I'm well aware of the search function and i always use it to its fullest but after days with out a clear answer i'm force to start a thread in order to get things clear.

I'm don't have an MS ecu yet but i'm doing my research in order to get one for my S5 N/A ae86 proyect. (traying to save me $600)

I downloaded megatune and was browsing trough it to see how it works, I have wolf3d on my rx7 right now and i clearly know my way around tuning since thats what i do for extra money in HONDAS.. Both the honda ecu and wolf are tuned only in injector timing milliseconds, and ignition timing.

Now as i'm looking on the megatune software ms has multiple VE tables. can someone explain why so many??? i see a good 9 under the basic tables tap, and about other 12 under the tuning tab. That its scaring the heck out of me

can some one explain what all those are?? and how to tune the VE table??
and what the VE really is??

i just need something to grasp the concept

 

The VE table is a table of the engine's volumetric efficiency (VE). This describes how effective the engine, intake, ports, and exhaust design are at flowing thru the engine. The VE is the amount of air actually in the cyl divided by the theoretical amount you could shove in at the intake pressure (post-turbo if you have one). Theres only one "master" VE table (at least for MS1), and thats the one under the "basic settings" menu. The other options under that menu are for starting pulsewidths, warm-up and first-start enrichments, acceleration enrichments etc. Under tuning it gives you a 3-d map of the master VE table that I find is easier to modify on the fly, and it gives a good indication of how smooth your map is.

The actual pulsewidth for the injector is calculated from the [VE at the current load/speed point] X [the intake pressure] X [the engine speed] X [the req_fuel value under basic settings] X [any enrichments active (coolant, time, tps_dot etc based)]

There is an alternate VE table that can be switched to and used for NOS or anything that you'd require a new table for (high boost levels, so you can have a greater number of bins in boost at the expense of part-throttle fuel economy), but if you arent using it, you can just leave it blank.

 

My MS only has *one* VE table. But then I am running very basic code.

The general way it works is the req_fuel is the theoretical pulsewidth per cylinder (rotor) for stoichiometry and 100% VE. The VE table is then the actual VE, times the fuel/air ratio difference from stoich. (So a 1:13 FAR is 14.7/13 times as big on the VE table)

The req_fuel doesn't have to be *exact* but getting it close makes life easier. In the end you're still just tuning a map and making the numbers bigger or smaller depending on if you need more or less fuel.

 

thanks for the explanation you clarify most of my table questions.

so from what i understand the VE table controls my injectors?? and the afr table shows my current a/f??

if thats the case, are there any formulas i can use to apply a fuel multiplayer ???
what i usually do is create a spreadsheet in ecxel with my target a/f, my actual a/f log, and the value in the table i want to use the multiplayer in.. then it just produces a new table value for me. makes fuel tuning super simple

is ms able to flip from VE table 1 and 2 base on a given load?? just wondering cuz that will allow to have more resolution on boost, then flip back to a regular low kpa map.

^above post wasn't there as i was writhing this one.

 

The VE table directly controls injector pulsewidth, along with a number of other inputs. The afr table contains the target afr values you would like to see at those operating points. Closed loop operation with a suitable wideband setup will attempt to trim the pulse width value to achieve the desired afr.

There is no need to mess with spreadsheet when tuning and datalogging. MegaLogViewer will open the datalog and MS settings file, and generate a new VE table for you to correct for operating conditions where the spread between desired and actual afr was significant. That VE table can be sent directly to MS, so no re-typing needed. Some details on that process are outlined here:
http://www.efianalytics.com/MegaLogViewer/

The theory of operation is all covered in probably too much detail here: http://www.megamanual.com/mtabcon.htm

 

Wideband

 

Thanks alot..

now that i understand its functions, i will be getting now soon. tuning is the best part of building a car

 

hey rotor connection what part of ct you from.