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. Exhaust reversion is another undesirable side effect that can be caused by overlap. Supercharged and nitrous race engines typically benefit from a wider LSA because they dont require as much overlap for exhaust scavenging as does the naturally aspirated engine, continues Bolander. 110 LSA: You will find the complete opposite scenario here. Good cam for a lower rpm street engine. 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. The second cam would have a rougher idle, produce more torque and would rev quicker. 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. A commonly held misconception is that intake/exhaust overlap contributes to lower cranking compression. Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). For a better experience, please enable JavaScript in your browser before proceeding. And better gas mileage. 13 The three power curves indicate that the wide (120-degree) LSA (green lines) lost considerable torque to the other two cams. 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 other thing is that you can make more power with a smaller aftermarket cam. by SStrokerAce Sun Dec 07, 2008 12:22 am, Post It is dangerous to be right in matters on which the established authorities are wrong. Good cam for a lower rpm street engine. Now here is where it gets tricky. 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. Thats just the way the customer wants to roll, and engine builders find its easy to deliver such a powerplant. 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. The engine has AFR heads, Crane rockers, a TCI balancer, a Scat Rotating assembly with Mahle pistons, an Edelbrock RPM Air-Gap intake, an MSD ignition, and an Aeromotive fuel system. by Paul H Tue May 13, 2003 1:24 pm, Post It will have slightly higher vacuum at idle, feel smoother through the power curve but have a bit less midrange. If identical and for a given displacement the 110 will give more power. Has anybody experienced it/ tried it? Do you like to go fast? 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. 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. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. Copyright 2022, S&S Motorsports LLC, All Rights Reserved - Powered by, http://www.webcamshafts.com/cam_glossary.html, http://www.newcovenant.com/speedcrafter haft/3.htm, Webcam 86A 108LC w/1.5 vs 86B 112LC w/1.3s. But nothing comes without a cost, and idle vacuum suffers as LSA shrinks. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. As boost increases, the air will be forced through the cylinder, vs. being trapped in the cylinder. Save my name, email, and website in this browser for the next time I comment. "It's not having what you want, it's wanting what you've got!" It's the scavenging effect of the high velocity exhaust gases rushing out that pulls the fresh fuel/air charge into the chamber. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open.. by xstfudonniex Fri Dec 12, 2008 5:24 pm, Post Big strokers like tighter LCA but it really depends on your combo and usage, theres great OTS cams but for a custom engine a custom cam is the way to go With identical cam lobes you won't see a bit of difference. The 110 is probably a better choice for a performance street engine. Howards Cams Retro-Fit Hydraulic Roller Camshaft and Lifter Kits CL120325-08. Camshafts with a substantial overlapping tendency should not be used in vehicles driven on public streets. The final, 108-degree cam stepped power up even further, with peaks of 572 hp at 6,300 rpm and 544 lb-ft at 5,200 rpm. also,, wider will produce a wider and more flat torque curve that doesn't fall off as abruptly up top rpms. 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. Some of the programs like engine analyzer pro and dynomation seem to like some of the wider lsa's.Thanks again JOE. So, you can enjoy a mighty acceleration power at 110 LSA. 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. 112 vs 114 lobe centers You cannot tell the differance in the two . Hopefully It will do fine in my 2276 mostly drag bug. LSA helps determine the cam's behavior; you can take a given set of lift and duration figures, change the LSA, and get cams with vastly different characteristics. 110 LSA: On the contrary, if you look at the powerband at 110 LSA, the powerband is comparatively broader. by Kdub Sat Dec 06, 2008 11:05 pm, Post Thanks again. Lobe Separation or Lobe Centers is another way of expressing the Valve Overlap, which was the term formerly used by cam manufacturers before industry standard verbiage changed. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 11 Doing LS cam swaps on the engine dyno is a breeze, each taking less than 1 hour. A wide LSA reduces valve overlap, softens the idle and improves overall drivabilityespecially on the street where performance engines benefit from 112 to 114 LSA. JavaScript is disabled. 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. Whatever you do, stay under 270 advertised duration and shoot for a 110 lobe separation. TH400 Vs Powerglide: Which One is Ideal for You? Part Number: HRS-CL120325-08. by mrsmythe Mon May 12, 2003 11:15 am, Post Simply put, the lobe center of the camshaft controls where the power curve is applied. 110 degrees on the lobe separation angles. Cam swaps are all the rage and for good reason. You cannot look at just the LCA without looking at other specs too. 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. If you want a lumper idle go with a cam with 108 LSA, the tigher the LSA the idle will be rougher. And better gas mileage. I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. That is why 106 LSA consumes less oil. by SStrokerAce Sat Dec 06, 2008 7:38 pm, Post Cam and Lifters, Hydraulic Roller Tappet, Advertised Duration 282/288, Lift .589/.600, Chevy, Big Block, Kit. 