J-Rod

http://forums.corvetteforum.com/zerothread?id=505355

Runge_Kutta
Senior Member


256 posts [100%]
WC CA

LS2 & LS7 8:05 PM 3/3/2003


I just wanted to ramble a bit here in regard to the upcoming
LS2 and LS7 - speculated (Mervz) to be the C6 engines. From
Mervz's post, the LS2 is 6.0 liters while the LS7 is a 6.4
liter engine.
http://forums.corvetteforum.com/zerothread?id=502610
As to power, the LS2 will have between 425HP and 435HP
depending on who you believe. Ernie says 435HP
http://www.lovecars.com/corvettecorner/c6.htm

while the April 2003 Motor Trend says 425HP. I suspect
that Motor Trend is lowballing to allow for a last
minute surprise. Motor Trend also speaks of a titanium
valvetrain which I assume to mean valves, valve springs,
and retainers. This may explain the comments about
a 7800RPM redline for the Cadillac CTSv.
http://forums.corvetteforum.com/zerothread?id=483562

The connecting rods may also be made of titanium.
http://forums.corvetteforum.com/zerothread?id=450510

Motor Trend made the comment that the new C6 engine(s)
will have considerably higher specific output but will
not depart significantly from the current GenIII architecture.

_____LS1___LS2___LS6___LS7___XV16
HP___350___435___405___500___1000
LT____5.7____6.0___5.7___6.4___13.6
Eta__61_4___72_5__71_1__78_1___73.5

If you look at the numbers, its not a dramatic improvement. In
any event, it's interesting to ask how this is going to be accomplished.

At the exhibition of the Cadillac Sixteen, Thomas Stephens
http://www.gm.com/company/investor_i...s/stephens.htm

said that the XV16 was a showcase for the future direction of the
small-block architecture. That engine has titanium valves, valve
springs, and two valves per cylinder. I guess this means that the
LS2 and LS7 are not three valve per cylinder engines!!
http://katechengines.com/
http://media.gm.com/events/productse...s/stephens.pdf

Check out his slideshow. So much for the 3V OHV engines going into
C6 (slide 17). I would, however expect to see the exhaust manifold integrated
into the cylinder head (slide 18). Also look at
http://media.gm.com/events/productse...t_manifold.htm

Back to the original slideshow. Look at slide 27. The specific
output (which is reputed to increase with C6) doesn't go over 70HP/L
for the 2V OHV engines. Maybe the LS7 will approach 80HP/L.
http://media.gm.com/events/detroit03...en_engine.html

It's amazing that the XV16 is only 695 pounds or 315 kilograms! That's
only 50% heavier than an LS1!!!

"The XV16's valves are titanium alloy, an extremely lightweight material.
The engine also employs titanium alloy valve springs, which are 40 percent
lighter than comparable steel designs. The titanium helps increase the
springs' natural frequency by 28 percent to allow for higher engine speeds."

"The GM XV16 also uses a dry-sump scavenge pump system integrated with the
main oil pressure pump. The dry-sump helps reduce overall height for
improved packaging while making the vehicle capable of more aggressive
cornering. The system has eight individual scavenge pumps to evacuate oil
from the sump for improved performance and fuel efficiency."

Well, I'd love to see more details on these babies. We can only hope
that C6 will use titanium as liberally as it is used in the XV16.

-----------

Some Q&A

Runge_Kutta
Senior Member


256 posts [100%]
WC CA

Re: LS2 & LS7 (Runge_Kutta) 1:33 PM 3/4/2003


>> Do we expect LS2/LS7 to be dry sump?
If you take Tom Stephens at his word then yes.

>> Even shorter/lower engine than LS1/LS6?

The dry sump system might lower it an inch or so (wild guess). I see no
reason why length and width might decrease. The titanium valves ought
to be shorter than the LS1/LS6 valves because the springs don't need to
be as tall.

>> Or does height saved down below simply become available
>> to use up top (taller/longer/larger runners, a second camshaft)?

The dual camshaft idea appears not to be the selected layout for the Gen IV
engine. Who knows what will become of it??

>> Do we expect cylinder deactivation with C6 debut, or a year or two later?

Again, if you believe Tom Stephens, cylinder deactivation will be on all C6's.
That's why Motor Trend states that the milage is going up. Motor Trend is
pretty clear about DoD on C6.

>> Two-cams-in-block still makes sense for a two-valve head design, yes?

That's not the way I read all of this. I'm really curious how the variable
valve timing will be done. Sounds like its just on the intakes but I
may be wrong.

>> How do you find these presentation files?

Google. Google knows all!!

>>>> I would, however expect to see the exhaust manifold integrated
>>>> into the cylinder head (slide 18).
>> And kill the aftermarket exhaust business? I doubt it.

