Nine Ball

iTrader: (38)

What makes the camshaft type different in the LS4? LS1 cams still fit in LS2s, and even in the LS7. The only thing different is the location of the cam reluctor, which is easily swapped around.

Intake manifolds are non-directional on LS1s too, you can bolt them up facing the opposite direction.

TonyGXP

heads may have the same cast # on them as the LS6 but the LS6 heads shouldn't bolt up, DOD, and our block was reduced in length by "1" inch to fit sideways..therfore it has to alter the cam,heads,intake, etc.?? dosen't it? besides the computer wouldn't know what to do without our specific lifters, and the other hardware for the DOD..

Nine Ball

iTrader: (38)

Are you positive that the block itself was shortened, or was it the "engine" assembly itself? Looking at this photo, it appears that just the serpentine belt offset has been shortened compared to the other vehicle offsets.

If the engine has LS6 head castings, then they are the same part # as LS6 heads, and are swappable. DOD is based on the block design, not the heads. The LS2 block is also ready for DOD, but is not used at this time. Speculation says DOD will appear in the 6.0L trucks first with the LS2 block.

Nine Ball

iTrader: (38)

Found another good photo

It appears they gained their 1 inch by relocating the water pump to the far right side of the photo, and moving their power steering pump to the top of the engine.

Normally, the water pump sits right up front and center, and sticks out pretty far. Look at the water pump positioning on the LS2 photo, its the rounded pulley in the middle of the belt system.

Just by comparing those photos, it appears the LS4 block is the same physical size as the LS2/LS1.

Jayzvette

I agree. It would have been too costly for gm to shorten the motor. That would have created many issues with cooling and oil passages. Shortening the drive acessories makes way more sence. The 243 heads are LS6 castings and are the correct dimensions booya

2000Firehawk

iTrader: (248)

Heads & cams can be swapped, BUT , if you want to retain DOD, you must use a DOD 'profile' camshaft...

Crank was shortened 13 mm – 3 mm at the rear and 10 mm at the front – and the entire accessory drive system was designed to reduce space. The water pump and all other accessories, including the power steering , are driven on a single-belt drive system – the longest drive system in a GM vehicle, and is special to the LS4.

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The all-aluminum LS4 is based on the Gen IV small-block architecture, but is modified to accommodate the "east-west" mounting position of the Grand Prix's front-wheel-drive chassis. To fit the "sideways" positioning in the Grand Prix, several changes were made to reduce the engine's overall length, including the use of a shorter crankshaft and a single-belt accessory drive system.

Other LS4 features include:

Aluminum engine block with cross-bolted main bearing caps
Aluminum high-flow cylinder heads similar to the 6.0-liter LS2 V8
Full-floating pistons
Lightweight, three-piece friction-welded composite intake manifold
10:1 compression ratio for fuel-efficient performance
Unique camshaft designed to accommodate DOD technology
Electronic throttle control integrated with new engine controller
GM Oil Life System to minimize required oil changes
Iridium-tipped spark plugs for 100,000 mile service


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The all-aluminum 5300 V-8 is the third displacement offering of the Gen IV small-block, which was introduced in the 2005 Chevrolet SSR, GTO and Corvette, as well as several 2005 GM SUVs. The 5300 V-8 shares a common architecture with these other versions, including a deep-skirt block, six-bolt cross-bolted main bearing caps, and structural oil pan, but is modified to accommodate the “east-west” mounting position of the Grand Prix’s front-wheel-drive chassis.

To fit the “sideways” positioning in the Grand Prix, several changes were made to shorten the engine’s overall length. The crankshaft was shortened by 13 mm – 3 mm at the rear and 10 mm at the front – and the entire accessory drive system was designed to reduce space. The water pump and all other accessories, including the power steering pump, are driven on a single-belt drive system – the longest drive system in a GM vehicle.

