What was Chevy's reason behind the L99 with automatic?

[CamaroJim56]

read this, then decide on a tune.

http://www.camaro5.com/forums/showthread.php?t=290879

[two_wheel_mayhem]

Shutting off half your injectors when not needed is a fair enough idea I suppose, but makes the other 4 work a little harder. You just killed half your horsepower and well, you are still gonna need the same power to run 55 mph down the highway.

The reason AFM sucks is the valvetrain, specifically the lifters. No matter what name GM has used over the years for this system it has and always will be problematic for some people.

[BlueStreakHouTX]

Originally Posted by JCunningham

im sure theres people on here that only have a range device lets ask them in a poll if they got better mileage.

I am using a Range on my 2012 2SS L99 since just before Christmas 2014... Ive only put about 200 miles on the car since install, so Im not sure if its getting better or worse mileage... jury is still out. But after installation, the car without AFM (and no tune) is a MILLION times more fun to drive.

But, if mileage does get worse, its worth it to me to get rid of AFM. I wont even begin to rant on how bad I hate AFM on this car. Its the one thing about this car (which I love more than anything) that I hate. I drove the car daily, and had to put the trans in S and use the paddles every time to keep AFM from engaging, and I can assure you that did not help my mileage any.

Having said that, Id put up with AFM if it performed as it is supposed to do (get better mileage, instant transition 4cyl to 8, no drone, etc), but it does not do any of those things well. I'll use Range until I tune my car this fall.

[PalmerGA]

Originally Posted by Low Saturn

Too bad it doesn't work the way it'sssupposed to. I get better MPG with AFM turned off.

Same here.

Originally Posted by Number 3

It works the way it's supposed to. It avoids the GG tax. Real world is another story. But just think about what you posted. You are saying you get better mpg when all 8 injectors are pumping fuel than when only 4 of them do.

You are reporting, shall I say, non scientific anecdotal results. So I would agree sometimes under certain conditions you could do better. But if you drove the EPA cycle the way it's driven, nope.

But... the EPA cycle is impossible to achieve in the "real world" of driving. Better in 8 cylinder mode than 4? Yes indeed - it's called "efficiency". The only way 4 are more efficient is when it's sitting on a test rack with no load.
On a 4,000 pound car, up and down interstate hills at 75 mph? No way.

Originally Posted by Number 3

Also not sure how you guys are reporting, "with it turned off". You can't turn it off on the Camaro or FST. On the C7 I believe you can deselect ECO mode.

Ever heard of the Range AFM Deactivation device?

[PalmerGA]

Originally Posted by CamaroJim56

...I find it hard to believe GM put the technology in the car, at an extra cost, for no reason.

Oh they had a reason... if the automatics were hit with the Gas Guzzle tax they would cost nearly $4K more than the M6s. That would kill A6 sales for the Camaro and send people down the road to other dealerships.

[JCunningham]

Also a under powered 4 cyl will get worces milage then a overpowered v8. Just look at a 4cyl s10 4x4blazer.

[PalmerGA]

Originally Posted by fpdsniper

I kept thinking "Wait! How did he get an LS3 in an automatic SS" not realizing he isn't talking about a Camaro...

I do the same. Just shows how moronic it was of GM to name a model "SS". SS has historically been a trim or powertrain option and should have remained that way. Should have called it "Caprice".

[Jsafe17]

Originally Posted by JCunningham

Also a under powered 4 cyl will get worces milage then a overpowered v8. Just look at a 4cyl s10 4x4blazer.

+1 years ago I had Toyota 4x4 truck and it got horrible mpg & it was slow slug.. my tongue in cheek name for it was "SS"

[Jsafe17]

Originally Posted by PalmerGA

I do the same. Just shows how moronic it was of GM to name a model "SS". SS has historically been a trim or powertrain option and should have remained that way. Should have called it "Caprice".

Agreed! Isn't that the name for the law enforcement version of that car? Or are they different?

When did GM start doing AFM? I know Cadillac had a variant of that in the late seventies early eighties.

[Number 3]

Originally Posted by Jsafe17

Agreed! Isn't that the name for the law enforcement version of that car? Or are they different?

When did GM start doing AFM? I know Cadillac had a variant of that in the late seventies early eighties.

Caprice or PPV is the long wheel base. It is the Caprice or Statesman in Australia. The SS is the Commodore and brought here as the SS.

[Jsafe17]

Originally Posted by Number 3

Caprice or PPV is the long wheel base. It is the Caprice or Statesman in Australia. The SS is the Commodore and brought here as the SS.

Actually if its just a short wheelbase variant of that car "SSCaprice" would be a fitting name!?

[two_wheel_mayhem]

Originally Posted by Jsafe17

When did GM start doing AFM? I know Cadillac had a variant of that in the late seventies early eighties.

First version were called "variable displacement" developed during ww2 days

Cadillac was the first GM production attempt in 1981 with their 4-6-8 turd.

[oldfriend]

Originally Posted by i2disturbedSS

Couldn't get the AFM to work well with the LS3-

But did they even try to use the famous Skipshift system on the auto transmition ?
One would think , that it should be possible , just tune that TRANSMITION to shift to whatever if certain parameters are alignd at any given moment
Sounds simple , doesn't ?

[LOBBS]

Originally Posted by Number 3

Sorry, but no. The government reports otherwise.

Also not sure how you guys are reporting, "with it turned off". You can't turn it off on the Camaro or FST. On the C7 I believe you can deselect ECO mode.

Sorry, but yes my fuel mileage is virtually unchanged with AFM disabled with a tune. We made no other changes to the stock tune other than to disable AFM from engaging. The AFM lifter system is now just a liability that I'll have to swap out at some point.