To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. I've seen a few comments in threads on here that have said things like "going to the 112LC from the 108LC gives 4lbft more torque at the bottom and 2bhp more at the top" yet this would seem to go against what webcam say on. For example, an oval-track small-block that needs to motivate the car off the turns quickly might have a narrow LSA of around 106 degrees, resulting in more overlap. The Idles increasing vacuum improves the idle quality and the engines overall performance. I'm surprized at these questions as well as some of the replies. " Brul spun the engine over with the dyno's starters and recorded 185 psi of cranking compression. The Fora platform includes forum software by XenForo. by jim martin Mon May 12, 2003 7:10 pm, Post by randy331 Sat Dec 06, 2008 10:00 pm, Post 3.75" stroke= 108 LSA 4.00" stroke= 110 LSA 4.25" stroke= 112 LSA 4.50" stroke= 114 LSA I can see exactly where his theory is coming from. The stock valvesprings supplied with the CNC LS3 heads were swapped out in favor of a set of dual springs from Brian Tooley Racing. But it also has a lot of lobe separation. Now its not shifting into 3rd and you are here. If all the specs remained the same what will going from a 110 to a 112 lsa do to driving characteristics? Because the lobes are closer together on the 101 LSA cam, the intake closing point is advanced (closes earlier) and the piston has more time to build compressionexactly what the gauge showed. A commonly held misconception is that intake/exhaust overlap contributes to lower cranking compression. 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. music to your ears? If the exhaust valve closes too early it will trap some of the spent gases in the combustion chamber, and if it closes too late it will over-scavenge the chamber and take out too much of the charge, again creating an artificially lean condition. I wouldn't assume 4 links fuel requirements will mirror yours at all. 106 LSA: There is a scale of standard cranking compression of the engine. Everyone has a different idea of gentle.While its true that the duntov cam may seem rough in a 283 it is still a factory offering and they never go to radical on there profiles for street cars.If you want a rough idle, try a 283 with a .550'lift roller and 13.5 to 1 compression,THATS ROUGH. As lobe seperation spreads does the powerband. A tighter LSA is always going to have more overlap, which allows the exhaust and intake systemif they're tuned wellto work together.". The graph above compares intake valve closing points of the three cams used in the test. Coupled that with the low first gear of the five speed, it ought to create some real traction problems. In reality, a cam with 220 at 0.050" and a lobe center angle of 112 will have the exact same mechanical overlap as a cam with 217 at 0.050" and a lobe center angle of 109. Test 1 was easy. 238/248 duration, 300/310 adv. 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. Okay, have a sigh because you have opened the right door. OK, what is hydraboost, and how do you like how the cam performs??? It produces peak torque earliercoming on quicker and strongerbut also it falls off quicker too. A wide lobe seperation is not always better than a narrow one, or vise versa. lobe centers and lobe separation are 2 different things . 106 LSA: At this LSA, the car machine has to confront the reduction of idle vacuum rate quite often. After spending 8 years in plant production engineering, Noah wanted to join Engine Addiction as a key member of all cars specific guides, reviews, repairs, suggestions, and more. That notion is completely false. Really wide lobe separation angles are used in boosted applications. But it is a piece of good news for your engine. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. Ultimately, it makes the 110 LSA an oil-consuming LSA. Either learn to fix it, or learn to write checks. I had an XE 274 in it. 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. The first cam featured a wide 120-degree LSA, while cam number two narrowed the angle to 112 degrees. As boost increases, the air will be forced through the cylinder, vs. being trapped in the cylinder. The introduction of Lunati'snew Bootleggerhydraulic series - with its wicked 108-degree lobe-separation angle, fast opening profile and plenty of area under the lift curve - will serve only to fuel the flames on this heated bench-racing topic. The 108-degree cam (blue lines) outperformed the other two, but idle quality suffered. The 402-inch LS2/LS3 hybrid stroker started out with an LS2 aluminum block. The tighter the lobe center, the lower the RPM range; the wider the lobe center, the higher the RPM range. We borrowed Westech Performance's shop mule, a 370ci small-block Chevy and its SuperFlow 902 engine dyno and spent a day running each cam back-to-back to gauge its effect on peak horsepower, peak torque, cranking compression, idle vacuum, and the powerband as a wholeall the variables that define an engine's character on the street and track. However, the plentiful exhaust overlap (31 degrees) meant there was lots of exhaust dilution at low engine speed and high vacuum. 