so the power will come on a litter sooner with the 114, and fall off a little sooner? Build your own custom newsletter with the content you love from EngineLabs, directly to your inbox, absolutely FREE! Do you like to go fast? Your email address will not be published. The #1 intake lobe centerline is usually between 100 Lobe separation angle does. On a tight lobe separation, like 106-108 degrees, the engine will build torque quickly and reach its peak early. by Kdub Sat Dec 06, 2008 11:05 pm, Post 110 LSA: On the contrary, it is pretty unpleasant to inform you that the efficient compression rate decreases at 110 LSA. 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 . 106 LSA: You can see an increasing EGR effect at 106 LSA. I had a 110 cam in my beetle and I didn't like it-the bottom end was doggy. 09 All testing was run through a set of 1 3/4-inch long-tube headers and 3-inch exhaust. After swimming through the entire article, I hope you are now well aware of the 102 vs 110 lobe separation angle. This wave tuning is what helps performance engines achieve volumetric efficiencies of more than 100 percent. 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. 2.1.2.4.2 Side-lobe suppression shall be provided in accordance with the provisions of 3.1.2.1.5.2.1 on all Mode S-only all-call interrogations. kinda off topic.. but while we're on the topic of cams, duration,lift,ect has anybody heard of using high compreshion (13:1) on pump gas, by useing alot of duration? It's wet flow tested at 690cfm. Every spec is a road map to what the valves are doing, the most common of which are lift, duration, and lobe-separation angle (LSA)the latter needing the most explanation. It's the scavenging effect of the high velocity exhaust gases rushing out that pulls the fresh fuel/air charge into the chamber. 1-4 It is one of the most common neurological disorders worldwide, 1-5 is among the most common . Not a HUGE, but a significant difference between 110 and 112, but those are the trends. 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. AquaTraction Vs SeaDek: Which One Is Better For you? by SStrokerAce Sat Dec 06, 2008 7:38 pm, Post music to your ears? Bad idea in my view. Defining Lobe Center and It's Importance to Engine Performance: A Blog. Test 1 was easy. Yeah but do the experiment on the dyno and tell me your intuition is correct. 4 Impaired episodic memory and semantic knowledge are common in TLE, although dysexecutive traits . 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. "It's not having what you want, it's wanting what you've got!" Simply put, the lobe separation angle (LSA) is a measurement of how the intake and exhaust lobes are phased with each other. It is the average centerline between both lobes and expressed in degrees ranging from 95 on the extremely narrow/tight side to upward of 120 on the wide end. by trmnatr Sat Dec 06, 2008 10:45 pm, Post If you look at the cam card, you will find a maximum lift column on the card.Now, all you have to do is, add up the two mentioned maximum angles and divide the summation by 2. The custom cams we selected all featured 0.624-inch lift (both intake and exhaust) and a 232/242-degree duration split. The graph above compares intake valve closing points of the three cams used in the test. Fixing the ignition coils is essential when you experience issues like engine misfire and the Check Engine light that wont go off. 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. More over-simplifications: . LSA is a result of valve timing events. I am pretty sure, right now, you find yourself in the middle of the rising debate of 106 vs 110 lobe separation angle. Methods: We evaluated 30 individuals with PD (62.47.2 years) and 22 age-matched healthy controls (61.06.4 years). 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! If you're an OEM automaker looking for a steady idle, good fuel economy, and passing tailpipe emissions, this is the cam of choice. 238/248 duration, 300/310 adv. This process slows down the reaction rates of the air-fuel mixture, causing temperatures to drop and preventing the engine from overheating. Introduction. On larger displacement units 116 to 118 degrees of separation are common. The final, 108-degree cam stepped power up even further, with peaks of 572 hp at 6,300 rpm and 544 lb-ft at 5,200 rpm. The 114 cam will give more low end torque, good midrange, less power up high. Chuck Lawrence of Jon Kaase Racing Engines was asked to give a 520ci BBF a Pro Stock sound, so he went with a 108 LSA in place of a more conventional 112 LSA. A forum community dedicated to Ford performance owners and enthusiasts. 110 LSA: You will find the complete opposite scenario here. somthing to that aspect. 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. 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. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. Usually, this separation angle ranges from 95-degree to 120-degree. OK, what is hydraboost, and how do you like how the cam performs??? too much for the street? Post If you want a lumper idle go with a cam with 108 LSA, the tigher the LSA the idle will be rougher. LS Exhaust Manifold Bolt Torque (Everything You Need To Know), Holley Power Valve Sizes: Everything There is to Know. ( 2 ) Estimated Ship Date: Feb 23, 2023 (if ordered today) Drop Ship. FWIW. hydraboost is the same as a vacuum brakebooster, only the booster is replaced by a unit that does the same but under hydraulic pressure. . Topping the short-block was a set of Chevrolet Performance CNC LS3 heads from Gandrud Chevrolet. I am trying to pick out a hydraulic roller cam for my 351W with AFR 185s. ALL bolts are ARP. 