Sound vs DOD MPG

How many guys would give up 2mpg to have "good cruise" sound?

A friend of mine bought a new 300C with the hemi and was complaining that the exhaust note, when in the 4 cylinder mode of the multi displacement system, sounds disgusting with a loud catback......

If the new C6 is getting almost 30mpg (but the GTO is only getting low 20's...) with out DOD....Is another 2 miles to the gallon worth hating a good flowing exhaust at cruise?

Honestly I'd rather have the gas milage

I'd rather the milage as well. I'm not as concerned with the note cruising as I am with it when I accelerate at WOT....:D

I haven't heard a dod car with exhaust yet...

I would assume, with headers and exhaust it would sound horrible cruising...even worse without cats. Thats not for me

Yeah, I guess that is the issue for me. The first thing I do is rip off the exhaust for something fairly loud.
My bud said you can't stand to be in the car when it goes into 4 cylinder mode it sounds so bad...... I don't think I could stand owning a new Camaro that I couldn't put loud pipes on.....

On a Camaro no. on a truck or non performance car most likely.

Corsa has been working on a catback that still sounds good in 4-cyl mode. Several months ago, I heard an early prototype on a Charger RT -- it still needed some work at that point, but I trust that they will figure it out (if they haven't already).

I like my car quiet at cruise... If I am going on something like the Hot Rot Power tour I don't want to be deaf by the time I get to the next stop. I think I’d go for the MPG rather than a little sound difference as long as it still sounds good at WOT!

I'll take the AFM.

I don't see a problem...Just give us a button where we can turn the DOD on or off as we please :shrug:

I don't see a problem...Just give us a button where we can turn the DOD on or off as we please :shrug:

Did you get a button for CAGS?

AFM will no doubt be needed/desired for CAFE. I'm no EPA/legal expert, but i'd venture that if it was possible to switch it off, then it wouldn't count. That's why i used the CAGS example. On a similar note, how about the 3.73 geared A4 4th gens that didn't even have a selectable first gear on the shifter because it woulnd't pass a drive by volume test with a sleectable first gear.

Unfortunately, unlike the above examples which were easily defeated, AFM will probably need a tune to remove. Odds are if you just unplug the solenoids for teh oil diverters, the rest of teh engine management will not respond accordingly and you'll still have dead holes.

how about the 3.73 geared A4 4th gens that didn't even have a selectable first gear on the shifter because it woulnd't pass a drive by volume test with a sleectable first gear
Those were 2.73 gears, and that's the first time I've ever heard that given as a reason for preventing the selection of first gear. Can anyone corroborate this?

Yes I have heard this before... quite a few years ago of course... My '95 had this, and it was a bit louder in 1st... (I bypassed the blockout). So it makes sense given the LT1's rather loud stock exhaust.

And as for the DoD sound, I personally think it sounds like a WRX in V4 mode, not as raspy of course, like a big arse version I guess....not that bad really, it still has the same tone as the engine in V8 mode, just the pulse is cut in half. Really isn't as bad as everyone makes it out to seem.... with a good exhaust, it will sound fine.

I don't see a problem...Just give us a button where we can turn the DOD on or off as we please :shrug:

Or at least be able to tune it out of the program ;)

Sound vs. AFM? Do you realise how boy-ricer that sounds? If performance is not impacted, I'd rather have a car that's dead quiet in cruise mode. But then I've always favored the Q-ship approach... i.e. walk softly, but carry a big stick.

If you're seriously concerned that your car isn't loud enough while cruising at highway speeds, you have other more issues that need attention. :D

Gotta vote AFM! I agree, exhaust note at cruising speed isnt that important, whereas GM satisfying CAFE is.

I LOVE a loud (not too loud), throaty exhaust when I'm cruising at 15-25-35mph.....at highway speeds I really don't care much....will I sound like a 4 if travelling at those speeds w/ DOD?

DOD/AFM > Sound

just give us a "tow" button like on trucks (which prevents DOD/AFM from kicking in). ;)

Sound vs. AFM? Do you realise how boy-ricer that sounds? If performance is not impacted, I'd rather have a car that's dead quiet in cruise mode. But then I've always favored the Q-ship approach... i.e. walk softly, but carry a big stick.

If you're seriously concerned that your car isn't loud enough while cruising at highway speeds, you have other more issues that need attention. :D

Looks like an electric car would suit you perfectly!!!
Immediate torque, dead silent!!:)
http://www.teslamotors.com/index.php?js_enabled=1

Half of the fun for me is hearing a good exhaust note. If it kicked into 4 cylinder mode and sounded like a Civic....... I think I'd have a problem with that.

