Retarding the camshaft (a higher intake lobe centerline number 108 vs. 104) will generally start the power band later in the RPM range and decrease the cylinder pressure. This may be of concern if you have vacuum assisted accessories, such as power brakes or steering. by ANT Thu May 15, 2003 6:44 pm, Copyright 2022, S&S Motorsports LLC, All Rights Reserved - Powered by phpBB Forum Software phpBB Limited. 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. All three terms are similar, as they all relate to the relationship between the centerline of the Intake lobe and the centerline of the Exhaust lobe. To illustrate the differences offered by changes in the LSA, we had Crane cams grind us three cam profiles that shared the same lift and duration figures, but differed only in the LSA. My engine shop builds all kinds of hot rod motors, and they told me that because I am running a 4 speed manual, I will better be able to take advantage of the 108 LSA. The intake lobe centerline is measured in crankshaft degrees. The only reason I . It creates an unsteady manifold vacuum condition that, on a fuel-injected engine, confuses manifold air pressure (MAP) sensors, making it hard for them to regulate fueling. 01 Choosing the right lobe separation angle for your LS cam shouldn't cause anxiety. Cam timing plays an important role not only in the power generated but also the overall character of the powerplant. Your best bet would be to talk to one of the experts at a cam company to get a custom grind if you're that into the specs. Good cam for a lower rpm street engine. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. 06 The ported heads featured a 2.165/1.590-inch valve combo. Elle concerne 264 taxons des degrs divers. 106 LSA: On the contrary, if we look at the 106 LSA, we will find it more advantageous and energy efficient than the 110 LSA engine. 106 LSA: There is a scale of standard cranking compression of the engine. Another related thought to consider when selecting a cam is inches of vacuum for your engine application when deciding upon a Lobe Center. So, which is better? so it is a solid flat tappet, torker intake, 1" 4-hole tapered spacer and 750 carb (QFT) transmission is a wide ratio toploader, rear is a 9" 3.89 geared 26"rear tires. 110 LSA: Oppositely, the cylinder pressure is comparatively lower at 110 LSA than at 106 LSA. I've seen that Webcam cams can be ordered with either of the above. by Paul H Tue May 13, 2003 1:24 pm, Post VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. The center of those 2 events is the LOBE CENTERLINE (ECL). Defining Lobe Center and It's Importance to Engine Performance: A Blog. If you drew a line that divided the intake lobe in half right at the point of maximum lift, then did the same to the exhaust lobe, then measured the distance in cam degrees between the two, that would be the lobe separation angle. A forum community dedicated to vintage Ford Mustang owners and enthusiasts. 106 LSA: The scale of efficient compression rises at 106 LSA. The valve covers, valvetrain, intake manifold, harmonic balancer, front cover, timing set, and cam were yanked. Getting back to the sound of an engine, its no secret that a raucous, lumpy idle is often preferred by street cruisers, regardless of the ill manners and inefficiency of such an engine setup. i've heard of this being done something about the massive amounts of duration allowes gasses to disipate? It is possible to advance and retard the timing events, but the distance between the centerline of the lobes will remain constant. The standard bore block was then stuffed with a 4340 forged steel 4.0-inch crank and 6.125-inch rods, along with a set of flat-top, forged JE pistons. The #1 intake lobe centerline is usually between 100 I think you are asking a lot of a cam . Post 554"/577" lift. Anybody do any real testing on LSA in a 3.75 stroke small block chevy?I have always used 104-106 and was thinking about trying a 108 or 110 design.I know there is a lot of variables but just a general opinion from any experts.This is for motor only no nitrous.600-640 HP engine combos.Much appreciated! One segment that truly benefits from a wider LSA is the marine marine market. THis is a real generalization, but the weaker your heads, the more you will like the smaller centers ( 106-108) the better the heads, and the higher the compression, the more it will like the wider centers ( 112-114)everything else falls somewhere in the middle( 108-110) Once you get close with the cam centerlines, it wont make much differance if you change it up or down by 2 degrees. 106 LSA: At this LSA, the car machine has to confront the reduction of idle vacuum rate quite often. Turbochargers are not as simple as they may sound; you may think of them only as power-boosting components. Meaning the lower lobe seperation will have a very quick and fast powerband (Snappy!) It has been tried in the VW business earlier, but then they gave it up because of problems with too high temperatures around the exhaust valve, causing them them to break. The only reason the advance or retard a camshaft profile is to get the timing events where they need to be. They also reduce stress on the outdrive. And better gas mileage. Bad idea in my view. If you take any of the . Idle vacuum showed a considerable spike to 14.7 in-Hg, likely the difference between being able to run power brakes and a mandatory leg workout. I have seen a dyno test where an engine using identical duration and lift made more peak power with a 112 LSA than a 110 LSA. (LOBE SEPARATION ANGLE)cam CRANES 110921 has the intake close at 45 degrees ABDC while the wider lsa CRANES 114681 closes the valves at 50.0 ABDC . 106 LSA: The overlapping is higher as 106 LSA is comparatively tighter LSA than 110 LSA. Increased overlap improves upper RPM power. Frankly cams with a 108-114 lca unless in the perfect combo you won't usually see more than 15hp and you won't really feel the difference except for either a peaky or broad power band. