As we all know, I can't go more than a year without some off the wall idea to discuss. The latest one is based off the Suburban I drove to San Antonio. I was watching the DOD engage and disengage, and it was seamless. It did seem like it didn't stay in V4 very much.

Perculate perculate perculate.

Obviously my money tree is stripped for the next few years, but that's about how long I can expect my current engine to last. So, I was thinking that an LSX454 equipped with DOD would probable be able to STAY in V4 mode during all cruise conditions, even pulling hills. When in DOD mode the instant mileage was showing as high as 35MPG in that Suburban. I figure that in a lighter vehicle, V4 on a 454 should at least be able to pull out 25+MPG. This means it would likely be able to put some really good mileage down, but under WOT still be able to blow the tires off the truck.

If this could also be done with VVT and direct injection...

I think this would require having a custom block done, no idea exactly what the block differences are between a DOD and a non-DOD block. Also don't know what the difference between a VVT and a non-VVT block are.

Thoughts?

Well SPeeder, a non-LSX 427 with DOD is easily possible using a 6.2 and adding cubes to it.

ECM/PCM tuning can force the ECM to stay in V4 mode. There are some plug into OBD2 port devices that force the ECM to either stay in V4 longer, or to disable DOD completely. These are in addition to the EFILive and similar way of doing things.

Going with the larger displacement would make it easier to stay in V4 mode, this is why the GEN 5 LT1 is 6.2 liters and not 5.5L.

The only ssue here is the block, if you are forcing the LSx block then some work would be needed.

The GEN 5 LT1 in the C7 Vette is the 1st GM vehcile to use AFM(DOD) in a mnual trans (7 speed) application. Even the GEN 5 Camaro used the L99 in their AFM applications with the autos, and the LS3 wasnt available with a manual or AFM. The L99 with its heavier valvetrain was limited to 6200rpm, the LS3 was 6600rpm with its lighter noin AFM/DOD valvetrain. The GEN 5 C7 LT1 has the AFM/DOD and has the full 6600rpm redline ability.

Your thinking is larger cubes and AFM/DI, I am thinking small cubes with forced induction.

Chrysler is sticking with port fuel injection for a few more years, GM is embracing DI. DI is great though as insetad of teh fuel taking heat from the hot exhaust valve/intake port the carefully controlled DI spray takes most of its heat from the intake charge air, thus increasing detonation resistance allowing for moor compression.

peace
Hog

i like the idea......but thinking how to do it and then the cost involved to make it work.....i start liking it less....

just to speculate a little bit - i would would like to see what the OHC/DOHC engines will be doing (provided thats the natural progression).....

with the cams directly pushing on the valves (maybe some type of lifter in between) come up with some type of hydrostatic type of valve or lifter to "turn it off" for the V4 mode, which i dont think would be too hard considering what they were able to do with VVT....

IF - big IF - they were to do that, there would be companies trying to figure out retrofits for other engines (maybe) but that depends on how far they stray from current block designs....

with that being said - an LSX block can be had from the aftermarket and if you are thinking 454 - why not go bigger? i do not see it staying in V4 mode going up hills, let alone towing - BUT - if we are talking retrofitting - why could you not have a switch to put in V4 mode manually?

if this were possible - here would be the way i would set it up - lets keep with the 454 - LSx454 short block...heads and cam from donor with VVT/DOD and all related sensors, hardware, wiring, ECM....with a manual V4 switch wired in - and a TVS2300 blower on top......now that "should" be able to tow uphill in V4 mode and net some good MPG, and just be down right awesome at the track.....

I wasn't sure how a blower would work on an engine that cuts half the cylinders in and out, since a forced induction system forces X amount of air in at a set RPM. Seems like this might cause pressure spikes inside the intake on a regular basis.

I do know that there are oil passage differences inside the block, as the system cuts out cylinders by using oil pressure to shut them off. Exactly how it does it, not sure but will be putting a little time into it. I figure I have 3+ years to figure something out on this.

Also, I wouldn't be set on only using an LSX454 for this. If an existing DOD block could be used to get the cubic inches this would be the easiest way to get there. Doesn't have to be a 454 either, could be a 427, could be a 472, just depends on what block could be found and what could be made of it. I'd want at least 400 cubes in such a project through. The key to making it work as I lined out would depend upon the engine being able to maintain cruise speed up most of the hills you would expect to encounter with half the engine shut down.

Right now, from what's been posted so far, Hog's idea of stroking a 6.2 out to 427 cubes sounds like the most promising, cost effective way of doing this.

