What is the rocker ratio on a Chevy Silverado?
The rockers offered ease of installation (simple bolt-down replacement), a 1.72:1 rocker ratio to slightly increase lift (stock LS was 1.7), and extra strong, CNC-extruded rocker bodies that featured billet trunnions with captured needle bearings.
Are the LS Fulcrum rockers Any good?
The factory LS roller fulcrum rockers are good, but full rollers are even better. Why on earth would anyone want to replace the factory rocker arms on an LS application?
Should you upgrade your LS rockers?
Don’t be, as the factory roller rockers employed on every LS application offer a great many positive qualities, but rest assured, there is additional power to be had with the right rocker upgrade.
How big of a block for LS6 rockers?
Rather than run the test one of the many stock LS applications, we decided to compare the rockers on a more dedicated build up. Starting with an aluminum 5.7L block, we proceeded to stroke and poke the LS6 out to 383c.i.
What ratio are LS3 rocker arms?
1.7 ratioThe GM Performance LS3 Rocker Arms feature a high performance 1.7 ratio with a cast iron housing & fulcrum roller.
Are LS3 rockers offset?
Yes, the intake rockers are offset.
What is factory rocker arm ratio?
The ratio of a rocker arm is determined by the distance between the centerline of the pivot point to the centerline of the roller tip (or area of contact with the valve stem), divided by the centerline of the pushrod to the centerline of the pivot point (X).
How do I choose my rocker arm ratio?
4:128:00Rocker Arm Ratio - Summit Racing Quick Flicks - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo 1.5 times 300 again easy numbers I can almost do it up here 450 for valve lift ok 0.45 0. If IMoreSo 1.5 times 300 again easy numbers I can almost do it up here 450 for valve lift ok 0.45 0. If I change that to a 1 6. I can pick up 30 thousands of additional lifts.
How much duration does 1.6 rockers add?
As rocker ratio is increased, so, too, is valve timing. Note how changing from the stock ratio, which is actually closer to 1.46:1, to a true 1.60:1 will increase your total valve duration by almost 20 degrees! This geometric increase is true for any cam in any engine.
How much lift do 1.6 rockers add?
With a 1.6:1 rocker, this gives us 0.508-inch valve lift at max lift, an increase of 0.031 inch. It doesn't sound like much, yet it was enough to show a sizeable gain, mainly because it increases the amount of time that the valves are open at higher lifts, allowing more air to flow through the heads.
How much HP do roller rockers add?
You can easily gain 20 horsepower with a rocker arm swap, but installing them isn't quite as simple as removing the stock rockers and bolting on new ones. For seasoned car guys, it's a quick process, but if you're new to the task of setting valve lash you might want to take some notes before you tackle the project.
What do higher ratio rockers do?
A high-ratio rocker arm increases valve lift at every point. It boosts gross valve lift by several hundredths of an inch, but it can make a camshaft seem a few degrees larger as well.
What does 1.5 mean on rocker arms?
One of the most popular ratios is 1.5, and what exactly does that mean? It means the rocker arm will open the valve 1 and a ½ times the amount the cam moves the lifter and the push rod, or what cam manufacturers refer to as cam or lobe lift.
Are roller rockers better than stock?
Besides the potential power benefits of an increase in rocker ratio, roller rockers have several additional power-adding advantages compared with a stamped rocker. The advertised ratio of aftermarket roller-tip rockers is more accurate than the claimed ratio of typical stock stamped rockers.
What is the LS3 engine?
The LS3 engine is a Gen IV, 6.2L aluminum-block V8 car engine that first appeared in the 2008 Chevrolet Corvette. The L99—introduced for the 2010 Chevy Camaro SS—is also a Gen IV 6.2L aluminum-block V8, but with the addition of Active Fuel Management and Variable Valve Timing. Below you’ll see references to the L99 as a result.
How much horsepower does a LS3 have?
Both the LS3 and L99 engine blocks can be pushed to 850 to 1,000 horsepower. Both engines use rectangle port cylinder heads and have a common 4.065-inch bore diameter. They also have the internal oil passages for Active Fuel Management (AFM), even if unused.
How much horsepower can a crankshaft handle?
Even though it’s cast, the crankshaft can handle about 900 hp and 7,000 rpm (for a limited time). A broken crankshaft is bad news. Upgrading to a forged crankshaft early in your build will save you the headache later. When you upgrade, a crankshaft with a longer stroke costs about the same and increases displacement.
Why do you port a cylinder head to 0.030?
It is also common to CNC port and/or mill them up to 0.030 inch to increase compression and better airflow. There are many aftermarket cylinder heads available. The heads flow better and have thicker decks to maintain head gasket seal. A wide range of runner and chamber volumes are available.
Do superchargers work with stock gas?
Many supercharger kits are bolt-on and work with stock internals and pump gas. More serious kits are available, but will require internal upgrades. Nitrous kits are also available, inexpensive, and easy to install. Street kits have lower settings that work with stock internals.
Can an aftermarket intake make more power?
The rectangle port intakes flow well, but an aftermarket intake can still make more power. Shorter runner intake manifolds and single-plane intakes make more top-end power, but can lose just as much low-end torque. Make sure the intended power band matches your gear ratio and torque converter.
