Buttercup

Are you kidding? Only 12%??? That's a lot! What kind of money do people spend to get a 12% increase in power?

Since this car is going to be a fat *** that little 12% is even more important.

Again, the tone of the exhaust note isn't going to change. It's the same displacement cylinders dumping into the exhaust, the same effective firing order (every other cylinder in the firing order is deactivated), the same exhaust manifolds, the same exhaust pipes, the same mufflers, the same ports, the same valve timing, the same materials, etc., etc., etc. The engine doesn't change into a Honda with AFM. It's like the engine running at half the RPM it really is with more load, which is noticeable but I don't think is bad.

Edit: Think of it like another transmission OD. Do you notice the sound of the engine change when it goes to a higher gear? Yes, of course. Does it sound like a Honda? Absolutely not. This is almost exactly like a higher gear. The interval of cyinder firings drops down and the load goes up.

CAMAROJOE

AS long as we get a Corvette mill. We get what they get.I dont think vette will get AFM.

blue 79 Z/28

anyone got any info or links on how this DOD works? shutting down lifters and bypassing oil somehow sounds damn hokey to me last time i checked, when a motor is spinning and valves stop opening you are picking up pieces

CamaroBoy96Z28

There's a great deal of information on the web. I chose to do a report on the system for my Thermodynamics class back in the spring. I dont remember the sites or anything but there's a great deal of info and drawings showing how the system works. The changes to accomodate the system are fairly basic once you look at how relatively little the block had to be modified and parts added for the oiling requirements are arranged. Its pretty neat.

blue 79 Z/28

i dont like it. should be all software and program, shutting off injectors and adjusting computers to certian cyl. i dont agree it should be mechanical like that. makes for modding a living hell. and i see issues with breakage under abuse. i feel its needed for suvs not performance autos. mustang at least doesnt have that nonsense

another thing i dont get still is why the hell they close the intake and exh valves in the cyl. how does the motor stop from grenading?? i mean a pistons going up and down where does the vacume and air volume/residual atomization from the intake tract go? in a normal motor, you lose the exh. valve by whatever means so its closed by pushrod or lifter or rocker arm breakage, and you can kiss your motor goodbye because its gonna hydraulic on air and charge.

Andy30thZ

Well.....No.
Here's a pretty good artical that explains Active Fuel Management.
It may be a little old but I think it is still accurate.

http://www.superchevy.com/technical/.../0405sc_gmdod/

notgetleft

You have to close the valves or you lose a lot of the benefit of AFM. If you don't close the valves then you're still pumping air through the dead cylinders, and pumping air takes energy. That's not even mentioning that if you were pumping fresh air into teh exhaust you completely defeat closed loop since the O2 sensors would be washed out in oxygen.

'hydraulic on air' huh? ROFLMAO. Unlike liquids, air IS compressible, therefore there will be no hydraulic lock. And yes, the engine will still have to compress the dead cyclinder with the valve close, however there will also be cylinders pumped to a vacuum creating the infamous 'return spring' effect to cancel out.

blue 79 Z/28

i didnt say hydraulic on air, you ROLMFSIDNTOSDJD funny guy. i said air and CHARGE as in fuel/air mix, as im sure residual will be around from the previous combustions and cycles form immediately before. say for eg. fuel ignites the left over charge from say poor octane and beating on the motor? just say, you get a hot spot, and when it compresses and you say let off into 4 cyl mode, all of a sudden the mix goes off, you have no valves but alot of gas exhaust and air, in there. i dont know about you but in high performance engines that use alot of air and fuel. you will blow your motor to kingdom come, if the piston compresses spent gasses without venting them you will do all sorts of hurt. what if you want a blower or nitrous? or a new cam that revs? etc. i see this being a real pain in the **** for other then stock apps. what im trying to say is. this seems like a good gas saver for stock soccer mom transports, but it limits performance with crappy lifters that are heavy a$$ turds, limited lift, complicated parts that can and will fail, and when they do look out! it has no place on a performance vehicle, just put it on the v6's then, if you want to save gas go buy an accord. camaro is meant to drive with a v8 not cry about gas. even though in canada we pay 25% more then usa. thats why they make them in v6.

pHEnomIC

When I saw a display for DOD at the autoshow a couple years ago, i challenged the guy on it. I said won't it sound funny with only 4 cylinders running? He said that it won't due to the way the emissions devices/muffler are designed. Aftermarket companies might have to do some additional engineering to fix it.

Dave89IROC

huh?

What fuel/air charge??


first, the fuel inectors and coils shut off

second, the solenoids shutting down the lifters dont just turn them off like a switch, it will take a couple of cycles to bleed off, so the cylinder be flushed clear by air, so no fuel left in there

blue 79 Z/28

bottom line its stupid and it better be an option that i can order without, cuz i know of no performance car with dod, its stupid, and weak. say goodbye to motors with aftermarket internal parts if its a standard on the motor. you dont see ford doing it in their mustang

Dave89IROC

all chrysler cars/trucks with new hemis(they call it MDS)..................

all internal parts are the same, just has fast bleed lifters

blue 79 Z/28

i said performance cars

MagnaPilot

Ford has not done such work on the SOHC modular motors mostly likely because they don't have lifters to perform such a feat, not to mention they appear to be working on a new motor rather than building on their current mill.

I don't know where you get that internal parts would be an issue. We're talking about 8 different lifters. The aftermarket could build them if they wanted. The cams are the same, the LS4 happens to have a little different grind on the AFM cylinders, but nothing that Crane or someone else couldn't perform. The block is nearly identical, again nothing to worry about there. The LS4 has a few small changes, but only for it's FWD platform. The aftermarket would have very little to worry about to adjust to AFM.


Unless the AFM is completly omitted from the 3v LSx motors, it's very likely that AFM will be standard on all but perhaps the highend Corvettes and perhaps the highest Camaro. The trucks need AFM, most other vehicles that have a V8 will need AFM, it will be cheaper for GM to create an universal engine rather than build multiple versions. As I said before, the only limitation to AFM is the valve lift that the cam can be ground for, and with 3v per cyl, the new engines may not need a large cam to make large hp.

Granted it's possible that the newer LSx engines wont need AFM if they get 3v per cyl. But given the politics of all, I would hope that someone finds a way to reflash the new PCMs for those who want to rid of AFM.

I personally would gladly take AFM on my new camaro just to avoid paying an extra 1 to 3 grand, when they could have avoided it. Especially if Camaro ends up weighing 3700+ lbs.

Z28x

Me too. I love the V8 sound on those short bursts of acceleration. When cruising at 75mph I'd rather a nice quite interior.