The biggest source of engine emissions is the startup phase.
These manifolds are an engineering approach to minimize this
startup emission problem. So, does GM reduce emissions with
the modified heads thus allowing them to use less downstream
treatment and potentially save money, space, and net an overall
emissions reduction or do they worry about the aftermarket
header business??

>> Assuming no DoD for the LS2/LS7 at first, will the C6 be able
>> still avoid the gas guzzler tax?

Motor Trend suggested mileage on the order of 20/30+. I think the
manual C5s are 18/28 or so. C6 will have the DoD plus be lighter.
I have heard the loose comment that 60% of mileage is the vehicle
mass.

>> I remember when all that came up. For the record, I have a Porsche
>> lover friend (aka Porsche nut) that attended a Porsche bash in MA
>> last weekend where he was told that titanium connecting rods stretch.
>> For their racing applications they change them after a race. Doesn't
>> sound like something for the street to me.

While I am no material scientist, I think that worry is baseless. I
couldn't image a reason that a well-designed Ti con-rod would
have a mechanical problem in this application. The NSX and Maranello
seem to be doing quite well. The one issue is on wear surfaces but
if your willing to pony up some bucks, that can be dealt with.

>> I think we could see the LS2 for the 2004 model year.

That thought had crossed my mind too. We'll see!!

One thing that hasn't been addressed is how these 2V engines are
going to get enough airflow to put out such big HP. I don't think
that it's a huge leap of faith to say that the head will have to
flow better and that the valves will have to be bigger.




---------------------------------------------

Curtis,
I'm not nearly as pessimistic about the prospects
of titanium connecting rods - although I wouldn't be
surprised if it didn't happen. I suspect that if it does
happen that the rods will be made using "Powder Metallurgy"
techniques. The current LS1 and LS6 engines already are made
this way but the powder is a steel alloy.
http://www.goradv.com/Consulting/Whitepm97.htm http://www.mpif.org/industry/spch02pub.pdf

There are several issues here. How high quality is
the available Ti powder? Is there adequate and stable
supply of sufficiently high quality Ti powder? How much
is this powder?? People banter about the number of
$8 dollars per pound for Ti. Is there sufficient
infrastructure to produce enough rods for 35K-40K
V8's per year.

I think the titanium industry is really trying to
break into the consumer markets. The issues are cost, cost,
and cost. Toward this end, there has been this new low-cost
beta (LCB) Ti-alloy used in the Z06
http://www.sae.org/automag/material/03-2001/

I don't think that this (Z06 exhaust) would have happened if
the price hadn't been cut. The next thing just over the horizon
is an additional cost cut as this new FFC continuous electrolytic
process comes on line.
http://www.roskill.com/reports/titaniummet

I think we are moving steadily towards increased fancy materials
in cars and trucks as people figure out how to make them more
cheaply and as newer and more demanding design requirements
make titanium (and the like) more viable.

Constrictor 98TA

Interesting reading for sure! As much of an advocate I am for technological advancements, it kinda makes me sad that GM already has replacements coming for the LS1. If some of these things come, like 3valve per cylinder, integrated exhaust manifolds, and redesigned blocks, that means aftermarket development for the LS1 will eventually begin to taper off.

I'm not saying the days are numbered as of yet, cause Im sure the LS1/LS6 engine still has several years of life left at GM, but change is coming soon.

Another thought on the integrated exhaust manifold idea, wouldn't that seriously limit aftermarket potential? I mean, we all know that GM isn't going to have performance enthusiasts in mind when designing it.

Cal

iTrader: (1)

Good post, interesting information. Amazing how much engine development is going on these days; must be due to CAD software making it too easy!

Gen I: 1955-1991
Gen II: 1992-1996
Gen III: 1997-?

BurnOut

iTrader: (1)

I'm not sure that I agree; look at the Ford camp... there are still changes being made and new products released for a motor that hasn't been in their performance car in 8 model years (read: 5.0L). Additionally, look at big block stuff... there hasn't been a factory installed performance-oriented big block from ANY of the big 3 since Jesus was knee high to a flea... but guess what?? AFR recently (within the last year or so) came out with a set of *** kickin' BBC heads, and even the folks in the Brand X camps have some (relatively) new goodies.

True enough, the GenII engines (LT1/LT4) don't have all that much in the way of new product development these days; because they never really needed it. Even though the LT1 and LT4 were different from old school SBC's in some very key areas, 95% of the design was the same. For instance, aftermarket heads, while requiring a few changes to play with the cooling system on an LTx motor, were esentially the same castings as traditional SBC stuff. Same port locations, same shapes, same... well, you get the idea. As for the intake manifold, look at the stock LTx piece... it is essentially the same design as one of the (if not THE) most powerful aftermarket intakes for the old L98/TPI motors, the TPIS Mini Ram. IIRC, there was an Edelbrock intake available for them, but I'll be damned if I can find one out there now. Perhaps also a Holley intake, though I may be mistaken.

