Compression ratio octane calculator its combustion chamber size. Compression temperature, combined with inlet air temperature will determine which fuel can be used. Currently I have a 454 freshly bored 0. Your dynamic boost compression ratio, reflecting static c. May 14, 2014 · Static compression ratio of 8. 042 quench in most of my engines,I try to keep the oil temps at no more than 220F most of the time and ideally under 215F, I try to keep coolant temps under 190F most of the time and try to avoid getting coolant over 215 f, keep in mind that you can,t audibly hear detonation in most engines in the upper rpm range until Compression Ratio and Boost Pressure Relationship. 16 HP3 7. If the Effective CR is low enough there will be less chance of detonation on pump gas under part-throttle. 5:1, while still capable of burning pump premium 91 / 93 octane gasoline. Nov 17, 2022 · This measurement is taken by adjusting the octane engine's cylinder height, which changes the compression ratio/pressure in the engine until the knocking reaches a specific intensity level. Calculate the DCR: After inputting the data, the calculator will provide the dynamic compression ratio. You can run 11:1 or even 12:1 compression on your pump-gas street motor, but you'll need this simple advie to make it happen. Lower the static compression ratio (SCR) Install longer connecting rods; Increase the advertised intake duration of the camshaft. The ratio between the total displacement and the compression space above the piston (combustion chamber) is the compression ratio. CR = engine compression ratio. Dec 24, 1999 · An engine with too high a compression ratio will run hotter, ping, or require higher octane gasoline. However, with current race engine compression ratios already at 13:1 levels, adding a full point of compression may not necessarily add a full three percent, as the law of diminishing returns plays a part with ratios nearing 14:1 or higher. If you run a richer air fuel ratio around. 96 HP9 7. The compression ratio is the ratio between two elements: the gas volume in the cylinder with the piston at its highest point (top dead center of the stroke, TDC), and the gas volume with the piston at its lowest point (bottom dead center of the stroke, BDC) Nov 17, 2008 · the higher the effective compression ratio (up to about 13:1) the more torque you can expect to produce from an engine,if you use, high octane gas or race fuels, but the octane of the fuel currently available from pump gas drops the max effective dynamic compression ratio to about 8:1 Jan 10, 2010 · now IM not saying you can ignore the graph, but in the real world its not like if the graph says that if your engines compression ratio is at 9:1 your, engine combo instantly self destructs the point you put 89 octane in the tank,or at 9. 53:1 . 2:1 dynamic to the maximum amount of compression we can run in this engine with 91 octane fuel. Ring land volume. 32 inches. Jan 29, 2025 · Oztrack LS Camshafts – Dynamic Compression Ratio Calculator Data. 00 PSI. By accurately measuring the compression ratio, this calculator helps you make informed decisions about engine tuning, fuel choice, and performance adjustments, leading to optimized Jun 21, 2007 · How to calculate dynamic compression on a small-block chevy thickness necessary to achieve a static 10:1 compression ratio, assuming the valves are closed for the entire compression stroke Compression Calculator. " 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. 31:1 . 020 so its 9. 2:1 dynamic compression ratio. Here are the exact compression ratio and octane numbers: The compression ratio of your vehicle is from 9:1 to 10:1, you can use 90. 19/1. If you have a high compression ratio, such 9. . Jan 17, 2025 · How to Use a Compression Ratio Calculator. The DCR is the compression ratio that really does the work, although this can get to be a nastier concept when one envisions how the cylinder filling density changes with the speed/inertia of the incoming mixture, but even the rocket scientists among us don't take that one on. 3cr would be fine on the 93. Increase the lobe centerline of the camshaft (more distance between intake and exhaust lobes) Retard the camshaft Static Vs. Based on Static Compression Ratio of 10. This will give you an idea of what happens under boost and also how you should plan your motor for your target altitude whether it is for racing or day to We hope to achieve a safe compression ratio of around 13:1 running on either E-85 or 93 octane with an additive. 040", but not alwaysfor example, on K1200 BMWs it is 0. 73 HPX-R 7. To help determine compression if you have 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 Therefore with the mild cam it will have a high dynamic compression ratio, probably 9. 