I don't really want it to be "loud" at cruise. But the way I understand it, if you have an exhaust that sounds good at WOT, you won't like it in 4 cylinder mode.
An exhaust like the new Z06 would do the trick.....but I wouldn't want to see that cost or complexity added to a car that needs to keep its MSRP down.

I LOVE a loud (not too loud), throaty exhaust when I'm cruising at 15-25-35mph.....at highway speeds I really don't care much....will I sound like a 4 if travelling at those speeds w/ DOD?

For us LS4 owners... we just put it in "3"... and its gone. But it doesn't sound like a standard 4 banger.... it still has a deep throaty thump to it, just the pulse it of the thump is different. I personally don't mind, and I will not hesitate to put a good aftermarket exhaust on my SS when money permits.

For us LS4 owners... we just put it in "3"... and its gone. But not it doesn't sound like a standard 4 banger.... it still has a deep throaty thump to it, just the pulse it of the thump is different. I personally don't mind, and I will not hesitate to put a good aftermarket exhaust on my SS when money permits.

I really look forward to your opinion after you put an exhaust on!!
Maybe none of this matters at all!!

I really look forward to your opinion after you put an exhaust on!!
Maybe none of this matters at all!!

The reason I will not hesitate, is because I've already heard the LS4 with an exhaust, both a complete kit, and with magnaflows and flowmaster 40's... both sound good IMO.

Sound vs. AFM? Do you realise how boy-ricer that sounds? If performance is not impacted, I'd rather have a car that's dead quiet in cruise mode. But then I've always favored the Q-ship approach... i.e. walk softly, but carry a big stick.

If you're seriously concerned that your car isn't loud enough while cruising at highway speeds, you have other more issues that need attention. :D


"boy-ricer" is the way a car sounds when 4 cylinders are working instead of 8. I like the button idea to toggle the function on and off as needed.

The reason I will not hesitate, is because I've already heard the LS4 with an exhaust, both a complete kit, and with magnaflows and flowmaster 40's... both sound good IMO.
Yup, i've heard a Magnaflow equipped SS too, sounds good! :)

There will be no button to turn off AFM on any car that offers it.

I doubt it will happen, but an "On - Off - Auto" selection would be great. Perhaps it would default to "Auto" every time you turned the ignition off/on. That way you can have it in full "cruise" mode, lock it into 4 cyl when you want max MPG even if you happen to put some load on it (going up a hill etc) or leave it in "auto" and let the computer do its thing.

Obviously, even when you lock it in 4 cyl, at some point you will need to switch to 8 cyl, perhaps 50% load??

I hate to sound childish, but I think DOD will be a problem for me. I will most likely want flowmaster super 40s on my Camaro, and the sound of the 4 cylinder mode will be upsetting. Even if it does not sound bad, it is just strange. Maybe it is something you can get used to. But, I think I would rather not. With a 6 speed auto or manual these cars will get great mileage anyway. Maybe the top level Camaro should not have the DOD and the others should?

Hmmmmm..... These guys with LS4 Monte SS's think that Flowmaster 40's sound like a helicopter in 4 cylinder mode.....or a WRX with exhaust.

www.ls1tech.com/forums/showthread.php?t=557895

Oh well, I'm sure the aftermarket is scrambling to find a solution!!

No on/off button for the DOD function = immediate reflash of the computer. Sorry, don't want to hear what a "4-banger" sounds like through the 5th gen's exhaust. I get to hear that signature coffee can exhaust note around my neighborhood every day. I'd be embarassed to drive the car if it sounded like little Johny's civic with the mismatched body panels and the triple decker wing.

I wonder if it would be as simple as pulling a fuse or something?? :shrug: Or will it HAVE TO be programmed out?? :confused: I'm just thinking of the C6 Z06 boys who can just pull a fuse to have the baffled muffler open and stay open at all times;). It made it easy for guys to hook a switch to that circuit to have a "cut-out" effect at the flip of a switch:thumb:.

Hmmmmm..... These guys with LS4 Monte SS's think that Flowmaster 40's sound like a helicopter in 4 cylinder mode.....or a WRX with exhaust.

www.ls1tech.com/forums/showthread.php?t=557895

Oh well, I'm sure the aftermarket is scrambling to find a solution!!

Unfortunatly, a solution is impossible in that regard...i don't care what anyone says, if 4 cylinders are firing its never going to sound the same as when its working like it should. Unless of course it can be tuned out.

I wonder if it would be as simple as pulling a fuse or something?? :shrug: Or will it HAVE TO be programmed out?? :confused: I'm just thinking of the C6 Z06 boys who can just pull a fuse to have the baffled muffler open and stay open at all times;). It made it easy for guys to hook a switch to that circuit to have a "cut-out" effect at the flip of a switch:thumb:.


