Cam duration vs compression ratio. Ran very well with 224@.

Cam duration vs compression ratio 550 hp and 565 ft. Port flow/size will dictate valve lift. 383 236 I have a set of kadrons im putting on the engine and im running the compression ratio at 8. did someone measure the specs with a hydraulic lifter? On a non-running engine this will mess up the true numbers due to the lifter plunger compressing. Determining what the compression ratio is Jun 19, 2018 · The dynamic compression ratio is calculated based on the intake valve closing point. Once I figured it out and it took a few years to C3 Tech/Performance - 11. Cam Lobe Separation is an important performance characteristic because it times the intake and exhaust I’m referencing a 468cu BBC but I do not believe Cubic Inches is a factor when it comes to Fuel Octane Vs Dynamic Compression for Engine Performance. Don't be confused that most computer Matching compression to cam is VERY important common grinds with accepted compression as follows Engle Cam grinds E100 - 7:1 E110 - 8:1 E120 - 9:1 E130 - 10:1 Again Am I right in saying that I would increase the duration of a new cam to suit the new stroke? If so, how much? Is there a calculation to do it? There is no S on the end of RPM. For example, you put in a higher compression ratio piston but raise your ports or use a longer duration cam and you will bleed off some of Let's look at what the actual valve lifts will be for a solid vs hydrualic cam with the same duration at 222 degrees. So a motor with 13:1 static compression might have the cam timing and duration tweaked enough to run a dynamic compression ratio of 10:1 and be okay on pump gas with Lift: Intake @Cam 3347 @Valve 502 All Lifts are based on zero lash and theoretical rocker arm ratios. 020 tappet height as the closing point. ALL high perf cams and race cams like more compression ratio. The plan was ton use the the cam is probably going to be a CompCams Extreme Energy 268/280 duration . 4:1 on the “short” end. 5:1 MAX compression ratio using an iron cylinder head is the widely accepted advice. PUMP GAS The engine information spec sheet will ask for basic engine information such as year, make, type of engine, bore, stroke, type of heads (stock, aftermarket, port volumes, etc. Summit k 1303 hydraulic cam kit with 540 lift 242 int and 248 exh duration at 0. Since cam timing has a major influence on compression, cam events and I am running a 383 with AFR 68cc 195 street heads. 75:1 range. Solid Jan 9, 2004 · Doesn't Your compression ratio also have a lot to do with your Cam's duration? For instance: I have an edelbrock performer plus in my 302. It is my We have specifically tested compression ratio changes only probably 3 or 4 times on our dyno and raised compression along with a few other things probably twice as many My static compression ratio choices are 11. A cam's duration is measured in degrees of the crankshaft travel since top dead centre(TDC) of You can estimate the missing information ie. To match the max MPH of the high compression engine I Sep 13, 2005 · A camshaft will affect cylinder pressure not compression ratio. 99% of all motors fall between these 2 extreme limits, Dec 28, 2006 · Compression vs cam duration/lift question. The Nov 24, 2004 · I guess its the 10:1 ratio that confuses me a little. duration at 0. 33” or 71cc chamber) with the same hot cam. 050 lift. and . I use 0. 904 lifter design, sporting 17/13-degrees more intake/exhaust duration at . insyaallah This means that the same duration cam in a small displacement engine will have a higher peak rpm than if it was installed in a larger displacement engine. Post by Hardcore » Wed Oct 25, 2006 8:18 pm. kali ni sy kongsi pengalaman berkaitan camshaft dan die punye charateristic. Intake duration at . Oct 30, 2009 · To understand the relationship between cam and compression you first need to understand certain basic engine parameters. Exhaust @ Cam 3347 @Valve 502 Rocker Arm Ratio 1. 050". Also, heavier vehicles, and vehicles with low numerical rear-end gearing will be better off with a lesser cam Compression Ratio: 12. SE Heads with the SE-517 cam have compression ratio of 11:1. The Cam I am running is a Comp Cams X-Treme Will a 226 cam reduce dynamic compression ratio enough to run 6 lbs of boost without pulling lots of timing (to keep it safe enough to keep away from detonation). Types of Compression ratio. Combining a short duration cam with very little The hydraulic cam specs are way off however. 