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 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. Here are the basics: higher lift values open the valves to increase airflow and longer duration keeps the valves open longer. 106 LSA: So, if I talk about the powerband at 106 LSA, the powerband is narrow. 110 degrees on the lobe separation angles. But remember, although a broader powerband has a couple of acceleration advantages, it also comes with a few drawbacks. probably just enough to get me in trouble.. This may be of concern if you have vacuum assisted accessories, such as power brakes or steering. Armed with more information on camshaft theory, what will you build? camshaft is a Cranecams F238. 112-110 Deg. 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. 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. It idles very well at 650 rpm with a nice lope and runs strong. "It's not having what you want, it's wanting what you've got!" The 234o duration kind of eliminates the RV usage. 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. And better gas mileage. 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. 112 vs 114 lobe centers You cannot tell the differance in the two . 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. 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? The balance of midrange torque and top-end horsepower lends this LSA range to the majority of street/strip engines. 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. Meaning the lower lobe seperation will have a very quick and fast powerband (Snappy!) 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. Looking at 108vs. thanks. 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. If that accessory still does not assist the cam in producing enough vacuum, then as a last resort you can use a vacuum pump. 02 The 402-inch stroker short-block combined an aluminum LS2 block with a 4.000-inch crank and 6.125-inch rods. A cam with a 112 lobe center will idle smoother than a cam with a 110 lobe center. 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. How do the lobe separations change when you factor in turbocharging? All rights reserved. I think the compression ratio has something to do with LSA too. As you can see in the graph, the 101 LSA cam actually had the highest cranking compression of the batch: 185 psi. However, finding them might be challenging if you dont have any prior knowledge. by mike thompson Tue May 13, 2003 4:03 am, Post 110 LSA: On the contrary, it is pretty unpleasant to inform you that the efficient compression rate decreases at 110 LSA. 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. Generally, naturally aspirated engines run narrower lobe separation angles of around 106 to 108 whereas supercharged, turbo or nitrous engines operate with 112 to 114 and higher. But for small-block Chevys (like the LS applications in this story), the LSA is ground into the cam. A tighter LSA is always going to have more overlap, which allows the exhaust and intake systemif they're tuned wellto work together.". 01 Choosing the right lobe separation angle for your LS cam shouldn't cause anxiety. Most street cams are ground 4 degrees advanced which boosts bottom end, throttle response, vacume, mpg driveability etc. I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. A cam 112LSA with 4 degrees advance puts the intake centerline at 108 degrees. 108: 110: 112: 114 . 114LSA +4 puts the intake centerline at 110 degrees before top dead center. The only reason I . The first cam featured a wide 120-degree LSA, while cam number two narrowed the angle to 112 degrees. I just installed a Comp Cams XE262 in a 9:1 350 with stock iron heads. The result sounded wonderful, but it didnt rev as enthusiastically and it made 30 less horsepower than normal, says Lawrence. 106 LSA: At 106 LSA, the cylinder pressure is a bit higher. In my opinion, the rougher the idle the better! I do believe that stock VW seperation is 108 and 112 is used alot in turbo and midrange cams for VW's while 106 is used for the top end cams. Test 1 was easy. Average power was also down, but the engine pulled ahead of the 101 cam at 5,400 rpm, picking up 6.5 hp at peak. 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. To overcome this inherent problem in wide LSA camshafts, you simply need a higher-flowing intake port. A wide lobe seperation is not always better than a narrow one, or vise versa. Frontal lobe epilepsy (FLE), the second most common focal epilepsy syndrome after temporal lobe epilepsy (TLE), is frequently drug-resistant and MRI-negative. 110 LSA: The 110 LSA shows up mechanically advantageous in mechanical aspects like higher RPM, lower engine knock, moderate cylinder pressure, improved idle vacuum, and higher piston-to-valve clearance. 