don't know how much of this data has been released yet but i've already read that the bore and stroke are differnent, hence the 6L vs. 5.7L but is there any information regarding the rest of the engine? is it the same LS block and head castings? are the controls and engine management going to be the same as the current car? is the power increase just proof of the old adage, "there is no replacement for displacement"?
ultimately, the question is, will a LS1 to LS2 (or whatever the Z06 engine is) engine swap be possible?

 

Different cam, different valves, cam position sensor moved to opposite end, oil channels changed...

 

The LS2 block has 4.00" bores and the LS1/LS6 blocks have 3.90" bores. The stroke for the LS2 is the same as the LS1/LS6 blocks. The engine "valley" has addtional structures and oil passages in it to accomodate DoD in the truck family and possibly DoD on future Corvette model years(after driving a 300C, GM would be passing up a great opportunity by leaving this option off the table for the Vette).

From another site, the LS2 head part number has been released in the GM parts catalog and it apparently cross references with the LS6 head. This will probably take some more research and time to figure out, as GMs information says the LS2 head is "based" on the LS6 head with revised flow.

Todd

 

so what is DoD? sounds like different but not significantly different. kind of like the difference between an L48 and an L98. fair comparison? but we know dimentionally the LS2 (and presumably later derivatives) have the same bolt patterns and mounting points as the current LS1, right?
basically, what i'm saying is if i ever run across, say, a '99 or '00 FRC with a blown engine really cheap i could theoretically just bolt the LS2/LS6x directly in with only minimal additional concerns, if any at all.

 

DOD is Displacement On Demand, which is the ability for the engine to shut down four cylinders and get slightly better gas milage. The LS2 uses parts that are set up for it, but doesn't have it because the switchover was detectable and too many people would bitch about something so minor.

 

Well, I don't believe that statement at all now. Go drive a 300C, there isn't a clue that it switches and the system appears to be almost identicle on both GM and Chrysler papers(maybe the engineering teams had lunch together). After a several mile test drive, during which I spent considerable timing checking out the change over from 8 to 4 cylinder, it was barely perceivable once going back to 8 cylinders from 8 and I bet 99% of the drivers out there could tell(especially while taling on the phone and reading the paper )

The change from LS1 to LS2 is a little more significant in the change from L48 to L98 IMO. More power was found, weight was extracted from the engine, effeciency is the same or slightly higher, and 90% of the engines peak torque is available over from just off idle to just before redline.

Todd

 

From Motortrend:

Latest is the Generation-IV, all-aluminum engine with cast-iron liners, its displacement bumped from 5.7 liters in the Gen III/LS1 to 6.0 liters in the new LS2. The new engine makes a fat, square 400 horsepower (up from 350) and 400 pound-feet of low-rev torque and yet spools to a lofty 6500 rpm. It packages neatly into the same space as the LS1 but shaves 15.4 pounds. Stroke remains 92mm (3.6 inches). The bores are hogged out to 101.6mm (4.0 inches) from 99mm (3.9 inches). The compression ratio is up from the LS1's 10.1:1 to 10.9:1 in the LS2, putting additional squeeze on the intake charge to improve brake-specific fuel consumption. Powdered-metal forged connecting rods spin on a cast nodular-iron crank.On the breathing side, Hill reports a 30-percent cut in restriction. Valve sizes are unchanged at 2.0 inches for the intake and 1.6 for the exhaust, with no fancy sodium fill for the stems. The deeper breathing comes from intake-manifold improvements and a hotter cam with greater lift. On the exhaust side, system backpressure is down 10 percent and the spent gas now flows out through thin-wall cast-iron manifolds. This reduces noise, relative to the former fabricated-steel units.

Engineers have (so far) dismissed Displacement on Demand for the LS2, reportedly after resonance problems with the Vette chassis made it obvious the car was running on four cylinders. Besides, GM says customers are happy with the C5's fuel economy--Motor Trend managed nearly 30 mpg on long trips--and the extra cylinder shut-down hardware adds valvetrain inertia that would cut the engine's rev capability. But one insider reports that a DOD C6 in early trials netted 35 mpg on the highway.
http://motortrend.com/roadtests/coup...te/index4.html

 

The C6 and the 300C don't share a frame.

 

Sorry Scissors, that doesn't explain it. It can be a VERY small part of it, but it won't affect the ability to notice the change much.

