Dynamic Compression Ratio Octane Chart










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Octane number (RON)=92. But if it touches the head at high revs it is probably close enough. This compression is governed by these thermodynamic equations to predict temperature and pressure in the compressed state. 8L with a 10:1 compression ratio (stock). 0:1 to run 87-octane pump gas. You could probably get away with 93 if you scale back the timing a lot, (i assume that you will be using megasquirt), but you won't make good power. 0 dynamic compression for a street car. Compression ratio (swept volume plus dead volume, both divided by dead volume) is another important parameter to consider for a race engine. Using their calculator with my existing cam, dynamic compression will be around 8. Your effective boost compression ratio, reflecting static c. Effective stroke is 3. 030" off, 0. As many others have posted it depends on alot more than just compression ratio, but if you're running all iron and carburated I would say 10. Dynamic 88s continued with the 371 cubic-inch Rocket V8 that was detuned to 240 hp (179 kW) thanks to a lower compression ratio that permitted the use of lower-priced regular gasoline. As mentioned above, dynamic compression is the determining factor for cylinder pressure. Just because your service manual says your car is 7. The stock cam is used resulting in a very fuel efficient, quick engine. While the various engine components (especially the cam) set the DCR traits for a specific engine - the effective DCR is affected by the factors you listed and others, such as an 8:1 static CR turbo engine where the DCR goes ballistic under boost, requiring more octane or other methods to. It's "close", though, as we use a "line" of 9. Octane boosters and higher octane racing fuel will allow you to run a higher final compression ratio. 0-liter VC-Turbo Engine seamlessly responds to unpredictable driving conditions on demand. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. Keep in mind, camshafts play a big role in determining the dynamic compression ratio. You could probably get away with 86 octane garbage pump fuel in a 15:1 blown alcohol ProMod motor without detonation,,,,, as long as you kept rpm's down to 600 or 700 rpm's. If you'd like to do your own math here is the formula: Square Root of: ((Boost Pressure in LBS + 14. Therefore a higher compression ratio is desirable. You must know the mechanical compression ratio of your engine to get reasonable results from this calculator. It will also estimate a dynamic effective compression ratio taking into account the cam timing and rod ratio. Bore & Stroke (in / mm): 3. The first thing to consider when determining the mechanical compression ratio is whether the engine will use 92-octane pump gas or high-octane race gas. cranking compression figures can vary so much that they are just about a waste of time other than checking for even cranking pressure between the cylinders,about 10 % variation is what is generally accepted. It has also proven to be very popular in the highly-stressed naturally-aspirated big blocks used in truck pulling. Camshaft is another, and combustion chamber design is a big one. It's a slow revving engine capable of running most fossil fuels through an adjustable compression ratio. 0:1 and 10:1 would likely be best since these fuels have a much lower propensity to knock. Premium Gasoline has a minimum octane rating of 91 units, measured by the anti-knock index (AKI), and up to 50 mg/kg (or ppm) of sulfur. 4L SRT engine, whereas midgrade gas is recommended for the 5. ) Cylinder Bore Diam. Question 15. Significantly increasing the static/dynamic compression ratio will increase cylinder pressures and the octane requirement of the engine. The engine may have a nominal compression ratio of say 8. Explore the 2020 Acura NSX and configure your own personalized supercar. Running a compression test or dynamic compression test is an important, but little-used and often overlooked engine diagnostic tool. NEW Label. 060 inch gaskets. The BMW R 1250 GS: concentrated performance meets impressive efficiency. 2 Engine work, rate of work per unit enthalpy flux The non-dimensional ratio of work. That is why all of the race fuel mfgs have charts which tell you which fuel to use based on static compression. Can be used for 4, 6, or V-8 engines. Air / Fuel Air Flow Fuel Injector Sizing Fuel Injector Sizing 2 Fuel Injector Pressure Change Intercooler Efficiency Engine Building Cam Timing Events Calc Adv Intake Valve Closing Compression Ratio Compression Tester Cylinder Head Volume Displacement Dynamic Compression Ratio Effective Compression Ratio Piston Speed Piston Volume Pressure Ratio. 95 to get 8. 0:1 compression ratio would be ideal. Effective Compression Ratio Static Pump Gas Race Gas Compression Blower Boost Pressure (psi) Blower Boost Pressure (psi) Ratio 135789 10 11 12 15 6 6. Our target compression ratio is thus 9. The distributor was a new rem. Output increases on each engine, and EPA fuel economy improves. @ 3,000 rpm 380 lb. Bumping up the static compression will get back what you lose. As such, the Static and Dynamic Compression Ratios are determined when the engine is built and never change. I will be using Aussie 98 octane fuel, which is the same as the US spec 93 octane I believe. Compression Ratio Blending Chart => click here. This is often referred to as "geometric compression ratio" but is also known as the "static compression ratio". The compression ratio of an engine is a very important element in engine performance. Desired pressure is 160-170 psi, so we need to increase pressure by 40-50 psi. Compression will be higher. There is one non ethanol gas station listed on this site 2 miles from my house, after checking with the dealer I was informed they do not have it Ethanol isn't ideal for anything used without high frequency; not just small engines. Also, some of the earlier domed, and other make domes pistons won't allow the compression ratios of the hemi or top hat combustin chambers, some not even close. Your dynamic cranking pressure is 174. This is commonly known as the dynamic compression ratio and is influenced by such things as ring and valve seal and, to the greatest degree, valve opening/closing events. Compression Ratio N/A N/A N/A 8. It won't run on pump gas. Compression ratio: 10. same quench + higher compression = worse on lower octane fuel (stock hybrid). RSR Advanced Dynamic Compression Ratio Calculator. Degree Wheel Spacer, Lifter Extension, Top Dead Center Finder-- How to make these. Your effective boost compression ratio, reflecting static c. As such it had a compression ratio of 7:5-1 Ive had the head skimmed by 40thou which has increased it to8:25-1. This chart shows the various levels of boost (PSI) and the effective compression ratio. Camshaft is another, and combustion chamber design is a big one. ASTM's petroleum standards are instrumental in the evaluation and assessment of the physical, mechanical, rheological, thermal, and chemical properties of crude oils, lubricating grease, automobile and aviation gasoline, hydrocarbons, and other naturally occurring energy resources used for various industrial applications. Performance software that does the math for YOU, also Interactive JavaScript Calculators. 