VMS-- DoD delete update

[edmanet]

Ok I finally got to take the G8 out for a long drive. I had Kirk turn off DoD.
Driving at a steady 70mph for almost 90 miles I averaged 24.2 mpg. On the 90 miles back with Xmas traffic, a smokey burnout, and a couple of full throttle bursts to 100mph I averaged 20.6 mpg.

Also, with headers, a catted exhaust and the stock mufflers there is no drone. :woohoo:

[R.Penguin]

Outstanding.

On another note re: AFM, I have been monitoring it with the DashHawk for several weeks. Interestingly, AFM does not engage at any speed/gear in extremely cold weather. My guess is that the ECM has to see a minimum temp. from one or more sensors before it will activate DoD.

Any other thoughts?

[screw991le]

Sounds like DOD is just a "green" thing to keep people happy.

[EcoBrick Bob]

Mine's going to be gone in a "FLASH" in Jan...(updating to 93 tune) Really annoying to rear passengers. Finally started using M-6. Bet it was going on and off every 15 sec. on our trip to Key West.

[RyaNCSU1]

I agree that their is minimal impact with DOD. Had mine turned off in an attempt to eliminate the drone. No luck unfortunately. Loud exhaust anyway.

[norm8332]

I only get 15.5 but I think i drive with a heavy foot.

[Chewy]

Seems to me in my car anyway that anything 68mph and above (unless going down hill) the DOD NEVER kicks in. I have NEVER EVER heard it kick in at those speeds on flat road.

I average however around 25mpg on the highway but I have NEVER been on a long trip. I am hoping to go one one and see what I get soon.

Snow tires don't help with MPG either.

[g8_795]

Outstanding.

On another note re: AFM, I have been monitoring it with the DashHawk for several weeks. Interestingly, AFM does not engage at any speed/gear in extremely cold weather. My guess is that the ECM has to see a minimum temp. from one or more sensors before it will activate DoD.

Any other thoughts?

The factory settings for DOD to come on are as follows:

Enable Engine Coolant Temp: 104 degrees
Enable Minimum Engine Run Time: 30 seconds
Disable above RPM: 3200
Maximum Throttle Position before Disable: 6%

For the guys with the VMS tune, some of these parameters are changed. I won't post them to respect their IP.

-Robert

[RyaNCSU1]

I dont know how some of you get the mileage you do. Even with DOD on the best I can get is low 20's, pretty much the same with it off. Then again I live in the mountains so I havent seen a flat road in a while.

[racerns]

Sounds like DOD is just a "green" thing to keep people happy.

I am sorry but that is just silly. Having worked in the automotive industry, GM is not going to spend the development cost and increased cost per car if there was not some direct benefit. This car is not marketed as "green". If it did not have AFM there is a good chance it would have to incure the gas guzzler tax.

Also, I have similar mods as the OP but I have kept my AFM. I did a hwy trip a few weeks ago and decide to do a ~70 mph cruise in steady traffic for the last 40 miles and averaged 26.9 mpg for that stretch. The AFM was on for most of the time. I don't see why you would get rid of the AFM unless you were changing the cam.

[Art708]

I dont know how some of you get the mileage you do. Even with DOD on the best I can get is low 20's, pretty much the same with it off. Then again I live in the mountains so I havent seen a flat road in a while.

Even on the flat roads that we have here in the Low Country the best I can get is 24 driving long distances on the interstate at around 75.

[bobyoung]

Outstanding.

On another note re: AFM, I have been monitoring it with the DashHawk for several weeks. Interestingly, AFM does not engage at any speed/gear in extremely cold weather. My guess is that the ECM has to see a minimum temp. from one or more sensors before it will activate DoD.

Any other thoughts?

I have noticed that the tranny shifts at a much higher RPM when the car is relatively cold too although i almost always warm it up first. Does the tranny warm up also while the car is idling when it's first started up when cold or do you have to be moving?

[GRRRR8]

Its warming up as its idling. I hit the rev limiter regularly until fluid warms up and a few times even warmed up. Thats a easy fix by bumping the limiter to 6400rpms.

[johnh]

On another note re: AFM, I have been monitoring it with the DashHawk for several weeks. Interestingly, AFM does not engage at any speed/gear in extremely cold weather. My guess is that the ECM has to see a minimum temp. from one or more sensors before it will activate DoD.

I noticed this too. I haven't had a chance to scan it, but I know the ECT was above 104. The hysteresis is 39*, ECT still had to be above 145...I was driving for a while.

Hopefully I will get some scans. The only other thing I can think is AFM is vacuum activated, perhaps the cold air is affecting it enough to disengage AFM. I don't see why you wouldn't want AFM on in the cold once the enigne/oil is warmed.

AFM has two benefits....one 3 mpg on the highway, and I think bigger no GGTax. I look at it this way..I can save money on the car cost (no tax) and gas money. If I do a cam, I will likely scrap AFM to allow some higher lift and higher revs. Till then save money. (Heck GGT of $1700 is 2/3 of a Livernois Stage 1 package)

[GRRRR8]

It has to be a certain temp to activate. It is electronically controlled with solenoids.