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. A cam with a 112 lobe center will pull approximately 16-20" of vacuum, which is good for power brakes. Nothing makes mouths drop like a car that sounds and looks like it can't keep it self still! Higher lift and longer duration profiles add power, but do so at higher engine speeds (especially true of duration). Every spec is a road map to what the valves are doing, the most common of which are lift, duration, and lobe-separation angle (LSA)the latter needing the most explanation. An icon used to represent a menu that can be toggled by interacting with this icon. To demonstrate changes to lobe separation in action, we ordered three camshafts from Comp Cams, all ground with identical lift (0.541 intake and 0.537 exhaust) and duration (230 intake and 236 exhaust) but with three different LSAs: a 101, a 107, and a 113. Fixing the ignition coils is essential when you experience issues like engine misfire and the Check Engine light that wont go off. While a cam with a 108 lobe center will idle rougher. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open.. Changing the lobe separation angle changes the amount of overlap that exists during the time the intake and exhaust valves are both open, echoes Doug Patton of Pro Line Race Engines. by SStrokerAce Sun Dec 07, 2008 12:22 am, Post The 402-inch LS2/LS3 hybrid stroker started out with an LS2 aluminum block. As boost increases, the air will be forced through the cylinder, vs. being trapped in the cylinder. Some prefer a narrow powerband, and some prefer the broader one. Most street cams are ground 4 degrees advanced which boosts bottom end, throttle response, vacume, mpg driveability etc. Okay, have a sigh because you have opened the right door. The taller lobe seperation will have a longer powerband but will have to rev higher to make the power than the lower lobe seperation! . A forum community dedicated to Ford performance owners and enthusiasts. After the next three pulls, it was clear the 113 cam was way down on low-end torque. All rights reserved. Next up was the 112-degree cam, which actually lost out in peak power slightly to the 120-degree cam, but offered considerably more torque. 04 Minor modifications to the factory windage tray were necessary to work with the new stroker assembly. Widening their separation angle helps increase upper rpm power output. 110 for sure. by Hoxviii Mon May 12, 2003 7:50 pm, Post 13 The three power curves indicate that the wide (120-degree) LSA (green lines) lost considerable torque to the other two cams. However, finding them might be challenging if you dont have any prior knowledge. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. 106 LSA: So, if I talk about the powerband at 106 LSA, the powerband is narrow. Pick the cam with the valve timing events that fit the engine best, forget about LSA, it is only a result of the events. I would say 114-117* would be a normal 1960's stock cam range and 117* to 120* is more what we see on modern engines. My lift will be about .580" intake and exhaust, with about 230/236 duration with a 1.7 rocker ratio, utilizing a Jesel shaft rocker system. ditto with the above. On the cranking compression test, Brul recorded 175 psi, a 10-psi drop from the outgoing 101 cam. thanks. Chevy Transmission Wont Shift Into 3rd: Finding the Main Culprit, Yamaha Lower Unit Drain Plug Size [Explained Everything], Does It Matter Which Ignition Coil Goes Where? The tightest LSA (101) was worth 21.5 lb-ft of torque and a much broader powerbandat the cost of much lower idle vacuum, which would make it more temperamental in a street car. If you're an OEM automaker looking for a steady idle, good fuel economy, and passing tailpipe emissions, this is the cam of choice. It made 472.4 lb-ft at peak, a 21.5lb-ft disparity from the 101 cam. What Are The Wastegate Stuck Open Symptoms? VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. If you compared these two cams side by side in identical engines, the first cam would actually have a slightly better idle and would produce slightly more peak power at upper RPM's. But to choose the perfect cam, all of that information needs understanding. The 234o duration kind of eliminates the RV usage. Exhaust reversion is another undesirable side effect that can be caused by overlap. Compression willl be 9.75:1. Selecting a camshaft for a given engines 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. by Marc Mon May 12, 2003 11:38 am, Post 02 The 402-inch stroker short-block combined an aluminum LS2 block with a 4.000-inch crank and 6.125-inch rods. Lobe separation angle does. = Moderately Tight 106-104 Deg. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. 68 Mustang, 306, AFR 185\'s, CI cam, FPA\'s, Bigs 650 DP, T5Z, 9" w/4.33's. I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. In the 106 LSA, the engine can reach the maximum torque, making the driving more efficient and saving energy. Read More Chevy 350 Ignition Coil Location And Everything About ThemContinue, What causes a car to bog down when accelerating? A mobile functional near-infrared spectroscopy (fNIRS) was used to record cerebral oxygenation signals in the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left parietal lobe (LPL), and right parietal lobe (RPL) and analyze the EC of the cerebral cortex. That lopey idle that is universally loved, and part of the allure of a tight LSA cam, is actually misfire caused from a combination of exhaust dilution in the intake manifold and poor cylinder filling at idle. The lobe separation angle is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes, says Eric Bolander of Erson Cams. The 108 LSA offered the lowest idle vacuum of the three (down 4 inches). "When you've properly tuned a performance motor, you create high- and low-pressure waves in the intake and exhaust that