1966 Toyota Landcruiserunder construction. 110 for sure. Once more the engine came apart to install the third test cam, a 107 LSA. However, it is fixable. Hey guys, can anyone tell me how rough of a idle a cam would be with a 108 lobe separation? Walter Noah is a process engineer who has a knack for resolving even the toughest technical issue. The wider lobe separation angle closes the intake valve later and reduces cylinder pressure, so that is where it's detonation resistance comes from. The second cam would have a rougher idle, produce more torque and would rev quicker. When boost or nitrous are introduced, and engine builders contemplate choices between single-, dual- or reverse-pattern camshafts then the discussion gets muchmore technical. Higher overlapping lets less oil fall through the oil inlet. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. TH400 Vs Powerglide: Which One is Ideal for You? The Fora platform includes forum software by XenForo. On engines equipped with independent intake and exhaust cams, the LSA is adjustable. This form of short-term memory is supported by the prefrontal cortex (PFC) and is believed to rely on the ability of selectively tuned pyramidal neuron networks to persist in firing even after a to-be-remembered stimulus is removed from the environment. For your convenience, I am providing a comparison table to give you an overall idea about the comparison. but less of it at the same time. LSA is a way of summing up the relative timing of the intake-valve events (intake opening, intake closing) to the exhaust-valve events (exhaust opening, exhaust closing) in relation to each other, and it's a great approximation of how the engine will operate. It may not display this or other websites correctly. LSA CAM TEST-108 vs 112 vs 120 Richard Holdener 239K subscribers 168K views 2 years ago WESTECH PERFORMANCE GROUP FULL RESULTS-CHANGE ONLY LSA-LS CAM TEST. I've seen that Webcam cams can be ordered with either of the above. 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. The 108-degree cam offered both the most power and torque, but idle quality suffered compared to the wider LSAs. by SStrokerAce Sat Dec 06, 2008 7:38 pm, Post Increasing the EGR effect has a good side in that it reduces the amount of oxygen in the combustion chamber. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. The only reason I . too much for the street? 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. This is ground into the cam and can't be changed without changing cams. We will also custom grind any of the above profiles with a custom lobe center, for an additional $20 dollars. What brand and what are the specs on your cam, 4-linked72? Re: Lobe separations on 383-406 cids.104-106-108-110. 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. 110 LSA: But, contrarily, at 110 LSA, you dont have to face the problem of engine knocking. Do you like to go fast? I think the compression ratio has something to do with LSA too. I would have to say that your cam choice sounds like a winner to me. 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. The power and torque curve lay directly in between the last two cams, as did the peak horsepower and torque, 488.7 at 6,200 rpm and 487.1 at 4,600 rpm, respectively. 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. 110 LSA) and Crane's #341191 (238/248, .563"/.587", 114 LSA), display considerably different characteristics. These numbers can vary a few inches one way or the other, depending on several other aftermarket factors and your individual engine specifications, so you may want to check your vacuum once the cam is installed. 06 The ported heads featured a 2.165/1.590-inch valve combo. Aluminum flywheel & pullies. I also like the 106 lobe separation with the intake on 103. . After consulting with many experts, you are still in confusion between 106 and 110- lobe separation angles. 