This table will create a map in your head, and I bet it will make your understanding crystal clear. 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. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. I am trying to pick out a hydraulic roller cam for my 351W with AFR 185s. BUT, 114 will have more vacuum at idle, which will work better with some fuelinjection. 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 110 is probably a better choice for a performance street engine. Looking at 108vs. pump gas, no additive's as well, runs good, i will put the highest octane in, which is 93.. The lobe separation angle is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. dont sound like a verry street friendly motor butany thoughts? This wave tuning is what helps performance engines achieve volumetric efficiencies of more than 100 percent. For any additional clarification or questions please contact our Tech Line at 714 523-0530. https://www.youtube.com/watch?v=57gfBu8uc6k&t=1s. That is why 106 LSA consumes less oil. The 114o lobe will add a lot more vacuum at idle. 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. by Kdub Sun Dec 07, 2008 1:20 am, Post 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. However, the plentiful exhaust overlap (31 degrees) meant there was lots of exhaust dilution at low engine speed and high vacuum. 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. Now its not shifting into 3rd and you are here. Anybody here run a 108 LSA? Topping the short-block was a set of Chevrolet Performance CNC LS3 heads from Gandrud Chevrolet. 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. 68 Mustang, 306, AFR 185\'s, CI cam, FPA\'s, Bigs 650 DP, T5Z, 9" w/4.33's. whats the difference in how the car will run. 112 vs 114 lobe centers You cannot tell the differance in the two . The LSA, or lobe separation angle, is ground into the cam and cannot be changed. If you look at any given cam catalog, you will find that the majority of street-oriented cams fall in this range. While a cam with a 108 lobe center will idle rougher. by bigjoe1 Sat Dec 06, 2008 10:48 pm, Post 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. We even treated them to some chamber work before installation. 106 LSA: As you know, the intake and exhaust lobes centerline distance is known as lobe separation angle. I think the compression ratio has something to do with LSA too. 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 Fora platform includes forum software by XenForo. The engine would idle a lot rougher and generate worse exhaust emissions largely because of unburned fuel.. JavaScript is disabled. All rights reserved. General topics - 76 LA built, CA car with m20. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. The only reason the advance or retard a camshaft profile is to get the timing events where they need to be. To further minimize any dyno variations, the engine's oil and water temperatures were kept the same for each pull. Good cam for a lower rpm street engine. As you tighten the centers ( 108 ) the same engine will make MORE power through the mide range and top end. So, which is better? 4-linked72, what cam are you using that has a 108 LSA? Maybe even 114. The #1 intake lobe centerline is usually between 100 It will also give you a smoother idle and probably even better gas mileage. = Moderately Wide 110-108 Deg. It's wet flow tested at 690cfm. to use this representational knowledge to guide current and future action. One segment that truly benefits from a wider LSA is the marine marine market. Despite no changes in lift or duration, this cam sounded much more aggressive than the other two with wider LSAs. When you don't have any overlap, you can't have any wave tuning. by trmnatr Sat Dec 06, 2008 10:45 pm, Post by 3V Performance Sat Dec 06, 2008 4:38 pm, Post It is dangerous to be right in matters on which the established authorities are wrong. - Sheryl Crow. by Marc Mon May 12, 2003 11:38 am, Post 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. 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. by xstfudonniex Fri Dec 12, 2008 5:24 pm, Post I personally prefer to sacrifice the small amount more power for better idle quality. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. Your email address will not be published. A cam 112LSA with 4 degrees advance puts the intake centerline at 108 degrees. 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. 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. A 232 deg duration cam with a 108 deg LCA will have the same valve overlap as a 236 deg cam with a 110 deg LCA and idle will probably be very similar. True enough, the tight LSA improved power through the entire rev range, from 3,600 to 6,500 rpm, but the extra power came with a penalty in idle quality. At a lower LSA, the engine reaches the peak of the torque earlier than the standard time but generates a lower RPM.On the contrary, at a higher LSA, the engine reaches the peak torque at a higher resistance level and generates a bulk number of RPM. 03 The 4.000-inch crank and 6.125-inch rods were combined with a set of forged asymmetrical pistons from JE. 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. The absence of engine knocking ensures that your car engine is reasonably combusting the fuel. I bet you won't see a bit of difference. 110 degrees on the lobe separation angles. A commonly held misconception is that intake/exhaust overlap contributes to lower cranking compression. Lower cylinder pressure is advantageous for your engine. The 108-degree cam (blue lines) outperformed the other two, but idle quality suffered. JavaScript is disabled. It a 355. thanks in advance. You are using an out of date browser. Overlap is the amount of time that both valves are open in the same cylinder. thanks. 