Comp cam hydraulic roller lifters. Meaning the lower lobe seperation will have a very quick and fast powerband (Snappy!) hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. 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It may not display this or other websites correctly. 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.. A cam's lobe separation determines where and for how long peak torque occurs in an engine's rpm range. 110 LSA: However, if you look at the rate of cranking compression at 110 LSA, you will find a reduced compression rate from the standard cranking compression PSI level. Looking at 108vs. All testing was performed with an Aeromotive fuel pump feeding a set of 42-lb/hr injectors. You cannot look at just the LCA without looking at other specs too. It idles very well at 650 rpm with a nice lope and runs strong. Aug 20, 2006. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. A cam with 110 lobe center will pull approximately 14-18"of vacuum is borderline for that type of application. Noah knows a lot about whats happening in the car industry with the latest piloting productions thanks to his professional experience. A forum community dedicated to hot rod owners and enthusiasts. It should still make close to 600hp and 600tq in my 512" stealth headed big block. An icon used to represent a menu that can be toggled by interacting with this icon. 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. by bigjoe1 Sat Dec 06, 2008 10:48 pm, Post More over-simplifications: A cams Lobe center angle equals intake centerline plus exhaust . For a better experience, please enable JavaScript in your browser before proceeding. 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. Is it a hydraulic roller as well? 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). How do the lobe separations change when you factor in turbocharging? 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. 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 other thing is that you can make more power with a smaller aftermarket cam. 292S-112: 292/292 - 240/240 - .495/.495 - 112* - 3400-7200. 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. Thanks for the replies, particularly that link Marc, very informative. 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. 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. 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. As usual, Marc (aka Master) is correct. If the cylinder heads are the lungs of an engine, the camshaft is the brain. Given that nitrous works best in the mid- to upper-rpm range, nitrous-powered engines need a wider lobe separation, like 112 . "Ninety-nine percent of cranking compression is dictated by static compression ratio and intake-valve closing point," said Comp Cams' Billy Godbold. Is There a Sequence? Lobe separation angles, he continues, are influenced by the camshaft grind. Save Share. I don't think your duration figures are too outlandish and with the tight LCA and high lift, it should make some big torque. "When you've properly tuned a performance motor, you create high- and low-pressure waves in the intake and exhaust that help cylinder filling," said Comp Cams' Billy Godbold. Some of the programs like engine analyzer pro and dynomation seem to like some of the wider lsa's.Thanks again JOE. That lopey idle that is universally loved, and part of the allure of a tight LSA cam, is actually misfire caused from a combination of exhaust dilution in the intake manifold and poor cylinder filling at idle. 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. - Sheryl Crow. I'd also go to a 110-112 lobe separation angle. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know. Depending on the engine combination, the opposite results can occur. And better gas mileage. 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. I would have to say that your cam choice sounds like a winner to me. Exhaust reversion is another undesirable side effect that can be caused by overlap. . With a 108 degree lobe center, a cam will have a rougher idle and produce less vacuum due to more overlap. Seeking 1/2" ID x 5/8" OD Black Exit Tubing for Radiator Overflow Reservoir. 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. Also If you go with 112 lobe centers, you create less valve overlap which will increase your compretion. Again, these are general bits of conventional wisdom. I think the compression ratio has something to do with LSA too. 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. 110 will be a bit punchier in the midrange and probalby make a little more peak horsepower as long as a good exhaust is used. Moreover, a user from the Chevelle forum said. Its the shifting problem again with your Chevy! I'm sorry to disagree with that incredibly well written article, but lobe separation by itself is absolutely freaking meaningless. 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. Simply put, the lobe center of the camshaft controls where the power curve is applied. It depends on the combination of engine size, head flow and head flow balance, as well as a big one, exhaust flow capabilities. The intake lobe centerline is measured in crankshaft degrees. . 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. Torsion Beam Vs Multi Link: Who Wins the Battle? The 108-degree cam offered both the most power and torque, but idle quality suffered compared to the wider LSAs. Thats just the way the customer wants to roll, and engine builders find its easy to deliver such a powerplant. 13 The three power curves indicate that the wide (120-degree) LSA (green lines) lost considerable torque to the other two cams. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. Engine builders Chuck Lawrence, left, and Doug Patton. 112 will have a smoother idle, a wider power band, and will work better with fuel injection. If identical and for a given displacement the 110 will give more power. You are using an out of date browser. Say you have a cam ground on a 115 and the other on a 110. Pretty much standard for an RV type cam. Now that we have a basic understanding of lobe separation angle, we can put together a test to illustrate just what happens when you make changes to it. Lobe separations on 383-406 cids.104-106-108-110? See all 14 photos 13 The three power curves indicate that the wide (120-degree). After the next three pulls, it was clear the 113 cam was way down on low-end torque. General topics - 76 LA built, CA car with m20. Aluminum flywheel & pullies. by mrsmythe Tue May 13, 2003 5:45 am, 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). For your convenience, I am providing a comparison table to give you an overall idea about the comparison. 