050" lift the valve is open. The following formula can be used to calculate the compression ratio of an engine. 3 to 1 or less will work with unleaded 87 octane, if you had a programmable ignition system you could work with a higher compression ratio with some heavy tuning, i would stay below 9. 7 pounds per. This is a long read so I want to tell you my conclusions first and then you can read why. Classified ads, photos, shows, links, forums, and technical information for the Volkswagen automobile. That is of course as you said, the comparison of combustion space with the piston at TDC compared with the cylinder volume at BDC. The chart is based on static compression ratio which is what is quoted by 99% of manufacturers of vehicles coming off of an assembly line. 0L HO has a compression ratio of 8. I want to run 211 cams with the upgraded cam plate and oil pump but with that upgrade I want to order the right ones. 100 octane. I'd like to find something that uses cranking pressure as a baseline, if such an animal exists. Running bp 98. Dynamic compression is figured from when the intake valve closes. KB Pistons High Performance Keith Black Hypereutectic Pistons. This increases the peak pressure and temperature. 8:1) of the 6500rpm Mustang V8, I'm guessing that this allows for a much higher redline - the faster burn speed of the compressed fuel-air mix in the Hayabusa engine would allow it to complete burning before the piston had completed its. Dynamic Compression Ratio. The shorter the duration, the less air brought into the cylinder, which also affects. 060-inch overbore (4. 6:1 static compression but I can run 92 octane just fine because I run aluminum heads and my dynamic compression ratio is 8. Mike, A small displacement engine will not be a torque monster. Thus the octane requirement might be higher per compression ratio. 8 combo XLR+1/4" inputs accommodate nearly any source, from phantom-powered microphones to your favorite guitar, and 8 dedicated outputs offer versatile playback options. Too high of a corrected compression ratio results in detonation. Doesn't always work. I burn 87 octane in my 09 Touring bike and it does not ever ping, spit. You could drop the running or dynamic compression with a set of aftermarket cams. Fuel Tank Capacity (U. Compression ratio 10. n-Octane C 8H 18 0. 32 city/42 highway/36 combined mpg rating for EX & EX-L trims. Capable of physically transforming for any compression ratio from 8:1 (performance) to 14:1 (efficiency), the 268-hp 2. 4L Naturally Aspirated Turbo. The octane number tells you how much cylinder pressure the gas can handle without detonating. With good cylinder head design that promotes high swirl and fast flame front propagation, a slightly higher compression ratio is possible. Google 'dynamic compression ratio' for more. Gasoline Octane Needed, a number of these let you use wrist pin offset, Average rate of acceleration from rest to X MPH, Cam. 0:1 mechanical ratio by 0. Download octane render for free. As a general rule, the best available pump gas will work with an 8. 9 in: Engine Control: BMS-O: Emission Control: Closed-loop three-way catalytic converter: Lubrication: Wet sump: Mixture Control: Electronic. More octane does not equal more performance, unless matching changes are made to the timing and maybe compression ratio too. It listed 9. If we plug those numbers in our modified formula (Trapped Cylinder Volume at IVC + combustion chamber volume at TDC) / combustion chamber volume at TDC = trapped compression ratio with numbers it looks like this: (334+ 36) / 36 = 10. 0:1 Firing Order: 1-8-7-2-6-5-4-3 Valvetrain: Overhead valve, two valves per cylinder, variable valve timing Fuel Delivery:. It's the ratio of cylinder volume at BDC vs TDC. Octane rating conversions. Conversely, if we hogged the chamber out to 60cc, the CR would now be 510/60, or 8. Therefore with the mild cam it will have a high dynamic compression ratio, probably 9. Calculate your engine’s dynamic compression ratio to determine octane needs: if you’ve ever been curious about your turbo/supercharged or high compression N/A engine’s “max” compression. 4) The type & octane of fuel you use is a main contributor to what compression to use, so the higher the octane the higher the compression you can use safely but it's still beneficial to run a lower rather than higher compression ratio. Yes, thats called dynamic compression ratio. Higher octane helps higher compression ratio wala motorcycles where in the compression ratio goes over 9 or 10, in our case it's 8. com and get the latest information, as well as detailed specs and features. I triggered my ECU to log at 70% throttle and Knock Retard is set for 5° per knock. 3 though with 87 octane, or use a octane booster if you go higher compression while in Mex. what you want is a dynamic compression ratio of 8. 0-litre straight-six) with a pair of small turbos on the side – the bore, stroke, capacity and compression ratio are identical between the two. Capable of physically transforming for any compression ratio from 8:1 (performance) to 14:1 (efficiency), the 268-hp 2. DCR Combinations that have worked-- The purpose of these pages is to helpfully show what DCR (Dynamic Compression Ratios) and SCR (Static Compression Ratios) have worked with what Octane gas. Everyone knows that high performance engines typically have higher compression ratios. 5 DCR for 93 pump gas, and at 8. The builder chose KB177 pistons which actually are. RON fuel in real driving conditions on the high compression ratio engine; - A linear improvement in the fuel consumption benefit between RON 95 and RON 102, meaning that each RON increase between these two values is beneficial to fuel consumption. A normal spark ignition engine runs at an average compression ratio of between 9:1 to 10:1. SYMBOLS Symbols 1 to 9 are designed as thumbtabs to indicate the content of a chapter. Compression Ratio Blending Chart => click here. You could probably get away with 93 if you scale back the timing a lot, (i assume that you will be using megasquirt), but you won't make good power. The higher the compression ratio the more energy can be extracted from the air-fuel mixture. 