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. Ultimately, it comes down to how you want the engine to run, the car's intended purpose, and what you are willing to tolerate. 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.. 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. 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. Realize what the engine is going in, however, as you may not be able to use the wildest cam out there. Come join the discussion about restoration, modifications, NOS parts, troubleshooting, VIN codes, and more! Cam timing plays an important role not only in the power generated but also the overall character of the powerplant. 110 LSA: You will find the complete opposite scenario here. 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. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. On a torque graph it tends to resemble a triangular shape.. Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). Once more the engine came apart to install the third test cam, a 107 LSA. As lobe seperation spreads does the powerband. That was just a glimpse of the information you were looking for. But, after comparing these two LSA based on a few mechanical aspects, such as maximum Torque, RPM, powerband, oil consumption, and many more, you will find the 106 LSA with better performance output. A cam with 110 lobe center will pull approximately 14-18"of vacuum is borderline for that type of application. I will be running an Edelbrock Performer RPM, with a Quick Fuel 750cfm with a screw adjustable vacuum secondary; it's called the Pro-vac. It may not display this or other websites correctly. " - Voltaire. After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. 4-Link72, do you run racing gas or pump with 10.5:1 CR? Defining Lobe Center and It's Importance to Engine Performance: A Blog. The final cam was tighter still, with a 108-degree LSA. 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. Fixing the ignition coils is essential when you experience issues like engine misfire and the Check Engine light that wont go off. I've seen that Webcam cams can be ordered with either of the above. 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. Given that nitrous works best in the mid- to upper-rpm range, nitrous-powered engines need a wider lobe separation, like 112 . I know a little about cams. 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. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. 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. (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 . I wouldn't assume 4 links fuel requirements will mirror yours at all. 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. You can modify the lobe center a little bit but not enough to change the actual overlap of the grind. 12 In terms of power production, the stroker LS3 performed best with the tightest lobe separation angle. Things like idle vacuum, fuel economy, and tuning all factor into picking the right cam. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open.. He also enjoys reading books a lot and his favorite author is Paula Coelho. It made 472.4 lb-ft at peak, a 21.5lb-ft disparity from the 101 cam. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. Also know as Lobe Separation; Lobe Center is simply the distance between the peak opening points on the Intake and Exhaust lobes. 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. More over-simplifications: All testing was performed with an Aeromotive fuel pump feeding a set of 42-lb/hr injectors. The ported heads were capable of supporting over 700 hp, so we knew they would not be restrictive on our stroker. Wide LSA cams are also applicable in forced-induction applications where less exhaust overlap is required. However, these rules are not absolute. 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. But, after comparing these two LSA based on a few mechanical aspects, such as maximum Torque, RPM, powerband, oil consumption, and many more, you will find the 106 LSA with better performance output. Lobe Separation Angle "LSA "Jump to Latest Follow 1 - 17 of 17 Posts . It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open. We will also custom grind any of the above profiles with a custom lobe center, for an additional $20 dollars. A forum community dedicated to hot rod owners and enthusiasts. i've heard of this being done something about the massive amounts of duration allowes gasses to disipate? The other thing is that you need to tune your ignition advance to maximize your performance. NOTE: Classic Inlines stocks the above profiles in 108, 110, and 112 lobe centers. When choosing a cam, power gains shouldn't be the only consideration. A 110-degree lobe separation angle means that the peak opening points of the intake and exhaust lobes are 110 degrees apart. 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. 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. The 110o will make more power overall. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. 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 . As a result, a wider valve opening system with no overlapping allows more oil to fall through the oil inlet. Introduction. . Good luck. More than any other component, the cam profile determines things like idle quality, mileage, and overall driveability. 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.
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