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. An icon used to represent a menu that can be toggled by interacting with this icon. ( 2 ) Estimated Ship Date: Feb 23, 2023 (if ordered today) Drop Ship. that is why people running 112 or 114 lobe centres retard the cam ,that way the exhaust event is back were it was before .this helps in exhaust valve tempatures--anyway today i talked too barry who is the owner of shadbolt cams and we talked about cam lobe centres -he considers 108 centre quite narrow and for a very narrow power band operation ,with a 112 he figures with the carbs with straight & even runs at the valves there should be no noticable loss of low end power, a 112 lobe would be a great choice for a great street strip motor -better lower torque followed with a flatter rising torque curve as well as rpm range extended 500-700 rpm -. So, now you, Read More Chevy Transmission Wont Shift Into 3rd: Finding the Main CulpritContinue, While changing the oil on your boats lower unit, you may need to change the drain plug, too. To overcome this inherent problem in wide LSA camshafts, you simply need a higher-flowing intake port. Aluminum flywheel & pullies. It also depends on displacement, some guys will run a bigger cam and widen the LCA to give a better idle but in my opinion it kills power. 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Another difference between the two involves the power curve. 1-3 Cognitive impairment is common in both FLE and TLE and adversely impacts quality of life and psychosocial functioning. . I probably would have gone with 3.55 gears had I knows better.. 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. The Idles increasing vacuum improves the idle quality and the engines overall performance. Ed JTO learn to park Joined May 31, 2009 180 Posts I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. Split duration/lift only helps when your intake/exhaust ratio is low on the exhaust side. It produces peak torque earliercoming on quicker and strongerbut also it falls off quicker too. Thanks for the replies, particularly that link Marc, very informative. 09 All testing was run through a set of 1 3/4-inch long-tube headers and 3-inch exhaust. Yeah but do the experiment on the dyno and tell me your intuition is correct. A narrower lobe separation angle can provide less power but can also lead to less wear. The graph above compares intake valve closing points of the three cams used in the test. The article was called "Separation of Power" and they tested 5 cams ranged from 106 to 114 LSA. 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. 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. The Fora platform includes forum software by XenForo. Engine builders Chuck Lawrence, left, and Doug Patton. This is ground into the cam and can't be changed without changing cams. Alternatively, if you are running a bigger camshaft to gain maximum top-end power, cam makers often suggest reducing the lobe separation angle to recover power lost in the lower rev range.. If you look at any given cam catalog, you will find that the majority of street-oriented cams fall in this range. Brul spun the engine over with the dyno's starters and recorded 185 psi of cranking compression. 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. 1-4 It is one of the most common neurological disorders worldwide, 1-5 is among the most common . As you can see in the graph, the 101 LSA cam actually had the highest cranking compression of the batch: 185 psi. Higher lift and longer duration profiles add power, but do so at higher engine speeds (especially true of duration). Depending on the engine combination, the opposite results can occur. We do not stock profiles with 109 or 114 lobe centers. I think you are asking a lot of a cam . I'm sorry to disagree with that incredibly well written article, but lobe separation by itself is absolutely freaking meaningless. 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. by jim martin Mon May 12, 2003 7:10 pm, Post But i would nt go any wider than 110. lobe centers and lobe separation are 2 different things . Lobe Separation Angle "LSA "Jump to Latest Follow 1 - 17 of 17 Posts . (2002) et rappel sur une carte hors texte. Contrariwise, 106 LSA car engines are the best choice for people seeking energy-efficient cars with moderate engine power. 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. by flat4racer17 Mon May 12, 2003 1:40 pm, Post I just installed a Comp Cams XE262 in a 9:1 350 with stock iron heads. thanks. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. 110 LSA: On the other hand, 110 LSA is a wider LSA with almost no overlap. Equipped with the 120-degree (LSA) cam, the hybrid stroker produced 570 hp at 6,200 rpm and 535 lb-ft of torque at 5,200 rpm. 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. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. General topics - 76 LA built, CA car with m20. Maybe even 114. Ultimately, it makes the 110 LSA an oil-consuming LSA. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know. To reiterate another point, I realize that wider LSAs tend to broaden the power band, but for a car I would like to bracket race a bit, as well as enjoy on the street, I was told that a narrower LSA will help the car accelerate at a faster rate. *If you do not have enough vacuum, you can in some cases install a vacuum canister or reservoir, which works by storing the peak vacuum in the reservoir. A cam's lobe separation determines where and for how long peak torque occurs in an engine's rpm range. A wide lobe seperation is not always better than a narrow one, or vise versa. by bigjoe1 Sat Dec 06, 2008 10:48 pm, Post Adding an aftermarket cam to an otherwise stock engine can boost output by 40-60 hp (or more) with no other changes (except possibly a valvespring upgrade). 4-Link72, do you run racing gas or pump with 10.5:1 CR? But to choose the perfect cam, all of that information needs understanding. If a street car has smaller lift and duration numbers, they might run 112 or 114. 