How much duration does 1.6 Rockers add?

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.

What’s the difference between 1.5 and 1.6 rocker?

1.5 rockers lift the valve 1.5 times the lobe lift of the cam, 1.6 lift the valve 1.6 times lobe lift. Generally, 1.6 rockers are used to improve the lift of a camshaft that has low lift. They can also be used to get the valve lift into a specific head flow range.

How much HP does rocker arms add?

For engine applications that demand a step up, replacing the stock stamped or cast steel rockers with aluminum roller rockers will typically produce a gain of 10 to 15 hp with the same lift ratio, and even more of a power gain with a higher lift ratio.

How do you calculate the cam lift on a 1.6 rockers?

of valve lift with a 1.6 rocker ratio. Valve Lift = 0.270 x 1.6 = 0.432 in. Example #2: A camshaft with 0.468 in. of valve lift with a 1.5 rocker ratio has 0.312 in.

What size rocker arms do I need?

The ratio of a rocker arm refers to the amount of movement on the valve side of the rocker arm in comparison to the pushrod side. A 1.5:1 rocker arm will move a valve 1.5 times the lift of the cam, assuming all things are in proper working order. If your cam has a lift of . 4 inches, multiply by 1.5 to get .

How can you tell the difference between 1.5 and 1.6 rocker arms?

What is cam duration?

Camshaft Duration is the measurement of the time one valve begins to open until it finishes closing. Duration is measured in degrees of crankshaft rotation, not camshaft rotation.

What is considered a long duration cam?

A 280-degree-duration cam holds the valves open longer than a 260-degree-duration cam. Holding the valves open longer allows more air and fuel into the engine and also allows more to get out through the exhaust. Longer duration (higher number) improves top-end power but almost always sacrifices low-end torque.

How is cam length measured?

How is it measured?
  1. Using a Dial Indicator and Degree Wheel, find the opening and closing points of the valves at 0.050 in. of lift. If the intake valve opens AFTER TDC, use a negative value. If the exhaust valve closes BEFORE TDC, use a negative value.
  2. Add the numbers together.
  3. Add 180° to find duration.

How do I choose cam duration?

What Is a Stage 2 cam?

Tuner Series Stage 2 Camshafts are designed to optimize horsepower and torque on engines featuring free-flowing intake and exhaust tracts, increased compression, and upgraded valvetrain.

What makes a cam choppy?

LSA (lobe separation angle) determines the choppiness, it has to do with the overlap of when both valves are open, as in when the exhaust valve is closing and the intake valve is opening to pull fresh fuel in on the intake stroke after pushing out the burnt fuel. Most GM cams come on a 112, 114 or 116 LSA.

How does cam duration affect torque?

Duration has a marked affect on the cams power band and drivability. Higher durations increase the top-end at the expense of the low end. As a general rule, cams with 220-235 degrees of duration tend to produce good low end torque.

What is the difference between a Stage 1 and Stage 2 camshaft?

Most Stage 1 type modifications are typically in the +10-15% power increase over stock. Stage 2: this is typically referred to an engine with a performance cam upgrade as well as the other components within a Stage 1 combination. A typical Stage 2 has generally +20-25% more HP than stock.

What is considered a mild cam?

An RV or towing camshaft, which is considered a mild performance or an economy cam, will often have a narrower LSA, between 112 and 114 degrees. Hot street camshafts usually have 110- to 112-degree LSA, while high performance and racing camshafts will often run between 105 and 108 degrees.

Does cam duration affect idle?

Again, keeping all else constant, more duration will make the engine less efficient at low rpm, with more overlap dilution of the induction charge, and the later intake valve closing reducing the trapping efficiency. Therefore, a long-duration cam will cause rough running at idle (lope) and a loss of low-rpm torque.

Can a cam increase torque?

Fortunately, choosing the right aftermarket performance camshaft for your particular combination will deliver big rewards. Increased power, increased torque, increased rpm potential and a broader powerband are just a few of the benefits that could result from choosing the right cam.

Do camshafts increase rpm?

Generally, cams with smaller duration numbers make peak horsepower at lower rpm. These cams are often used for stock replacement, daily driver, and towing applications. As you increase the duration, you increase the peak power the engine can make. However, you also move the power curve higher in the rpm range.

Why do cammed cars lope?

Lope is a result of the intake and exhaust valves both being open at the same time. This is called overlap. Mild cams have little or no overlap at any valve opening that makes a difference. Hotter aftermarket type cams have a lot because it aids high RPM breathing.

Why do performance engines lope?

the lope comes from what is effectively(in engine combustion terms) an overlap between one cylinder opening and another closing. These cams are designed to maximize the engine combustion cycle at very high RPMS with VERY large and Very Dense fuel air mixtures.

Why do high performance engines lope?

A compression leak may come from a cylinder head gasket and cause the engine to lope sometimes. This usually happens because the engine has high mileage, or a particular failure, like overheating, caused the gasket to blow. To check for a leaking head gasket, do a cylinder compression test using a vacuum gauge.

Does camming a car make it faster?

Does Camming A Truck Make It Faster? In most cases, yes, but it depends on the model of the truck and which custom cam you use. With that said, aftermarket cams are designed for high-end performance, so you can typically expect to experience faster speeds after camming a truck.