1 2 3 4 5 6 7 8 9. Explore the 2020 Acura NSX and configure your own personalized supercar. It's only one of the factors required. all affect it. Theoretical air/fuel ratio: A=14. Wild, lumpy cams may require 24-30 degrees depending on the compression ratio, cylinder head port sizes, etc. Is there a chart or something that says 'this compression ratio is good for this elevation with this gas'? How do they base this? I normally ride from. 0-litre straight-six) with a pair of small turbos on the side – the bore, stroke, capacity and compression ratio are identical between the two. 5:1 for the base version. ) Cylinder Bore Diam. This works OK on older, slower ramped cam lobes, but the faster lobe profiles may need to have 25 degrees or more added to be accurate. I'm ready to learn. A compression ratio of around 7:1 is ideal if you expect to use regular octane gasoline in a properly timed daily driver. 696 is standard atmospheric pressure at sea level. Explore the features and specifications of the BMW X3. Static compression was set up at 12. 5cc For the above calculated 6. 5 with the sweet spot at 8. 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. Small cam and low compression can give the same cranking compression as a large cam and high compression. Compression Ratio. 5 but up there you definately need 110 octane, or some form of liquid lead additative. (approx 6%, 3%, 1%, till you max out on compression for the application) 14. In order to feel a little more comfortable that the nozzle you select is the right one for both your vehicle and your wallet, it's helpful to understand terms like compression ratio and octane ratings. They achieve all that - and also help increase compression ratio -without any increase in the Vortec 7400's octane requirements. 5t dynamic pressure turbo dohc 16-valve 4-cylinder. Multimedia tools downloads - Octane by Refractive Software LTD and many more programs are available for instant and free download. Air / Fuel Air Flow Fuel Injector Sizing Fuel Injector Sizing 2 Fuel Injector Pressure Change Intercooler Efficiency Engine Building Cam Timing Events Calc Adv Intake Valve Closing Compression Ratio Compression Tester Cylinder Head Volume Displacement Dynamic Compression Ratio Effective Compression Ratio Piston Speed Piston Volume Pressure Ratio. The European octane rating is RON. operation that increases parasitic losses. This script is one that calculates a desired octane rating gasoline fuel from blending two other gasoline fuels of known octane rating by volume. Since no compression builds until after the intake valve closes, it's the corrected compression ratio that gives the best indication of how pump gas friendly your motor will be. I am sure that the ratios vary by manufacturer and model. Stops knocks, and raises MPG in high compression engines. 7) * Compression Ratio = ECR. We ride in 100 degree weather and I have yet to hear it falter. I think in terms of an engine as having three compression ratios…. Plus, the motor seems to run better and I can advance the timing and speed up the advance curve from stock settings. Cam specs, chamber design, piston materials, carbon build up, etc. If you run a richer air fuel ratio around. For the Y engines, the optimal total timing at WOT typically falls in the 36°-40° range depending upon the compression ratio if you take fuel octane out of the equation. Static ratio is what is normally quoted as a comparison. In order to feel a little more comfortable that the nozzle you select is the right one for both your vehicle and your wallet, it's helpful to understand terms like compression ratio and octane ratings. Note: Some dynamic compression ratio calculators (like KBs) ask for an additional 15 degrees of duration be added to the IVC @ 0. The values in the chart are conservative. 91 is suggested octane for that ratio in an automotive application. 5/1 compression with port injection. (726cc) 44. High compression was first made popular during the 60's with big v-8 racing engines(4-stroke) and compression ratios went up to 13-1 or more. 5 : 1: Water cooling circuit with thermal management for engine and gearbox: Adjustable camshaft phasing and variable valve timing VarioCam Plus: Fuel quality: minimum 98 octane, unleaded: Electronic engine management (Continental SDI 9) Integrated dry-sump lubrication. To go to a higher compression ratio with no problem.     I've been working on a 2D car physics simulation as a hobby project, and old threads on these boards have been a great help. What is the optimum dynamic compression ratio for 87 octane?. If you’d like to do your own math here is the formula: Square Root of: ((Boost Pressure in LBS + 14. No OEM that I can find has supplied 12/1 compression and boost. 5:1 drag motor can run 91 octane without pinging. Fuel Octane and Dynamic CR Fuel octane influences the compression ratio that can be used and an engine's CR must, for best results, be tied to cam duration. 6L engine is delivered with a slightly lower static compression ratio. 2:1 allowed by the fuel’s. Too high of a corrected compression ratio results in detonation. Think of two engines that are identical except for their camshafts. Which of-course gives you more BHP and to make a specific type of motor run with higher compression ratio, higher grade fuel is needed. 5-liter L15B7 Engine (For this study, the Atkinson Ratio is the ratio of effective expansion stroke length to effective compression stroke length where the extremity of each stroke is determined by the location corresponding to 1mm of valve lift. Dynamic 88s continued with the 371 cubic-inch Rocket V8 that was detuned to 240 hp (179 kW) thanks to a lower compression ratio that permitted the use of lower-priced regular gasoline. Where CR is the compression ratio. Premium pump gas works way better in it than hi test. Octane Calculator When your engine builder recommends a different octane than is available, sometimes it is necessary to mix two different fuels to obtain the correct octane. Apr 2, 2013 #2. As such, the Static and Dynamic Compression Ratios are determined when the engine is built and never change. The engine may have a nominal compression ratio of say 8. That means less "dynamic" or "swept" compression Now a third example, a 268 degree cam on 106, IVC is 60 degrees, that means 120 degrees of crank rotation compressing the mixture. If you are building your engine from scratch, it is a good idea to try to build it with a relatively low compression ratio, such as 7. 