What is a good lobe separation angle? Some engine specialists refer to it as that 106 sound—the NASCAR and short track oval sound where preferred lobe separation is usually specified between 104 and 106 degrees.
What is a good lobe separation angle?
Some engine specialists refer to it as that 106 sound—the NASCAR and short track oval sound where preferred lobe separation is usually specified between 104 and 106 degrees. The primary function of narrow lobe separation is to impel urgent acceleration off the turns when the throttle is opened.
How do you find the lobe separation angle?
To check your LSA you calculate it by adding the intake and exhaust Lobe Centerline figures together and dividing their sum by two (Ex: 112 intake Centerline + 116 exhaust Centerline = 228 / 2 = 114-degree LOBE SEPARATION ANGLE).
How does lobe separation affect performance?
“On a naturally aspirated engine, the lobe separation angle has an effect on whether the engine reaches peak torque a little earlier or later in the rpm range. Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range.
How does lobe separation affect vacuum?
Narrower LSA: Increase chance of engine knock. Increase cranking compression. Idle vacuum and quality is reduced.
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.
What is lobe centerline angle?
First let us define the lobe centerline angle. In simplest terms it is the angle between the intake and exhaust lobe peaks. The LCA dictates two important valve timing attributes: valve overlap around TDC, and how much intake or exhaust valve closure delay there is past the end of the relevant stroke.
Does engine vacuum increase with RPM?
Restricting the airflow and creating vacuum helps slow the engine down and limit rpm. The vacuum created by the piston pulls air from outside, through the intake, into the cylinder. This allows more air/fuel into the cylinder and rpm increases.
What does putting a bigger cam do?
A bigger cam will open the intake valve wider, allowing more fuel and air into the cylinder. The larger the cam, the more fuel that is let in.
Should I advance my cam?
Not to be confused with ignition timing advance, advancing a camshaft will change the timing of the valve events in relation to where the crankshaft is positioned. Changing either affects engine performance, but a camshaft that is properly installed in an advanced position can noticeably improve performance.
Is lobe separation and Centerline the same?
Keep in mind that often the intake centerline and the lobe separation angle will be the same number, but they represent completely different functions. Valve overlap is a function of both duration and lobe separation angle.
What makes a cam more choppy?
the more overlap the “rougher the idle. reversion is bad at idle but turns into scavenging at the speed the cam was designed for. larger duration and smaller lsa will have more overlap, this is true.
How is the lobe separation angle of a camshaft chosen?
Selecting a camshaft for a given engine’s purpose usually involves a compromise between low- or high-end power options, and the lobe separation angle (LSA) is one of those factors where engine builders have to make a choice between those priorities.
What is the lobe separation angle in NHRA?
Five-hundred cubic inch NHRA Pro Stock engines that rev to 11,000rpm operate on 116 degrees and 800-plus cu in Pro Stock Mountain Motors 120 to 122. The lobe separation angle or LSA is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes.
What is the lobe separation angle exposed valve test 2?
LOBE SEPARATION ANGLE EXPOSED Valve Test 2 114 Cam (PN 11HR00239) For the second test we skipped to the opposite side of the spectrum. This cam was ground on a much wider, 114 LSA. Again we yanked the intake manifold, valve- train, and front of the engine to swap in the new bump- stick.
What happens when you change the lobe separation angle?
“Changing the lobe separation angle,” says Doug Patton of Pro Line Race Engines, “changes the amount of overlap that exists during the time the intake and exhaust valves are both open. On a naturally aspirated engine, the lobe separation angle has an effect on whether the engine reaches peak torque a little earlier or later in the rpm range.