A cams Lobe center angle equals intake centerline plus exhaust . All testing was performed with an Aeromotive fuel pump feeding a set of 42-lb/hr injectors. Do you know what the best lobe separation angle for your car engine is? If you take any of the . Compression willl be 9.75:1. I just installed a Comp Cams XE262 in a 9:1 350 with stock iron heads. 08 Additional components used to build the stroker included a set of Comp hydraulic roller lifters, ARP head studs, and a new oil pump. Lobe separations on 383-406 cids.104-106-108-110? Tests have shown that, for a given cam profile, a tighter (smaller) lobe center will produce more average horsepower and a quicker revving engine. 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. whats the difference in how the car will run. Comp cam hydraulic roller lifters. The 108 LSA offered the lowest idle vacuum of the three (down 4 inches). Attenuation of Seizures, Cognitive Deficits, and Brain Histopathology More than any other component, the cam profile determines things like idle quality, mileage, and overall driveability. " - Voltaire. by Marc Mon May 12, 2003 11:38 am, Post 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. 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. The ported heads were capable of supporting over 700 hp, so we knew they would not be restrictive on our stroker. You must log in or register to reply here. I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. by SStrokerAce Sat Dec 06, 2008 7:38 pm, Post 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. 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. music to your ears? Lunati's New Bootlegger Camshaft Series Has Strong Race - Dragzine by Kdub Sat Dec 06, 2008 11:05 pm, Post 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 -. What Is the SBC Header Bolt Torque? 106 LSA: You can see an increasing EGR effect at 106 LSA. That means your engine can produce more power with a minimum amount of fuel combustion. 06 The ported heads featured a 2.165/1.590-inch valve combo. Here are the basics: higher lift values open the valves to increase airflow and longer duration keeps the valves open longer. 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 cam with a 112lobe center will idle smoother than a cam with a 110lobe center. 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 will be running an Edelbrock Performer RPM, with a Quick Fuel 750cfm with a screw adjustable vacuum secondary; it's called the Pro-vac. For a better experience, please enable JavaScript in your browser before proceeding. The higher the compression and the higher you try and rev it, the more it will like a wider lobe center. 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. Turbochargers are not as simple as they may sound; you may think of them only as power-boosting components. Either learn to fix it, or learn to write checks. Engine knocking generally occurs when the burning of the fuel by the engine is uneven. Lobe sepsration is an advanced description for overlap.If you take a cam on a 112,and grind it on a 108,you add more overlap,the time the valves are both open.Narrower lobe centers mean more low end and midrange torque,along with a peakier powerband,and a slightly rougher idle.Tradeoffs are sensitivity to octane ratings,total timing, and air fuel ratio.A lot to swallow I know,hope this helps you. 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. A commonly held misconception is that intake/exhaust overlap contributes to lower cranking compression. But for small-block Chevys (like the LS applications in this story), the LSA is ground into the cam. Overlap is the amount of time that both valves are open in the same cylinder. Increasing the EGR effect has a good side in that it reduces the amount of oxygen in the combustion chamber. 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. Icao Annex 10 Aeronauticaltelecommunicationsvolumeiv-Surveillanc 106 LSA: At this LSA, the car machine has to confront the reduction of idle vacuum rate quite often. 114 lsa cam sound clips | LS1LT1 Forum But nothing comes without a cost, and idle vacuum suffers as LSA shrinks. Pontiac 326 Vs Chevy 327 Differences & Similarities. For a better experience, please enable JavaScript in your browser before proceeding. This cam also offered the highest torque output at 4,000 rpm with 522 lb-ft. Based on the peak numbers alone you might be tempted to grab the one with the tightest (108-degree) LSA, but there is more to a cam test than power. 106 LSA: As you know, the intake and exhaust lobes centerline distance is known as lobe separation angle. 106 Vs 110 Lobe Separation Angle: Real Impacts You Must Learn 112 will have a smoother idle, a wider power band, and will work better with fuel injection. 01 Choosing the right lobe separation angle for your LS cam shouldn't cause anxiety. With the first cam loaded in the engine (the 101 LSA) Westech's Steve Brul made three dyno pulls, the average of which was saved to compare to the next cam. 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. A cam 112LSA with 4 degrees advance puts the intake centerline at 108 degrees. Hey guys, can anyone tell me how rough of a idle a cam would be with a 108 lobe separation? Mistakes that weaken a supercharger's performance If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. #2---Choosing a Cam - Hughes Engines The 402 was run with a FAST LSXR LS3 intake and matching 102mm throttle body along with stock LS3 rockers, a Holley HP management system and 7.4-inch hardened pushrods (from Comp Cams). Thanks for the replies, particularly that link Marc, very informative. The 114 cam will give more low end torque, good midrange, less power up high. I know a little about cams. However, these rules are not absolute. I have Crane hydraulic link bar style roller lifters, so I dont have to use the spider style. For your convenience, I am providing a comparison table to give you an overall idea about the comparison. A few other major and, Read More Heres What Causes Your Car to Bog Down When AcceleratingContinue, Your email address will not be published. 