5:1 compression) will do nothing for you!. For example, if the atmospheric pressure is 14. Dynamic Compression Ratio. Modern bike engines tend to run compression ratios in the 10:1 to 12:1 region. The compression ratios you are quoting are theoretical ratios and not effective ratios so yes cam profile will figure in. However, steady-state octane number requirements were generally below 75 RON at 8:1 CR. Heavy loads and low octane fuel spell detonation on an engine with too much compression. Check the compression. Knock may occur more easily. 8L with a 10:1 compression ratio (stock). 6 or whatever. Diamond's ring compressors are precision machined from heat treated aluminum and hard anodized for years of use, for the builder who does a lot of repeat bore sizes. By your logic my 8. 5 to 1 and the lt-4 have 10. 1:1 93 Octane 12. The standard engine remains the 5. This is considered the minimum compression ratio needed to make serious power from a Harley-Davidson engine. 57, which is worth about 0. For racing engines this dynamic compression ratio is generally more then 9:1. 524 PSI) Sachs A engine compression ratio is 8:1 (8*14. This is the compression ratio that the engine actuall experiences when running, and it is determined primarily by the timing of the valve events. Engine Test Stand-- Build a stand to test fire your motor on. 62 inches) Redline 14,000 RPM Valve Train DOHC; four-valve Ignition System CDI (electronic advance) Lubrication System Forced lubrication wet sump Starting System Electric Carburetion Keihin CVK30 (2), Constant velocity, Diaphragm-type Transmission Type 6-speed, constant mesh. The compression ratios you are quoting are theoretical ratios and not effective ratios so yes cam profile will figure in. Camshaft is another, and combustion chamber design is a big one. Re: compression, how high is too high on 98fuel. 7:1, so we need to change something. CR and intake valve closing are the two most significant factors in the calculation of the combustion chamber pressure. At this point, because the engine is reaching 100% volumetric efficiency, the dynamic compression ratio IS EQUAL TO the static compression ratio. Also available for Motorcycles in 2 ounce bottle. publication x30024 ©continental motors, inc. The dynamic compression ratio is a more advanced calculation which also takes into account gasses entering and exiting the cylinder during the compression phase. However, installing the same spark plugs Kenny Bernstein uses in his 300+ mph Top Fuel car (running Nitromethane at a 2:1 air/fuel ratio and over 20:1 dynamic compression) in your basically stock Honda Civic (running 15:1 a/f ratios with roughly 9. Cranking compression is kind of like a Dynamic Compression indicator. Plus, the motor seems to run better and I can advance the timing and speed up the advance curve from stock settings. 3 US quarts 2. In a dynamic sense, the compression ratio in every engine varies somewhat in practice, according to many variables. 7L HEMI engines compression ratio of 10. There is compression. This increases the peak pressure and temperature. Both the gas admission and pilot fuel injection are electronically controlled. The engine has been recalibrated for 2002 to meet emissions regulations. Dynamic Compression Ratio Explained. I've only read people discussing static compression. You can run. The higher compression + boost will lead to higher octane requirements to avoid detonation. my Kawasaki ninja 250 has 11:1 compression ratio and the manual says to run 87 octane. Elevation - posted in REV Chassis - Mountain Sleds: Is there a rule of thumb regarding safe compression ratios and elevation? I noticed that a few of the head makers offer different compression ratios 13. 30 city/38 highway/33 combined mpg rating for LX CVT and Touring trims. It is a measure of a fixed volume reduced to another, and both will provide the most power when squeezed around an 8:1 dynamic compression ratio on 93 octane. Compression ratio from Compression Gauge reading, adjusted/effective compression ratio, Dynamic Compression Ratio, Est. Because E85 has a much higher octane rating than gasoline (100 octane or more), the engine's compression ratio can be spiked considerably under full-load without worry of premature combustion, or. Our target compression ratio is thus 9. Compression Ratio Calculator v2. 020-inch below the block deck surface, which is excessive, but we can use that to our advantage. 5:1 drag motor can run 91 octane without pinging. 4) over stock (10. Each engine is different. Camshaft timing events must be directly tied to compression ratio. 5 more dynamic compression if you have aluminum heads. DPS™ Dynamic Power Steering Anti-theft system Digitally Encoded Security E S™) / DiMEnSiOnS / L x W x H 105 x 61 9 x 59 4 in (2,667 x 1,572 x 1,510 mm) Wheelbase 67 5 in (1,714 mm) Seat height 30 4 in (772 mm). 6 or whatever. Just to get to. 7:1 stoichiometric air-fuel ratio (at which all the fuel burns and all the oxygen is used), even on regular. Octane number (RON)=92. With that combo I never had an issue with ping at all. Cam specs, chamber design, piston materials, carbon build up, etc. 4) The type & octane of fuel you use is a main contributor to what compression to use, so the higher the octane the higher the compression you can use safely but it's still beneficial to run a lower rather than higher compression ratio. 1 2 3 4 5 6 7 8 9. Desired pressure is 160-170 psi, so we need to increase pressure by 40-50 psi. 005-inch below for example), this improves the compression ratio but also limits the thickness of the head gasket since we are limited to roughly 0. 040 quench under towing load scenarios? KB's site suggests no more than an 8:1 dynamic CR under the best (light load?) conditions without getting exotic. you don't test for compression ratio you measure it with burette and pipette. 7 lbs = 1 ratio, so 147 lbs compression is 10:1 at cranking speed. what mod did you do to run 10:1 Reply Quote. DCR Calculator. Due to the higher compression ratio, we were unable to run pump gas for our test, but we did use 106 octane leaded race gas. Where does the argument of static vs dynamic compression ratio come in when talking about combustion temps and therefore NOX emissions? If I have done my math right the dynamic compression ratio of a stock M cam B230F is 8. And until I figured this out to be true I went through two engines. As the compression ratio, , increases, increases, but so does. 6:1 and below ish. The key factor is the dynamic CR based on the intake valve closing point. 