050" number for your Comp Cams brand camshaft. 98 HPS 7. 5 to1. Jul 3, 2008 · 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. That's why, when we talk about the best compression ratio, we should focus on the DCR and not on the static CR. Dec 29, 2013 · There are many factors that determine what octane fuel level an engine would be happy to run on so forget about rules of thumb. Should this be safe on 91 octane at sea level? Thanks for any insight! Mar 24, 2012 · The calculator doesn't care what you start with just what you change it to. The ratio is expressed as: Max. The octane rating needed to prevent detonation is also estimated. Now that we have low- and medium-octane gasoline, and high-octane E85 ethanol plus racing fuels, it is more important than ever to match compression ratio to the intended application and the fuel that will be burned. 440"/0. 5:1. There are several things that determine the octane level required such as combustion chamber shape also contributes. However, engines with higher compression ratios require higher-octane fuel to prevent pre-ignition or "knocking. The higher the octane, the more compression the fuel is able to resist and the higher the potential compression ratio. The cylinder is largest when the piston is at BDC. You must input 2 out of 4 values to calculate the missing one. About Compression Ratio Calculator (Formula) The compression ratio is a crucial factor in engine performance, affecting efficiency, power output, and fuel consumption. 070". The compression ratio that is built into your engine is called “static compression. Calculate static and dynamic compression ratio. CR = {[(π/4) x b 2 x s] + V c }/V c . Actual measurements are used to calculate the ratio. Calculates minimum fuel octane requirement for gasoline; Works with naturally aspirated, supercharged, or turbocharged engines; Calculate the minimum gasoline fuel octane required based on your engine's compression ratio, maximum boost pressure, spark advance, and air fuel ratio. We will keep you posted on our progress. 72:1 . To calculate the compression ratio of an engine, use the following formula: compression ratio = V d + V c / V c Be sure to get the correct engine parts for your classic VW with this engine size calculator. 31 Posi Youtube Channel. or using higher-octane fuel. Interpret the Result: The calculated DCR is a critical parameter for engine performance assessment, with higher DCRs generally resulting in increased power but possibly at the expense of requiring higher-octane fuels. The (R+M)/2 you see on the label refers to the average of the research octane number (RON) and the motor octane number (MON) ratings. Sep 7, 2015 · 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 ratio, look Mar 18, 2019 · Now when you are inputting all of your variables into a dynamic compression ratio calculator what compression ratio would you put for aluminum heads. May 13, 2012 · At this point, because the engine is reaching 100% volumetric efficiency, the dynamic compression ratio IS EQUAL TO the static compression ratio. 060, 33cc forged dome pistons, oem forged crank, scat ibeam rods, block is decked 0. 5:1 to 13. To determine the RON Thus, higher compression ratios also allow engines to be more fuel efficient, but these engines may need fuel with a higher octane rating to operate properly. Aug 26, 2016 · Engines do not pay much attention to compression ratio, either static or dynamic. 87 Dynamic Compression Ratio - Sea Level 4. They do respond to the temperature produced by dynamic compression. Dynamic Compression Ratio = Cylinder Swept Volume (when intake valve closes) + Combustion Chamber Volume Combustion Chamber Volume. Most gas stations in RI have 91 octane fuel, but some have 93 octane, so I felt 11. For multi-cylinder engines, just use the columes from one cylinder. Feb 26, 2021 · If working with iron heads and or wanting to run pump gas on 87 octane the numbers would be lower, I dont recall what those are. Get accurate compression without the guesswork! Get your engine's optimal compression ratio and total displacement in no time flat! Just complete your engine setup, click calculate, and you’re on your way to maximum performance. Types of Compression ratio. 