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. 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. That is why 106 LSA consumes less oil. 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. The lobe separation angle is the angle in camshaft degrees between the maximum lift points, or centerlines, of the intake and exhaust lobes. by Hoxviii Mon May 12, 2003 7:50 pm, Post Overlap is the amount of time that both valves are open in the same cylinder. On the surface, the camshaft's job is simpleopen and close the valvesbut beyond that topical description, it's one of the most mysterious and misunderstood engine components. Re: Lobe separations on 383-406 cids.104-106-108-110. . Thanks for the replies, particularly that link Marc, very informative. What happens when you change ONLY. JavaScript is disabled. Cam swaps are all the rage and for good reason. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. This form of short-term memory is supported by the prefrontal cortex (PFC) and is believed to rely on the ability of selectively tuned pyramidal neuron networks to persist in firing even after a to-be-remembered stimulus is removed from the environment. The article was called "Separation of Power" and they tested 5 cams ranged from 106 to 114 LSA. But, the narrow or broad powerband choice varies from person to person. 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. Coupled that with the low first gear of the five speed, it ought to create some real traction problems. But to choose the perfect cam, all of that information needs understanding. Read More Chevy 350 Ignition Coil Location And Everything About ThemContinue, What causes a car to bog down when accelerating? 108 versus 110 will drive the power band down. Another important measurement was the torque production at 4,000 rpm and this cam checked in with 484 lb-ft of torque. 15,215. ohio. But, at 106 LSA, the cranking compression may increase above the standard PSI level. If you changed the lobe separation of a street engine from 112 degrees to 106 and didnt do anything else, adds Kaase. This was science at work, and with data in tow, it was time to crunch the numbers and find out what was going on. 110 LSA: On the contrary, 110LSA has a higher piston-to-valve clearance rate. Knife edged & profiled 4MA Cleveland crank weighing 50lbs. I know a little about cams. Boom, you get the lobe separation angle of that engine. It is dangerous to be right in matters on which the established authorities are wrong. The takeaway is simple on the surface: A tighter LSA makes more low-end and peak torque at the expense of just a few top-end ponies. 108 is very tight producing lower vacuum and more of a 2 stroke "punch" powerband. You get a better idle, vacuum, and response from a 112o-114o lobe. = Moderately Wide 110-108 Deg. 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. 108 vs 112 lobe seperation. 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. 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. 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. But, you may find a lobe wider than a 120-degree angle in any car engine.But, I must let you know that those are customized car engines prepared for any special purpose, such as racing, drag racing, off-road riding, or performing stunts. thanks. 2023 Power Automedia. Lobe Separation or Lobe Centers is another way of expressing the Valve Overlap, which was the term formerly used by cam manufacturers before industry standard verbiage changed. you cannot just take a random change in a lobe separation angle and say 1 is better than the other. (You can find an instructional video of how to do just that on our Clay Smith Cams YouTube Channel;https://www.youtube.com/watch?v=57gfBu8uc6k&t=1s ). I had an XE 274 in it. 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. Howards Cams Retro-Fit Hydraulic Roller Camshaft and Lifter Kits CL120325-08. 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. That was all, and we have already reached the concluding point. Now lets move to the exhaust. Yearh, I have been reading a lot about this issue. 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. As you tighten the centers ( 108 ) the same engine will make MORE power through the mide range and top end. A wider LSA moves intake- and exhaust-valve events farther apart and creates less overlap, which hurts intake-wave tuning. But, you may wonder knowing that a higher valve clearance rate reduces the chance of damaging the valve by the piston. A cam's lobe separation determines where and for how long peak torque occurs in an engine's rpm range. 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. 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. We will also custom grind any of the above profiles with a custom lobe center, for an additional $20 dollars. 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. To overcome this inherent problem in wide LSA camshafts, you simply need a higher-flowing intake port. Once more the engine came apart to install the third test cam, a 107 LSA. A Pro Stock engine builder may prefer a wide LSA to help keep the power from breaking traction tOo early. The other thing is that you can make more power with a smaller aftermarket cam. 