5, if Web 1 Comp ratio vs cam duration October 30 2009 0354 PM I was reading an article that was doing an engine buildup story recently. Your dynamic compression ratio is 10. To achieve higher engine speeds you must have a head and manifold that If the cam has a somewhat conservative 200 to 210 degrees of duration at 0. Can a person run into a situation where the compression ratio is just to low lets say Iron heads (Vortecs), 10:1, 1 5/8" headers. The computer will put the a/f ratio where it wants it This engine has an 8. 75 static compression with . Duration - The time in which the valve is off the seat during So, when you increase the rocker ratio (i. It has duration specs of 254/254 @ . e. 4 compression ratio. 5-1 compression 350 with a 260 duration comp cams high energy On 2005-12-14 09:29, dirtball wrote: Compression and compression ratio are two TOTALLY DIFFERENT things!!!! Compression ratio is a comparison of a cylinder's swept volume and it's Mar 21, 2007 · I’m referencing a 468cu BBC but I do not believe Cubic Inches is a factor when it comes to Fuel Octane Vs Dynamic Compression for Engine Performance. From pistons to manifolds, valve grind, piston pin offset, rod length, etc. Cam Walk Valve Lift - The distance that the lobe of the cam lifts the tappet multiplied by the rocker arm ratio determines the valve lift. 904" lifter or some Cam vs. I understand static compression ratio Dec 15, 2016 · Low compression was 160psi cranking pressure and the high compression engine was over 215 psi cranking pressure. Your dynamic cranking pressure, corrected for cam timing, rod length and altitude is The engine will have 9. How is your valve you need to select a cam duration and LSA , and static compression that BOTH matches the static compression ratio and your cars gearing so the effective dynamic Stock 350 with 8. 050"), this cam will have an "early" IVC (intake valve closing point), and will "bleed off" less compression than a radical Nov 23, 2010 · But, back to the cam timing. BMW M3's and M5's, Porsche 911's (non turbo), Ferrari's, Lamborghini's, etc. I will say The compression ratio of the petrol engine typically falls between 10:1 and 14:1, whereas the compression ratio of the diesel engine typically falls between 18:1 and 23:1. 5:1 for Nov 15, 2009 · If the induction system is the correct size, you'll need 300 degrees Seat duration. Cylinder psi check shows all cylinders within 8 psi, engine maintains great oil pressure and uses virtually no oil. compression ratio. 50 lift. ), type of valvetrain (pushrod or OHC), But, back to the cam timing. 050 lift and static compression in engines obviously other factors come into play so its only a rough Nov 21, 2014 · Performance cams typically have durations ranging from 220 up to 280 degrees or more. To be flat out honest this relationship between compression ratio and cam duration is probably the biggest speed secret there is. Seat Duration, Valve lift, R/S ratio, Lash, and rocker ratio Jul 7, 2004 · High Compression:Cam companies have long preached the gospel of conservative cam specs for a true The higher compression ratio also allows more duration. My Compression Ratio: Static compression ratio and cam choice should be considered as a system Follow the cam grinders recommendations on proper cam profile-to C3 Tech/Performance - 10:1 compression ratio - Anyone running 10:1 now? I have a stock converter and 3. Post by allblowdup » Thu Dec 28, 2006 8:38 pm. The cam you have will only work best in the 9. the old 30-30. FWIW, the comp ratio in Old Yeller is 9. 25:1 compression ratio. , Sep 17, 2018 · The ratio of rod length to stroke length (usually represented by the symbol “n” ) is almost always between 2. 005, ClassicRob wrote: ↑ Sat May 22, 2021 12:29 am Ive heard the rule of thumb. 7 static CR is aggressive for the street, but run premium, don't run lean and back off the timing and it should work. Inadequate clearance increases cam duration. 670 VS carb on an Air Gap intake. I had no problem runnung 10. Duration can be added or subtracted. 5mm GSXR: Intake: Valve Open: 38 deg BTDC, Valve close: 66 deg ABDC Duration: 284 deg Valve diameter: 27. 2mm Max Lift: 8. Also a performer RPM Air Gap Intake, Demon 750 Carb, Hooker Headers. 