Smallest Comp cam VVT cam clearance for L99.

[Royal Tiger]

Wait until the new Silverado motors go to crap with 1-7 cylinder deactivation.

So back to my question, is for example a BTR Stage 2 cam, needing new springs every 25k miles as opposed to a Stage 3?

[Moto-Mojo]

I’m not disputing this because it seems the OP has done the homework but makes this statement; “From my research, you cant just shut off AFM and ride with the stock cam and stock AFM lifters. Its best, in a reliability standpoint, to take it all off the engine.”

Since many of us either have a Range Device or tune AFM out, are you suggesting this has some sort of damaging effect on the valvetrain? Or are you just saying that over time, with AFM ALWAYS off, there is a reliability issue? What about someone who ALWAYS uses the paddles? Did GM not account for a paddle shifting owner? Hell, I always figured the back and forth of on and off did more harm than one or the other.

[Tran2la]

I will share this info. This is what I received from Gwatney Performance Innovations.
Its the lobes specifications of the L99 STOCK Camshaft. I requested this info since they were going to use the Non AFM lobes for the new camshaft I was having custom made.

Its funny how GM advertised LSA as being 115 degrees and GPI states that the LSA is different not only from what GM stated but also between the AFM and NON AFM lobes.
Still waiting for the custom grind Stock cam.

AFM lobes



NON AFM Lobes



I will see what the end result would be once I get the cam card that is supposed to come with the new cam.

[qcman]

Originally Posted by Moto-Mojo

I’m not disputing this because it seems the OP has done the homework but makes this statement; “From my research, you cant just shut off AFM and ride with the stock cam and stock AFM lifters. Its best, in a reliability standpoint, to take it all off the engine.”

Since many of us either have a Range Device or tune AFM out, are you suggesting this has some sort of damaging effect on the valvetrain? Or are you just saying that over time, with AFM ALWAYS off, there is a reliability issue? What about someone who ALWAYS uses the paddles? Did GM not account for a paddle shifting owner? Hell, I always figured the back and forth of on and off did more harm than one or the other.

I've read here its better they are tuned out than not. The lifters don't collapse in that situation & the engaging and disengaging puts some wear on the Cam lobes I believe. Jertm who is a GM mechanic commented to that effect I can't recall exactly what he said. in other words nothing bad about disabling AFM in a tune or with a Range.

[KTMracing09]

Aside from more wear engaging and disengaging. I felt I got better gas mileage with afm tuned out than I did with it constantly kicking on and off.

[qcman]

Originally Posted by KTMracing09

Aside from more wear engaging and disengaging. I felt I got better gas mileage with afm tuned out than I did with it constantly kicking on and off.

For sure especially in the city where I drive 90% of the time with this car. The in and out was brutal on gas around town it was constantly switching. AFM was a bit better on the highway than after tuning out but its pretty minimal and I don't drive in that situation enough to matter anyways. Its a curse of a "feature".

[Moto-Mojo]

What a gawd-awful invention to feign better gas mileage to some gov't committee. We chase the silliest crap in this country all in the name of some useless, feel-good notion promoted by lobbyists with grant money. But don't get me started!

[Tran2la]

Camshaft is in. Heres the results. A bit more than stock.

Duration 200/209 Lift .528/.528 115+7 LSA

[WoodBoss]

How do you like it? So for this do you just change the lifters and leave the valve springs stock?

[Tran2la]

It will be a while before I will be able to "feel" it. But as for other questions...
Yes just changing lifters to LS7 and springs stay the same. Also cam phasing is not altered. Full phasing of the cam can happen.

[pir4te]

Another way to retain full movement authority / longer duration / greater overlap is to swap the 52° full advance on park phaser for the 46° full retard on park, and grind using the pre-2009 VVT core.
Softer cranking, more dynamic compression, a win overall given you are going to be retuning anyways.
I previously had 26.2° authority using a 224/230 115+4 .555 AFM cam (.500 on 1.7)
Thing is to reduce pumping losses or tip the combustion phasing to more expansion than compression (Atkinson) you don’t need anywhere near that authority.
The way I use 46° authority is managing dynamic compression, scaling from 8 for startup, high RPM and low octane; to 10.8 at idle, high load and ethanol. My static CR is 14:1.

[crank383]

I'm planning on installing the Texas speed AFM VVT cam in my L99 SS 2014. The cam is the AFM 2. The lift is only .500/.501 with duration at mid .220's. my question is will I need to run a phaser limiter with this stock lift cam with some higher duration????