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

[two_wheel_mayhem]

Originally Posted by LOBBS

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.

Well of course not. No one is driving the way that they do the EPA testing. It's all political. They let them avoid a gas guzzler tax because GM tried. No one really cares if it works well for the consumer. I average about 15 mpg in my SS, that car is everything the green party hates.

[Jsafe17]

Originally Posted by two_wheel_mayhem

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.

Yeah l remember everyone hated those Caddies back in the day too... sounds like there's nothing new under the sun decades later. Do you know much about why the military designed it? (I assume that is who developed it?) I know we have the military to thank for most FI as well so not all is a bust from uncle sam.

[Chevy_cowboy]

Originally Posted by 2013 ZL1 #7860

L99 also has VVT... Many cams and tunes are now using the VVT to make a broader power curve than the same motor with an "LS3" swap (no VVT). Why do people think the L99 is a downgrade from the LS3? Last time I checked the L99 was quicker...

Having not owned both, I'm in no position to judge which is superior for anyone else, but I sure see a lot of people on this forum asking about disabling or removing Afm/VVT, presumably in an attempt to make their L99 perform more like a LS3. I haven't noticed any LS3 owners asking about adding those systems to their car.

[PalmerGA]

Originally Posted by Chevy_cowboy

Having not owned both, I'm in no position to judge which is superior for anyone else, but I sure see a lot of people on this forum asking about disabling or removing Afm/VVT, presumably in an attempt to make their L99 perform more like a LS3. I haven't noticed any LS3 owners asking about adding those systems to their car.

Performance in the L99 vehicles is awesome, unless... AFM kicks in. In Sport mode with lots of right pedal there's no problem. Or, if you use the paddles. It's the other times, under "normal" driving, that AFM spoils the fun. A tune or a Range device makes it a fun car all the time.
(** And without AFM involved, the L99 "performs" slightly better, in a straight line, than the LS3 - somebody had to say it ).

[2013 ZL1 #7860]

Originally Posted by Chevy_cowboy

but I sure see a lot of people on this forum asking about disabling or removing Afm/VVT, presumably in an attempt to make their L99 perform more like a LS3.

Because people are sheep and will follow whatever "so called experts" say. Even if a few years later it turns out the better option was keeping the VVT...

[Rocky1974]

Originally Posted by 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.

Not to mention all the oil consumption problems that go hand n hand w/AFM. GM Built millions of 5.3's w/AFM for the '07-'13 trucks and SUVs. They've turned into massive oil burners and a massive headache for GM. Every dealership in my area has them lined up for engine rebuilds. And what's really sad, is that unless the AFM is turned off, the rebuilds don't solve the problem. It just gets GM past the 100k mark, so it's no longer their problem. All you people who have it and haven't turned it off, be prepared to buy your oil by the case, down the road.

[maddoggyusa]

the biggest drawback with L99 is no NPP option!!! did they fix this issue with the corvette? can you get NPP with auto?

[Enduring]

Originally Posted by maddoggyusa

the biggest drawback with L99 is no NPP option!!! did they fix this issue with the corvette? can you get NPP with auto?

Yes, because the Corvette had the LS3 with the automatics. Now it has the new LT1 which has the NPP option available and has AFM. The L99 was only in the automatic Camaros.

[BaylorCamaro]

What absolutely baffles my mind is how the GT500 got around the GG Tax and the SS would have been nailed with the GG tax if they used the LS3 on the auto's.

[willhe64]

I gained 2 mpg when I put my tvs2300 on my Camaro. Mostly because I can out around in lower gears now because of the bottom end torque. Superchargers can be very efficient when not hammering the boost.

[lsaterz28]

We have a G8 GT with mods and tuned V/8 full time lost about 1/2 mile MPG
also Have SS/RS vert with mods and tuned V/8 full time lost about 1 mile MPG.
Both cars are now much more fun to drive.

[Jsafe17]

Originally Posted by PalmerGA

(** And without AFM involved, the L99 "performs" slightly better, in a straight line, than the LS3 - somebody had to say it ).

Nah your tranz performs slightly better... driver mod the M6 and LS3 is, well the LS3

[two_wheel_mayhem]

Originally Posted by Jsafe17

Nah your tranz performs slightly better... driver mod the M6 and LS3 is, well the LS3

Autos are always the best for drag racing

[Jsafe17]

Originally Posted by two_wheel_mayhem

Autos are always the best for drag racing

Yep I had a built 4l60 w/yank 3600 in my 99z28 H/C Nos those M6s loose in the 60ft or just bit more and out mph you at the line. But if anyone did a motor swap LS3 vs L99. Which would you all choose.