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LS3

R

Runge_Kutta

Guest
OK, let's look at the two different 3V head designs that use
a single internal camshaft. I am reasonably sure that the LS3
will use a variation of what is shown in patent 6505589 but
I wonder what the valvetrain will look like. From Figs. 1
and 2 in 6505589, you can see that the head is designed
for direct injection from the top of the combustion chamber.
Patent 6505591 details an intricate way to simultaneously
actuate the exhaust valves while maintaining space for
the DI at the top of the combustion chamber. Patent
6668546, Fig. 5, shows the combustion chamber of both
the single and dual internal camshaft designs from a
ways back.

http://www.freepatentsonline.com/6505589.pdf (DI port is #68 in drawings)
http://www.freepatentsonline.com/6505591.pdf
http://www.freepatentsonline.com/6668546.pdf (Look at Figure 5)

Here's the new valvetrain. As you can see, there is no longer
any place to put the central injection DI injectors.

http://www.freepatentsonline.com/6962134.pdf

This could mean many things. First, that no 3V head will
get central injection. It could also mean that there will
be a DI version and a non DI version of the heads. Lastly,
GM could have decided to abandon low pressure, air assisted
DI for high pressure side injection.

Someone needs to spill the beans here ...

Next, DaimlerChrysler is also in the OHV 3V business

http://www.freepatentsonline.com/6895925.pdf
http://www.freepatentsonline.com/6964252.pdf

as is Ford (atually, this could be OHV or OHC)

http://www.freepatentsonline.com/6267096.pdf

You might also want to look at these:

http://www.freepatentsonline.com/5560329.pdf
http://www.freepatentsonline.com/6505592.pdf (DI port is #62 in drawings)
http://www.freepatentsonline.com/6601557.pdf
 
R

Runge_Kutta

Guest
Well, it's now quasi-official that the 6.2L LS3 is the base engine for
the 2008 Coupe and Convertible. It is also interesting that there will
also be a performance oriented differential gearing to go with the
automatic transmission. Given a larger displacement engine and
a 2.73 rear versus a 2.56, mileage will suffer. Since GM is doing this,
one can only assume that other features will mitigate or negate this
mileage loss. Obvious candidates are 1) weight loss, 2) VVT, and/or
3) DOD. Also, the manual transmission gets an upgrade from the T56
to the TR-6060 (as seen in the 2007 Mustang Cobra and 2008 Viper).

Since the LS9 is a 3V engine, I cannot believe that the LS3 is not the
same. Some suggest that it will just be using L92 heads. Where does
LS8 fit into all of this? If I were making an engine line up, all based on
the same basic engine, I'd make the weakest one port fuel injected,
the mid-power one would use direct injection, and the beast would use forced
induction. That's my guess for the LS3-LS8-LS9 family.

But does the aluminum frame go across the board in 2008?? If so,
the Z06 has to be repositioned. If the LS3 moves to 450HP and
the Z06 stays a hair over 500HP, the Z06 also needs to be repositioned
(pricewise).

Who knows ... ???
 

motorman

Well-known member
Joined
Mar 7, 2002
Messages
849
Location
pa
Corvette
2008 Crystal Red Tint Coat
a 1939 BMW used the across the head push rod to operate the exhaust valve on their cross flow head. chevy's new for 2007 NASCAR engine uses a raised cam like the top cam in the 2 cams in the block engine to get shorter stiffer push rods
 

JBsC5

Well-known member
Joined
Nov 28, 2001
Messages
1,219
Location
Northern NJ
I am not convinced that the aluminum frame will go across the range..(and I'm just shooting the breeze) I believe there is quite a bit of rigidity lost when converted to aluminum.

otherwise I believe your right on target with your assumptions.

I do believe we will see an A6 automatic as part of the z06 package...

The tranny's stout in the truck lineup and from what I've heard...its actually a better performer than the Manual.
 

NORTY

Well-known member
Joined
Sep 7, 2006
Messages
851
Location
Carlsbad,Ca.
Corvette
2006 C6Z DSOM
I am not convinced that the aluminum frame will go across the range..(and I'm just shooting the breeze) I believe there is quite a bit of rigidity lost when converted to aluminum.
I think you're right about the AL frame going "across the range." However, the AL frame is very stout.

I do believe we will see an A6 automatic as part of the z06 package...
Chevrolet has never offered an automatic in any Z06, going back to the first Z in 1963. I doubt it'll happen now.
The tranny's stout in the truck lineup and from what I've heard...its actually a better performer than the Manual.
The MXO is designed to take 670ft. lbs of torque. "Performance" is subjective here, but the auto is a darn good tranny.

Keep on :w
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,453
Location
CenCoast CA
Corvette
71 04 12 19
It's not "quasi official"

It's a fact. The base engine for '08 will be the 6.2L LS3 but...it won't have the three-valve head. All that three-valve head stuff is protype wet-dreams. It was widly-publicized in the 03-04 period, most notably in an article in Automotive Engineering (SAE's magazine). In the end, GM Powertrain found it neither needed the cost nor the complexity to reach the 500hp mark with LS7 In fact, they exceeded it with 505 and left plenty on the table for the future. The LS3 will hardly need a three-valve head to get to 425-430hp. I'll guess that the 6.2 probably won't need a 3-valve head to get to the 620hp the Corvette SS is rumored to have. My guess is the existing LS7 head and the supercharger will do it...maybe add a cam-phaser and DoD.

You won't see an automatic Z06, either. While the A6 is in trucks, it's not used with anything larger than 6.2-liters. The only automatic in a GM vehicle capible of handling the LS7s torque is the Allison five-speed auto used with the Duramax in light and medium trucks. The idea of the Allison in a Vette is laughable. Someone said 6L80 can handle 670 lbs/ft torque. Well, that's only kinda sorta true. The 6L80's maximum gearbox torque rating is 664 lbs/ft, however, the critical figure is the maximum input torque rating and, for the 6L80E, that's only 439 lbs/ft, far below the output of the LS7. Sorry..ain't gonna happen.

Lastly, on the aluminum frame anyone thinking it lacks rigidity needs to familarize themselves with the facts. Yes, on a strengh per mass basis, aluminum is not as strong as steel, but because aluminum is lighter, the Z06s aluminum hydroformed rails can be made thicker to have the same strength as the steel frame but still end-up lighter. The reason the aluminum frame probably will not be used in a base C6 is cost and probably capacity.
 

JBsC5

Well-known member
Joined
Nov 28, 2001
Messages
1,219
Location
Northern NJ
Well until GM figures out a way to get the clutch pedal up and down in the manuals they should put an automatic in the Z...

Too bad about that automatic...I hear the prototype was kicking some serious @ss!

Why does GM not recommend removing the top in the C6 Z06? Because they don't like the sun or because the chassis is not rigid enough to handle the roof being removed...

I believe the chassis as it is presently designed is capable of being a rigid platform with the roof permanently attached...

Not with a removable roof though....(unless with a throughly redesigned chassis)

JMO and thanks for your input Hib!

Your always respected .....(even if we don't always agree)
 

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