AFM Tuned Out, Gas Mileage?

[kd4hey]

To those with an L99 & that have had the AFM tuned out. How bad has this affected your gas mileage?

I have had my 2SS L99 for 2 1/2 weeks & am considering CAI, Headers & exhaust mods, but after reading about all the AFM drone issues am really considering the AFM delete.

Currently with 2200 miles on the car I am averaging 20MPG (combined). So how far can I expect that to drop?

2nd question, Is there anyway to set-up the AFM Tune-out to activate it at will (select AFM On or Off while driving)? It would be good to have it available for long trips, etc.

Thanks!

[brantley847]

I just bought a borla S type and I am waiting to see how the AFM really affects it before I make that jump...

However, almost EVERYONE I have talked to on here..actually said they had a MPG increase after tuning out. I don't know how that is possible, but my guess is most of them have mods like headers, CAI, tune, exhaust and are getting their improved MPGs from those products. The tune I am sure gives back what you lose honestly...

[ravensjeff]

Originally Posted by brantley847

I just bought a borla S type and I am waiting to see how the AFM really affects it before I make that jump...

However, almost EVERYONE I have talked to on here..actually said they had a MPG increase after tuning out. I don't know how that is possible, but my guess is most of them have mods like headers, CAI, tune, exhaust and are getting their improved MPGs from those products. The tune I am sure gives back what you lose honestly...

I'd say you are correct about all of this.

As far as I know, you can not have an on/off switch for this function. But never say never. AFM is a bonus if you do alot of long distance/highway driving. Otherwise, it doesn't activate.

[brantley847]

Originally Posted by ravensjeff

I'd say you are correct about all of this.

As far as I know, you can not have an on/off switch for this function. But never say never. AFM is a bonus if you do alot of long distance/highway driving. Otherwise, it doesn't activate.

Yes and no...

There is no option to turn AFM on or off at will...(at least it has not been created yet..lol)

AFM turns on ALL THE TIME. It is almost annoying...i was under the impression it was highway driving only. Apparently this is not the case and has a mind of its own. You could be cruising at 40-50 mph on a smaller state road and it comes on. If anyone intends to keep their stock system (which is a great system if you prefer the quieter hum) because it runs quiet and smooth on the interstate. However, I don't interstate drive very often so I wanted some gurgle...this is when anyone who has purchased aftermarket realizes AFM turns on anywhere at anytime as long as the RPM levels present itself. However, you can avoid this by utilizing the paddle shifters and keeping the RPM out of that range where the AFM kicks on...personally, my music is loud as hell at most given times so I avoid noticing drone...we will see how the Borla does for me with AFM in the next few months

[Bewenched]

Well, I've got Pacesetter long tube headers, SLP Catback, Diablosport Trinity programmer, CAI and as long as I'm not romping on it my gas mileage hasnt changed much, Now it's very hard not to play

[HeavyD]

I think someone said with a diablo tuner you can set AFM to only come on when in certain gears. They had it programmed to only come on in 5 and 6th, so the sound was ok most of the time.

[WeeZee]

Im sorry to be a dick but who cares about miles per gallon, you bought a SS camaro not a ford Fiesta. When the tank is empty fill it, you obviously have a good job to have an SS camaro ($35k+) so just do the mods and don't look back !!!

[Darth_Emma]

Originally Posted by kd4hey

To those with an L99 & that have had the AFM tuned out. How bad has this affected your gas mileage?

I have had my 2SS L99 for 2 1/2 weeks & am considering CAI, Headers & exhaust mods, but after reading about all the AFM drone issues am really considering the AFM delete.

Currently with 2200 miles on the car I am averaging 20MPG (combined). So how far can I expect that to drop?

2nd question, Is there anyway to set-up the AFM Tune-out to activate it at will (select AFM On or Off while driving)? It would be good to have it available for long trips, etc.

Thanks!

I have headers, cai, full exhaust, and a tune. (I also added a supercharger this week, but I haven't gotten it back from the shop yet, so I can't comment on that).

When the headers went on and I got the first tune, I had AFM tuned out and my fuel economy improved because of the tune. The car runs much more efficiently with a good tune. Your car will have more power at the same rpms so it will use less gas.

A tuner can program you car so that when you're in D the car behaves one way, for example you might want it to be similar to how it drives when stock. I think they should be able to leave AFM on when in D.

Then they can create a different tune for M mode (a more sport tune for example) and turn AFM off when in M. You'd need to ask your tuner for sure, but I don't see why not.

IMHO, just turn off AFM! I think it is just a gimmick by GM to get past the gas guzzler tax and actually does very little if anything to improve overall fuel economy.

The biggest factor that will affect your fuel economy is the weight of your right foot on that long pedal on the right.

[jtzako]

I'd love to tune out AFM but I'm not willing to risk warranty issues right now. Considering that when I'm driving, even when maintaining speed I can hear/feel the AFM kick on and off constantly as I roll down the road I dont see how it is saving enough fuel to even account for 1 mpg.

[mlee]

Originally Posted by HeavyD

I think someone said with a diablo tuner you can set AFM to only come on when in certain gears. They had it programmed to only come on in 5 and 6th, so the sound was ok most of the time.

That was probably me... but I did it with EFI Live, in fact that's how I'm set up now. I did have a Diablo too and could turn it all on or all off.

I did plenty of tests on and off and you DO lose ~3mpg in mixed driving. Since most people turn off AFM at the same time they are tuning it's basically a wash. The tune alone will get you some nice MPG gains and you lose it back by turning off AFM.

[2010 Bumblebee]

Originally Posted by HeavyD

I think someone said with a diablo tuner you can set AFM to only come on when in certain gears. They had it programmed to only come on in 5 and 6th, so the sound was ok most of the time.

First let me say, I'm not a tuner. However, I looked at the tune thru efi live and you can set the MIN and MAX RPMs in which AMF will operate for every single gear. The tune I'm looking at it is operational between 675 RPMs and 3000 RPMs. It can also be further tweaked by the vacuum settings for the AFM within that same RPM range listed above. You can also just completely turn it on and off.

The vacuum tables look more slightly more complicated to me because they are numbers I can't relate to, but the RPMs are easy be understood.

So if you wanted to keep your AFM you could just tune out the areas that bother you like say at a certain RPM in a certain gear or the more complicated way at a certain vacuum at a certain RPM at a certain gear.

You could also change the range of the whole thing to say between 675-1500 RPMs or 675-1100 RPMs and still keep it. That way it would only activate mostly when you are off the throttle.

AMF used to bug me, but it doesn't anymore. When it did it was usually on a back road around 30-35 MPH. So if I figured out what gear I was in and what RPMs I could just lower the RPM factor for that gear..

[mlee]

I looked through the RPM ranges and just decided doing it gear by gear was best. RPMs are set at a good range anyway.

5th and 6th gear has worked well and I don't even notice AFM anymore. Like you said... 30-35 mph or slow speeds is where it is annoying to turning if off in the low gears works great.

[383ss]

I tuned mine to only come on in 5th and 6th gear and made it more agressive. I get 4mpg more on the highway vs it off and its not annoying or noticeable. anyone who says they gain by turning it off is full of it.

[Number 3]

FYI the exhaust drone is made much worse with the aftermarket exhaust. The stock exhaust on the L99 has several flex couplings that are specially engineered to isolate the exhaust from the body when the 4 cylinderodes are present. The after market systems don't have these so you feel and hear much more.

I understand that late 2010 cars had an enhancement to the flex couplings to improve NVH