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. Hopefully it turns out great. Most cars use more than, Read More Does It Matter Which Ignition Coil Goes Where? If you changed the lobe separation of a street engine from 112 degrees to 106 and didnt do anything else, adds Kaase. If you want a lumper idle go with a cam with 108 LSA, the tigher the LSA the idle will be rougher. Although both wide (112-116) and narrow (102-110) lobe separation angles do have an effect on overlap, it's still possible to get a lot of overlap with very wide lobe separation angle cams. 106 LSA: At 106 LSA, the cylinder pressure is a bit higher. However, finding them might be challenging if you dont have any prior knowledge. Given that nitrous works best in the mid- to upper-rpm range, nitrous-powered engines need a wider lobe separation, like 112 . 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. 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. . I don't know about 13 to one but I have seen 12 to one on a 350 chev in hot rod article, BUT the guy soft petals around on the street with no full throttle use and puts racing gas in at the track. This overlapping has a direct influence on the oil consumption rate of the engine. On the cranking compression test, Brul recorded 175 psi, a 10-psi drop from the outgoing 101 cam. If identical and for a given displacement the 110 will give more power. 106 LSA: 106LSA results in a decrease in piston-to-valve clearance. to use this representational knowledge to guide current and future action. 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. Like one cam is 112 degree and the next is 108 the 108 cam will allow less "leakage"? Engine builders Chuck Lawrence, left, and Doug Patton. also,, wider will produce a wider and more flat torque curve that doesn't fall off as abruptly up top rpms. 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. The taller lobe seperation will have a longer powerband but will have to rev higher to make the power than the lower lobe seperation! The SAME can be said. Moreover, a user from the Chevelle forum said. by ANT Mon May 12, 2003 1:47 pm, Post Some of the confusion on this subject comes from what the meaning of "bottom" and "top" is to the speaker, I suppose. Compression willl be 9.75:1. Also If you go with 112 lobe centers, you create less valve overlap which will increase your compretion. Many later model engines use wide lobe separation angles to reduce overlap for idle quality and fuel economy. 110 LSA: On the contrary, 110LSA has a higher piston-to-valve clearance rate. 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. Well, it is quite a natural event that you may not find the lope separation angle mentioned at the engine body. However, these rules are not absolute. ( 2 ) Estimated Ship Date: Feb 23, 2023 (if ordered today) Drop Ship. by lazaris Fri Dec 12, 2008 2:18 pm, Post The #1 intake lobe centerline is usually between 100 Bolander says those cams help promote torque in a controlled and predictable manner, especially in no-wake zones and around the docks. Another difference between the two involves the power curve. 07 Though the CNC-ported heads offered plenty of flow, it was necessary to upgrade the supplied valvesprings. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. Due to the tightness and frequent overlapping of the intake and exhaust valves, the engine cant generate the high RPM as it is supposed to. A narrow, more specific power band is also a product of a narrow LSA, as is a lumpy idle qualityoften referred to as the 106 sound. 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. So, without wasting any moment, lets find out the answer. The 120-degree cam minimized torque production through most of the curve, while the 112-degree cam offered more torque but slightly less peak power. How To Properly Replace Ignition Coils, Chevy 350 Ignition Coil Location And Everything About Them, Heres What Causes Your Car to Bog Down When Accelerating. Well, If I am not mistaken, you must be looking for which angle has what impact on your engine or which would be the best. 12 In terms of power production, the stroker LS3 performed best with the tightest lobe separation angle. 554"/577" lift. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. But, you may find it quite shocking that the piston-to-valve clearances decreasing rate raises the chance of damaging the valve by the piston. While most of our customers know what lift and duration are, most are unfamiliar with the term Lobe Center and how it affects the engines performance. 