5:1 ratio rockers and the. Static compression ratio of 9. 036" HG (10. But most important of all is inlet air temperture. Most vehicles built today use a 8. 0:1 to run 87-octane pump gas. As a general rule, the maximum final compression ratio should not exceed 12. Question 15. Learn more about all the specifications for the 2020 Nissan Altima. Factors that limit compression ratio The limiting factor for compression ratio has always been the fuel's ability to resist detonation. The purpose of these pages is to helpfully show what DCR (Dynamic Compression Ratios) and SCR (Static Compression Ratios) have worked with what Octane gas. For example: A Twin Cam has a published static compression ratio of 9:1. Posted By NoShortcuts 6 Years Ago. 3 × atmospheric pressure, or 13. It factors the cam profile-more precisely, the intake valve closing point-with the SCR to get an operating, or. The message board provides a dynamic environment that I can use to build articles and it allows members the ability. It is very important to know or predict compression ratio with a high degree of certainty, so appropriate fuel choices can be made. 5 to 1 to 10 to 1. As mentioned above, dynamic compression is the determining factor for cylinder pressure. 050" lift the valve is open. 2:1 allowed by the fuel’s. Camshaft is another, and combustion chamber design is a big one. The Max Safe ECR for US Gas is as Follows: 91 Octane 12. Another thing to really consider should be actual compression instead of ratio. 2: Throttle Valve Diameter: 48 mm / 1. 67 compression height) than stock. Keep in mind, camshafts play a big role in determining the dynamic compression ratio. 5/1 compression with port injection. This is one of two engines we offer using a used block, capable of running on 87 octane pump gas. Modern bike engines tend to run compression ratios in the 10:1 to 12:1 region. 5:1), the ECU can adjust valve timing to control how much air is actually getting pulled into the combustion chamber, which affects actual dynamic compression. Let's say at 4000 RPM this motor is consuming. RON fuel in real driving conditions on the high compression ratio engine; - A linear improvement in the fuel consumption benefit between RON 95 and RON 102, meaning that each RON increase between these two values is beneficial to fuel consumption. 5 the calculator returns a dynamic compression ratio of 8. find 94 and 11. They are designed to achieve 7. But if it touches the head at high revs it is probably close enough. With a steel rod and light weight piston and you may get by with. A 10-to-1 compression ratio means that the air- fuel mixture gets squeezed down from the full volume of the cylinder to a volume that is just roughly one tenth of the cylinder. The mysteries of compression ratios investigated and unravelled - Visordown is the world. 5 to 2 points. Detonation was especially detectable at low engine speeds. The clearance volume is very small in comparison with the displacement volume (e. The only accurate way to know what your comp ratio is is to calculate it for this you will need to know your engines chamber volume,then divide your chamber+swept volume by swept volume. A normal spark ignition engine runs at an average compression ratio of between 9:1 to 10:1. 5/1 effective compression ratio, the effective displacement would be 37. In a spark-ignition engine, the air-fuel mixture gets heated during the compression cycle and is thereafter triggered by the spark plug to burn rapidly, as per the engine design requirements. 5:1 for "pump gas". What compression ratio would be safe to use on an iron headed 390 Fe on premium fuel? This will be a steet engine. 040 quench under towing load scenarios? KB's site suggests no more than an 8:1 dynamic CR under the best (light load?) conditions without getting exotic. 7:1 dynamic compression (as per my normal convention) by virtue of balancing when the intake valve closes with the engine's static compression ratio. 7120/0630 Head Flow Chart. 62 inches) Redline 14,000 RPM Valve Train DOHC; four-valve Ignition System CDI (electronic advance) Lubrication System Forced lubrication wet sump Starting System Electric Carburetion Keihin CVK30 (2), Constant velocity, Diaphragm-type Transmission Type 6-speed, constant mesh. Gas that sits loses 'octane' quickly. 2016 Toyota Land Cruiser Specs, Engine Specs, Weights, Dimensions and Trailer Towing. An engine with a 12:1 compression ratio needs close to 100 octane. Using some different online calculators, I got a static compression ratio of 9. 9:1 high speed. Since no compression builds until after the intake valve closes, it's the corrected compression ratio that gives the best indication of how pump gas friendly your motor will be. CR is about 11. As a general rule, the maximum final compression ratio should not exceed 12. Compression Ratio. When the engine is assembled, use one of the. 5 to 2 points. These pistons, combined with the factory heads, make a compression ratio of about 9. Racing Fuel in a 598 V8 vs 91 octane fuel + ACES IV on a dyno. A compression pressure of 120 psi is too low to support optimum efficiency. Dynamic Compression Ratio (DCR) is an important concept in high performance engines. 4) over stock (10. The fun thing about compression ratio is that there's multiple values. This is quite hard to believe given the higher flow carburetor (100 cfm more), considerably larger valve setup, and increase in compression ratio of 11. The older 115s and 135s had compression up in the 120s, 130s or higher but the later model engines designed to run on lead free low octane fuels went all the way down into the 90-100psi range. 0-litre straight-six) with a pair of small turbos on the side – the bore, stroke, capacity and compression ratio are identical between the two. The higher the Compression Ratio or the pre-compression pressure, then the higher is the thermal efficiency of the internal combustion engine. I'm ready to learn. You can run 10:1 on open chamber iron heads with the right cam. 0 SkyActiv-G (Mazda's PE-VPS) is 2. Some of the OMC Looper V6 engines have staggered compression as well meaning that cyls #1-4 will have higher compression than cyls 5-6 will. 5:1, a useful value for cylinder pressure would be (7. 078 and gap was 0. The M-Track Eight from M-Audio is an 8-input USB 2. Compression Ratio Blending Chart => click here. It has also proven to be very popular in the highly-stressed naturally-aspirated big blocks used in truck pulling. 75 corrected) and 205 CCP. From 1950 to 1974 the 88 was the division's top-selling line, particularly the entry-level models such as the 88 and Dynamic 88. Wow! According to the chart, my 98" 615/585 build will be at 10. 