Engineers devised an elongated water pump manifold, which features a remote-mounted pump that feeds the stock Gen IV coolant passages via the unique manifold. The design allowed the drive system to be mounted closer to the engine block. Because of the 5300 V-8’s relatively low inertia, which can be up to 50 percent less at the crankshaft damper than a 6.0L V-8, a hydraulic belt tensioner was used instead of a conventional rotary tensioner.

Unique position

The sideways position of the 5300 V-8 required revisions to the lubrication system. Engineers tested 5300 V-8 equipped test vehicles on racetracks, subjecting them to high-load turns that guided the development of special oil pan baffles that ensure lubrication during cornering. In addition, because Gen IV engines don’t have a block-mounted oil filter – it’s located on the oil pan – the 5300 V-8’s filter offers easy access.

Because of the front-drive layout, the 5300 V-8’s exhaust manifold routing includes two manifolds joined by a single crossover pipe, which connect to a single underbody catalytic converter. The crossover pipe allows the use of a single oxygen sensor, unlike north/south V-8 applications that have two oxygen sensors.

"There's nothing like the satisfying feel of a V-8 engine and the LS4 provides a level of performance rarely available in competitors' vehicles," said David Muscaro, assistant chief engineer of small-block V-8 for passenger cars. "But when all eight cylinders aren't required to maintain performance, DOD technology effectively turns the engine into a more efficient V-4."

TonyGXP

Does that answer the question of "are this LS4's parts interchangeable?"

I believe so...MAN these parts are gonna be expensive if they switch to rwd in a couple of years!!

Nine Ball

iTrader: (38)

Yes, it appears you guys can slap on ported heads and swap out blocks for larger displacement LS2 blocks. Just reuse the LS4 shortened crank.

Not sure what changes are made to the cam for DOD use. Maybe just a different sensor perhaps?

LS4 GXP

Camshaft specs:
Camshaft Lobe Lift - Intake - Non Displacement on Demand Cylinders
7.2 mm
0.283 in
Camshaft Lobe Lift - Intake - Displacement on Demand Cylinders
7.33 mm
0.289 in
Camshaft Lobe Lift - Exhaust - Non Displacement on Demand Cylinders
7.2 mm
0.283 in
Camshaft Lobe Lift - Exhaust - Displacement on Demand Cylinders
7.33 mm
0.289 in

Nine Ball

iTrader: (38)

hmm, I wonder if there would be any effect on DOD by slapping in a cam with all equal lifts. It appears that the DOD lobes just have slightly more lift, probably to make slightly more power when operating in 4-cyl mode. I'll bet the DOD doesn't care what camshaft is in there, they all spin the same

ChipC

Here is another article that has some good information:
http://www.popularhotrodding.com/fea...dod/index.html

While it's not our LS4, it is basically the RWD (LH6) version that is used in their mid-size SUVs. It is a Gen IV architecture with DOD. So the concepts and possibly some parts will interchange. It is also using the E40 PCM.

Here is the part I found interesting:

For hot rodders wanting to modify their DOD-equipped LH6s, it's important to know that the switching lifter has a lift limitation of 15mm (at the valve). The factory cam uses 12.2mm of that (about .480 inch), giving the LH6 a theoretical valve lift limit of .590 inch. It's worth noting that this limit is for the lifter; a different valve spring would almost surely have to be used at this valve lift. Interestingly, it seems possible to grind a custom camshaft, which would only provide increased lift and duration to the non-DOD cylinders (2, 3, 5 and 8), thus allowing higher lift with standard non-switching lifters in those cylinders.

Chip

BigMikeGXP

Seems like more people posting here and Clubgp than on ls4wbody. Would be nice to be able to post on Clubgp...have not been "let in" yet. Just bought an 06 GXP the other week and it was the first car ive had. But I always came to this website for information on ls1 engines...had a 01 silverado...just have not ever been registered till now. Also wondering...very many people going to the Alamo City Shootout that Chris is posting about on ls4wbody?

LS4 GXP

it's usually a pretty big event I hear, I know of a few people flying down from Ohio to spectate, I'm driving down, meeting guys from Detroit and Chicago on the way.

NJGXP

Thx gonna go check it out.