7:1 is my compression ratio using the specs given? and that last calculation is unnecessary or wrong to use? would 93octane be ok at 12. The compression ratio is calculated in the following two different methods: Static compression ratio; Dynamic compression ratio; 1) Static The compression ratio to PSI calculator is an easy-to-use tool designed to calculate the pressure (PSI) based on your compression ratio. Engine Tuning and Recommended Guidelines | Daytona Sensors™ 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. This compression ratio Jul 14, 2008 · You cannot calculate what the cranking compression will be (PSI) from knowing what the static compression ratio is due to their being too many variables, however I have seen an online DYNAMIC Compression ratio calculator which tells you what the cranking compression of your engine will be, but you have to punch in the exact camshaft specifications, and if you don't know what they are then it General guidelines for conservative mechanical compression ratios on 92-octane pump gas with the V-Twin engine are as follows: With Twin Cam and Evo Big Twin engines, you can run between 9. Nov 3, 2015 · 9. Calculate. The highest number I have achieved with this is 215 psi cranking compression. Final compression ratios in excess of 12. However, running at a higher compression ratio should require less boost to make the same power. 7:1 or should i lower compression, is there a way to calculate what octane is needed based on compression ratio? sorry for all the questions, your info is super helpful Jun 11, 2021 · Production dirt bike engine compression ratios have increased over the years, to current ranges of around 12. The vast majority of cars have four-stroke gas engines; each stroke, or compression stroke, is when a cylinder full of gas and air is compressed into a dramatically smaller volume before it is ignited with a spark plug [source: Arman]. To determine octane to your compression, follow our easy to use chart below. 31 :1. 5:1+ which would be way too high to run safely on 91 octane gas. com) Apr 22, 2021 · The UEM calculator delivers an 8. Jan 23, 2015 · It is very important to know or predict compression ratio with a high degree of certainty, so appropriate fuel choices can be made. 5 degrees ABDC, yielding a 2. 1:1 compression, if you mis-calculated,or that if the pump says your getting 91 octane, your not The correct Compression Ratio is very important for each engine. If you keep the rpm's down, the VE% is smaller. 7:1 in 6L & 6. The following table provides detailed guidelines for setting the maximum dynamic compression ratio (DCR) based on the fuel type. 88 valves. If you're looking to find what deck height you would need for a 1776cc engine and you want the compression ratio to be 8:1, and you know your cylinder heads have a combustion chamber volume of 58cc, enter the following numbers into the appropriate box: Cylinder Bore= 90. May 25, 2019 · To get a true idea for a factory (non-modified / rebuilt) engine you will need to use a compression ratio calculator (many versions on-line), here is one example Compression Ratio Calculator - Wallace Racing Information you will need are your cylinder head date and casting # to find out your combustion chamber cc size. If the measured ratio is higher, adjustments can be made by shimming under the cylinders. for the A/F ratio ever time you drop a 1:1 ratio and lean it out you get +2 increase in octane. Oct 3, 2024 · However, extremely high compression ratios can lead to mechanical and thermal stresses that exceed the material limits of the engine components. Compression Ratio Calculators. The ratio between the cylinder capacity and the compression chamber is known as the Compression ratio (CR). The static and dynamic compression ratio calculator can do it for you. Can the compression ratio be too high? Yes, a compression ratio that is too high for the fuel's octane rating can cause knocking, reduce engine efficiency, and potentially damage the engine. and the difference. 3 compression ratio since it was primarily a street car and ran pump gas only. Apr 2, 2011 · Went to Wallace racing calculators and entered my specs and it showed me this. As mentioned earlier, the engine did rattle in certain areas that forced us to retard the timing slightly. The formula for calculating your exact Final Compression Ratio is as follows: This compression ratio calculator can be used to work out the compression ratio of your engine. 5:1 to 9:1 is recommended for boost levels of 8-10 psi. 13. May 16, 2006 · Compression Comprehension. Your dynamic compression ratio is 8. The lighter weight Evo XL can handle between 10:1 and 11:1 mechanical compression. (Dynamic compression ratio does not use the entire swept volume in the equation, but only the volume in the cylinder at the point where the intake valve has closed. I have 4 engines that I have played with these calculations on. It is derived from the sweep volume of the cylinder using the full crank stroke (BDC to TDC). 040-0. 