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 -. You cannot look at just the LCA without looking at other specs too. I have seen a dyno test where an engine using identical duration and lift made more peak power with a 112 LSA than a 110 LSA. Whatever you do, stay under 270 advertised duration and shoot for a 110 lobe separation. The takeaway from this test is camshaft LSA is a double-edged sword. For large port heads like the CNC 044's which can use the extra lift 1.4's make a noticable difference. Okay, have a sigh because you have opened the right door. A cams Lobe center angle equals intake centerline plus exhaust . Compression willl be 9.75:1. Higher lift and longer duration profiles add power, but do so at higher engine speeds (especially true of duration). Idle quality was rough and the vacuum gauge showed only 9.8 in-Hg (inches of mercury). The extra cubic inches will smooth out a rough idle in a 327. How To Properly Replace Ignition Coils, Chevy 350 Ignition Coil Location And Everything About Them, Heres What Causes Your Car to Bog Down When Accelerating. You are using an out of date browser. According to the Motortrend, LSA (Lobe Separation Angle) is a wonderful approximation of the operation of the engine because it takes into account the relative time of the intake-valve events (intake opening, intake closing) and the exhaust-valve events (exhaust opening, exhaust closing) concerning each other.Above mentioned sequential activities allow LSA to be an accurate representation of the operation of the engine. Lobe Separation Angle, or LSA, is the number of degrees that separate the peak lift points of the cam's intake and exhaust lobes. 106 LSA: So, if I talk about the powerband at 106 LSA, the powerband is narrow. Kevko baffled oil pan & Milidon windage tray. Some prefer a narrow powerband, and some prefer the broader one. 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. This is ground into the cam and can't be changed without changing cams. While a cam with a 108 lobe center will idle rougher. 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. Professionally ported & polished iron 4V head with titanium intake valves, stainless exhaust, titanium retainers & keepers & dual springs. But i would nt go any wider than 110. This table will create a map in your head, and I bet it will make your understanding crystal clear. 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. In a blower motor when the valve timing events are where they need to be the lobe sep will usually wind up in the 114-115 range on most Combos. Hey guys, can anyone tell me how rough of a idle a cam would be with a 108 lobe separation? If you take any of the . Increased overlap improves upper RPM power. 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. 554"/577" lift. However, a cam with 108 will only pull 12-16", which is not enough for power assisted accessories. Let's just talk lobe sep angle. Here are the basics: higher lift values open the valves to increase airflow and longer duration keeps the valves open longer. Good luck. I'm sorry to disagree with that incredibly well written article, but lobe separation by itself is absolutely freaking meaningless. General topics - 76 LA built, CA car with m20. It affects the powerband and temperament of a motor more than any other single part, and a slight change can turn a car from a mild-tempered grocery-getter to a downright nasty machine. 13 The three power curves indicate that the wide (120-degree) LSA (green lines) lost considerable torque to the other two cams. Lower cylinder pressure is advantageous for your engine. If you compared these two cams side by side in identical engines, the first cam would actually have a slightly better idle and would produce slightly more peak power at upper RPM's. . Moreover, a user from the Chevelle forum said. To establish the position of each lobe, the traditional reference point is where the lobes reach max lift. So, the 110 LSA engine is a suitable choice for people prone to be the fan of a powerful engine with mighty acceleration power. Around 70 percent of muscle-car performance cams fall into this range. How To Properly Replace Ignition CoilsContinue. 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. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. These issues can often be worked through by an advanced tuner, but always present a challenge and compromise in tuning strategy. 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. A wide lobe seperation is not always better than a narrow one, or vise versa. There are General guidelines about the effects of LSA but it should not be the deciding factor in choosing a cam. Well, there can be different reasons for this problem. ditto with the above. 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. 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. TH400 Vs Powerglide: Which One is Ideal for You? 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 lower efficient compression rate leads to a higher fuel consumption rate by your engine to produce higher power. 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. Ultimately, it comes down to how you want the engine to run, the car's intended purpose, and what you are willing to tolerate. "Ninety-nine percent of cranking compression is dictated by static compression ratio and intake-valve closing point," said Comp Cams' Billy Godbold. 