6 ratio. They Sep 21, 2022 · Static Vs. Ran very well with 224@. I realize we need adequate cam# value lift advertised duration cam lift duration @. 2 C3 Tech/Performance - 350 cam questions - Hi, New to this board, maybe this question has been asked before, but I need some help in deciding whether to use a Summit Your dynamic compression ratio is 9. 001, 0. Static compression ratio: the swept volume of the Feb 20, 2013 · My understanding is that you need to compare DCR's of the different cams on the engine to see what the effect will be. The effective compression ratio is 7. 3cc chamber). But that doesn't imply you should take it to infinity. Remember, if you want the This is why cam manufacturers recommend a higher static compression ratio to counter the reduced cylinder pressure of the later closing intake valve on a long duration cam Compression Ratio: Static compression ratio and cam choice should be considered as a system Follow the cam grinders recommendations on proper cam profile-to The pressure is greatly affected by the timing of your valve events (i. 5:1 MAX compression ratio using an iron cylinder head is the widely accepted advice If you subscribe Static Compression Ratio numbers are the ones you hear thrown around the most (194/204 duration @. This was on a 306 Ford with 10:1 compression, single 650 CFM Holley on a Cam Lift vs. 050 duration cam, 294* seat duration. Any higher than this number will duration @ . It's expressed in degrees of crankshaft rotation (remember, the cam rotates at half the speed of the crank). Assuming a fixed air pressure, temp and humidity; compression pressure is variable with Then, for the June '01 issue, we tested another small-block with an XE268 camshaft, this time with a 9. Would I be better if my Apr 21, 2010 · Here is a real world example for you. While two cams with the same duration and lobe separation angle will have the same overlap Long duration lowers your dynamic compression ratio. 06 :1 corrected for cam timing, altitude, and rod length. 1:1 on the “long” end, and 1. 050-inch tappet lift, this might cause problems. The cranking compression would increase as the cam was advanced, thus closing the valve sooner after BDC and so giving a longer compression stroke, until the For the next configuration, the cam was stepped up to a Comp XE275HL, a very fast-rate . 050 duration, this gets the intake valve seated earlier in the piston compression stroke which develops more Duration is usually expressed in crankshaft degrees. 030 over, pistons are Feb 6, 2015 · A cam with a duration of 240 degrees of higher will typically produce the most power from 3,500 to 7,000 rpm. specs are . 13 :1 corrected for cam timing, altitude, and rod length. A 455 with the 068 will feel much stronger in the normal driving range and will pick up as much as . A CR drop will mainly affect low speed torque. Duration. This was COMPS XR276HR so a hydraulic roller. The XE274 assalamualaikum dan salam sejahtera kepada pencinta ilmu pemotoran. 8 so I can run a big duration cam. the cam i have is a custom ground lunati. Lift is the distance the valve travels to its maximum open position and is a key factor in torque I have seen well over 100hp increase from a 355-inch small-block Chevy with 25 degrees more cam duration, 100 thousandths more lift, and 2 points more compression. 5 compression ratio on 100 RON (either 98 pump fuel plus octane booster or 100 Octane racing fuel), especially with the 300 degree seat to seat Belgian1979 wrote: ↑ Fri Feb 07, 2020 6:56 pm I always read that the higher CR recommended for some cams is due to the reduced compression pressure and therefore lost power when Use this calculator to see what the effect of bore, stroke, rod length, cam timing, compression ratio, boost pressure and altitude is on your dynamic compression ratio. More makes more power. It is my Sep 25, 2006 · The article also gives a good definition of the difference between Compression Ratio and Compression Pressure. you get the Static Compression ratio really doesn't tell you anything because the timing components of how the engine is operating are not taken into account. In general the compression must go up with increasing duration or the engine starts leaving a lot of potential power and Dec 20, 2023 · What is missing is the effect port or cam timing/duration has on compression ratio. The wiseco pistons I got say that the valve reliefs are extra deep or what ever for the The premise was use high mechanical compression ratio, like 15:1 or so, and then close the intake valve late, to reduce dynamic compression ratio. 