L99 Delete Whats involved?

[pharmd]

Originally Posted by MerF

Why? How does it affect your driving experience exactly?

Its the reason the car will be slower than the LS3...its also a weak link in longevity and performance (we suppose). The AFM lifter design is a weaker design that necessitates lower lift cams for safety. You cannot go as big with an aftermarket cam with these lifters installed. Most shops will tell you that if your serious about performance to install the AFM delete kit.

Bottom line: If your concerned about MPG and don't plan on doing very many mods, and 12.9 @ 109 is FAST to you, leave the AFM alone.

If you plan on installing mods in an effort to run below 11.50, and don't really care about giving up 2-3 MPG, remove it and don't look back.

[MerF]

But the post above says just disable it...which implies they are saying that the program of AFM is what is lowering the performance.

I know what you are saying is true, I was basically drawing out a bad response so I could point and snicker. Thanks for ruining my fun.

[King Mouse]

Originally Posted by MerF

Why? How does it affect your driving experience exactly?

There is a vibration when it kicks down to 4 cylinders. It also makes the tranny seem like it is shifting too much when in reality the afm is kicking in and out.

It does make sense that the lifters would be weaker.

I will say over and over again. I do love my car. This is just something I could do without. I am also trying to learn as much about it as I can.

[MerF]

Originally Posted by King Mouse

There is a vibration when it kicks down to 4 cylinders. It also makes the tranny seem like it is shifting too much when in reality the afm is kicking in and out.

Ah, so there is a discernible difference. I had not heard of much negative feedback of the AFM activating, is this a widely accepted consensus among all of the L99 owners?

[King Mouse]

I'm not sure if it bothers anybody else. I'm kind of waiting to see the opinions of other forum members.

[Number 3]

Well, first, let me assure you that AFM won't be a durbility issue. It is on many of the V8s in the Full Size Truck line up and they are tested for more severe conditions for loading and trailering. Don't be worried about durability.

AFM will give you better fuel economy. Hard to say how much, but should be at least 1 or more. GM did not want this car to have a guzzler penalty so unlike the G8 GXP, you have an AFM motor with the automatic.

The L99 does not have reduced HP during anything close to performance driving. AFM kicks in under light throttle low load conditions. Unlike the trucks, you can actually get in to AFM mode cruising on the highway for long stretches. The trucks have so much aero drag that they will often stay in V8 mode.

The only real drawback I can see is that in AFM mode the engine is running on 4 cylinders. Many of you won't notice it. I am sensitive to it and I can pick it up most of the time. Is it objectionable? To some it may be. To me, well I'd get the LS3 manual.

It isn't invisible, but it isn't obtrusive either. You'll just have to make your own determination.

And I don't know the answer to this, but I'd make damn sure messing with the calibrations didn't void your warranty. Just sayin'..............

[PatrickfromMD]

Originally Posted by mike@newera

George pretty much covered everything that needs to be changed to get rid of the AFM in the L99, assumming that it will be exactly the same as it is in the G8. We currently sell cam packages that delete everything and come with a cam and upgraded valvetrain components as well for the G8, see the upcoming September issue of GM High Tech Performance magazine as one of our custom kits gets tested in a G8GT.
The VVT is going to have an advantage over the engine without it, once the modding starts in my opinion, you can put a pretty big cam in it and by adjusting the cam timing, gain 30-50 lbs of torque down low and make it peaky up top making the lower end of the rpm band pretty much respond like it has a different cam in it. That is why I ordered an automatic, plus we need a test car of course to develop camshaft profiles for this VVT function.

Mike

Mike,

I’m interested to know more about the VVT offerings you will have available in the future. I believe we share the same opinion to leverage the advantages of the L99 motor and lessen the disadvantages.
I have a couple questions you might be able to help with. I read the L99 has relieved pistons that reswulte4d in a 10.4/1 cr vs. 10.7 for the L99. This was done to allow more piston to valve clearance when the cam phases is advancing and retarding the cam. How do you get more cam profile into an engine that already has tight piston to valve clearances? Do you limit the amount of degrees the phaser can dial in? Do these cam options necessitate to removal of the AFM lifters?
I understand the lifters are the primary reason for the lower 6200 rpm redline. A more aggressive cam (maybe we are just talking lift and not duration) may add additional stresses to the AFM lifters. Do you have a lesser profile allowing one to retain the AFM?
I have read in some of the G8 forum’s that some car owners have tweaked the AFM to kick in earlier and have seen noticeable mpg benefits.
I’m shooting for the best of both worlds, broader torque curve than the LS3, better mileage than the LS3 and more peak HP than the LS3 (at least until 6200 rpms that is)
I still have not ruled out a supercharger, hopefully the mods you may be carrying will be compatible with that as well.

[kanakattack]

I owned a 300C that also had AFM, although it was called something else, really did not have an issue with it. In stock form I really couldnʻt tell when the AFM went on. and it did not affect the cars performance. I put a aftermarket Borla cat back and it magnified the AFM "drone", I would really caution anyone that is planning to do any exhaust mods to wait and see if there is a system that would address this, there were some that did come out later that took care of the dreaded drone. I still am amazed that people donʻt look at the positives of the auto performance, really think about it, itʻs 70 lbs heavier, but is still quicker to 60, itʻs 26 hp less, but is only a tick or two behind the manual. If everything was equal I think the L99 would really outperform the LS3.

[NickPic]

a tune will solve ur the AFM problem and gain some extra ponies as well as better mpg. tune is a WIN every which way

[PatrickfromMD]

Originally Posted by quickdraw

I don't eve know about that because the auto has taller gearing.

Actually it appears the Manual has taller gearing when your multiply the transmission ratios to the final drive ratio.

[bballr4567]

There are G8 guys that are tuning the actual AFM perimeters and getting far better MPG. I think one guy was almost at 27 MPG. With the GM tune the AFM kicks off with a little bit of throttle.

Now, in a smaller car I can bet that the Camaro should be able to get very close to 30 with the right tuning to the AFM.

[THE EVIL TW1N]

Originally Posted by bballr4567

There are G8 guys that are tuning the actual AFM perimeters and getting far better MPG. I think one guy was almost at 27 MPG. With the GM tune the AFM kicks off with a little bit of throttle.

Now, in a smaller car I can bet that the Camaro should be able to get very close to 30 with the right tuning to the AFM.

They weigh practically the same. And the G8 looks to be more aerodynamic.

[bballr4567]

Originally Posted by THE EVIL TW1N

They weigh practically the same. And the G8 looks to be more aerodynamic.

Camaro SS: 3850
G8 GT: 3995 (its listed as that but Ive seen as high as 4135)

Camaro CoD: .35
G8 CoD: Couldnt find one

However, the Camaro is already listed at least 1 MPG higher and it is a smaller car. I can see some people getting very high 20s with a simple tune.

[REAPER SS]

Keepem coming. I'm trying to learn as much as possible about the AFM.