Dynamic compression ratio vs octane
WebMar 22, 2024 · When the 6.245” rod length and the 51½° ABDC intake valve closing events are added to the calculation values, the dynamic compression ratio is 8.6:1. That becomes a problem as the DCR limit … WebTherefore with the mild cam it will have a high dynamic compression ratio, probably 9.5:1+ which would be way too high to run safely on 91 octane gas. However, that same 11:1 …
Dynamic compression ratio vs octane
Did you know?
The biggest limiting factor when attempting to increase compression ratio is the threat of detonation. This is defined as uncontrolled combustion that occurs after the spark plug has fired. Think of the combustion process not as an explosion, but rather, more like a brush fire burning across a large field of dry … See more When we talk about compression, this should be more accurately defined as static compression ratio. This is literally the ratio of the volume of the cylinder with the piston at the … See more Of course, too much ignition timing can cause other problems. For modern engines, a three-dimensional timing map based on both load and RPM will go a long way toward … See more Some may be concerned about the iron heads, as there is a concern with enthusiasts that iron heads are more detonation prone than aluminum heads. We actually performed a dyno test several years ago using a … See more This effect can be moderated by other atmospheric conditions. For example, high humidity levels tend to reduce octane sensitivity slightly since the additional water in the air finds its way into the combustion … See more WebMar 22, 2007 · Dynamic Compression using DCR Calculator: 7.97. This is one MEAN CAM. Excellent Torque and revs easily over 6000 rpm. Has an exhaust note to die for. …
http://www.wallaceracing.com/eff-cr.php WebApr 13, 2024 · 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. 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 10.5
WebJun 29, 2010 · The cam has 255* intake duration and the 52* ABDC is the .050 lift figure. I had no problem runnung 10.75 static compression with .040 piston to head and 93 octane. My concern is running the same 10.75 compression with .080 piston to head instead of the .040 clearance. The quench thing concerns me. The reason for this: I'm designing … WebApr 10, 2010 · 9,699 Posts. #2 · Apr 9, 2010. Building a motor to a dynamic compression ratio number just means it will detonate at higher rpm where you won't hear it. 10:1 compression is too high for pump gas, I don't care where you live or how big a cam is in it. At some point in the rpm range that big cam that bleeds off your low rpm compression …
WebDetermining 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. …
WebThe ratio of the cylinder volume at IVC over the volume above the piston at TDC represents the dynamic compression ratio. The DCR is what the air fuel mixture actually “sees” … duty sharingWebAdditional comment actions. Compression ratio is independent of any airflow. It's simply the ratio between the volume of the piston at the bottom of its stroke vs top of its stroke. Also, be cautious with too much air. Most stock ECUs have a maximum allowable fuel flow rate, and if you jam in too much air you'll likely get a lean condition. duty signifiesWebThe ratio of the cylinder volume at IVC over the volume above the piston at TDC dictates the dynamic compression ratio.The reduced volume that gets compressed represents your dynamic compression ratio and it is always less than the static compression ratio. In most cases it is up to 2 full points lower. Because it is based on fixed values ... duty short storyWebNov 20, 2024 · Step 7 – Determine the compression ratio: Use the formula below to compute the compression ratio. Compression ratio = { (swept volume + clearance volume) / clearance volume} Swept volume = (π) x … in an extinction burst:WebSep 1, 2002 · Then, for the June '01 issue, we tested another small-block with an XE268 camshaft, this time with a 9.75:1 static compression ratio that produced a cranking compression of 175 psi. in an external partner organizationWebJul 20, 2011 · 87 octane compression ratio cut-off point. Jump to Latest Follow 1 - 15 of 15 Posts. Clint Cummins ... Keep in mind the chart is for dynamic c.r. vs. static. X2 with BigDog, 9.5 is safe, maybe 10:1 max with a good tune and aluminum heads. I think VP-110 is running about $12.00 a gallon if you buy bulk. duty shoes letterWebJun 21, 2007 · This engine will think it is running with 6.17:1 compression and will be happy with 80-octane fuel. As a general rule, the best available pump gas will work with an 8.0:1 dynamic compression ratio ... duty show