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. Part Number: HRS-CL120325-08. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Brul slid the 113-LSA cam, the widest of the test, into the engine's heart and set about putting all the pieces back in place. by Paul H Tue May 13, 2003 1:24 pm, Post 106 Lobe Separation Angle | The De Tomaso Forums Lucky for us, Brian Tooley Racing stepped up with a dual spring package that allowed us to safely run our 0.624-lift cam. In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. Defining Lobe Center - Clay Smith Cams "Ninety-nine percent of cranking compression is dictated by static compression ratio and intake-valve closing point," said Comp Cams' Billy Godbold. What real difference does the lsa on a cam make? 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. 07 Though the CNC-ported heads offered plenty of flow, it was necessary to upgrade the supplied valvesprings. 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. But you always have a cam card with the engine. A forum community dedicated to vintage Ford Mustang owners and enthusiasts. Tests have shown that, for a given cam profile, a tighter (smaller) lobe center will produce more average horsepower and a quicker revving engine. Mechanical aspects like maximum torque, narrower powerband, higher cranking compression rate, efficient compression rate, effective EGR effect, and lower oil consumption rate increase the car engines efficiency and make it energy efficient. "When the low-pressure wave in the exhaust reflects into the intake, the pressure delta actually helps pull air and fuel into the cylinder. The valve covers, valvetrain, intake manifold, harmonic balancer, front cover, timing set, and cam were yanked. 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. As you tighten the centers ( 108 ) the same engine will make MORE power through the mide range and top end. It is the DESIGNED events that yield CENTERLINE. A 112-114 degree lobe center will have a better idle and produce more vacuum with less overlap. Build your own custom newsletter with the content you love from EngineLabs, directly to your inbox, absolutely FREE! While a cam with a 108 lobe center will idle rougher. So, this LSA is suitable for your engine and its components. Is a 108 Lobe Separation 2 Much? | Hot Rod Forum Cylinder-head flow and LSA are directly related: as a rule of thumb, the better the head flows, the wider the LSA can be. by mrsmythe Mon May 12, 2003 11:15 am, Post Like one cam is 112 degree and the next is 108 the 108 cam will allow less "leakage"? 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. 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.". Unfortunately, good street manners are often at odds with performance, as wilder cam timing usually decreases idle and (low-speed) driveability. I just bought a 86b Webcam and Im using 1.5's. 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. Test 1 was easy. Usually, this separation angle ranges from 95-degree to 120-degree. If you look at any given cam catalog, you will find that the majority of street-oriented cams fall in this range. It idles very well at 650 rpm with a nice lope and runs strong. 114LSA +4 puts the intake centerline at 110 degrees before top dead center. However, in application, there is a lot more to consider. Camshaft Kits - 108 Lobe Separation (degrees) - Summit Racing I'd run it, just be sure to check valve to piston clearance, coil bind and retainer to guide boss/seal clearance. 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. The final cam was tighter still, with a 108-degree LSA. Lobe Separation Angle Explained and How it Affects Horsepower - MotorTrend GRIND #: CRB3 3194 /3196 HR111. The 110 is probably a better choice for a performance street engine. A cam with a 112 lobe center will idle smoother than a cam with a 110 lobe center. I think the compression ratio has something to do with LSA too. If you changed the lobe separation of a street engine from 112 degrees to 106 and didnt do anything else, adds Kaase. Brul spun the engine over with the dyno's starters and recorded 185 psi of cranking compression. by SStrokerAce Sun Dec 07, 2008 12:22 am, Post dont sound like a verry street friendly motor butany thoughts? How do the lobe separations change when you factor in turbocharging? not exactly true, Ive seen custom grinds that are on 108 lca, smooth idle, high vacuum an even able to run efi, usually on an off the shelf cam it is true. by farmer Mon May 12, 2003 3:14 pm, Post 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. It may not display this or other websites correctly. This is one of the many reasons why Clay Smith Cams always recommends degreeing your camshaft in using the Lobe Center Method. A lower efficient compression rate leads to a higher fuel consumption rate by your engine to produce higher power. There are General guidelines about the effects of LSA but it should not be the deciding factor in choosing a cam. This overlapping has a direct influence on the oil consumption rate of the engine. He also enjoys reading books a lot and his favorite author is Paula Coelho. It is possible to advance and retard the timing events, but the distance between the centerline of the lobes will remain constant.