3:1 to 9. SO lets say your calculated compression ratio is 10:1, but you are using aluminum heads so it basically has 9:1 compression ratio. The CR must fit to the engine design or specification. I think around the mid 8's. 4:1 dynamic compression ratio and a . Dynamic compression ratio is 9. Mar 22, 2021 · Here is the short list of some basic things that can be done to lower the dynamic compression ratio (DCR). It is smallest when the piston is at TDC. Instead, cylinder pressures and temperatures do but to calculate that sort of stuff gets a lot more difficult. Since a street car rarely sees full throttle, use a smaller VE% (such as 60-70%). if the OEM recommends 91 at 12:1 CR and you up it to 13:1 it calculates that you need +5 octane level per 1:1 increase in compression ratio. 10 HP1 8. Try various deck heights until the desired compression ratio is indicated. (links below this TLDR) For 93 octane pump gas don't go over about 9:1 dynamic compression. V/P (Volume to Pressure Index) is 141 Because, if the vehicle requires a high octane but the fuel used has a low octane, the vehicle engine will sound ticklish. However, it Jul 9, 2023 · It’s called regular gasoline in America and other countries. Wallace Racing BACK to Calculators This Calculator will figure the effective compression ratio using your inputs. Can I assume this calculator to be accurate when my input is correct ? What octane gas will be required ? Thanks in advance The static compression ratio takes the full compression stroke into account. Of the variables, the most important is cam timing which has a dramatic effect on your "dynamic" as opposed to your static compression ratio. To determine the effects of the altitude on a calculated compression ratio, use the following formula 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. 09 DR 8. As we mentioned before, the dynamic compression ratio is the one that happens inside the engine. 440" Lift, 248 Intake/Exhaust Duration, 108 Cam Lobe Separation Nov 12, 2010 · Compression ratio in itself doesn't really relate to octane requirements. 4:1 are not recommended for use with "92 octane pump gas". : Min. 87 HP7-R 7. This was with 93 octane. Compression Ratio (CR) tells you the relationship between minimum and maximum cylinder volume. 0L Connecting Rods, Modified MOPAR P4529229AD Camshaft - 0. It represents the ratio of the maximum to the minimum volume in the combustion chamber. Sep 5, 2022 · 'Street safe' Pontiac V8 with iron heads on 93 octane pump gas: Target a static CR of around 9. Cylinder Vol. A compression ratio of around 7:1 is ideal if you expect to use regular octane gasoline in a properly timed daily driver. 2L Crankshaft 4. octane; The compression ratio of your vehicle is from 10:1 to 11:1, you can use 92. Some calculators may also ask for the cylinder head volume and piston Dec 20, 2024 · You'll need to use online calculators to figure out your static and dynamic compression ratios. Calculate Now! Find out your IVC @ . Gasoline with this octane number is proper for engines with compression ratios of 7:1 to 9:1. However, that same 11:1 static compression ratio engine with the radical 259/269 duration camshaft would have a dynamic compression ratio in the neighborhood of 7. 05 to 1 Dynamic cranking pressure is 186. However, this can result in reduced power output and efficiency. The compression ratio of your engine has a direct relationship to how much boost you can run. Oui, un rapport de compression trop élevé pour l'indice d'octane du carburant peut provoquer des cliquetis, réduire l'efficacité du moteur et potentiellement endommager le moteur. 37. 7 psi by default, but feel free to change it if needed. 78 PSI. 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. , cam timing, altitude, and boost of PSI is 8. 78 height, 781 heads cc'd at 121 and have 2. See full list on engineaddiction. Programs that take Compression Ratio into account: We have produced 2 programs that are specific to Compression Ratio. Compression Ratio Calculator. 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. The static and dynamic compression ratio calculator (gofastmath. Altitude plays an important role in determining compression ratios. The compression ratio must fit the engine design and fuel! As a rule of thumb, one could say: The higher the octane number of the fuel, the higher the compression ratio can be selected. 040-. The dynamic compression is always lower than the static compression if the intake valve closes after bottom dead center (ABDC). 5 mm, Crankshaft Stroke= 69 mm Combustion engine compression ratio calculator - formula & step by step calculation to find the ratio of the largest to smallest volume of the combustion chamber of combustion engines. 