That's what I'm thinking as well. With all of the special AFM parts, it would probably be more costly to upgrade the internals of a L99 as well. (cam, RR, etc.) That will be a long debate I'll have with myself about which motor to get. I'm pretty much set on the L99, but will have to see what the aftermarket provides. My current camaro is already faster than either, so which is fastest probably won't be a concern.

 

Perhaps the aftermarket can make extra HP and torque by tweaking the L99's VVT?

 

the L99 doesn't have VVT.

EDIT: it does have VVT.

 

And single cam VVT is pretty worthless anyway.

 

if you are going to upgrade the cam and valvetrain on the l99 engine you will need to eliminate the AFM/DOD by replacing the l99 lifters with LS1,2,3 lifters

the L99 lifters and valvetrain are very limited, that is why the L99 only has a 6000 rpm rev limiter and the LS3 camaro will have a 6600 rpm rev limiter from the factory

 

It may be like the L76 and be limited to 6000 rpm because of the AFM/DOD hardware AND because it has the solid valves vs. the hollow sodium filled valves found on the LS3.

 

I'm wondering who is going to be the first to pull the AFM stuff and step WAY up with a solid roller setup backed by a 4500-5000 stall converter.

 

im building a 415 stroker LS3 to take the place of my L99 camaro engine

 

VVT in 3v ford is mostly for helping pumping losses cruising(cams are retarded) and emissions. no EGR. wide lobe seperation.

programmer only get 7hp by fooling with it on a 345rwhp n/a 4.6 in my car club.

RWTD did the tuning. he added 7 lb-ft throughout the rpm band. i guess it's free power, but not really much.

 

check out the G8 guys with the L76. basically the same engine except its a 6.0 vs. the 6.2 on the L99, other than that, it shoud be a just about identical engine.

 

I haven't decided yet if I will go LS3 or L99 in my '93 but I want the 6 speed auto tranny for sure.

 

Others have suggested bits and pieces of the reasons -- I'll put it all together and confirm:

1. GM doesn't like to put AFM with manual transmissions. There's a shock that goes through the drivetrain when an AFM-enabled V8 switches from 4-cylinder to 8-cylinder mode. With a manual trans, they feel that too much of the NVH from that shock enters the passenger compartment. So, no AFM with a manual.

2. The AFM-enabled version of the LS3 is the L99. The valve opening events on the standard LS3 cam are too agressive for the special lifters used with AFM, so the L99 necessarily has a less agressive cam (and therefore less horsepower). The only other differences I'm aware of are the AFM-specific hardware and related programming changes.

 

if your going to put it in your 93, it would be no question in my mind to go with the LS3. The L99 will probably only get 1 - 2 mpg better than the LS3, with both being auto. The LS3 would have less hassles.

 

1. I don't know of any manufacturer that offers AFM (or whatever they call it) with a stick.

I agree with you on the NVH, especially since (I’ve read that) the deactivation happens on the compression stroke (so it can reactivate on a compression stroke and improve throttle response) and that the ECM will occasionally reactivate each cylinder for a single (2 revolution) cycle to keep that cylinder’s charge ready for sudden acceleration.

2. I’ve read that in the L76 the issue was that the AFM lifters could not collapse far enough to soak up all of the LS2 cam’s lift so the cam profile had to get a haircut for the L76. I suspect that the LS3/L99 had the same issue.

 

Yeah, I don't either. I didn't mean to imply that GM was the only manufacturer that felt this way... but GM is the only manufacturer whose opinion on the matter counts when we're talking about Camaro's engine options.