05 To ensure our stroker combo had sufficient airflow, we installed a set of Chevrolet Performance CNC-ported LS3 heads from Gandrud Chevrolet. Builds More High-RPM Power Increase Piston-Intake Valve Clearance Decrease Piston-Exhaust Valve Clearance EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA) Tighten (smaller LSA number) Moves Torque to Lower RPM Increases Maximum Torque Narrow Power band Builds Higher Cylinder Pressure Increase Chance of Engine Knock Increase Cranking Compression A lower efficient compression rate leads to a higher fuel consumption rate by your engine to produce higher power. It is the average centerline between both lobes and expressed in degrees ranging from 95 on the extremely narrow/tight side to upward of 120 on the wide end. It will have slightly higher vacuum at idle, feel smoother through the power curve but have a bit less midrange. 112 vs 114 lobe centers You cannot tell the differance in the two . I have 108 for LSA and my headlights take awhile to go up when the car is idling. Good cam for a lower rpm street engine. The world of fuel injection is where wide LSA cams like the 113 really shine. However, a cam with 108 will only pull 12-16", which is not enough for power assisted accessories. Realize what the engine is going in, however, as you may not be able to use the wildest cam out there. The 290 advertised duration and 114 lobe separation would contribute to a lazy power curve. Around 70 percent of muscle-car performance cams fall into this range. The 30-30 Duntov is on the high end of the duration recommendation. such as 290 @.050? Simply put, the lobe separation angle (LSA) is a measurement of how the intake and exhaust lobes are phased with each other. Cam and Lifters, Hydraulic Roller Tappet, Advertised Duration 282/288, Lift .589/.600, Chevy, Big Block, Kit. A cam with a tighter LSA will require a looser torque converter, may not be able to run vacuum-assisted brakes, and doesn't play nice with fuel injection. This process slows down the reaction rates of the air-fuel mixture, causing temperatures to drop and preventing the engine from overheating. Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. 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. So, you can enjoy a mighty acceleration power at 110 LSA. It's the scavenging effect of the high velocity exhaust gases rushing out that pulls the fresh fuel/air charge into the chamber. i've heard of this being done something about the massive amounts of duration allowes gasses to disipate? After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. Lobe seperation cant be seperated from duration,the 2 are connected.the old duntov cam had a lot less duration than many new cams so the valve overlap was not extreme and the engine ran with a gentle lope.Increase the duration by 20* and this cam would shake a 283 out of the car at idle,but then increase the lobe seperation by 4* and the motor will have a gentle lope again. probably just enough to get me in trouble.. What Is the SBC Header Bolt Torque? Thanks for the replies, particularly that link Marc, very informative. 03 The 4.000-inch crank and 6.125-inch rods were combined with a set of forged asymmetrical pistons from JE. 108 Lobe Separation These are my motors specs 1979 - 347 Stroker 10:1 Compression Holley 670 Street Avenger or a Holley 650 (I have both) Roush 200 Cylinder Heads (minor head work) 1.6 Roller Rockers Shorty BBK Headers 373 Rear End 5 Speed Transmission Cross Gap Intake (Power Band 1500-6500) FlowMaster Dual Exhaust (of course no Cats) MSD 6Al Yeah but do the experiment on the dyno and tell me your intuition is correct. Unfortunately, good street manners are often at odds with performance, as wilder cam timing usually decreases idle and (low-speed) driveability. Frontal lobe epilepsy (FLE), the second most common focal epilepsy syndrome after temporal lobe epilepsy (TLE), is frequently drug-resistant and MRI-negative. changing just the LSA on my cam wouldnt make a bit of difference on vacuum operated items E ericnova72 More for Less Racer Joined Jan 13, 2007 22,026 Posts I know a little about cams. = Moderate 108-106 Deg. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. Its the shifting problem again with your Chevy! Tight LSA cams make excellent low-end torque and have a beautiful power curve. How To Properly Replace Ignition CoilsContinue. by mrsmythe Tue May 13, 2003 5:45 am, Post I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. The absence of engine knocking ensures that your car engine is reasonably combusting the fuel. But i would nt go any wider than 110. i think a little more torque will be good for my car.With the XE274 it was a little slugish until around 3000 rpms. 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.