I thought I better jump online & tell you guys we're still working very hard on L99 VVT & AFM camshafts.
Here's my quick explanation as to what VVT & AFM do in the L99 engine.
1. VVT allows us to change camshaft timing by grinding the camshaft with a lot of advance in the camshaft & slowly pulling the advance out as rpm increases.
The result is you can get the best of both worlds. Instead of being limited to +4 advance for example, you can run more advance & then slowly pull it out through the entire rpm pull. The result is a healthy power gain in the lower & upper rpm range.
Comparing the exact same camshafts next to each other we typically see about 15hp/tq down low & about 10-12hp/tq in the upper rpm range.
These gains will vary from camshaft to camshaft. As the camshafts get bigger in duration & your piston to valve clearance decreases, you find that you can put less advance in the camshaft. As a result we see less low end power gains from the VVT, but you can still get big power gains in the upper rpm range.
Stock Camshaft with Phaser disabled to full advance:
2. AFM is another item everyone is constantly discussing. The AFM lifters are a very limiting component on the L99 engine. These lifters realistically only want to go about .500" lift before the guys at Comp Cams have started seeing failures. The AFM friendly lifters require considerably less aggressive lobes to live more than just a few thousand miles. As a result we will offer AFM/VVT specific camshafts that will keep your AFM lifters happy & still gain a good bit of power.
By swapping out the AFM lifters and going to a more aggressive lobe we were able to get a solid increase in both hp & torque over the entire pull! These VVT only camshafts will require lifters to replace the AFM lifters currently in half of the cylinders.
We will be offering both VVT/AFM camshafts & camshafts for guys wanting to remove AFM. The removal of AFM will solidly gain 15hp thanks to the more aggressive lobes we can use when the AFM lifters are thrown out.
Graph showing a AFM friendly lobe compared to more aggressive lobes without AFM lifters:
With the removal of AFM we're now up over 100 flywheel horsepower at peak! The cool thing about that is while the L99 engine started approximately 30hp down from the LS3, we're now within 8hp when comparing similar duration camshafts!
Imagine if the L99 had the same compression as a LS3 engine, it would easily make more hp across the board!
If your determined to keep the AFM lifters in your car & still want a camshaft we can offer gains up to approx. 80hp by just sliding in the camshaft kit!!
AFM/VVT Friendly Camshafts:
VVT Camshafts (require AFM Lifter Removal)
We will be offering roughly 3 different afm/vvt camshafts & 3 different VVT specific camshafts designed for stock cylinder heads. These camshafts will be designed with the p/v limits of the stock heads in mind. When our aftermarket casting LS3/L99 heads are complete we will be able to offer additional camshafts with more room for adjusting the VVT!!
I will be putting together packages shortly, but everyone hang tight. We're testing a few more lobe configurations before we settle on what will be used in the productions kits!