Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

DOD (Displacement On Demand) system in NSW Highway Patrol Cars

426Cuda

SUBLIME!
Joined
Dec 15, 2013
Messages
4,181
Reaction score
3,015
Points
113
Location
Wagga Wagga
Members Ride
VF Redline Sedan - A6 Spitfire MSE...
Hi all,

I have a VF SS series 1 sedan with the L77 engine that in a former life was a NSW highway patrol car (verified by front page in the logbook, as well as minor holes in trim and bodywork and stuff like that).

I'm aware of the upsides and downsides of this, however mine has been trouble free so far. I've heard that in these cars the DOD system that shuts off half of the cylinders at part throttle cruise is disabled or removed, along with other differences like the transmission cooler, the alternator and the brakes (these last three I have verified to be the case).

Firstly, is that likely to be true, and how would I tell? The way the car drives currently, I don't get any tell-tale signs of any shift in engine operation in the conditions where DOD is supposed to work.

Secondly, if it is true, is it done electronically in the ECU or do they use different lifters/a manual spec engine?

For the moment, I'm just curious, but at some point in the future I would like to do intake/exhaust/camshaft changes. DOD not being there would mean I'd need to spend a lot less money.

Yes, the auto L77 has AFM. Personally i've never heard of police variants having this disabled. They may though?
In the VF (unlike the VE) there's no indication in the DIC or elsewhere that AFM has activated. Like you, FORG and others have mentioned, when mine was stock, I couldn't pick it by sound or feel. The only way I could tell, was to watch the instant fuel consumption whilst cruising. I.e, it would drop, then increase significantly with the lightest of throttle application or on an incline. I know this happens even without AFM, but it is different. You can pick it.
Once tuned with exhaust, OTR etc it was easy to pick AFM starting or stopping. A change in exhaust note gives it away every time, and yes, the fuel consumption changes too.
I hope this helps.
 

redvxr8clubby

Active Member
Joined
Jan 5, 2015
Messages
879
Reaction score
171
Points
43
Location
Sunshine Coast QLD
Members Ride
VX Clubsport R8 & VE SS
Was it introduced for VE2?
AFM started with VE I think MY 9.5 it was early 2009, pretty sure I recall Wheels magazine testing a VE Calais AFM in December 2008 ran it from outskirts of Sydney to outskirts of Melbourne squeezing more fuel into the tank than its stated capacity. My VE SS (built mid 2009) is AFM (L76), VEII was late 2010 - AFM would have been around at least a year and a half before VEII.
 
Joined
Jan 27, 2019
Messages
31
Reaction score
10
Points
8
Age
59
Location
Maitland, NSW
Members Ride
VF SS A6
AFM started with VE I think MY 9.5 it was early 2009, pretty sure I recall Wheels magazine testing a VE Calais AFM in December 2008 ran it from outskirts of Sydney to outskirts of Melbourne squeezing more fuel into the tank than its stated capacity. My VE SS (built mid 2009) is AFM (L76), VEII was late 2010 - AFM would have been around at least a year and a half before VEII.
The article was by John Cadogan. It can still be found on his website. AFM was introduced before VEII so later series Is have it.
 

krusing

Well-Known Member, Possibly for the wrong reasons
Joined
Jun 21, 2014
Messages
5,349
Reaction score
3,941
Points
113
Location
Melbourne, Bayside
Members Ride
2002 VY L67 Calais Sedan, 2012 VE L77 Calais Wagon
My VE S2 L77 with AFM is noticeable with the exhast note and little bit of vibration when it goes into 4cyl Mode
After replacing the fuel pump recently, and putting all back togther, and the exhaust back on,
I noticed the 4cyl mode vibration was worse.
After it had cooled down as I parked it on ramps, I got under it and undid the compression clamps [connections] [at the cats], lifted the exhaust up so there was little to no weight on the exhaust hangers at the front, tightened the nuts back up again, and took it for a test drive, the vibration had almost disappeared, it was still there, but not as noticeable.
In saying that, if DOD was active, you would defiantly notice it. and/or it should display on the dash.
 

stooge

Well-Known Member
Joined
Apr 3, 2014
Messages
3,099
Reaction score
2,980
Points
113
Location
wa
Members Ride
Turbo Alpaca
Mines a vf1 ssv with the l77 and you can tell when dod kicks in as you are cruising along the exhaust note will change and make a sort of farty drone and if you tap the accelerator it will snap out of it.
If you drive using active select it shouldnt come on(it doesn't on mine).
At first i was going to disable it but its pretty good for fuel so i ended up just leaving it.
 
Joined
Jan 27, 2019
Messages
31
Reaction score
10
Points
8
Age
59
Location
Maitland, NSW
Members Ride
VF SS A6
Mines a vf1 ssv with the l77 and you can tell when dod kicks in as you are cruising along the exhaust note will change and make a sort of farty drone and if you tap the accelerator it will snap out of it.
If you drive using active select it shouldnt come on(it doesn't on mine).
At first i was going to disable it but its pretty good for fuel so i ended up just leaving it.
Do you have an after market exhaust or intake? I've heard these can make that drone happen. The stock system is designed to damp it out.
 

stooge

Well-Known Member
Joined
Apr 3, 2014
Messages
3,099
Reaction score
2,980
Points
113
Location
wa
Members Ride
Turbo Alpaca
Do you have an after market exhaust or intake? I've heard these can make that drone happen. The stock system is designed to damp it out.

no just the stock system, I did eventually put a set of bimodal mufflers on but I could hear the dod kicking in before I changed them and with them closed it is pretty much the same as the original non bimodal set.
I don't think it is worth putting a custom system on until you disable dod because it does sound pretty crap with just the bimodals open.
 
Joined
Jan 27, 2019
Messages
31
Reaction score
10
Points
8
Age
59
Location
Maitland, NSW
Members Ride
VF SS A6
no just the stock system, I did eventually put a set of bimodal mufflers on but I could hear the dod kicking in before I changed them and with them closed it is pretty much the same as the original non bimodal set.
I don't think it is worth putting a custom system on until you disable dod because it does sound pretty crap with just the bimodals open.

I've heard as much. A DOD delete will figure into any mods I might do down the track, but If DOD is already not there by virtue of government spec, I'd save ~$1000 or so.
 

Dylan kingswood

Well-Known Member
Joined
Dec 5, 2017
Messages
265
Reaction score
476
Points
63
Age
33
Location
Hobart
Members Ride
2011 s2 Ve ss
I have a Manuel s2 I got the delete plate for 400 when I cammed mine and personally even if already changed I’d upgrade your lifters and rods regardless when throwing a new cam in their not like my old 4.2 and 5 litres where the intakes off and everything’s there it’s all hidden under the heads
 
Top