I can't imagine that AFM will be something you can beat by pulling a fuse or installing a resistor in the connectors. Unlike CAGs or other simple solenoid operated systems, AFM not only is turning off lifters, but it also shuts off fuel to the deactivated cylinders. If you just disconnect the oil diverter solenoids (or whatever the hell they are), the ECM will still cut fuel and the car will still be running on 4 cylinders, only even less efficiently since it will be pumping air through the holes. This would also then no doubt piss off the ECM which would see all that extra air in the exhaust and assume the car was way lean.


What's funny is it seems so many are worried about sound and the 'inconvenience' of having to get a tune to get rid of AFM to fix it.. What i think most of you are totally forgetting it torque managment. All 05+ LSx (auto and manual) applications have HORRENDOUS torque management built in that holds back the car's performance and make it inconsistent as hell. A tune should be a MANDATORY mod for any real performance enthusiasts with a modern car.

What i think most of you are totally forgetting is torque managment. All 05+ LSx (auto and manual) applications have HORRENDOUS torque management built in that holds back the car's performance and make it inconsistent as hell.
What exactly is torque management anyway? How does it work?

Also, just for clarification: Does the C6 Z06 have it?

Torque management pulls timing and closes the throttle blades slightly (on cars with ETC) to reduce torque during upshifts, off the line, etc to reduce shock on the drivetrain, wear on the clutches, etc.

I can't say for sure how bad the C6 ZO6 has it, but i'd bet it does since the regular C6s are completely hamstrung by it.

If I can't be allowed to turn the DOD on and off then I wouldn't want it at all...That's all we need is a bunch of Camaros running around that sound like oversized Civics :yuck:

does anybody have a clip of a DOD car in 4 cylinder mode or one going from 4 cylinder mode to 8 cylinder mode, id like to hear it for myself.

I dont think the sound will be a huge issue for me. It'll be my DD and at best it'll get full bolt-ons and tune. Considering most driving conditions, AFM wont kick in unless its freeway driving and trace amounts of city cruising unless the engineers/programmers make the system slightly more aggressive. As it sits, the system doesnt make that much of an impact in real world driving from the studies I've read, testimonies and the nature of its criteria to engage, cutting the cylinders. AFM may hardly even get used which I hope is not the case...

does anybody have a clip of a DOD car in 4 cylinder mode or one going from 4 cylinder mode to 8 cylinder mode, id like to hear it for myself.

I have yet to see one myself... If I had a way to hang the camera out of the trunk I would record one for you, but I don't feel like taking a chance of droping my $600 camera while driving 45mph.



I really wish people would understand that the V4 does mode not in any way sound like a civic or any other Inline 4 cyl engine. Not even remotely. It likens to a (horizantally apposed 4 cly engine) like those in the WRX and Porsche cars. Though its still not the same, as the actual tone... or frequency is lower than. There is nothing quite like it really. But thats as close as it gets.... it in no way sounds tinny, or raspy or anything else for that matter... it sounds like a V8 skipping every other cylinder (but not in a bad way).

The current '05 and '06 LS4 motors use a sort of patchwork ECU at the moment, the '07s are supposed to be able to use AFM more often as well as log pretty much everything you do with the car.... and I mean everything due to a much more powerful ECU. The AFM code in the old ECU is supposedly currently inside of tables that were not designed for AFM... the new ECU was probably made specifically for that purpose, perhaps with the newer ecu's, they'll be able to program out AFM, or worse, not program at all. I haven't heard if the '07 LS4's are getting better mileage yet, or actually use AFM more. There aren't many on forums yet.

Thats all the crap I can think of at the moment. If I can find a wired mic maybe I'll take the laptop out and get a recording for you guys.

I have no idea how it'd react to a catback, but honestly, with the stock exhaust, the sound is so similar, you really don't notice it. It may be just a hair quieter, but to my ears, the tone is more or less the same as it is when running on 8.

I have yet to see one myself... If I had a way to hang the camera out of the trunk I would record one for you, but I don't feel like taking a chance of droping my $600 camera while driving 45mph.

<snip>

Thats all the crap I can think of at the moment. If I can find a wired mic maybe I'll take the laptop out and get a recording for you guys.
How about video from the inside? Have a friend ride in the trunk recording?

I believe that the AFM equipped SUVs have mufflers that are tuned to mask the change in tone when going into 4 cylinder mode. I'm sure GM's engineers will do a good job with the exhaust sound. Stock V8 camaros have always sounded good.

Give me AFM for sure. Better fuel economy and quieter cruise, what's not to like?

People who think this sounds like an I4 with a coffee can exhaust are thinking way too simplistic. The number of cylinders is only a small part of what defines an exhaust note. Will you notice a difference in exhaust note when AFM activates? Of course! If you're listening for this and already have it in your head that AFM is somehow an evil performance killer than you'll think it sounds bad.