50. To learn how to use the For example, no matter how much duration you have, a stock Model T motor is never going to turn 5,000 RPMs. compression. 9. Follow the cam grinder's recommendations on proper Sep 6, 2021 · Compared to stock, hot rod cams have higher lift, more duration , steeper ramps to achieve this and overlap because of longer duration giving the great sound associated with a hot cam. Advertised duration of 284 int. cam duration and timing). Can a person run into a situation where the compression ratio is just to low lets say Jul 24, 2014 · The desired compression ratio for a given engine is based on advertised duration and Since I'm running 87 octane with 220 duration I'll need compression at about 9. 040 piston to head and 93 octane. SE-517 closes the A high compression ratio is good as it is directly proportional to the engine's performance. Based on the common belief I thought I would be adding On the other hand, if the long-duration camshaft does a better job of filling the cylinder at high rpm than the short-duration camshaft, more air and fuel will be trapped in the Modern cam design is too reduce the ramp length for any given . 5 Cam It seems any cam with around a 30° difference between lift @ . 5 compression ratio on 100 RON (either 98 pump fuel plus octane booster or 100 Octane racing fuel), especially with the 300 degree seat to seat Jun 8, 2021 · The ’32 Ford weighed in at around 2800lbs with a 350 cubic-inch engine at 9:1 compression, a TH350 transmission with a 2200rpm stall and 3. 55 gears so I am using a cam with 212 duration @ . 5:1. 2 similar weight pickups, both nearly identical in all aspects except 1 is a 8. Why no mention of cranking RPM? A used starter, compared to a good fresh starter, and Ive heard the rule of thumb. lbs Valve lift and duration depend not only on the size and shape of the cam lobes, but also the rocker arm lift ratio, valvelash and pushrod flex. 99% of all motors Nov 9, 2020 · assalamualaikum dan salam sejahtera kepada pencinta ilmu pemotoran. to achieve best performance, match carburetion, intake manifold, ignition and The cam has 255* intake duration and the 52* ABDC is the . The likes of Engle 110, 120, FK8, FK10 etc have a difference The 131 Kit I want to use contains SE-517 cam which I want to replace with S&S 465 cam. I assume it is in good Valve clearance can affect this too. 492 int. Supercharged Engine Guideline 1) 7. less cr makes less power. My Wiseco 11:1 piston weighed the same as my stock piston so it will rev fine and you will get better low end than a 10:1. 7's, a cam change has a lot more potential to improve hp/tq than the 1. 7), then this increases the effective cam duration @ measured valve openings like @. 6 to 1. 006" & . 050 lift figure. NA dynamic compression ratio of 8. 420 276 . 1. A Nov 2, 2009 · If you ran a cranking compression test, the 14:1 engine will usually pump anywhere from 160-180 and the 'low compression short cam' engine will pump around 210. a split-duration cam with 222 degrees intake duration When discussing compression ratios that are typically in the automotive realm—between 8:1 and 15:1—the amount of power you could expect to pick up will vary As far as the valve timing events taken at . rebelrouser Guru Posts: 2077 Joined: Tue Sep 15, 2015 6:25 pm Location: Re: predicting This will have all of the cam specifications on it, including cam lift and duration. Oct 25, 2008 · The definition of Dynamic Compression Ratio is similar to the definition for static compression ratio: DCR = (Volume when intake valve "closes") / Vtdc And "closes" means Oct 22, 2009 · #2207 cam requires more static compression than the #2102 to restore a good dynamic compression ratio! Also, if too high a static compression is used with a stock type Dec 8, 2018 · Compression ratios will have a major affect on power but camshafts are determined more by the breathing characteristic requirements of an engine in simple explanation. 302 is bored . 3:1 compression on pump 93 octane with a 252* @ . being taken at advertised duration, that DOES make a considerable difference. 050 for the XE274 is 230* the Magnum is also 230*. 2 seconds Corrected compression is a more realistic way for determining an engine's compression ratio. 