4195 / 4200. There are several things that determine the octane level required such as combustion chamber shape also contributes. The dynamic compression ratio is a formula that is backward calculated by motoring an engine and watching, with a pressure measuring instrument, what sort of cylinder compression pressures are made from different combinations of manifolds, ports, valve sizes and shapes, cam timing, connecting rod lengths, throttle opening, RPMs, etc. If the pistons are closer to the deck (0. The dynamic (or cranking) compression is a derivative of the static compression. 6:1 static compression but I can run 92 octane just fine because I run aluminum heads and my dynamic compression ratio is 8. I know there is more to be said about this. If its 290 gross horsepower and 428 lb-ft of torque weren’t enough, the 455 was available in two states of tune, along with a low-compression (8. Which of-course gives you more BHP and to make a specific type of motor run with higher compression ratio, higher grade fuel is needed. The octane number tells you how much cylinder pressure the gas can handle without detonating. NOTE: Also modify the intake manifold to maintain port alignment. Compression Ratio vs. Dynamic Compression Ratio (DCR) is an important concept in high performance engines. We were able to make significantly more power with a a properly designed and tuned E85 engine!. The 88 series was also an image leader for Oldsmobile, particularly in the early years (1949-51) when it was one of the. 042) regaurdless of static compression ratio once you go above about 9:1 static compression,or you engine can run into detonation problems. 4:1 are not recommended for use with "92 octane pump gas". If E85 or high-octane race fuel is going to be run, a compression ratio between 9. Im wondering if anyone has done the work to find out if using the recommended fuel would benefit me over saving a few dollars a tank. So now I am a little reassured although I am sure to have made some incorrect assumptions. DCR, quite simply, is the static compression ratio after some of it is bled off by the intake valve closing after the piston passes bottom dead center. Compression ratio is 11. So not knowing a cam, its impossible to accurately calculate static compression ratio. 1:1 and that’s exactly the combination we safely ran on the dyno. 00, stroke 3. Determining what the compression ratio is after the intake valve closes provides valuable information about how the engine will perform with a particular cam and octane. Good thing I had compression releases installed!! Looks like I'll be carrying octane boost with me. If the engine overheats again, have a The coolant level Yamaha dealer check and. 8 is only 172 cu in. Also, some of the earlier domed, and other make domes pistons won't allow the compression ratios of the hemi or top hat combustin chambers, some not even close. See important specifications about the 2020 Lincoln Aviator Reserve model such as features, dimensions, capacities, engine, and safety and security features. ) Gasket Bore (in. Maximal's fast burn rate makes it particularly beneficial in large-bore, large-displacement naturally-aspirated drag racing applications. I burn 87 octane in my 09 Touring bike and it does not ever ping, spit. The chart is based on static compression ratio which is what is quoted by 99% of manufacturers of vehicles coming off of an assembly line. We were able to make significantly more power with a a properly designed and tuned E85 engine!. Output increases on each engine, and EPA fuel economy improves. 5 with the sweet spot at 8. If we plug those numbers in our modified formula (Trapped Cylinder Volume at IVC + combustion chamber volume at TDC) / combustion chamber volume at TDC = trapped compression ratio with numbers it looks like this: (334+ 36) / 36 = 10. The displacement growing was achieved by the new forged steel crankshaft with 92. Engine Building Educational Links. (approx 6%, 3%, 1%, till you max out on compression for the application) 14. ~ Static & Dynamic Compression Ratio, Cranking Pressure (Gauge), Dynamic Cranking Pressure, Dynamic Boost Compression Ratio, Effective Compression Ratio, Compression Ratio Without Altitude Correction ~ Effective Piston Stroke Length - Octane Numbers for Static Compression Ratio - Additional Calculator ~ Find Compression Height ~ Find Deck Clearance. No OEM that I can find has supplied 12/1 compression and boost. I am sure that the ratios vary by manufacturer and model. 5:1, a useful value for cylinder pressure would be (7. 1:1 93 Octane 12. Therefore with the mild cam it will have a high dynamic compression ratio, probably 9. The Oldsmobile 88 (marketed from 1989 on as the Eighty Eight) is a full-size car that was sold and produced by Oldsmobile from 1949 until 1999. Curb Weight with Technology and Entertainment Packages (lbs without/with. I theorize it will net the results you want. looking at various compression ratios depending the p/c combinations available varying from 9. 25:1 should not run on gas below 98 octane. It is formulated for use in all naturally aspirated engines with compression ratios of up to 13:1. 5:1 and power dropped to 310hp at 7400rpm with 251lb ft of torque at 3250rpm. The M-code version was produced from 1970 through 1971. 5%; r = 10:1 is 60. Theoretically, if the compression ratio is raised from 10:1 to 15:1, the thermal efficiency will improve by roughly 9%. 27 trapped (aka dynamic) compression ratio The later we close the intake valve the smaller the trapped volume and the lower the trapped compression ratio. Design characteristics of an engine can help to raise the spark knock threshold without raising the required octane rating. Had 212-218 psi cranking compression. Sorry for making my first (I think?) thread a question. From looking at other cam profiles the power band should be from 3000 - 7500pm. These bikes don't have what you would call high compression. cranking compression figures can vary so much that they are just about a waste of time other than checking for even cranking pressure between the cylinders,about 10 % variation is what is generally accepted. my Kawasaki ninja 250 has 11:1 compression ratio and the manual says to run 87 octane. The subject of compression ratio and fuel octane comes up more when dealing with customers who want to run pump gas rather than with customers running race gas. I don't know if 93 octane would work with an 11-12:1 compression ratio with that cam. 62 / 96 x 92 Block Material: Cast aluminum Cylinder Head Material: Cast aluminum Compression Ratio: 11. A subsciption is required to use the Automath section. Dynamic compression ratio (DCR) is a more important factor in determining how well an engine runs and whether it will run OK on pump gas (93 octane or lower). 