AFM mode

[Grennan]

Can we for once in this forums history refrain from turning this into an AFM Cricle Jerk?

Some tuners dont like it because of the complaints they get when it kicks in, it sounds like rubbish. They dont have the time nor the patience to deal with that or to spend countless hours researching the exhaust stuff you did Pirate, most places sell one exhaust fits all and if they were to custom make exhausts to fit the AFM needs like Pirate has sourced, theyd be charging 4 grand for a basic system. So they simply disable it.

Tuning wise, some tuners dislike the way it lags a little when you want that power. Simply put, tuners cater for the drive in drive out customer to please the masses. If you want it re-enabled, im sure they will. They just have countless complaints from ######## who just says ohh this drones without doing the reseach or this doesnt have the throttle response of X car (PS, you can read some threads in this forum of dyno warriors and see the type of attitude these workshops face).

As I said, for me personally, I dont give it a **** if its on or off. If I had a choice it would be in the bin. I gain next to naught with it on over having it disabled. If you do a lot of cruisey driving I would recommend looking into keeping it on.

 

[bozodos]

Yeah you pretty much said what I was going to reply with Grennan.

I know you have your own very strident views on AFM Pirate, but the tuners I've spoken to personally don't feel that it's of any benefit to keep turned on in the Gen 4. I also don't think that you should use that as an implication of incompetence, especially when you're not a tuner yourself. At least try and give a balanced response rather than presenting your opinion as fact.

Name dropping drag racers from US based forums is great and all, but do you seriously assume that most tuners are stuck in 2004? It's simply not true. OP probably should have asked the tuner BEFORE creating the thread to be honest.

I'm not talking about the Gen V gear, because it's irrelevant to this particular topic.

 

[Grennan]

Name dropping drag racers from US based forums is great and all, but do you seriously assume that most tuners are stuck in 2004? It's simply not true. OP probably should have asked the tuner BEFORE creating the thread to be honest..

I think most tuners are under the assumption that the customer wants performance and arent to worried about petrol consumption. Correct assumption or not I think by default its turned off.

I guess if youre new to the modification scene its something you just arent aware of. I tend to ask a lot of questions before giving my car to a workshop. Someone who will not sit down with me and explain things (even though I know the answer) I wont leave my car with them and one of the first things I asked was if the AFM would be turned off and my tuner C&A advised to turn it off for my above reasons. It wasnt because of performance it was more the resonance the engine gives off under cylinder shut down and said a lot of customers return the car because it sound bad. Thats not a failing of the engine or the AFM system, its just that exhaust manufacturers make a system to suit a large variety of cars. Pirate has done a hell of a lot of exhaust research of his own and i applaud someone who does that research, however the sheer amount of time that went into it, in my books, is absolutely ridiculous for a bolt on V8 modification and im sure workshops view it in the same light. Why on earth would I cut and chop mix and match parts for the sound when for half the price and probably a small fraction of the time when I can slap a Defillipo system on it, disable AFM and the customer creams his pants.

 

[ari666]

because youre forgetting what AFM is actually designed for. its not designed for sound, nor for performance, its designed for VEHICLE EMISSIONS. so the big thirstly V8's could still pass CARB.

and for a go fast racer, lets face it, tuners turn it off because it shows a poofteenth more on a dyno sheet. and we know how everyone loves a good dyno sheet, regardless of the implications it has on drivability and fuel consumption.

i personally would be PISSED if a tuner turned off AFM without asking me, specifically it means the car no longer passes vehcile emission, which i know no one cares about, but even still i rather keep the tech functioning as it was designed to. failing that have the entire system removed properley. im still waiting to see the threads pop up on "i switched off AFM and now my rollers have exploded". if the mechanicals are still there, leave AFM switched on, if you wanna gain 1 HP and add 1/3 fuel consumption, then remove the whole lot.

my 2c

 

[bozodos]

Well as Grennan mentioned it's more about the lag of turning it on and off, and the exhaust harmonics than wringing every last kw out, especially when tuning on 98 and achieving very similar fuel economy with it off regardless. The 2 tuners I've asked about it said that there just isn't any benefit to leaving it on (unless the customer specifically asks). It also means the owner doesn't need to spend a fortune on an exhaust that won't drone at highway speeds.

If it was beneficial, where's the data showing how much more fuel is saved with it enabled in a tuned car vs disabled?

It's more economical with later VE/VF to leave the lifters etc in with the system disabled, the lifters were apparently revised in 2009 or so, and no longer tend to have the failures that they used to.

 

[Grennan]

Ari, the hardware is EXACTLY the same in the L98 engines which have the system disabled. It may have a little to do with emissions(probably more state side than here), id suggest it has more to do with keeping the in theory fuel usage figures down in the automatic models which is why they didnt even both activate the software for the L98 which has lower fuel figures on paper than the L76.

Lifters have ALWAYS been a GM weak point, regardless of cylinder shut down technology. MY 9.5 they were revised. Hell Hamish has complained of lifter noises and he has a L98 (MY9.5+), Reaper LS3 blew his into a million chunks. You could maybe argue that using the same lifters in the L98 as well as the L76 could be the issue. But over the course of the VE, Lifters have been a very very common issue, regardless of engine, even the earlier 6L (which IIRC did not share hardware) had the issues.

As far as fuel consumption goes. As I said and have said on numerous occasions it really depends where you do your driving. 1/3 added consumption is widly off the mark if youre having your car tuned.

Im currently sitting at 14L/100km on a mostly suburban drive which is pretty much dead on what I was getting prior to turning it off.

My freeway usage is SLIGHTLY more, typically in the +1L/100km range. Which is around an eight increase.

In my case, doing most suburban stop start driving, I found the system to rarely ever be enabled, by the time I got cruising I got a redlight and had to start the entire process again, which rendered the entire thing useless.

 

[PIR4TE]

Bozo I don't charge for fixing cars, there's better tastier and fun ways to make a quid. It's more a passion and academic persuit of mine for more than thirty years: nevertheless ima non-profit professional tuner who can tune more efficiency and performance out of this engine than 95% of the mongs who set themselves up to gouge money from those who don't know better.
The guys I mentioned are hardly commercial by comparison to most Aussie operators with über brand-hyped retail outlets, rather more like-minded, analytical, professional colleagues who can help deliver world-leading results using variable displacement, variable camshaft events, e85 and NA performance research (from this decade).
Anyway, here's a good start to inform your opinion in future.

 

[Robbo VS3]

Pir4te and Grennan know their stuff when it comes to AFM, this is an interesting read. Just to add my 2c, in my eyes AFM leans more towards a gimmick than a worth while fuel saving function. I have the auto SSV but with the L98, I get 720km out of a full tank of 98ron fuel so around 8.5L/100km (freeway driving) and 14L/100km (around town) and im stoked with that, I could'nt care less that it does'nt have AFM, and I can fit any exhaust without worrying about AFM drone.
Also just had full exhaust, CAI and custom dyno tune done and I drove my same freeway track again and still got 720km to a tank. I thought the tune may have given me even better economy, but meh still happy with the result, and it goes hard and sounds mean now.

 

[ari666]

lol yeah 1/3 fuel consumption was a bit rich... after ive had a few cans i sometimes speak ****...

sometimes.

 

[bozodos]

Pirate I didn't know you considered yourself a tuner these days. Nonetheless, I think it's exceedingly poor form of you to bag out the majority of those in the industry here, not to mention arrogant to think you can do a better job.

I (and anyone else with a brain) would take the word of those who work on these cars day in day out for years on end with proven results over amateur 'tuners' on the internet.

OP, what did you end up doing?