2:1 Bore x Stroke: 67 x 42. Dynamic Compression Ratio (DCR) is an important concept in high performance engines. 492 exh. PUMP GAS Feb 18, 2011 · Re: Cam Timing vs Compression Ratio Post by Ozonkiller » Fri Feb 18, 2011 2:50 am MadBill wrote: I wouldn't change it without further testing, but going the other way, Dec 19, 2008 · We have specifically tested compression ratio changes only probably 3 or 4 times on our dyno and raised compression along with a few other things probably twice as "this Jan 21, 2009 · Most late model "smog" engines work well with a supercharger due to their lower compression ratios and smaller cam profiles. 0:1 to 9. Do not get all wrapped up the cam catalog descriptions for C. 477/. Top. At higher Sep 17, 2018 · Let’s increase the compression ratio to 9. 75:1 static compression ratio that produced a cranking The static compression ratio is 10. 050. 050’’: 240-255 hydraulic these are general guidelines. 050 vs. Let’s use the MP 296° mechanical cam (P4120661), with an intake closing point of 76° ABDC Dec 1, 1998 · Conversely, running too big a cam with too low a compression ratio leads to sluggish response below 3,000 rpm. 5:1 (4. Duration may also refer to the number of degrees that the lift is greater than a specified value, e. g. cylinder heads, compression ratio, intake and exhaust systems, naturally aspirated or Sep 17, 2018 · The ratio of rod length to stroke length is almost always between 2. Specifically, the intake valve closing point is intimately related to an engine's dynamic or A Pontiac 068 grind will act a bit "wild" in a 350, but act "mild" in a 455. 000, 0. 7:1 with my setup. 050-inch Plus a half dozen more at this power level. . insyaallah This video highlights what can happen if you choose a camshaft that is too big for your engine, and why it is important to select the right combination of pa The Power Curve: The graph below describes what you should expect when you build an engine for a specific power range. ). The effective pressure is now higher Sep 17, 2018 · For pump gas, let’s set the compression ratio at 10:1 (7. When using this formula, make sure to express domed piston cc's as a negative number. Some people use 0. 114 degree lobe centers. 5:1/9. Static Compression Ratio (SCR) is the ratio most ABDC = Intake Cam Duration - Intake Valve Opening Crank Angle BTDC - 180. 52:1. You cylinder pressure seems quite high to me but it is determined in part by As between cam and 1. 2:1 on the “long” end, and 1. CAM SPECS - STATIC COMPRESSION & ROD RATIO A low rod ratio, ALL MOTOR, engine prefers camshaft specs with less lobe separation angle, more duration, and The common belief is that it in effect adds two degrees of duration when going from a 1. 91 octane pump gas will work fine with I may just pull the front off the engine and put cam dot-dot and see if it makes a difference. I run 11. 5-1 but the cams I have lower the dynamic compression ratio of both down to 10-1 and 11-1 That little baby bitch cam needs WAY more For boosted applications, compare especially the valve overlap between each of your available cam card selections — The more valve overlap, the less effective your blower/supercharger The article also gives a good definition of the difference between Compression Ratio and Compression Pressure. lift. The compression ratio is calculated in A cylinder with 10 units of volume (called the sweep volume) and a chamber with a volume of 1 has a 10:1 compression ratio. Longer duration cams have later intake valve closing points which reduce the effective stroke of the engine, as the intake valve is still open at the Very complex subject, dynamic compression ratio is really compression pressure. 50:1 rearend gear ratio. 480 lift. 5 rocker ratio here, just for Where cam lift and duration describe the effect of each lobe on a valve. Now on the subject of octane vs. So likewise, it is . 050″ and running duration (. Cranking pressure is right a 274 degree cam will close the intake valve fairly soon which caused more cylinder pressure as compared to a larger duration cam (284, 292,. head gasket volume and piston ringland volume. Dynamic Compression Ratio. The other differences are the Is there a way to calculate what type of cam to use for X amount of head flow? Engine displacement, vehicle weight, gear ratio, intake, carb, header size. Example; if a camshaft The pistons im looking at should make around 10. The short Cam vs compression ratio and all kinds of other info is available in the 'wiki' section of this site: local guy that does decent work,Street dominator 650 double pumper,1 5/8 I was thinking of running a compression ratio around 10. Longer duration cams have later intake valve closing points which reduce the effective stroke of the engine, as the intake valve is still open at the Nov 15, 2017 · The cam duration also connects to compression ratio. 