Why does the L99 get special treatment?

[topgun1]

I've been trying to understand Chevy's reason for making 2 versions of the 6.2liter V-8 engine. Why does the L99 get 1) Active Fuel Management, 2) variable valve timing, and 3) a transmission that you can "optimize" the shift points.

The fuel economy is only 1 mpg better for the L-99 versus the LS3, so what is the big deal with the AFM and why doesn't the LS3 have it. The detuned, but supposedly faster L-99, doesn't really make much sense. In Chevy's history, there was the same engine, whether it was auto or manual, like the LT1 or LS1, etc.

There is launch control on the 422-hp 6speed manual, but evidently (in preliminary testing) is still 0.3 seconds slower than the 400 hp auto, which doesn't make alot of sense to me.

My beef is that if they are going to have these power-enhancing and fuel-saving technologies on one engine, they should have it on the other, or just offer one engine, with an auto or manual. The competition should be focused on rival cars, not battles for what engine is faster in the same car!, but that's just my two cents worth.

what are your opinions?

[shank0668]

Originally Posted by topgun1

I've been trying to understand Chevy's reason for making 2 versions of the 6.2liter V-8 engine. Why does the L99 get 1) Active Fuel Management, 2) variable valve timing, and 3) a transmission that you can "optimize" the shift points.

The fuel economy is only 1 mpg better for the L-99 versus the LS3, so what is the big deal with the AFM and why doesn't the LS3 have it. The detuned, but supposedly faster L-99, doesn't really make much sense. In Chevy's history, there was the same engine, whether it was auto or manual, like the LT1 or LS1, etc.

There is launch control on the 422-hp 6speed manual, but evidently (in preliminary testing) is still 0.3 seconds slower than the 400 hp auto, which doesn't make alot of sense to me.

My beef is that if they are going to have these power-enhancing and fuel-saving technologies on one engine, they should have it on the other, or just offer one engine, with an auto or manual. The competition should be focused on rival cars, not battles for what engine is faster in the same car!, but that's just my two cents worth.

what are your opinions?

all the o-60 1/4 mile i would bet is bs

[topgun1]

yeah, i'm with you on that--i'm waiting for some real track testing numbers.

[camaro&T/A]

The reason they used 2 different engines is because AFM doesn't work wth the manual. the reason it's less powerful isn't because of the automatic tranny, it's because of the AFM. it's probably quicker becuase a computer can shift faster than a person (quicker reaction time) why they bothered with it for 1mpg idk...

[boxmonkeyracing]

Originally Posted by camaro&T/A

why they bothered with it for 1mpg idk...

for the first time in the camaro the auto is actually getting better mpg then the manual. a manual z28 ls1 could get upwards of 28 mpg highway where as the auto got 25. AFM is the shiznit and made up for the 6th gear the manual had. but now they both have 6 gears. . .and AFM is supposedly good for only 3%.

[The_Blur]

Originally Posted by camaro&T/A

The reason they used 2 different engines is because AFM doesn't work wth the manual. the reason it's less powerful isn't because of the automatic tranny, it's because of the AFM. it's probably quicker becuase a computer can shift faster than a person (quicker reaction time) why they bothered with it for 1mpg idk...

GM promised AFM and VVT, and they delivered. I'm guessing they tried to put these features in the manual, but the LS3 is just not capable of it without serious modification. I'm fairly certain that someone posted that the manual cannot use AFM at all, but I can't remember the justification for this. The fuel efficiency is a first because it means that the auto will be more fuel efficient than the manual, as boxmonkeyracing stated.

[ralniv]

A slight correction to your gripe... you can't optimize the shift pts on the L99 (at least not without adding mods). GM optimized the shift pts on the L99.

Why did they do it? Probably wanted to showcase some advanced technology and give the appearance of going green. The LS3 didn't get it because GM's AFM doesn't work with manual trannies. I don't know why it doesn't work with manuals. I would expect the Gen V engine with a manual transmission will get some technological love.

I'm glad to see GM squeeze better performance from an automatic transmission. The auto drivers have always been shafted on performance and fuel economy. The role reversal is refreshing; especially since I drive an automatic due to an abundance of city driving.

[headpunter]

they actually are the same architecture and use the same block, heads and pistons/crank. the diffrence is the ls3 block doesnt have the bosses drilled for the afm equipment that goes under the knocksensor plate. so you re getting the same engine just less hp in exhange for the afm equipment.

[MajorTom]

The auto version is probably mostly for the image of going green. And I think that when we see real 1/4 mile times we'll see the truth about performance. And I bet there's not much of a difference with a good driver in both cars.

The fact that the Automatic is supposed to be a tad faster has no effect on which transmission I want in my Camaro.

[Mblock66]

People need to quit assuming that Auto is "faster".

Some bogus numbers were released and I can't believe people embrased them. The car in production trim hasn't even been released to anyone to test yet. Even with shifts optimized a lighter car with launch control and more power is going to win with a very good driver. Don't forget that GM has put no lift shift technology into its cars now. Like in the Cobalt SS.

You no longer have to lift off the gas when shifting. So there is no loss of RPM and with a clean shift there is now no advantage for the auto.