Todd

 

If you put up a poll you will find that most Corvette owners do not want DOD. Now many object because they remember GM's 8-6-4 disaster of the past, which probably has nothing to do with the current set up. However qs01coupe, in his quote from MotorTrend, lists all of reasons needed to leave off DoD. We enjoy the decent mileage that Corvettes achieve, but it is still fairly low on the list of priorities.

strike one: strike two: Not only strike three, but there is no fork'in way that I, and likely many of the people here, would want to limit the rev capability of the motor to gain 5 mpg
[Modified by need-for-speed, 1:21 PM 6/19/2004]

 

Well, those who sit around because everyone is happy typically find themselves on the bottom when the competition gets going...The resonance problem is a very simple fix as there is a tremedous amount of information on mounting technologies and bushings that can eliminate just about any issue. I am betting DoD shows up on the C6 in the coming model years as the engineering team most likely needed time to solve other issues and not figure out a proper material for the mounts(if the resonance issue is that bad).

Personally, I like the technology and it is a shame GM is scared to offer it. There is a large group of "safety" clowns who would love nothing more than rid the world of sports cars and having a (not just a, but a VETTE) that gets better MPG than most of the vehilces those clowns drive makes one of their arguments very difficult.

Lastly, don't bash a technology based on heresy, go drive a 300C and see what the technology is about. Once you do, you will see the system is seemless. The debacle of the old 4-6-8 is ancient history with modern computers, there is absolutely no comparision(besides, GM learned from it and found the short comings and then Chrylser beat them to it).

Oh, as for the poll, they don't have a 35mpg plus Corvette to compare it too. You put up that poll, especially today AND making sure the people polled understand what DoD does for them, and I gurantee the results would show DoD would be desired. All the performance of the C6 AND a increase in MPG. Typicall of polsters to try and compare results of a poll to nothing

Todd

 

http://forums.corvetteforum.com/zerothread?id=845533

oh, and

 

Just in case

Todd

 

Yes, exactly. What it comes down to is that the DOD system is simply not ready yet, at least not for the Vette, and will probably show up in the 06 or 07 model year.

Don't fret that GM is "scared to offer it." I'm betting they're just taking the time to get it right.

 

While MDS, or Multi Displacement System, works great on the 300/Magnum it really has no need on the C6.

The fact you can get into a 300C/Magnum RT and get 25mpg stated, closer to 28 real world, in a 4100lb car with an auto and still run low 14/high 13 second quarter miles is great, without MDS those numbers would not be anywhere near that.

Do you need a system like that on a 3100lb car that already gets 30mpg on the freeway? Not at all. It has no value. It has tons of value on the 300/Magnum, V6 manual gas mileage in an auto V8, it becomes a huge selling point for the car. On a C6 it becomes something else to break, again no value on having it on the vehicle.

The only way DOD would make it onto the C6 is if it was too costly NOT to have it. Meaning all LS2's had DOD and the C6 did not, history or not, the bean counters would win that fight.

I assume the whole thing is sensative to cylinder pressue and a host of other things, it'd probably cause havoc with camshaft changes and just another thing for people who mod to take off of the car.


[Modified by NoOne, 3:29 PM 7/3/2004]

 

NoOne,

It would be wise to remember that oil is not a right in this country, but simply a luxury our economy has the ability to supply in high amounts and at remarkably low prices. That will change and even you will start singing for such systems. The DoD technology is extremely simple and it is VERY ready for the market, your assumption on its operation is very wrong. It is sensitive to a oil pressure signal sent to particular lifters. Once you get 25miles for your 1 gallon, it is gone, but you could have had 30 miles....The earlier you start, the better the future looks in the oil reserves(known oil reserves).

Todd


[Modified by WhiteDiamond, 5:15 PM 7/3/2004]

 

The issue with DoD is the car resonantes badly when you knock out cylinders on a Vette. Keep in mind that there is not as much sound deadening in a C6 as there are in some passenger cars. The engineers who field tested the C6 with DoD said that the car sounded awful, it resonanted, etc... In other words folks would NOT like it. I'm not saying its a bad idea in many cars and trucks. I'm not even saying it would be a bad idea in a c6 if it didn't make the whole car sound like a lumber truck with a broke muffler...

 

I for one hope DOD is only an "option" in '06 or '07 as I will never own a car with it. Just my opinion..5 MPG is in no way worth it to me.

 

The only way DOD would be beneficial in the Vette is if they increased the displacement to the point fuel mileage began to suffer, in order to chase the Viper or GT. If they stick a 7.0L + engine in the Blue Devil or Z06 to out perform the high end competition, and needed to add DOD to avoid the gas guzzler tax, I don't think anyone would be too unhappy. I'm sure we'd be nervous about the added complexity, and potential loss of top end RPM, but if it allowed them to stick a big enough engine in there to wipe the Viper and GT off the map, no one would complain that much. But with all the performance of the LS2, and 28 MPG on the road as is, why screw with DOD just to get 33 MPG? Like has been said above, it does not offer enough return on investment for the added complexity and cost of the system. No one buys a Vette for fuel mileage, and with the current 28 MPG highway, fuel mileage is a selling point already!