The way I see DOD is it's just one more thing that might get messed up when you start bolting on aftermarket performance parts.

 

You guys asking to defeat this feature are nuts. It has so many good benefits. I'm guessing this is the same bunch of people that disable EGR just because it's an emissions device.

DOD will only activate at cruise. It will improve fuel economy, reduce emissions, and make the car more quiet. At idle it will still sound great. At WOT it will still have full power and sound fantastic.

Who really wants to add noise, pollution, and suck fuel just for the sake of it?

For those concerned about the sound. It only activates at light cruise, when you can barely hear the car anyway. I can see some consternation for those people who rip the exhaust off and might be worried about it. Question: Have you heard an LSx engine running on alternating cylinders? I have ran my LT1 on four cylinders just for the heck of it before (through programming). It sounds very similar to all 8, the biggest difference is that it's more quiet (which I would love at cruise anyway). It's not qoing to sound like a Honda with a fart can at WOT!

As long as the transition is seamless I vote for better fuel economy, reduced emissions, and more comfortable cruise volume. If anything, this should be on a performance car more than anything.

 

THERE IS NO MORE DOD...

its all refered to as Active Fuel Management...

GM doesnt want to get confused with the old olds set up... so they have renamed it....

 

No, I do not plan on racing my car; I never said I planned on it. Putting mufflers on your car does not void your engine warranty. But changing the programing would.

 

I like the idea of it, the more gas mileage the better. Besides, it'll be a real strong selling point to have a Camaro that gets much better gas mileage than it's counterparts -- especially with rising gas prices.

As someone said before, as long as it's seamless and unnoticable, than go for it. As for noise, bah, i'll be more than happy to have a quieter car while cruising on the highway.

Some of you against it are just going to have a deal with it like CAGS. Also, like CAGS, i'm you'll be able to disable it -- After that, it's not GMs problem, so don't start whining when your warranty is voided.

 

I agree with most of what you say and I started this thread to get opinions of what people thought. I like good gas mileage as much as any. Ship shift was to save on gas but I did away with it on every M6 car I have. Traction control I leave on most of the time but alot of times in good weather i cut it off. I have nothing against it being there as to DOD but would like to make it a choice to have or not. I will buy one either way.

 

But the thing about the skip shift is it affected the way you drove, I got rid of mine the first time it tried to get me killed when turning left at a light.

But I'll say again for those that may have missed it, since I seem to be the only one at this point that has DOD, or AFM as they call it now.....the car idles on 8 cyl always, never 4. Under ANY kind of load, the car is on 8. The ONLY time the 4 kicks in is at CRUISE, when you wouldn't have much bark no matter what exhaust you had.

 

I have DOD on my Durango. You can't tell when it is actuated.

 

I really, really, doubt GM is going to put a switch in the car to turn it off. This is something I don't think the EPA is going to want to see in a car, and I don't know if it would adversly affect CAFE numbers or not, but I could see it doing that. I doubt it is going to be an option either. It is either going to be on the engine, or it is not.

I wonder why GM is dragging their feet on a DoD (or whatever it is now) system on the v6s? Honda's v6s use cylinder deactivation, and it seems to work fine.

 

You ever hear a Honda just cruising by with a loud *** exhaust? They still sound like garbage to me. I don't know what kind of exhaust note a GM v8 is going to have in "v4" mode, but I would bet there is going to be an audible difference while cruising, especially when everyone starts ordering the catbacks for their cars.

 

there are a few things that go into exhaust tones... 1 cylinder sequence, 2 head degrees, 3 rpm, 4 displacement 5 explosion noise

the amount of air being forced out of the muffler hasnt changed, the cylinder sequence is still the same, head degree is still the same, rpm... well its only v4 mode when its running below 2k rpms anyway 4 displacements the same, there is only half the explosions...

the loud *** exhaust from the honda, is when they havent down shifted... this active fuel management wouldnt work very well with a manual transmission i think.

with active fuel management if you are coasting you shouldnt be hearing your exhaust anyway...

trust me you cant really hear the tahoe when its on v4 mode... but as soon as those other cylinders kick on it has a great tone to it...

 

its supposed to be going into the Inline 6's and 5 i think...

soo... your atlas engines will be getting it...

 

A V8 car with a loudmouth sounds just as bad as a fart tipped honda at cruise when it's droning your ear off (IMO of course). I'd just as soon not take a long drive in either one thanks. Any wide open obnoxious exhaust on any car is going to sound like **** when it's operating at/near it's resonance point.

But that's not even the point. With true dual exhaust, getting 1 cylinder event per R for each muffler is not going to sound the same as an I4 that is sending 2 cylinder events per R into the exhaust. The resonance should be totally different. Also factor in the typical V8 is going to be geared to be cruising 2K rpms or less at legal highway speeds whereas the typical honda is cruising at 3k+ on the highway. This should also help resonance.

I mean, i bet there is a difference in sound. But now, instead of a loudmouth droning your ear off at light cruise at 2k on the highway, it's effectively running ar 1K rpms in terms of the # of events per time (wow, events per time, is that like frequency, woah, no way, what does math/physics have to do with this, i should stiock to V8=good I4=bad and stop confusing things with science), which should kill the bad drone and instead sound like it does just off idle. That's all that's happening, it's halving the frequency of your exhaust note

 

All of the things you have stated account for exhaust note to some degree, but some of them not really all that much. 1 Cylinder sequence-yes, this is why LS1s sound different than LT1s for the most part, even with an identical exhaust system on them.2 head degrees-, yeah I guess, but I doubt that unless you heard to engines back to back, one with a 12 degree head, and one with a 15 degree head, that you are going to hear any difference between them. 3 RPM-well, this one is obvious, but I don't think it really fits in with the other characteristics you have mentioned at all. 4 Displacement-this will have an effect too, but I have been suprised at how similar a small block and a big block Chevy can sound when they both have the same flowmasters on them.5 Explsion noise- I really have no idea what you mean about this.

The number of cylinders firing, the degrees of rotation they fire in, and the setup of the exhaust system it is running through, are the things that effects the exhaust system the most. I don't know how a v4 GM engine will sound, but when the loud aftermarket exhuasts start going on the 5th gens, there is going to be a noticable difference in sound. I am not saying it will sound like a Honda, because I have no idea what it will sound like.

 

I was obviously poor with my choice of wording, as I did not mean to imply that a GM v8 in 4banger mode is going to sound anything like a Honda I4 engine. My point as that at cruise, in 4 cylinder mode, there is going to be a difference in the exhaust note, and I wonder what it will sound like.

On a side note, you are right about the Loudmouths. They drone unbelievably on the highway, and can sound like crap when they are doing so.