Timeline for Is there a rule of thumb for estimating volumetric efficiency?
Current License: CC BY-SA 3.0
25 events
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| Mar 16, 2017 at 15:47 | history | edited | CommunityBot |
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| Dec 21, 2016 at 7:21 | history | edited | Zaid | CC BY-SA 3.0 |
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| S Oct 22, 2016 at 9:59 | history | bounty ended | CommunityBot | ||
| S Oct 22, 2016 at 9:59 | history | notice removed | CommunityBot | ||
| Oct 17, 2016 at 5:06 | comment | added | SteveRacer | New information: stoichiometric is DEAD. Efficiency no longer caters to the old mandate. GDI has proven this. Deal with the heat; deal with the NOx. Racers knew this forever but were wary of the line where pistons and valves melt. There is a new era upon us, and I think it will be nifty keen, efficient, powerful, and even environmentally friendly. What was chemically true before has been assaulted by some guys that turn wrenches and engineer outside the box. There are now platforms that can run 20:1 and sill get 25 mpg on a V8. | |
| Oct 14, 2016 at 18:52 | answer | added | Netduke | timeline score: 1 | |
| S Oct 14, 2016 at 8:51 | history | bounty started | Nick C♦ | ||
| S Oct 14, 2016 at 8:51 | history | notice added | Nick C♦ | Draw attention | |
| Sep 16, 2016 at 11:13 | history | edited | Zaid | CC BY-SA 3.0 |
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| Aug 11, 2016 at 12:12 | answer | added | StevetotheH | timeline score: 0 | |
| Jul 30, 2016 at 3:05 | comment | added | SteveRacer | @Zaid (cont) On the other hand, on the tag:engine-theory front which I know you are a devout champion, it really would be a cool thing to derive. But as a turbo guy (with cars that go over 100% VE), I honestly doubt there's any "rule of thumb" that would be useful. Every block, intake, cam profile, every everything is gonna be different. | |
| Jul 30, 2016 at 2:56 | comment | added | SteveRacer | @Zaid I hit enter for a space, and ended the comment early. What I wanted to say I've never encountered a bad MAF that needed that level of diagnostic inquiry. My oldschool shadetree is to look a g/s at idle, spray the magic cleaner, and check again. In the meantime, as Ben said, there's no crime in assumng VE is 100%, especially at peak torque RPM if known. Keep in mind that a scan tool OBD II translation of "220 Khz" or "3.22 volts" may be different than actual ECU scaling of predicted CFM from ECU maps. | |
| Jul 29, 2016 at 21:59 | comment | added | Moab | installuniversity.com/install_university/installu_articles/… | |
| Jul 29, 2016 at 12:23 | comment | added | Zaid | @SteveRacer that's a great link there | |
| Jul 29, 2016 at 12:03 | comment | added | Ben | @Zaid Most free calculators assume theoretical VE is 100. I don't think there is anyway outside of model specific details. | |
| Jul 29, 2016 at 11:48 | comment | added | Zaid | @Ben that's a nice video but he's using the PID's to calculate VE and then comparing it to a baseline number. I want to know if there is a way to roughly establish what that baseline number should be without knowing model-specific details. As an example, a rule of thumb for any naturally-aspirated, four-stroke reciprocating engine with a single throttle-body. | |
| Jul 29, 2016 at 8:08 | comment | added | I have no idea what I'm doing | Good question, always wondered that myself. How do people find the VE for their engines anyways? Do professional service manuals list them? | |
| Jul 29, 2016 at 6:59 | comment | added | SteveRacer | epi-eng.com/piston_engine_technology/volumetric_efficiency.htm | |
| Jul 29, 2016 at 3:22 | history | tweeted | twitter.com/StackMechanics/status/758865343813083141 | ||
| Jul 29, 2016 at 2:01 | comment | added | Ben | also a link to a motorage article searchautoparts.com/automechanika-chicago/commitment-training/… in the video the truck used doesn't have a maf but displays a calculated airflow pid i think he addresses this point in a video response. | |
| Jul 29, 2016 at 1:53 | comment | added | Ben | You can use online calculators like otctools.com/ve to roughly estimate VE. It requires the car have a maf and doesn't account for elevation, humidity etc... I'm sure there are paid tools that do though. I tried writing a program to do this at one point but I couldn't get the math to work right or the formula was wrong. | |
| Jul 29, 2016 at 1:48 | comment | added | Jason C | I don't know the answer to this (and cursory research shows the outlook may be grim) but don't service manuals publish spec ranges for MAF values that you can check against? You can also compare to known good sensors. But I guess that's not helpful for the goal of a quick scan-tool-only test. I dunno though, the only car I'm familiar with is my own and it uses a MAP sensor instead, and those are easy to test with a vacuum pump and a voltmeter. | |
| Jul 28, 2016 at 23:24 | comment | added | Pᴀᴜʟsᴛᴇʀ2♦ | I think there may be too many factors involved, namely because every engine is different in how the intake will flow, cam profile, and how the exhaust flows. All of these will have a factor in the volumetric efficiency ... at least that's my gut check on this. | |
| Jul 28, 2016 at 22:54 | comment | added | Zaid | Just to be clear, this question is about roughly estimating VE, unlike this one | |
| Jul 28, 2016 at 22:53 | history | asked | Zaid | CC BY-SA 3.0 |