People said the same thing about the vettes with this tranny. Now the LS3 Manual is running 11.7's and the Autos are still running 12.2's

[greenrail]

Originally Posted by camaro&T/A

The reason they used 2 different engines is because AFM doesn't work wth the manual. the reason it's less powerful isn't because of the automatic tranny, it's because of the AFM. it's probably quicker becuase a computer can shift faster than a person (quicker reaction time) why they bothered with it for 1mpg idk...

The reason they botherd is because of CAFE Standards. Everywhere any manufacturer can produce improvements (no matter how small it may appear to us as enthusiasts) is a gain for the overall fleet averages sold in a given year.

That really shouldn't be an issue. I much like others here, would wait to see what verified track tests show.

[Angrybird 12]

Has anyone mentioned the possibility that the AFM is only on the Automatic because the Valvetrain isn't as strong as the normal Valvetrain and if it was on the Manual and you missed a Shift or downshifted too soon you could over rev the engine and destroy the valvetrain...Most Automatics will not downshift untill the rpms are in a safe range. also may be why the AFM has less horsepower.

[CamaroSpike23]

Originally Posted by topgun1

I've been trying to understand Chevy's reason for making 2 versions of the 6.2liter V-8 engine. Why does the L99 get 1) Active Fuel Management, 2) variable valve timing, and 3) a transmission that you can "optimize" the shift points.

The fuel economy is only 1 mpg better for the L-99 versus the LS3, so what is the big deal with the AFM and why doesn't the LS3 have it. The detuned, but supposedly faster L-99, doesn't really make much sense. In Chevy's history, there was the same engine, whether it was auto or manual, like the LT1 or LS1, etc.

There is launch control on the 422-hp 6speed manual, but evidently (in preliminary testing) is still 0.3 seconds slower than the 400 hp auto, which doesn't make alot of sense to me.

My beef is that if they are going to have these power-enhancing and fuel-saving technologies on one engine, they should have it on the other, or just offer one engine, with an auto or manual. The competition should be focused on rival cars, not battles for what engine is faster in the same car!, but that's just my two cents worth.

what are your opinions?

the L99 is an LS3 with AFM.
AFM does not work with a manual (tho we've discussed possiblities for that elsewhere)
History is changing, CAFE restrictions are adding to the pressure auto makers have already.
some people want their cake and eat it too, AFM gives you that. nice strong off the line, 400 hp, 4 cyl running when cruising. GM wants to sell as many of these cars as possible. offering a powerful engine that has the capability to save on the mpg's is what some people want. not everyone who buys this car is going to hot rod the hell out of it.

and your beef is correct, to an extent. they aren't battling it out between the two cars to see which one is the best between them, they are getting baseline numbers to throw to the masses (and the competitors' faces) almost every car that has come out has been tested in the auto and manual trim, not to fight against itself, but to get the numbers for both auto and manual

Originally Posted by shank0668

all the o-60 1/4 mile i would bet is bs

why, cus an auto has to be slower than a manual? cus the manual has to have better fuel economy?

or is it cus the auto is now a 6speed as well, and can therefore have a larger array of gear ratios.... speaking of which, auto's 1st gear is like ~4:1 where the manual is ~3:1. freakin crazy. which leads to the auto being able to get out of the hole a lot faster/easier with less power.

Originally Posted by Mblock66

People need to quit assuming that Auto is "faster".

Some bogus numbers were released and I can't believe people embrased them. The car in production trim hasn't even been released to anyone to test yet. Even with shifts optimized a lighter car with launch control and more power is going to win with a very good driver. Don't forget that GM has put no lift shift technology into its cars now. Like in the Cobalt SS.

You no longer have to lift off the gas when shifting. So there is no loss of RPM and with a clean shift there is now no advantage for the auto.

People said the same thing about the vettes with this tranny. Now the LS3 Manual is running 11.7's and the Autos are still running 12.2's

wow... you need to quit assuming the Manual is "faster"


i can show you plenty of cars with less than 350 hp that are faster than 500hp cars. hell, the bolt-on record for LT1s is 11.9 for the manual and.....wait for it.....11.6 for the auto. both motors pushing 346 hp.

and the manual driver is one hell of a driver too.

Originally Posted by Skyman 08

Has anyone mentioned the possibility that the AFM is only on the Automatic because the Valvetrain isn't as strong as the normal Valvetrain and if it was on the Manual and you missed a Shift or downshifted too soon you could over rev the engine and destroy the valvetrain...Most Automatics will not downshift untill the rpms are in a safe range. also may be why the AFM has less horsepower.

thats a possiblity, the main reason is that you get a slight "jerk" from the motor when it shuts down or starts up those 4 cyls. with an auto, the torque converter/tranny fluid takes that and you dont feel it, whereas with the manual, it would be a lot stronger of a jolt

[SoFlaZ]

It just came to me, the L99 is a L92 from an Escalade with a LS3 intake manifold instead of a vortec mani and probably a different cam for low end torque reasons in a large SUV. It's not so much that its special treatment, thats just how the motor comes I guess. Though idk how hard it would be to outfit the LS3 at least with VVT.