Every other physical characteristic that defines an engine's exhaust note is in place in V4 mode. It sounds more quiet and like running at half the actual RPM. Does your V8 sound like crap at 800 RPM but great at 1600???

I haven't heard an AFM equiped car with an aftermarket exhaust but I have ran my LT1 on 4 cylinders for s$!ts and giggles. With a cam and full exhaust, including the true duals with x-pipe, it still has the same exhaust tones just at half the intervals. Granted I, unfortunately, can't completely close off 4 cylinders so I ran on 4 active cylinders with 4 just pumping air but IMO it's a good indicator. I showed it off for a few other enthusiasts and they were surprised at how good and smooth it sounded on "only" 4 cylinders.

People say the Subarus are the only good sounding 4-bangers out there. That's why some people are describing the sound as such. It really doesn't sound bad, in fact it sounds good, like these V8's do. They just don't like the AFM for some reason.

If I could add AFM to my LT1 at reasonable cost I would!!! At WOT I want great performance and a wild exhaust note. At cruise I want fuel economy and quiet. Why wouldn't you?

It's not about volume - it's about tone.

If I could add AFM to my LT1 at reasonable cost I would!!! At WOT I want great performance and a wild exhaust note. At cruise I want fuel economy and quiet. Why wouldn't you?

I agree if AFM gave great gains in fuel mileage. But the reality is 12% increase on the highway is the norm that I have read, provided you are going slow enough. (which equals 3.6mpg from a car getting 30mpg) I'm not sure I'm all that worried about another 3.6 mpg from a 30mpg car. (provided the Camaro can get 30mpg) Also, I thought LS4 owners are not seeing the fuel mileage as advertised. So I'm not sure that I want the added complexity (cam swap?)and 4 cylinder sound on my new Camaro that will be a fair weather summer driver.

It's not about volume - it's about tone.


It may be just a hair quieter, but to my ears, the tone is more or less the same as it is when running on 8.

Anybody who has concerns on this, go drive an SS w/ DOD, and de-select the DOD mode from the DIC, so you don't see when its on 4 or 8, then try to figure when its on 4cyl mode. I will all but guarantee you wont be able to tell from the exhaust or driving feedback. And also, this hasn't been addressed, but the SS ALWAYS idles on 8cyl, so theres no need to worry about that.

How about video from the inside? Have a friend ride in the trunk recording?

I believe that the AFM equipped SUVs have mufflers that are tuned to mask the change in tone when going into 4 cylinder mode. I'm sure GM's engineers will do a good job with the exhaust sound. Stock V8 camaros have always sounded good.

I could give it a shot, never been in my trunk to see how it sounds, but from the cabin, it's rather hard to hear at driving speeds. I'll try a slow roll, I generally can get it going at 20mph... maybe you could hear it then.

I agree if AFM gave great gains in fuel mileage. But the reality is 12% increase on the highway is the norm that I have read, provided you are going slow enough. (which equals 3.6mpg from a car getting 30mpg) I'm not sure I'm all that worried about another 3.6 mpg from a 30mpg car. (provided the Camaro can get 30mpg) Also, I thought LS4 owners are not seeing the fuel mileage as advertised. So I'm not sure that I want the added complexity (cam swap?)and 4 cylinder sound on my new Camaro that will be a fair weather summer driver.

So far there hasn't been reason to believe that a cam swap would be a huge issue. I believe the current limitation is of Cams that have .590 lift or less... don't qoute me on that number though. I haven't heard of anyone doing it yet, they are all under warranty.

Remember, if the Camaro comes out tilting the scale at 3700 lbs or more, it could very well not get 30mpg like the 4th gens did. My Impy SS tilts the scale at the weight, probably around 3900 with a load... with AFM and a good road condition I can pull 28mpg easy. If I go a little slower, which I do sometimes I'll hit 30. I've hit over 32 mpg in the right trip, but I've also only got 22mpg before as well (crossing west texas at 85 mph) GM will need this more for their trucks, and large cars, but I sure wouldn't want to pay a gas guzzler tax on a new camaro if we can help it.

I agree if AFM gave great gains in fuel mileage. But the reality is 12% increase on the highway is the norm that I have read, provided you are going slow enough.

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 ass 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.

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

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

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.

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:death:

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.

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.


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/engines_drivetrain/accessories_electronics/0405sc_gmdod/

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:death:

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.

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.

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 arse 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.:p

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.

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 arse 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.:p


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

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:death:

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

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

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

all internal parts are the same, just has fast bleed liftersi said performance cars:p

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:death:


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.

I'd rather the milage as well. I'm not as concerned with the note cruising as I am with it when I accelerate at WOT....:D

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