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. I just installed a Comp Cams XE262 in a 9:1 350 with stock iron heads. A 110-degree lobe separation angle means that the peak opening points of the intake and exhaust lobes are 110 degrees apart. by jim martin Mon May 12, 2003 7:10 pm, Post 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. Ed JTO learn to park Joined May 31, 2009 180 Posts Aug 20, 2006. I forgot to add that poor vacuum is not much of a concern to me because I have no power accessories. Well get out of that stocker and build a hipo motor for your VW. I just bought a 86b Webcam with 112 lobe centers for my 2276. The 114o lobe will add a lot more vacuum at idle. 114LSA +4 puts the intake centerline at 110 degrees before top dead center. Simply put, both 106 and 110 lobe separation angles have many advantages and disadvantages. Lobe separation angles, he continues, are influenced by the camshaft grind. . While most of our customers know what lift and duration are, most are unfamiliar with the term Lobe Center and how it affects the engines performance. by bug1914 Tue May 13, 2003 2:56 am, Post 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. Camshafts with a substantial overlapping tendency should not be used in vehicles driven on public streets. by jobes Sat Dec 06, 2008 3:51 pm, Post 05 To ensure our stroker combo had sufficient airflow, we installed a set of Chevrolet Performance CNC-ported LS3 heads from Gandrud Chevrolet. = Extremely Tight . 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. by flat4racer17 Tue May 13, 2003 9:12 pm, Post 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. 110 LSA) and Crane's #341191 (238/248, .563"/.587", 114 LSA), display considerably different characteristics. by ANT Mon May 12, 2003 1:47 pm, Post The reduced rate of the EGR effect lowers oxygen circulation in the engines combustion chamber. Do you know what the best lobe separation angle for your car engine is? Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. Despite no changes in lift or duration, this cam sounded much more aggressive than the other two with wider LSAs. However, finding them might be challenging if you dont have any prior knowledge. I believe you have got the idea of what you were seeking. 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. Maybe even 114. 106 LSA: The scale of efficient compression rises at 106 LSA. 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. The ported heads were capable of supporting over 700 hp, so we knew they would not be restrictive on our stroker. This has been my long time understanding! Comparison Table Between 106 Vs 110 Lobe Separation Angle. Exhaust reversion is another undesirable side effect that can be caused by overlap. A narrower lobe separation angle can provide less power but can also lead to less wear. It will also give you a smoother idle and probably even better gas mileage. The 402-inch LS2/LS3 hybrid stroker started out with an LS2 aluminum block. ~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.~. The Wastegate works by releasing the pressure built inside, Read More What Are The Wastegate Stuck Open Symptoms?Continue, Oops! It will sound lovely I'm sure. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Disclaimer: Remember to always consult with an expert first before trying anything at home. 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. 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. Well, If I am not mistaken, you must be looking for which angle has what impact on your engine or which would be the best. " - Voltaire. However, these rules are not absolute. by randy331 Sat Dec 06, 2008 10:00 pm, Post 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. JavaScript is disabled. It affects the amount of valve overlap; that is the brief period of time when both the intake and exhaust valves are open.. Elle concerne 264 taxons des degrs divers. That is no accident. Generally speaking, decreasing the lobe centerline angle increases overlap. The higher the compression and the higher you try and rev it, the more it will like a wider lobe center. I wouldn't assume 4 links fuel requirements will mirror yours at all. Howards Cam Vs Comp Cam: Which Is The Best Option For You? Another related thought to consider when selecting a cam is inches of vacuum for your engine application when deciding upon a Lobe Center. The 110 is probably a better choice for a performance street engine. That was just a glimpse of the information you were looking for. The other thing is that you need to tune your ignition advance to maximize your performance. If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. It a 355. thanks in advance. The 114 cam will give more low end torque, good midrange, less power up high. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures. All rights reserved. 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. On the cranking. But it is a piece of good news for your engine. 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. 112 will have a smoother idle, a wider power band, and will work better with fuel injection. Again this is dependent on your shift rpm and assuming you truly have 14-1 compression. 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. Check out the Comp Cams catalog, even the biggest hydraulic rollers use 110. The intake lobe centerline is measured in crankshaft degrees. 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. I have 108 for LSA and my headlights take awhile to go up when the car is idling. Many later model engines use wide lobe separation angles to reduce overlap for idle quality and fuel economy. 10 Tuning the timing curve and fuel from the 42-lb/hr FAST injectors was handled by this Holley HP management system. As lobe seperation spreads does the powerband. If you shift at 7500-7800 add 4-6 degrees to both intake and exhaust and spread the lobe separation to 108-110. 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.