can we turn afm on/off? or delete it??

[jdpickering]

garfin: Why no AFM on the maual transmission V8?

DougHoulihan: the AFM is done elecronically as we move from 8 cylinder to 4 cylinder mode or 4 cylinder to 8 cylinder mode. The manual transmission is mechanically in specific gears and does not allow us to electronically change from 4 cylinder to 8 cylinder mode.

Wonder what this will do to the EPA Fuel Milage for the Manuals. If you don't want AFM get a Manual

[greysteel_M6]

You'll have to tune it out, Idk if it will be available on hand helds though.

[DGthe3]

There is an easy way to bypass AFM: stay on the gas. It will never deactivate the other 4 cylinders.

[Kyle2k]

All that aside how easy/hard will it be to get rid of it? Just a cam/lifters upgrade or what?

[Grape Ape]

Originally Posted by Kyle2k

All that aside how easy/hard will it be to get rid of it? Just a cam/lifters upgrade or what?

All you really need will be a tune, but you have to have a tune unless you like staring at a check engine light (and maybe some stumbling and stalling at cruise).

An LS3 cam would probably bring the power up to LS3 levels, but if you are swapping the cam you might as well go a little hotter. that would probably sound better to.

[AnEvilPenguin]

I've built up ALOT of Gen 3 and 4 engines, AFM has a LOMA that cuts back on oil going to two cylinders on each bank, so the 4 cylinders that the lifters are not being pumped up let the valves stay closed so that they are not taking in any air or fuel mixture. also the PCM/VCM cuts off spark and the injectors to those cylinders. this only happens on cruising, decel, AND long idling, but on acceleration all 8 cylinders are firing. As for the sound, YES there is a really annoying sound when the afm is cutting off the 4 cylinders WHILE you have a loud exhaust, the exhaust sounds like a big 4 banger with a bad wrist pin. that is the best way for me to describe it. FYI almost all of the gen 4 engines have the afm bossed engines even if the car/truck does not have the afm feature, they just do not have the 1/8" holes drilled into them and instead of having a LOMA they just have the standard flat valley cover from Gen 3 engines. and YES afm can be permanently disabled, through computer mods, or block off the LOMA oil feed holes, I recommend that you just do it through the computer, because when you block off the holes, you will still have to reflash the PCM/VCM for new spark and fuel maps

[TheMadHatter99]

I'm not sure if this has been answered before (I usually skip most of the engine threads) but this has been bugging me since the info was revealed.

Is there a reason we can't get the SS manual tranny with AFM? Is it because AFM isn't compatible with a stick or is it because the LS3 can't take that technology for some reason?

I'm curious because I was really hoping to get a V8 stick that got at least 25mpg's, if not more. I know the final numbers aren't out yet and I plan on waiting a year or so anyways so I'll be able to see what everyone is getting in the real world, but I was just curious why the AFM tech wasn't making it onto the V8 sticks.

[boxmonkeyracing]

AFM does not work with a manual due to computer not knowing what gear you're going to go in etc. . .

[jmliptak]

Originally Posted by boxmonkeyracing

AFM does not work with a manual due to computer not knowing what gear you're going to go in etc. . .

There is a whole thread out there on this. The L99 is an LS3 with the AFM essentially, if Whiterag is around (he posted earlier in the engine forum) he can likely provide additional details.

[tsg1391]

Originally Posted by AnEvilPenguin

YES there is a really annoying sound when the afm is cutting off the 4 cylinders WHILE you have a loud exhaust, the exhaust sounds like a big 4 banger with a bad wrist pin

that is what i thought, but thanks for clearing up that we can tune it out... i guess i will take mine to a tuner to get it taken out after i get an exhaust put on

[Rob@WretchedMS]

You can tune it out, but seriously, all your going to gain is lost fuel mileage. It turns off in milliseconds, and you won't have any idea when it's actually working other than the MPG goes up.

I can understand the 'old school' thought process that would want it turned off, but i can also give you the opinion of driving a G8, and you can't tell it's on, it's really a good thing.

[gunslinger]

There HAS to be some sort of accellerated wear from the engine firing on only 1/2 the cylinders and creating some "unusual" harmonics for a V8...

[Kyle2k]

Originally Posted by Rob@WretchedMS

You can tune it out, but seriously, all your going to gain is lost fuel mileage. It turns off in milliseconds, and you won't have any idea when it's actually working other than the MPG goes up.

I can understand the 'old school' thought process that would want it turned off, but i can also give you the opinion of driving a G8, and you can't tell it's on, it's really a good thing.

I don't think it is a old fashion issue...it's the desire in the future to tune it for max performance and the likely-hood of encountering problems while doing so. Removing it for the hell of it or the sound is stupid.

[AnEvilPenguin]

Originally Posted by gunslinger

There HAS to be some sort of accellerated wear from the engine firing on only 1/2 the cylinders and creating some "unusual" harmonics for a V8...

the engine is still balanced, it seems like people are not really understanding the DOD/AFM, it does not just shut off 1/2 the engine, it shuts off 2 out side cylinders on one bank, and the 2 inside cylinders on the other bank, making the engine fire,miss,fire,miss,fire,miss,fire,miss, and repeat.... no odd vibrations are created because a smooth firing pattern is kept, now, if it was fire,fire,miss,fire,miss,miss,fire,miss, and repeat... That would be a completly different story