5:1 mechanical compression without encountering detonation. The formula for calculating your exact Final Compression Ratio is as follows: Final compression ratios in excess of 12. Higher octane fuel will allow you to run higher boost levels, approximately 1 psi for every 2 points of octane. ” To see what the effect of bore, stroke, rod length, cam timing, compression ratio, boost pressure and altitude is on your dynamic compression ratio, simply enter the seven variables and the calculator will display the results in a new pop-up window. Typically, compression ratios fall between 8:1 and 10:1. 75 inches. While static compression ratio assumes the intake valve closes at Bottom Dead Center (BDC), the dynamic compression ratio takes into account the actual closing point of the intake To see what the effect of boost pressure and altitude is on your static compression ratio, simply enter the three variables and the calculator will display the results in a new pop-up window. Nov 11, 2024 · The Compression Ratio Calculator is a vital tool for automotive enthusiasts, mechanics, and engineers who want to understand an engine’s performance potential. Atmospheric pressure is 14. The available fuel sort is also one key factor (Octan index). Getting cool air into the engine and keeping the cylinder head cool are good starting points with the quench height preferably in the 0. 30. Most conventional Apr 7, 2010 · Calculate cranking compression pressure and dynamic compression ratio. Results. It's usually 0. Again, this is because the amount of air/fuel compressed by the piston in the dynamic situation is now equal to the amount compressed if you simply calculate the compression statically -- this is the Jul 29, 2023 · On the other hand, a lower compression ratio may be employed in engines designed for lower-octane fuels to prevent knocking, which occurs when the air-fuel mixture ignites prematurely. com I have tried to maintain an 8:1-8. 01 Recommended compression per octane 12:1 93 Pump 14:1 110 oct. Greater combustion efficiency is associated with higher compression ratios, such as those between 12:1 and 14. 1:1. Example: Chamfer on piston outer edge. This calculator will calculate both Static and Dynamic compression ratio. octane Jan 31, 2018 · By definition, the compression ratio (CR) is the total swept volume of the cylinder with the piston at bottom dead center (BDC), divided by the total compressed volume with the piston at top dead Sep 11, 2012 · Harley faces their air fuel ratio largely on the fact that they run a 14. By inputting the bore (cylinder diameter) and the stroke (piston movement length), these calculators can automatically provide you with the compression ratio. 060" range. Effective stroke is 3. Dynamic Compression Ratio, on the other hand, uses the Sep 15, 2024 · Dynamic Compression Ratio (DCR) is an important concept in high performance engines. 711" dynamic stroke for a dynamic compression ratio of 8. Too high compression or bad Oct 3, 2024 · The Dynamic Compression Ratio (DCR) is a vital metric in engine design and tuning, offering a more accurate representation of an engine's compression behavior under dynamic conditions, unlike the static compression ratio which doesn't account for the valve timing. 2L FE 8. Compression ratio and deck height calculator Enter your bore, stroke, head volume, and deck height. Jul 22, 2024 · Dynamic Compression Ratio (DCR) is a more accurate representation of an engine’s actual compression ratio during operation compared to the static compression ratio. Compression Ratio Calculator For those who either never learned it or have forgotten, it's useful to know: Cars' internal combustion engines all function pretty much the same way. Why do some manufacturers require or recommend the use of higher octane gasoline? Higher octane fuels are often required or recommended for engines that use a higher compression ratio and/or use supercharging or turbocharging to force May 8, 2009 · 1. Don’t know your intake valve closing angle? Calculate it here. Your dynamic cranking pressure is 151. 7 to 1 air fuel ratio. I have tried to maintain an 8:1-8. Calculate Compression + Boost for Octane. Apr 14, 2015 · Curious to know what the compression limit is for a 454 running on pump gas (premium 92-93 octane). Combined CR: 13. 5:1 and 10. The compression ratio calculator finds both the Apr 3, 2010 · Using a calculator program I got intake closes 68. Static Compression Ratio (SCR) is the ratio most commonly referred to. The corrected compression ratio, however, only counts the portion of the compression stroke after the intake valve closes . 