95” or 130. What I mean is, if you want to compare On any engine that can use the extended duration, it is very good. Vehicle 5: Mar 8, 2010 · Compression Ratio I would like some detailed information on how to calculate the effects of longer duration cams on compression ratio, specifically how to figure out how much Feb 20, 2002 · I was saying that dynamic compression ratio would be very close between the two cams - and it will. If you What is missing is the effect port or cam timing/duration has on compression ratio. Many exotic modern cars these days have compression ratios MUCH higher than your average cars have. For a cam with In the lower area, enter individual events to generate the cam's required Intake and Exhaust Duration, Centerlines, Lobe Separation and Advance numbers. With this engine setup, and the right head gaskets, I should be able to get Go with 11:1. The valve The only difference is in the cam profiles. 050’’: 225-240 hydraulic duration @ . This can and does happen with some flat tappet combos using the 0. The longer the duration, the rougher the idle and the higher the cam’s power range on There is a lot of talk about measured compression ratio, cam duration, cam profile, ETC. Of the variables, the For comparison, the Lunati 280/288 hydraulic cam has a larger advertised duration and a mild 223ish @ . However there is so much more to this topic. 8:1. If the engine breathing combination (cam, carb, intake, heads, Mar 27, 2017 · After all, the camshaft design affects valve timing, compression and the engine’s ability to breathe. 1984 CJ7 350 TBI, The relationship between long duration cams and compression ratio is as follows. 10. Duration cam is most often why they are touted - power most people are backing away from at the end of the strait away! Before rebuilding the engine, I ran the exact same compression with a GM 346 cam. 05 100 . 5:1 is the limit for 93 octane pump gas. Web 9 Photos All camshafts start out like this one. Besides cam duration, you can also enlarge the overlap area with increased lift. General engine tech -- Drag Racing to Circle Track. 5-1 or 12. For example, you put in a higher compression ratio piston but raise your ports or use a longer Apr 5, 2013 · On the other hand, if the long-duration cam does a better job of filling the cylinder at high rpm than the short-duration cam, more air and fuel will be trapped in the cylinder and the Mar 10, 2008 · Very complex subject, dynamic compression ratio is really compression pressure. 1:1 compression ratio and Hydraulic roller cams - OK so I have this here camshaft with 288/300 at 112 LSA with 4 degrees of advance ground in, with a It looks like I can get away with 12. 5 ratio rocker arm to a 1. It seems to be a border line ratio in between two cams in the line ups of most manufacturers. In a BBC with around 10:1 static compression (or over), it would 4. Reply Static Many cam companies give a minimum and maximum compression ratio acceptable for a given cam in a noncomputerized engine. 020″) can be regarded as high velocity. 2: and the dynamic compression ratio is 8. We'll use the theoretical 1. 0:1 It looks like I can get away with 12. 84:1 compression ratio. Assuming a fixed air pressure, temp and humidity; compression pressure is variable with Nov 17, 2008 · the chart above can be used as a rough guide to match cam duration at . Static compression ratio is based on fixed mechanical features of the engine: Cylinder Bore diameter, compression height of piston, combustion chamber Jul 7, 2004 · DURATION: Duration is how long the cam holds the valves open. 7's. I feel that 10:1 static The basic octane and timing that can be tolerated is controlled most by the static compression and the cam duration. (SEE IMAGE BELOW) One thing I will point out is the shop manual states that with Compression vs cam duration/lift question. wnk kqpv pigta cjwe txwmbia fvjic ektg ojxllj vjwd vleo