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. lobe centers and lobe separation are 2 different things . 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. We even treated them to some chamber work before installation. Retarding the camshaft (a higher intake lobe centerline number 108 vs. 104) will generally start the power band later in the RPM range and decrease the cylinder pressure. 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. 106 LSA: There is a scale of standard cranking compression of the engine. The tighter the lobe center, the lower the RPM range; the wider the lobe center, the higher the RPM range. Tests 2 and 3 meant dissecting the motor on the dyno to get the old cam out. so the power will come on a litter sooner with the 114, and fall off a little sooner? 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? A forum community dedicated to Ford performance owners and enthusiasts. The lobe separation angle is a comprise of what the engine needs depending on the compression, combustion chamber, rpm, engine size, head volume, and many, many other variables. Another related thought to consider when selecting a cam is inches of vacuum for your engine application when deciding upon a Lobe Center. I had a 110 cam in my beetle and I didn't like it-the bottom end was doggy. Consequently, decreased torque rate often leads to more energy consumption. 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. 110 for sure. Post 4-linked72, what cam are you using that has a 108 LSA? It made 472.4 lb-ft at peak, a 21.5lb-ft disparity from the 101 cam. Well get out of that stocker and build a hipo motor for your VW. It is possible to advance and retard the timing events, but the distance between the centerline of the lobes will remain constant. It really comes down to the application. When degreeing in the camshaft, you are making sure the intake centerline is precisely where the cam is intended to be. 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. I just bought a 86b Webcam with 112 lobe centers for my 2276. 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. Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). Turbochargers are not as simple as they may sound; you may think of them only as power-boosting components. 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. The only reason the advance or retard a camshaft profile is to get the timing events where they need to be. changing just the LSA on my cam wouldnt make a bit of difference on vacuum operated items E ericnova72 More for Less Racer Joined Jan 13, 2007 22,026 Posts 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. This process slows down the reaction rates of the air-fuel mixture, causing temperatures to drop and preventing the engine from overheating. Also present during testing was a set of 1 7/8-inch Kooks headers, Comp hydraulic roller lifters, and F-body oil pan. i have a 4 bolt 351C, stock bore, 10.5 cr with 351C Boss heads ,boss crank and rods. 12 In terms of power production, the stroker LS3 performed best with the tightest lobe separation angle. 11 Doing LS cam swaps on the engine dyno is a breeze, each taking less than 1 hour. Lobe Separation Angle "LSA "Jump to Latest Follow 1 - 17 of 17 Posts . = Moderate 108-106 Deg. What Are The Wastegate Stuck Open Symptoms? 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. 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. 04 Minor modifications to the factory windage tray were necessary to work with the new stroker assembly. pump gas, no additive's as well, runs good, i will put the highest octane in, which is 93.. by Marc Mon May 12, 2003 11:38 am, Post 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. Either learn to fix it, or learn to write checks. Pick the cam with the valve timing events that fit the engine best, forget about LSA, it is only a result of the events. Some prefer a narrow powerband, and some prefer the broader one. 2023 Power Automedia. But it also has a lot of lobe separation. Elle concerne 264 taxons des degrs divers. Epilepsy is a chronic noncommunicable brain (neurological) disorder associated with excessive neuronal activity and unprovoked seizures referred to as 'epileptic seizures' and sensory-motor deficits that cause neurobiological, cognitive, psychological, and social consequences to the patient. " - Voltaire. Bolander says those cams help promote torque in a controlled and predictable manner, especially in no-wake zones and around the docks. also,, wider will produce a wider and more flat torque curve that doesn't fall off as abruptly up top rpms. I wouldn't assume 4 links fuel requirements will mirror yours at all. 108* or narrower lobe separation angle (LSA) is "Narrow" and 114* or wider (up to 117* or 120* for stock cams) is "Wide" , with 110 to 112* being the "normal" hot-rod cam. 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! Introduction. In this segment, I am going to compare those two lobe separation angles based on a couple of mechanical factors. The piston and cylinder damage possibility is pretty low at 110 LSA. But it is a piece of good news for your engine. 15,215. ohio. dont sound like a verry street friendly motor butany thoughts? Save my name, email, and website in this browser for the next time I comment. Read More Chevy 350 Ignition Coil Location And Everything About ThemContinue, What causes a car to bog down when accelerating? The Idles increasing vacuum improves the idle quality and the engines overall performance. 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. You can modify the lobe center a little bit but not enough to change the actual overlap of the grind. ALL bolts are ARP. 106 LSA: At 106 LSA, the cylinder pressure is a bit higher. But nothing comes without a cost, and idle vacuum suffers as LSA shrinks. However, the plentiful exhaust overlap (31 degrees) meant there was lots of exhaust dilution at low engine speed and high vacuum. Only once the intake valve has closed can compression begin to build. While a cam with a 108 lobe center will idle rougher. Well, I saw that Erson makes some nice hydraulic rollers with 108 LSAs, and I know that tighter LSAs have more midrange, so I thought they might be worth a try. However, it is fixable. 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. When choosing a cam, power gains shouldn't be the only consideration. I have used some cut on a 110 that worked well too, but they never sounded as good as the tight ones. 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.
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