot rumor out of Detroit is that the 6.0 liter LS2 will be retired and replaced with a new 6.2 liter V8 making 403hp. No torque numbers mentioned. The new engine also may be the premium engine for the Camaro and Impala.

need-for-speed

I think of the same thing every time I read one of those responses.

In defense, I guess you could argue that the guy who buys the '07 will get a very large discount (approx $8K), spend $2K on mods and have the same or more HP than the stock '08 for $6K less. But of course, for $2K in mods, the guy w/ the '08 would have more HP than the '07 w/ similar mods or you could argue that w/o mods, the '08 would have the same HP as the the '07 w/ the bolt ons, but then again, the '08 would be "factory" HP with no worries WRT to warranty, but the guy who bought the '07 can return his to stock 3 years later, sell the bolt on parts, and suffer less depreciation upon resale than the guy who bought the '08 while having enjoyed similar performance for 3 years.......and so on and so on




To each his own.

shopdog

The engine isn't new. It has been out in the Yukon, Denali, and Escalade for a year. In the Caddy, it is rated at 403 hp and 417 ft-lb of torque. But that's almost certainly not the tune it will have in the Corvette. For one thing, the intake manifold used in the Escalade, optimized for low end torque, won't fit under the Corvette hood. So it will have to be different. Odds are it will sport better flowing manifolds in the Corvette, maybe a less truck-like cam, and a higher performance tune. The persistent rumor is that it will come in at 425-435 hp in the Corvette. That's a reasonable ballpark given the larger displacement and assuming Chevy will tune it to favor more hp rather than more torque in the Corvette.

insider

Well if they add direct fuel injection, that right there is good for +40hp. Hopefully they will do that. It makes sense, better gas mileage and better emissions as well. They have it on lesser models, so why not the Corvette?

ZPirate

You may be right that the new Corvette engine is based on the new for 2007 6.2 liter engine in the Denali and Escalade as the 6.2 Vortec is all aluminum and has varible valve timing. But if that is the case the Corvette engine will be different from the Vortec in its tuning and redline. In addition it may have different internals and cams. So in essence it is still a new engine. BTW the 6.2 Vortec is referred to as the L92. I suspect it will have a different designation in the Corvette if in fact it is the basis for the new Corvette engine.

shopdog

I seriously doubt they'll do that for 2008. The added complexity and cost of a whole new valve geometry, high pressure fuel system, etc would make it unlikely for anything less than a new model introduction. Perhaps when the C7 comes out.

I think it is important for people to understand that they're putting this truck engine in the Corvette as a consolidation (ie cost reduction) measure. They hope to save millions of dollars a year in labor and overhead costs by reducing the number of different engines they have to build. Making the Corvette engine radically different and more complex than its sisters in the other car and truck lines would defeat the purpose.