Engine Mod--Is This Possible?
 

One of the members here is selling an SS on which he says he's disabled the DoD. My question is almost the opposite.

I noticed tonight that the engne idles in V8 mode. This seems incredibly stupid and wasteful in an engine that's designed and advertised to provide optimum mileage along with the horsepower and torque. Hell, if they were still making the Monte SS it would probably have auto stop/start at idle. So...

Is there any way to mod the engine so it idles in 4 cylinder mode?

I hope not, it would sound terrible at idle.

Honestly I could be mistaken but I think dod only works at highway speeds. And even then I think it's a stupid system

It's not about the miles per gallon, it's about the smiles per gallon!

If you wanted something easy on gas shouldn't of got the SS imo

I know a couple of people who had DoD tuned out of the car. One person who is here on the forum (Devin) said his MPG improved once it was tuned out.

Keep in mind, in '06-'07 DoD was a new concept to GM cars. I believe they still offer it on current vehicles and if so, I am sure they spent time to improve it.

As far as making it idle at 4 cylinder mode, hard to say. You would need someone familiar with DoD settings and an HP Tuner to probably answer that question.

I was getting bout 275 miles a tank with DOD (and 2 qts of oil every 5000 miles) with mostly highway driving and once it was tuned out and had a nice tune overall I could get a bit over 300 miles. Hell I filled up outside of Cleveland on the way to Detroit to be safe (345 miles) and still had a 1/4 tank left to go! (PS. I have a heavvyyyy right foot)

IMO DOD doesn't do much good for anything (more harm!), and to agree with Turbomonte, if you bought a SS and are worried about mpg, you bought the wrong car for you.

I'll third what turbo said.

It seems counter intuitive to be concerned about increasing fuel mileage on a ls4. Its the biggest engine available in this platform and is intended for performance, not fuel economy.

As far as turning DOD on at idle, keep in mind that there is a reason why it doesn't do this from the factory. If the GM engineers could've got better fuel economy out of it with some simple tweaking to bring the DOD activation speed lower (even down to idle), then Im sure they would've. My guess is that it's an NVH issue to do so, but that's just speculation.

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These are the parameters in the tuning software. It appears that the fact that it kicks on and off are set somewhere to say that it can only activate in 4th. Doesn't look like the option to turn it on during idle is there.

Also, how much could idling in 4 cyl save? Cars don't use that much fuel idling normally, just when cold and it is commanding a lot of fuel.

Why on Earth would I buy a car with a V8 if I wanted to save fuel? Oh, I don't know. The smoothness, the low RPM's, the fact that, unlike the 3.5 and the 3.9, I can actually find parts for the LS4...the list is is long as my arm.

How about, given a finite fuel budget, why wouldn't I want to save fuel whenever possible, so it's available when I truly need to waste it, e.g. embarrassing Mustangs? This is the philosophy I used on my GTP, which was the first car I owned with a DIC. I averaged 26 mpg, well above the EPA combined, and still did the Battlestar Galactica launch on a regular basis.

Hmmmm. So all the owners here who mod their cars seeking higher HP and torque are on a wild goose chase? I mean, if the GM engineers could've gotten more HP and torque out of the engine, they would've....

Gm engineers could of got more power out of the car if theu wanted to..... I'm sure they probably decided against doing so do to how much the cost of the vehicle would go up and at that point not be in the range of selling...

A v6 is just as smooth as the ls4. low rpm's are from transmission gearing, engine means nothing for this either. Lastly please tell me you don't actually trust the dic....

Typically the engineers all figure out the medium ground for all issues.

How much power AND mpgs can we get? How loud can we go without it hitting a certain decibel. How far can we push this engine, but still keep it reliable for mass production and last at least 100,000 miles.

Sure, they can always push one way or the other, but they are trying to find the proper middle ground for long-term owning and the general publics wants.