5:1 with dynamic compression at 9. 5 kg air by kg fuel. The octane number tells you how much cylinder pressure the gas can handle without detonating. It's the ratio of swept to fixed volume. 15cc, and 243/799 heads have a volume of 64. This is how you do it. With the BMW R 1250 GS you will experience the Boxer even more directly. OCTANE NUMBER REQUIREMENT MAPPING - Octane number requirements were investigated under both steady-state and dynamic conditions. Forced induction needs lower compression since you are effectively increasing compression by increasing the amount of air in the cylinder. If you'd like to do your own math here is the formula: Square Root of: ((Boost Pressure in LBS + 14. Typically the dynamic compression ratio for engines on pump fuel is 7. Compression Ratio Estimated Cylinder Pressure @ TDC given 60% volumetric efficiency at cranking speed Percent Change from 8:1 CR Nominal Dynamic* PTDC = 1atmosphere · volumetric efficiency · nominal CR1. I now run 10. 5 additional. (it's a hike, about 11 miles away from me). We must also, at this point, consider if it is proposed at this stager or at a later point in time, to use Nitro-methane, the question of the actual compression ratio to be used will be determined by the amount of Nitro-methane in the Methanol and as a guide Chart 1 gives approximate values on the conservative side. 4) The type & octane of fuel you use is a main contributor to what compression to use, so the higher the octane the higher the compression you can use safely but it's still beneficial to run a lower rather than higher compression ratio. there isn't any chart for 150=91 octane. sputter, puke or gag. How to Calculate Compression Ratio from Scratch As an example, let’s calculate the CR for a popular big-block Chevy application. this guy wants around 250whp with a turbo. Displacing 5. 0 liter Coyote V8, which has a compression ratio of 11:1, and you start to see where Ford is going with this. 0:1 Horsepower 197 hp @ 6350 RPM on 93 octane Torque 214 lb-ft @ 5000 RPM on 93 octane Redline 6375 RPM continuous 6500 RPM three second overspeed Specific output 123 horsepower per liter Valvetrain Twin independent variable cam timing Ignition Coil-on-plug Pressurize, direct injection, electric return-less fuel system Fuel. High compression was first made popular during the 60's with big v-8 racing engines(4-stroke) and compression ratios went up to 13-1 or more. You have to be prepared and understand what it does to the tuneup because it can do things that effectively work against you,” Lee explains. Too high of a corrected compression ratio results in detonation. Compression ratio is a simple ratio between the volume in the cylinder and combustion chamber when the piston is high at TDC over the volume when the piston is low at BDC. The compression ratio of your engine determines the octane rating of the gas you must use in the car. Effective stroke is 3. Compression Ratio vs. So the high-speed effective compression ratio may be approximated by multiplying the base 9. As a general rule, the best available pump gas will work with an 8. By your logic my 8. 67 compression height) than stock. ON/CR octane number per compression ratio requirement The conversion of pure ethanol is denoted by the gray line in each chart, and dynamic imaging apparatus. 7120/0630 Head Flow Chart. In simpler terms: It is like a higher (numericly) gear ratio in that it spreads the work out over a longer/bigger distance. Download octane render for free. (140 mm) Fuel. This compression ratio calculator can be used to work out the compression ratio of your engine. CR and intake valve closing are the two most significant factors in the calculation of the combustion chamber pressure. 050" x the rocker ration, be it 1. 5:1 or 9:1 compression ratio. Determining what the compression ratio is after the intake valve closes provides valuable information about how the engine will perform with a particular cam and octane. Mazda managed to achieve a high 10. Normally I run 93 octane pump gas which of course I can only find in 10% ethanol around me, but I know where I can get 89 octane Ethanol-free gas. 4 : 1 Maximum power: 152 kW @ 5200 rpm Maximum torque: 305 Nm @ 3600 rpm Redline / Cutout: 5600 / 5900 rpm Recommended Fuel: 91 Octane (ULP) Engine Control Module (ECM) / Powertrain Control Module (PCM) Details ECM - Delco 09356445 PCM - Delco 09356445. MotorSports Racing Fuels - Racing Gas, Nitromethane, Methanol, Racing Lubricants, Additives, Race Fuels, Race Additives, Race Accessories and More!. The engine block is equipped with two chain-driven counter-rotating balance shafts. You have to be prepared and understand what it does to the tuneup because it can do things that effectively work against you,” Lee explains. Compression Ratio Calculator Static and Dynamic compression ratio. 7:1 stoichiometric air-fuel ratio (at which all the fuel burns and all the oxygen is used), even on regular. 1 2 3 4 5 6 7 8 9. LBS @ 2500 RPM Oil Type SAE 10W-30 SAE 10W-30 Oil Capacity w/ Filter 2 US quarts 2 US quarts 2 US quarts 2. 0:1 with the preceding rod, stroke, and cam intake closing event, you would need about a. Fuel Type Unleaded gasoline with octane rating of 87 or higher Oil Cooling without Engine Cooling Forced air cooled, Fly-wheel fan Engine Type 4-stroke OHV, V-twin cylinder, gasoline Number of Cylinders 2 Displacement 44. Compression The engine does not start. That way the engine can benefit at high RPM from the maximized amount of intake charge afforded by the late intake valve closing, and still achieve sufficient compression of the mixture as a by-product of the dynamic compression ratio. To go to a higher compression ratio with no problem. 67 compression height) than stock. 0:1 static compression and an intake valve which closes at 70° ABDC, or 9. If is too high, the mixture will ignite without a spark (at the wrong location in the cycle). 310-inch) and 4. RACE-GAS produced similar results in peak horsepower and torque as the 111. 4:1 low speed, and 7. Primary reference fuels with octane numbers of 20, 40 and 60 are used in this study. This helps in maintaining higher compression ratios for greater efficiency and power. 