This overlapping has a direct influence on the oil consumption rate of the engine. OK, what is hydraboost, and how do you like how the cam performs??? It will also give you a smoother idle and probably even better gas mileage. But, the narrow or broad powerband choice varies from person to person. In terms of horsepower, the disparity between all three cams was only 6.5 hp, with a scant 100 rpm separating the peaks. 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. On engines equipped with independent intake and exhaust cams, the LSA is adjustable. It is the angle that separates the intake and exhaust lobe for a particular cylinder, and is measured in camshaft degrees. 110 LSA: But here, quite surprisingly, you have to face the reduction of the EGR effect due to the 110 LSA. 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. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. However, a cam with 108 will only pull 12-16", which is not enough for power assisted accessories. 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. 108 is very tight producing lower vacuum and more of a 2 stroke "punch" powerband. O onovakind67 Registered Joined Dec 14, 2001 6,242 Posts music to your ears? Comp cam hydraulic roller lifters. "When the low-pressure wave in the exhaust reflects into the intake, the pressure delta actually helps pull air and fuel into the cylinder. Usually, this separation angle ranges from 95-degree to 120-degree. I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. There are General guidelines about the effects of LSA but it should not be the deciding factor in choosing a cam. The Crane has a smoother idle, broader power band, and . The only reason the advance or retard a camshaft profile is to get the timing events where they need to be. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. 68 Mustang, 306, AFR 185\'s, CI cam, FPA\'s, Bigs 650 DP, T5Z, 9" w/4.33's. The tighter the lobe center, the lower the RPM range; the wider the lobe center, the higher the RPM range. We promise not to use your email address for anything but exclusive updates from the Power Automedia Network. 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. So, which is better? Defining Lobe Center and It's Importance to Engine Performance: A Blog. 106 LSA: 106LSA results in a decrease in piston-to-valve clearance. The custom cams we selected all featured 0.624-inch lift (both intake and exhaust) and a 232/242-degree duration split. Some of the confusion on this subject comes from what the meaning of "bottom" and "top" is to the speaker, I suppose. 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. Either learn to fix it, or learn to write checks. 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. It made 472.4 lb-ft at peak, a 21.5lb-ft disparity from the 101 cam. 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. This is ground into the cam and can't be changed without changing cams. So, the 110 LSA engine is a suitable choice for people prone to be the fan of a powerful engine with mighty acceleration power. 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 -. Things like idle vacuum, fuel economy, and tuning all factor into picking the right cam. 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. This may be of concern if you have vacuum assisted accessories, such as power brakes or steering. Our content is merely suggestive, not intended to use without proper safety precautions and advice. This is very critical for manifold vacuum, throttle response, emissions, and gas mileage. 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. Whatever you do, stay under 270 advertised duration and shoot for a 110 lobe separation. After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. And better gas mileage. The LSA, or lobe separation angle, is ground into the cam and cannot be changed. The engine would idle a lot rougher and generate worse exhaust emissions largely because of unburned fuel.. The lobe separation angle is the angle between the two camshaft lobes that act on the valves. Save my name, email, and website in this browser for the next time I comment. Some prefer a narrow powerband, and some prefer the broader one. The intake lobe centerline is measured in crankshaft degrees. AquaTraction Vs SeaDek: Which One Is Better For you? The 110 is probably a better choice for a performance street engine. The higher the compression and the higher you try and rev it, the more it will like a wider lobe center. 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. In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. It will have slightly higher vacuum at idle, feel smoother through the power curve but have a bit less midrange. Some of the programs like engine analyzer pro and dynomation seem to like some of the wider lsa's.Thanks again JOE. I have Crane hydraulic link bar style roller lifters, so I dont have to use the spider style. 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. And better gas mileage. But there is a drawback of higher cylinder pressure: higher cylinder pressure may sometimes lead to piston or piston ring problems. 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. 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. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. With a 108 degree lobe center, a cam will have a rougher idle and produce less vacuum due to more overlap. If that were the only consideration, the 101 cam is the clear winner. 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. hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. 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. Like one cam is 112 degree and the next is 108 the 108 cam will allow less "leakage"? A tighter LSA is always going to have more overlap, which allows the exhaust and intake systemif they're tuned wellto work together.". I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. 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. 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. But nothing comes without a cost, and idle vacuum suffers as LSA shrinks. Pretty much standard for an RV type cam. Engine builders Chuck Lawrence, left, and Doug Patton. The ported heads were capable of supporting over 700 hp, so we knew they would not be restrictive on our stroker. Contrariwise, 106 LSA car engines are the best choice for people seeking energy-efficient cars with moderate engine power. by Kdub Sat Dec 06, 2008 11:05 pm, Post A cam with a 112 lobe center will idle smoother than a cam with a 110 lobe center. That is why 106 LSA consumes less oil. 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! Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. As you tighten the centers ( 108 ) the same engine will make MORE power through the mide range and top end. Ed JTO learn to park Joined May 31, 2009 180 Posts 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. 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. 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. Camshafts with a substantial overlapping tendency should not be used in vehicles driven on public streets. The 108-degree cam offered both the most power and torque, but idle quality suffered compared to the wider LSAs. The world of fuel injection is where wide LSA cams like the 113 really shine. 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. 110 LSA: On the contrary, 110LSA has a higher piston-to-valve clearance rate. by randy331 Sat Dec 06, 2008 10:00 pm, Post 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. . Build your own custom newsletter with the content you love from EngineLabs, directly to your inbox, absolutely FREE! . It is possible to advance and retard the timing events, but the distance between the centerline of the lobes will remain constant. by mrsmythe Tue May 13, 2003 5:45 am, Post = Moderately Tight 106-104 Deg. The 114 cam will give more low end torque, good midrange, less power up high. you cannot just take a random change in a lobe separation angle and say 1 is better than the other. I'd run it, just be sure to check valve to piston clearance, coil bind and retainer to guide boss/seal clearance. Here are the basics: higher lift values open the valves to increase airflow and longer duration keeps the valves open longer. Again this is dependent on your shift rpm and assuming you truly have 14-1 compression. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know. The exhaust has an opening even and a closing event. 11 Doing LS cam swaps on the engine dyno is a breeze, each taking less than 1 hour. When choosing a cam, power gains shouldn't be the only consideration. If you want a lumper idle go with a cam with 108 LSA, the tigher the LSA the idle will be rougher. Similarly, 110 LSA is also found to be a more fabulous performer in several mechanical aspects. 106 LSA: There is a scale of standard cranking compression of the engine. While a cam with a 108 lobe center will idle rougher. For Example: A 110-degree lobe separation means that the peak opening points of the Intake and Exhaust lobes is 110 degrees apart. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. Really wide lobe separation angles are used in boosted applications. NOTE: Classic Inlines stocks the above profiles in 108, 110, and 112 lobe centers. This process slows down the reaction rates of the air-fuel mixture, causing temperatures to drop and preventing the engine from overheating. 01 Choosing the right lobe separation angle for your LS cam shouldn't cause anxiety. They also reduce stress on the outdrive. Lobe separations on 383-406 cids.104-106-108-110? This has been my long time understanding! = Tight Below 104 Deg. 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. Despite no changes in lift or duration, this cam sounded much more aggressive than the other two with wider LSAs. 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. by Hoxviii Mon May 12, 2003 7:50 pm, Post Now lets move to the exhaust. If the cylinder heads are the lungs of an engine, the camshaft is the brain. 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. Also know as Lobe Separation; Lobe Center is simply the distance between the peak opening points on the Intake and Exhaust lobes. 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. Seeking 1/2" ID x 5/8" OD Black Exit Tubing for Radiator Overflow Reservoir. 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. If a street car has smaller lift and duration numbers, they might run 112 or 114. Once more the engine came apart to install the third test cam, a 107 LSA.
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