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! Post 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. As a result, you can enjoy a pleasing engine outcome. If all the specs remained the same what will going from a 110 to a 112 lsa do to driving characteristics? When degreeing in the camshaft, you are making sure the intake centerline is precisely where the cam is intended to be. The center of those 2 events is the LOBE CENTERLINE (ECL). by flat4racer17 Tue May 13, 2003 9:12 pm, Post The takeaway from this test is camshaft LSA is a double-edged sword. The intake air control valve (IAC), which regulates idle speed, also has to work overtime and often attempts to "catch" the idle, but usually shoots high or low. After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. A cam card with its myriad numbers, acronyms, and abbreviations is one red-pen stroke away from a failed math test. Since we were only changing the lobe separation angle, we had to make sure every variable (air/fuel, timing, water, air, and oil temps) was identical during testing. . In a blower motor when the valve timing events are where they need to be the lobe sep will usually wind up in the 114-115 range on most Combos. 108: 110: 112: 114 . Well, it is quite a natural event that you may not find the lope separation angle mentioned at the engine body. 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. Enter lobe separation angle. 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. I think that cam had 110 lobe sep. Im loking at a summit cam with close to the same lift and duration #s but 114 lobe sep. Some of the confusion on this subject comes from what the meaning of "bottom" and "top" is to the speaker, I suppose. The 108-degree cam (blue lines) outperformed the other two, but idle quality suffered. 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. Save Share. 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. I also like the 106 lobe separation with the intake on 103. 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. One segment that truly benefits from a wider LSA is the marine marine market. (ICL + ECL) / 2 = LOBE SEPARATION ANGLE (LSA) LSA is a RESULT of the PROPER events. 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. 10 Tuning the timing curve and fuel from the 42-lb/hr FAST injectors was handled by this Holley HP management system. A forum community dedicated to hot rod owners and enthusiasts. When choosing a cam, power gains shouldn't be the only consideration. Its also critical that valve overlap is kept to a minimum as the induction system can create a suction that pulls water into the motor, adds Bolander. 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. = Extremely Tight . Now its not shifting into 3rd and you are here. A Pro Stock engine builder may prefer a wide LSA to help keep the power from breaking traction tOo early. 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 As a result of this fall, the idle of the engine has to face suffering quite often. The extra cubic inches will smooth out a rough idle in a 327. It is an important note you must keep; due to the lobe separation angle, there creates an overlapping of intake valve opening time and exhaust valve closing time and vice versa. The balance of midrange torque and top-end horsepower lends this LSA range to the majority of street/strip engines. 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. So, the 110 LSA engine is a suitable choice for people prone to be the fan of a powerful engine with mighty acceleration power. If that were the only consideration, the 101 cam is the clear winner. However, it is fixable. Tight lobe separations, such as 108 or shorter, will cause the peak torque to build earlier in the RPM range and peak-out in a short amount of . The valve covers, valvetrain, intake manifold, harmonic balancer, front cover, timing set, and cam were yanked. Build your own custom newsletter with the content you love from EngineLabs, directly to your inbox, absolutely FREE! (You can find an instructional video of how to do just that on our Clay Smith Cams YouTube Channel;https://www.youtube.com/watch?v=57gfBu8uc6k&t=1s ). 4-linked72, what cam are you using that has a 108 LSA? Also, the wider LSA contributes to chassis stability in drag racing by avoiding the delivery of a ferocious blast of power that would break tire traction. Compression willl be 9.75:1. These issues can often be worked through by an advanced tuner, but always present a challenge and compromise in tuning strategy. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. Moreover, a user from the Chevelle forum said. so the power will come on a litter sooner with the 114, and fall off a little sooner? So the wider LSA introduces a broader and therefore longer torque band.. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. Either learn to fix it, or learn to write checks. JavaScript is disabled. = Tight Below 104 Deg. 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. Coupled that with the low first gear of the five speed, it ought to create some real traction problems. The only reason the advance or retard a camshaft profile is to get the timing events where they need to be. These favorable mechanical features depict the powerful acceleration capacity of the engine with higher oil and energy consumption rate, overheating problems, and other mechanical problems. However, in application, there is a lot more to consider. A wider lobe center will give you more overall torque (comes in earlier and stays later). 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. The world of fuel injection is where wide LSA cams like the 113 really shine. A cam 112LSA with 4 degrees advance puts the intake centerline at 108 degrees. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. A narrower LCA will increase valve overlap and close the (intake) valve earlier, which explains the typical rougher idler and more midrange behaviour. 4 Impaired episodic memory and semantic knowledge are common in TLE, although dysexecutive traits . 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. 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. On the cranking compression test, Brul recorded 175 psi, a 10-psi drop from the outgoing 101 cam.
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