51) of the 11,000 RPM Hayabusa engine and the low compression ratio (9. Now it's consuming 10% more air than the dynamic compression ratio. Adding the benefit of the compression ratio increase from 10. Has anyone else experienced this problem with Hypereutectic pistons chipping caused by a bad distributor? I had my 351C M code motor professionally rebuilt late 2012. I recall reading somewhere that the old 372 had a comp ratio of 10. You're completely incorrect, possibly you have been reading an "effective" compression ratio chart. You have to realize that there is more to this than just the DCR. You must know the mechanical compression ratio of your engine to get reasonable results from this calculator. 01 Recommended compression per octane 12:1 93 Pump 14:1 110 oct. The higher the Compression Ratio or the pre-compression pressure, then the higher is the thermal efficiency of the internal combustion engine. Too high of a corrected compression ratio results in detonation. Though small engines tend to show their issues in more. Final compression ratios in excess of 12. With 360 inclinable technology, the GX50 delivers powerful performance in a compact package. (considers cam timing and rod ratio) This calculator will give you the proper compression ratio with a known piston head volume. It is just a general chart for quick reference. 3 though with 87 octane, or use a octane booster if you go higher compression while in Mex. Normally I run 93 octane pump gas which of course I can only find in 10% ethanol around me, but I know where I can get 89 octane Ethanol-free gas. Turbo charging or increasing the compression ratio changes the mixture density (more air and fuel molecules are packed together). An electronic returnless fuel system uses a high-pressure pump to deliver fuel directly to the injectors at variable pressure, adjusted to meet the precise demand. Theoretically, if the compression ratio is raised from 10:1 to 15:1, the thermal efficiency will improve by roughly 9%. While there are still volumes more that could be learned about the "black art" camshaft selection and design, hopefully you will find these rules helpful in peeling back the some of. Compression Ratio; Dynamic Compression Ratio Calculator; Effective Compression Ratio; Blower Pulley OD/UD Chart; Horsepower - Torque Calc; Pressure Loss From Fuel Line Length; Max RPM Calculator; Octane Mix Calculator; Mortgage Refinance Loan Calculator;. Desired pressure is 160-170 psi, so we need to increase pressure by 40-50 psi. 8:1 with the dished pistons, which yours likely has and that is because the 454 from the mid 70's up was mainly used for heavy duty purposes. Your effective boost compression ratio, reflecting static c. The one with more volume of charge making more power. Compression ratio for pump gas Discussion in 'Engine Topic' started by BackyardCustoms, Apr 2 , 2013. Octane number (RON)=92. Just because your service manual says your car is 7. Compression Ratio VS Octane Requirement Chart « on: February 15, 2013, 01:50:26 pm » This is from the 2007 Polaris 440 manual, it is available from other sources as well. 15″ and stroke measuring 49. Mazda managed to achieve a high 10. I want to build a destroked long rod EJ257 too but we wanted to try messing around with the EJ205 as it gets overlooked a lot. Some guy said you should use high compression pistons: "thats pretty low for an allmotor honda. This is why some engines require 100+ octane with an 11:1 compression ratio while others are perfectly fine on 91 octane with a 13:1 compression ratio. Just as you can't determine your MPH just from axle ratio without knowing rpm, trans gear, tire OD, etc. If this is your first visit, be sure to check out the FAQ by clicking the link above. For the South African market, the engine was revised slightly in order to be able to cope with the country’s lower octane fuel; different pistons were utilised, dropping the compression ratio to 10. Factors that limit compression ratio The limiting factor for compression ratio has always been the fuel's ability to resist detonation. While intended mostly for Jeep engines, it'll work just as well for any other engine too as long as you can provide all the necessary specifications. 87, and a projected cranking compression of 165. My 383 has 10. They don't care about dynamic compression ratio. You don’t want to discover you have too much compression, or too little, when the engine is assembled. 5 but up there you definately need 110 octane, or some form of liquid lead additative. That means less "dynamic" or "swept" compression Now a third example, a 268 degree cam on 106, IVC is 60 degrees, that means 120 degrees of crank rotation compressing the mixture. Compression Ratio. Also, the engine has the short connecting rods (144 mm) and other pistons lower the compression ratio to 9. so my question is, is what is the highest compression ratio i can have and run on 91 octane gas? and does my altitude have a large effect on compression ratio?. Compression Ratio: 13. those are static numbers, in reality when your motor is running a 11:1 with a cam its actually pushing out around 8:1 to 9:1 at the most. Examples are plentiful. The subject of compression ratio and fuel octane comes up more when dealing with customers who want to run pump gas rather than with customers running race gas. 5/1 effective compression ratio, the effective displacement would be 37. Dynamic compression ratio (DCR) is a more important factor in determining how well an engine runs and whether it will run OK on pump gas (93 octane or lower). 039 gaskets and a little over 7. By way of an example, a standard CBR600RR has a 12:1 compression ratio, while an FW Developments supersport-tuned RR will run at around 15:1. Where CR is the compression ratio. Cam timing to reduce cylinder pressures - posted in Engine: I remember someone telling me in an earlier post " good luck with your cylinder pressures of 195 psi" It appears correct as my hi comp head has lifted 3 thou on number 3 pot and done a gasket. 64 : 1, and dynamic ratios of 8. (it's a hike, about 11 miles away from me). 018 gaskets, which is basically saying your cam is too big for your combo, or your compression is too low for that cam. Adding the benefit of the compression ratio increase from 10. 042) regaurdless of static compression ratio once you go above about 9:1 static compression,or you engine can run into detonation problems. (approx 6%, 3%, 1%, till you max out on compression for the application) 14. 3:1 on street fuel so long as your dynamic ratio is 8. You don't need high octane fuel until you start getting into the 11-12:1 comp ratios. For racing engines this dynamic compression ratio is generally more then 9:1. If you are going to increase compression at all higher than stock, need to run the highest at the pump.