The point is that there are PLENTY of LSx powered cars/trucks (don't forget that; the LTx motors were never isntalled in trucks) on the road, and I think that as long as people keep modifying them, the aftermarket will keep developing new products.

J-Rod

My only hope is that the LS2 and LS7 blocks can interchange with current LS1/LS6 components. If so a big inch motor will become really easy.

I was reading a post from someone who saw one of the alpha mules of the Corvette awhile back. Here is what he had to say:

http://www.z06vette.com/forums/showt...highlight=Mule

The interior had more than a few things of interest. First off, attached to the dash was a note saying that this car had a “gamma block 1 series” LS2 engine, or something like that. LS2 was definitely in the description. The note was warning the operator that the oil dipstick had not been calibrated for this engine and that the engine uses 6 quarts with an extra half a quart to fill the oil filter. The interior of the car also had an extensive data acquisition system in the trunk with several obvious thermal couple connectors.


-----

Encounter

I looked over the car for about half an hour and waited for the driver to come back. When he did, I asked him if he could tell me anything about the car. He just confirmed that it was a C6 prototype with a C5 body. The only other thing he said that was the Chevy was working on some powertrain enhancements for the C6. He started the car and drove off. The exhaust had a nice rumble to it and I could hear the low speed shutter characteristic of the C5 as it starts from a stop.

--------
Again, my hope is that they will do VVT with the conventional 2 valve motor we have now with more cubic inches, and that many of those part will interchange.

If so that would be a very good thing for many of us...

Slowverado

CAL, i believe it is more like this...gen 1 small blocks were prior to 55, gen 2 is from 55 to 97/98, and the gen 3 is the ls1/ls6/lq9/lm7 etc.

redz_02

iTrader: (4)

look at the 5.0 its been gone for years, and there are a crap load of parts for them.

Ramair346

I was at a bar a couple weeks ago with a friend who was meeting up with another friend. This other guy gets here and we ended up on the topic of cars. My friend says, person X (don't wanna throw a name out there) works in the Corvette plant. My jaw dropped and the interrogation began. All he would confirm is that the base C6 will be 425hp and the Z06 will come out in a year and be 475hp. He also said that the 3 beta cars that were spotted were not covered with the proper garb and heads rolled at GM. He also said the rear end is almost identical to the C5.

ToplessTexan

Still haven't got that one licked I see.

Cal

iTrader: (1)

Matt, by GEN I, I was refering to the original small-block Chevy, what people now call the SBC. Chevy didn't have any V8's at all prior to '55 because Ford had the patent rights to the idea! '53 and '54 Corvettes had straight-6 engines, and all Chevy eight cylinder engines before '55 were straight-eights.

The Gen II LT1 engines were introduced in the '92 Corvette, and first appeared in the fbody in '93, although there was a LT1 SBC produced in '70-?? (I had one,) totally different engine of course. The LS1 followed the same pattern, being first introduced in the '97 Corvette, then appearing in fbodies in '98. Also interesting is there was a BBC 454 in the '70s that was the first LS6.

OliGeorgs

Not that it has anything to do with the LS engine family currently in production, but Chevy produced V8s in 1917-1919 and it came in the Chevrolet Eight 1928 and 1919 model years.
Just a little trivia for you.

blackLS1

Where can I find more info on the advanced engine building techniques/new concepts like were mentioned in the articles?

Cal

iTrader: (1)

Hey that's interesting, I just checked up on that. Since Henry Ford patented the V8 in 1914, I bet Chevy had to pay some heavy royalties for using the design in the Chevrolet Eight . . . That would explain why very few Chevrolet Eights were produced. Apparently, it took 40 years for the patent to expire.

BigPlanTransAm

i dont know black ls1 but i too would like to hear more about these kinds of things

OliGeorgs

What was the patent, Ford had? Cadilac built a V8 in 1914. Check this out http://www.442.com/oldsfaq/ofhst.htm
By the way, the 1918-1919 chevy V8 had 1.5" valve lift.

Seifer

damn, a integrated exhaust manifold sounds really bad...

i hope that the ls2/ls7 are very similar to the ls1/ls6.. maybe that will allow for head swapping, and crank swapping to build a big-inch motor for low end dollars, or if you get stuck with a ls2 with integrated exhaust, you could put some nice s2 ls6 heads on so you could put headers on your car.

i am pretty sure if they do utilize an integrated exhaust manifold, GM will make performance heads available for racing.

NHRATA01

iTrader: (10)

Yeah, I don't like the sound of integrated exhaust manifolds either.

But I'd say odds are all the parts will swap since the block design of this new generation is going to carry over. So heads, internals, etc should all be interchangeable.

PacerX

iTrader: (4)

"Apparently, it took 40 years for the patent to expire."

Patents only provide 14 years of protection.