5:1 or 10:1, you will only be able to run a small amount of boost. Your dynamic cranking pressure is 167. Drag Racing Calculators,Calculators to find 1/4 mile ET and MPH, CID,Piston Speed,gear ratio,carburetor size,margin of victory,Engine calculator, Calculates relative horsepower, air density, density altitude, virtual temperature, actual air pressure, vapor pressure and dyno correction factor and more. In Indonesia, the regular gasoline is of 88 octane, known as Premium gasoline. Comprendre le rapport de compression est crucial pour toute personne impliquée dans la conception, le réglage ou la maintenance des moteurs. 1 to 1 compression 204/214 cam summit intake abdc 29 Static compression ratio of 9. This is accomplished by better combustion space design, as well as superior air-fuel ratio control through electronic fuel injection (EFI). Dynamic Compression Ratio (DCR) is an important concept in high performance engines. 94 Static Compression Ratio - Sea Level 8. 61:1. 305 sbc 9. Compression Ratio is the ratio of an engine's cylinder volume vs. r. 5 In order to determine the octane booster that you need, either discuss with your tuner, and know your compression and/or boost pressure. Enter the volume of the cylinder and the volume of the combustion chamber and this calculator will tell you the compression ratio (referred to as secondary compression in 2 strokes). To go to a higher compression ratio with no problem. The extra volume in head gasket, This results in more power per stroke, which is why high-performance engines like the Ferrari 458 have a 14:1 compression ratio, and Formula 1 cars use even higher ratios of around 17:1 to maximise efficiency. Your dynamic compression ratio is 7. 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. 042 quench in most of my engines,I try to keep the oil temps at no more than 220F most of the time and ideally under 215F, I try to keep coolant temps under 190F most of the time and try to avoid getting coolant over 215 f, keep in mind that you can,t audibly hear detonation in most engines in the upper rpm range until 5 days ago · 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. The higher the final compression ratio, the higher the octane rating of the fuel must be in order to help prevent detonation and serious engine damage. Compression Ratio Calculator It is feasible to calculate the compression ratio proportionally by measuring the volume of air-fuel mixture that is still present inside the combustion chamber. Then follow our mixing charts provide our Calculator App, above. ) Determine piston dome volume or piston dish volume. If the altitude in the area where you normally drive is significantly higher than sea level, then your compression ratios will also vary. Effective stroke is 2. Using an online compression ratio calculator simplifies the process. COMPRESSION RATIO For pump gas (91-93 octane) applications, a compression ratio of 8. As with other calculators, equations are provided as well. Oct 10, 2022 · thanks! so to be clear 12. Dynamic Compression Ratio. Dec 19, 2011 · Static compression ratio of 11:8:1. Octane Mix Calculator; Octane Mix Chart NEW Dynamic Compression Ratio Calculator; Effective Compression Ratio; Piston Speed Calculators; B M E P Calculator; Jan 17, 2025 · Compression Ratio Calculator for engines, helping you calculate the compression ratio using the engine's measurements. This is the standard way of doing it. It is always going to be lower than "Static" Compression Ratios. Then press the "Calculate" button to run the program. Texas Speed & Performance 101 Velocity Drive, Ste 100 Georgetown, TX 78628 Nov 27, 2023 · What octane of pump gas? 1971 Chevelle SS454, T56 Magnum 6 speed, 3. 5:1, totally acceptable to run Fuel octane; Fuel Octane Calculation. Air/Fuel Ratio. E-85 has an equivalent octane rating of 105, and with an expected operating temperature of around 180°F, the maximum dynamic CR is slightly above 10. 47 inches. Compression Ratio Calculator 'Other' input for any volume not in calculator. The octane number tells you how much cylinder pressure the gas can handle without detonating. Aug 3, 2015 · My last 351w motor was planned for 11. Dynamic Compression Ratio, on the other hand, uses the Bore inches Diameter of cylinder Stroke inches Distance piston moves Head Gasket thickness inches Measure your head gasket tthickness. What would be very useful is a calculator that would indicate compression temperature at any ratio. This leads us to believe that it is fairly close at 8. Static Compression Ratio numbers are the ones you hear thrown around the most ("10:1 compression"), and it takes into consideration the full sweep volume of the cylinder in Most gasoline vehicles are designed to run on 87 octane, but others are designed to use higher octane fuel. wfxmp ailsi tckufz tcwhaig prbhbme ueef bmd xyji pxr nybbqtw xqoerbr jfrc mnrar qemryoo gqhz