help cylinder filling," said Comp Cams' Billy Godbold. I am pretty sure, right now, you find yourself in the middle of the rising debate of 106 vs 110 lobe separation angle. Also If you go with 112 lobe centers, you create less valve overlap which will increase your compretion. That way you can discuss what you want from the engine and how changes in LSA or any of the other specs will affect how the engine performs. The 108-degree cam offered both the most power and torque, but idle quality suffered compared to the wider LSAs. Armed with more information on camshaft theory, what will you build? There are General guidelines about the effects of LSA but it should not be the deciding factor in choosing a cam. The lumpy-idling 101 LSA cam churned out an average of 484.0 hp at 6,100 rpm with 493.9 lb-ft of torque at 4,400 rpm. by jobes Sat Dec 06, 2008 3:51 pm, Post If the overlap phase occurs too early, it will create an overly rich condition in the exhaust port, severely decreasing the gas mileage. However, in application, there is a lot more to consider. I normally run a 106 to a 108 because I like the "hit" a tighter LC cam has when it come up on the came. 05 To ensure our stroker combo had sufficient airflow, we installed a set of Chevrolet Performance CNC-ported LS3 heads from Gandrud Chevrolet. Similarly, 110 LSA is also found to be a more fabulous performer in several mechanical aspects. 106 LSA: As the 106 LSA is a tighter LSA, it fails to generate maximum power. by farmer Mon May 12, 2003 3:14 pm, Post 108: 110: 112: 114 . Making this the biggest obstacle to overcome when selecting a cam profile with one of our tech advisors, explaining the definition and importance of the Lobe Center. Lucky for us, Brian Tooley Racing stepped up with a dual spring package that allowed us to safely run our 0.624-lift cam. A wider LSA moves intake- and exhaust-valve events farther apart and creates less overlap, which hurts intake-wave tuning. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. 106 LSA: You can see an increasing EGR effect at 106 LSA. Whatever you do, stay under 270 advertised duration and shoot for a 110 lobe separation. The lobe separation angle is the angle between the two camshaft lobes that act on the valves. If two cams are identical with the exception of lobe separation angle (we'll say 108 and 114) the cam with 114LSA will make more low end power than the 108LSA cam? It is the DESIGNED events that yield CENTERLINE. On the surface, the camshaft's job is simpleopen and close the valvesbut beyond that topical description, it's one of the most mysterious and misunderstood engine components. Do you know what the best lobe separation angle for your car engine is? by lazaris Fri Dec 12, 2008 2:18 pm, Post in some cases,, the average torque can equal out. This is why the LS series, and many other modern engines, can make great power on top and bottom with wide LSA camshafts and why a plethora of factory cylinder heads are flowing near (or above) 300 cfm. "When the low-pressure wave in the exhaust reflects into the intake, the pressure delta actually helps pull air and fuel into the cylinder. Brul spun the engine over with the dyno's starters and recorded 185 psi of cranking compression. Check out the Comp Cams catalog, even the biggest hydraulic rollers use 110. The same is true for intake valve closing. The lobe separation angle in a natural car engine conveys a considerable impact, especially regarding the maximum torque. by Mr. P. Fri Dec 12, 2008 6:36 pm, Powered by phpBB Forum Software phpBB Limited, General engine tech -- Drag Racing to Circle Track. If the cylinder heads are the lungs of an engine, the camshaft is the brain. The balance of midrange torque and top-end horsepower lends this LSA range to the majority of street/strip engines. The 114o lobe will add a lot more vacuum at idle. on average with a N/A motor if you stick the two cams in at the track the tighter lsa will be faster at the expense of idle quality. Its the shifting problem again with your Chevy! also,, wider will produce a wider and more flat torque curve that doesn't fall off as abruptly up top rpms. Because during the lower units oil change, you can go through the issue that the lower plug, Read More Yamaha Lower Unit Drain Plug Size [Explained Everything]Continue, Among the crucial parts of a vehicle ignition system is the ignition coil, also called a spark coil. 108 vs 112 lobe seperation. The 112-degree cam offered nearly all the low-speed and mid-range torque of the 108 cam but the peak power suffered above 5,200 rpm. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. The exhaust has an opening even and a closing event. Hey guys, can anyone tell me how rough of a idle a cam would be with a 108 lobe separation? The custom cams we selected all featured 0.624-inch lift (both intake and exhaust) and a 232/242-degree duration split. 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The lobe separation angle is a comprise of what the engine needs depending on the compression, combustion chamber, rpm, engine size, head volume, and many, many other variables. 03 The 4.000-inch crank and 6.125-inch rods were combined with a set of forged asymmetrical pistons from JE. hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. JavaScript is disabled. How do the lobe separations change when you factor in turbocharging? Overlap is the amount of time that both valves are open in the same cylinder. Howards Cam Vs Comp Cam: Which Is The Best Option For You? Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. Enter lobe separation angle. I also like the 106 lobe separation with the intake on 103. With minimal overlap and a steady manifold vacuum signal, they work great with fuel-injection systems and are the norm on modern pushrod engines, such as the LS and Gen III hemi. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know.
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