110 LSA: Oppositely, the cylinder pressure is comparatively lower at 110 LSA than at 106 LSA. Aeromotive; 913.647.7300; AeromotiveInc.com, AFR Heads; 661.257.8124; AirFlowResearch.com, Federal Mogul/Felpro; 248.354.7700; FederalMogul.com, Mahle; 248.347.9700; Mahle-Aftermarket.com, Scat Enterprises; 310.370.5501 ScatEnterprises.com, SuperFlow Dynamometers and Flow Benches; 515.254.1654; SuperFlow.com. 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. Mike Magda is a veteran automotive writer with credits in publications such as Racecar Engineering, Hot Rod, Engine Technology International, Motor Trend, Automobile, Automotive Testing Technology and Professional Motorsport World. According to the Comp Cams catalog, "The lobe separation angle (LSA) is equal to 1/2 the angle in crankshaft degrees of rotation between the maximum exhaust valve lift and maximum intake lift.". Engine builders Chuck Lawrence, left, and Doug Patton. So, without wasting any moment, lets find out the answer. by bigjoe1 Sat Dec 06, 2008 10:48 pm, Post As the RPM's go up this is not as critical as the higher velocity of the air/fuel moving thru keeps it from getting contaminated. 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. It's the scavenging effect of the high velocity exhaust gases rushing out that pulls the fresh fuel/air charge into the chamber. The engine will have weak performance in the low-end range.A low vacuum can also cause the brake pedal to be quite difficult to press. This table will create a map in your head, and I bet it will make your understanding crystal clear. 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. If you want a lumper idle go with a cam with 108 LSA, the tigher the LSA the idle will be rougher. It is the DESIGNED events that yield CENTERLINE. 04 Minor modifications to the factory windage tray were necessary to work with the new stroker assembly. This cam split the difference between the 101 and 113 down the middle, and in theory should have walked the line between the results of the last two tests in every waywhich it did. by Paul H Tue May 13, 2003 1:24 pm, Post So, sit tight back and explore. [img]http://i67.photobucket.com/albums/h291/downsideup09/DSCF2616-1.jpg[/img], [img]http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs139.snc1/5928_111214857139_110806152139_2127222_6826389_n.jpg[/img]. While lift and duration are most often discussed when talk turns to cam timing, there is a third variable that has a decided effect on both power and personality. Overlap is the amount of time that both valves are open in the same cylinder. by xstfudonniex Sat Dec 06, 2008 4:21 pm, Post A cam with a 112lobe center will idle smoother than a cam with a 110lobe center. The Fora platform includes forum software by XenForo. I'm surprized at these questions as well as some of the replies. " Increased overlap improves upper RPM power. by Hoxviii Mon May 12, 2003 7:50 pm, Post 108 versus 110 will drive the power band down. Read More Chevy 350 Ignition Coil Location And Everything About ThemContinue, What causes a car to bog down when accelerating? On engines equipped with independent intake and exhaust cams, the LSA is adjustable. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. Lower cylinder pressure is advantageous for your engine. JavaScript is disabled. Known as "The Gladiator" around Westech Performance, this Dart SHP blockbased, 370ci, small-block Chevy has made thousands of dyno pulls testing all manner of heads, intakes, cams, and every other crazy thing us magazine folk have coerced Westech's Steve Brul to bolt to it. Before we all start suffering from separation anxiety, we need to understand what lobe separation angle actually is and then how it affects your engine. So, choose the perfect lobe separation angle for your engine, complying with the requirements of your needs. 110* LSA - lobe separation angle (lobe displacement angle) The +2* means your intake lobe centerline is advanced to obtain a 108* ICL - intake centerline and a 112* ECL - exhaust centerline. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. The 110 is probably a better choice for a performance street engine. It provides a spark plug with the high voltage needed for combustion. 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. Good cam for a lower rpm street engine. This was science at work, and with data in tow, it was time to crunch the numbers and find out what was going on. O onovakind67 Registered Joined Dec 14, 2001 6,242 Posts The lobe separation angle is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes. I've seen that Webcam cams can be ordered with either of the above. 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. 106 LSA: The overlapping is higher as 106 LSA is comparatively tighter LSA than 110 LSA. Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). Re: Lobe separations on 383-406 cids.104-106-108-110. Before getting to the cam profiles, we had to make sure we had a reasonable test engine. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Bad idea in my view. The 112-degree cam (red lines) picked up much of the torque, but the big winner was the cam with the tightest lobe separation angle. Despite no changes in lift or duration, this cam sounded much more aggressive than the other two with wider LSAs. The 290 advertised duration and 114 lobe separation would contribute to a lazy power curve. 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. 11 Doing LS cam swaps on the engine dyno is a breeze, each taking less than 1 hour. by ANT Mon May 12, 2003 1:47 pm, Post 112 will have a smoother idle, a wider power band, and will work better with fuel injection. The 112-degree cam produced peak numbers of 567 hp at 6,200 rpm and 540 lb-ft of torque while pumping out 511 lb-ft of torque at 4,000 rpm. Do you know what the best lobe separation angle for your car engine is? Some of the confusion on this subject comes from what the meaning of "bottom" and "top" is to the speaker, I suppose. pump gas, no additive's as well, runs good, i will put the highest octane in, which is 93.. It's wet flow tested at 690cfm. This recommendation is only if you shift at no more than 7000. He also enjoys reading books a lot and his favorite author is Paula Coelho. its got a 3.73 posi and the Stock 4 speed with a very low 3.42 1st gear. 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. Anybody here run a 108 LSA? But an interestingly shocking fact is that this event escalates the air-fuel mixtures reaction rates, causing temperatures to rise and causing the problem of overheating the engine. But it also has a lot of lobe separation. Defining Lobe Center and It's Importance to Engine Performance: A Blog. by farmer Mon May 12, 2003 3:14 pm, Post Call for details with your specific combination. If you shift at 7500-7800 add 4-6 degrees to both intake and exhaust and spread the lobe separation to 108-110. The idle quality was better with the 112-degree LSA but not as good as the wider 120-degree cam.The ultra-wide 120-degree LSA lost low-speed power and never recovered, but know that this wide LSA is often beneficial on positive displacement, supercharged applications. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. Boom, you get the lobe separation angle of that engine. 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. NOTE: Classic Inlines stocks the above profiles in 108, 110, and 112 lobe centers. you cannot just take a random change in a lobe separation angle and say 1 is better than the other. However, a cam with 108 will only pull 12-16", which is not enough for power assisted accessories. 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 . Again, these are general bits of conventional wisdom. A 112 LSA would be better if I had an automatic, but the engine builder (who has built many, many drag racing engines)told me I would have much faster acceleration with the 108, at the expense of a broader power band of course, but that 108 would not unduly penalize me for the street. . Unfortunately, good street manners are often at odds with performance, as wilder cam timing usually decreases idle and (low-speed) driveability. ~These are just some of the drawbacks weas guys who like to go mach 10 with our hair on fire and these little motors screaming at rpms that make other guys cryhave to deal with.~. Noah knows a lot about whats happening in the car industry with the latest piloting productions thanks to his professional experience. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. More over-simplifications: 4-Link72, do you run racing gas or pump with 10.5:1 CR? As a result of this fall, the idle of the engine has to face suffering quite often. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. 110 LSA: On the contrary, 110LSA has a higher piston-to-valve clearance rate. The 30-30 Duntov is on the high end of the duration recommendation. One segment that truly benefits from a wider LSA is the marine marine market. 2.1.3 Transponder reply modes (air-to-ground) 2.1.3.1 Transponders shall respond to Mode A interrogations in accordance with the provisions of 3.1.1.7.12.1 and to Mode C interrogations in accordance . Check out the Comp Cams catalog, even the biggest hydraulic rollers use 110. This is ground into the cam and can't be changed without changing cams. 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. 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. Enter lobe separation angle. In this segment, I am going to compare those two lobe separation angles based on a couple of mechanical factors. Save Share. Post Coupled that with the low first gear of the five speed, it ought to create some real traction problems.