Detailed writeup on DOD

http://www.fastfieros.com/tech/DOD5_3.htm

What truck are you wanting to put this in? Is the race block set up for the DOD? I have had to much time on my hands again, so I was just looking into the pieces needed to put either a LS7 427, or the LSX 454 into a GMT400 truck. Not that I will do this now because, I bought my headers for a gen 1 sbc. I have found the crank I need to put the 24x onto a block to be able to use the 411 pcm. I have been always wondering about the sensors. The other option would be a stroked LQ4 block. Someday I will have to look into this again. It would be awesome to have a truck get 35mpg, That beats most cars. I will have to keep track of what you come up with.

The LSX block, the LS7 block, and the $6,000 HIP'pped C5R racing alum block ALL have no provisions ofr AFM/DOD capabilities.

I think stroking out a stock L99 6.2 or other AFM/DOD 376/6.2 to 400+ cubes will be the easier,most cost efficient method of accomplishing enough torque while in 4 cyl mode to pull hills.

There are LS3/99 416 and 427 shortblocks ready to sjip from Mast Motorsports. They state LS3 stuff as no-one wants the AFM/DOD stuff, but the pistons/crank will fit in an L99 6.2 block.

These are 24x reluctor engines
LS3 416
http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=90

416 LS3 Forced Induction
http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=91

427 LS3
http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=91

Then they have some 58x reluctor engines

416 LS3

http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=96

427 LS3

http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=96

427 LS7
http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=100

440 LS7
http://www.mastmotorsports.com/2010/product-view.php?cat=Short Block&id=95


Here are their handbuilt Naturally Aspirated engines (575-680hp N/A)

http://www.mastmotorsports.com/2010/category-view.php?cat=Hot Rod Muscle Car Handbuilt N/A

And their handbuilt forced induction engines (750-800 hp blown engines)
http://www.mastmotorsports.com/2010/category-view.php?cat=Hot Rod Muscle Car Handbuilt S/C

Just to give you an idea on whats out there.

Just remember that the 2014 C7 Vette Stingray with its GEN 5 Direct Injected 6.2l 460hp engine and new 7 speed manual trans is the FIRST GM application of a manual trans and AFM/DOD.
In the Camaro, they had the LS3 for manual trans use and it didnt have AFM/DOD, then they had a different engine in the Camaro, the L99 which had AFM/DOD and a manual trans. The L99 has a low rev limit of 6000 or 6200rpm as compared to the 6600rpm rev kimit in the LS3 brother engine.

In the GEN5 5 LT1 with Direct Injection and AFM/DOD, the rev limit is up 600 rpm to 6600rpm. There were some advanmcements in lifter and valvetrain design to enable the full rev limit with eth heavier valvetrain compnents needed for AFM/DOD use.
Some of teh new LT1 parts shoudl be looked to for ideas on AFM/DOD use.


peace
Hog

Chevy97, I dunno right now. My truck's pissing me off right now because it's acting like it isn't happy unless it has half a dozen things wrong with it. I fix one thing, something else breaks like immediately. So, for right now I've decided to fall back and regroup. In fact, I'm considering just turning it into a hauler/spare vehicle and getting something different for a daily driver. If I do that, I'll be doing nothing further to it. Not going to do anything until after I sell my house, which with any luck will be going on the market this week. Man I hope it sells this time, I am SOOO sick of living in a neighborhood. I'm a country boy at heart and have never felt comfortable having neighbors I can see.

Cannot blame you there. I live in the country. City life isn't for me.

Hmmm. This is interesting! I've got my 555 Gen VI setup with a gear vendors for extra mileage. Wonder if I could drop cylinders too.

NU72 wrote:

Hmmm. This is interesting! I've got my 555 Gen VI setup with a gear vendors for extra mileage. Wonder if I could drop cylinders too.

Wrong block. It would be something if you could. Jealous though. It would be nice to have 555 under the hood. I would need a bigger gas tank.

Read the link I posted on how DOD works. You have to have a block set up for it as it uses oil pressure to make it work, so the block should need the appropriate passages to operate. If you wanted a 555 with DOD I think you'd have to have a block cast with the oil passages. With the block, you could use the bits off an existing DOD to make the rest of it work and EFI Live to make the computer like it.

Yeah, I just excited about the DOD option and was only thinking about the computer setup not the physical block.

Mileage isn't all that bad. I get about the same as I did when it was a 454. When I drive it nice of course!