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Air per Cylinder Estimated and VE table question..


k4nnon
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Hey all link g4x plug and play unit for evo 9. Im trying to verify that my VE table values represent correct and actual referencing of percentage of cylinder filling.. Iv used a simple calculator provided by Evans Performance Acadamy and im confused by the values or even what i should do to get correct and actual values. I would like to get my VE table dialed in as accurately possible so i would like this information to be right. Providing some information to help decided if my values are close to correct or not.

Engine is 2100.5cc,,, So i have engine displacement set to 2100 in link. Speed density IAT/MAP/BAP set correctly.

Idle is steady around 1000 and Lambda hovers around 1.000 plus or minus a little.

VE fuel map is at 55 in this idle area.

Estimated air per cylinder measured is between 0.1460 and 0.1550 so i figured the difference of 0.1500.

With this information plugged into the calculator, my estimated airmass g/s is a 5.

This calculator specifies proper numbers for a 4cylinder engine to be between 3.5 and 4.5. 

So do my numbers make sense or is there a proper way to figuring this out and what should i be looking at to get everything dialed in as correctly as possible. Any input is appreciated thanks!!!!

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Firstly, are you in Modelled fuel mode? If not, then the number in the fuel table has no relevance to VE whatsoever, and you can stop here! 

Secondly, what injectors? Are you sure you have the correct Flow Rate, dead times, Short Width Pulse Adder (if supplied).

Thirdly, have you tuned things like injection angle, Charge Temp Approximation?

There are a huge number of various parameters (all described in much better detail than I can do here in the Help) which determine the fuelling, and the number in the fuel table is affected by each and every one of these.

 

We'll be able to help you a bit more if you provide more details, plus a copy of your current tune, as there might be something that's having an effect that you're not aware of, so don't know to share the details with us.

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4 hours ago, Confused said:

Firstly, are you in Modelled fuel mode? If not, then the number in the fuel table has no relevance to VE whatsoever, and you can stop here! 

Secondly, what injectors? Are you sure you have the correct Flow Rate, dead times, Short Width Pulse Adder (if supplied).

Thirdly, have you tuned things like injection angle, Charge Temp Approximation?

There are a huge number of various parameters (all described in much better detail than I can do here in the Help) which determine the fueling, and the number in the fuel table is affected by each and every one of these.

 

We'll be able to help you a bit more if you provide more details, plus a copy of your current tune, as there might be something that's having an effect that you're not aware of, so don't know to share the details with us.

Hey thanks for the input. Using Modeled fuel mode, injectors are FIC 2150's, but were recently cleaned and flowed by FIC with an average of 2234 at 43.5psi. So i have my injector data as 2230s with the injector data provided by FIC for dead times and short pulse adders. Fuel pressure referenced with sensor and set at 43.5psi base. I have played with injection timing and have that set richest possible at idle. I have not messed with Charge air approximation because i have not had time to get on the dyno yet. Pretty sure i have everything set up correctly thus far, just looking for a way to verify if my VE table numbers are falling in line with actual cylinder filling. Im still learing the link stuff so i appreciate any input anyone can give to help me learn if im doing things incorrectly or not. Thanks again and i look forward to any further input or advice. Other then that I have the street tune dialed in pretty close and wot follows target well.

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Assuming your injectors flow what the data that defines them says and your lambda is on target then the air mass calculation is correct - your VE must be correct (ignoring the small error from charge temp influence in this case).  However, with injectors that large you will be well down in the region where even SPWA wont be enough to deal with the extreme changes in flow gradients and the erratic variation.  So there is likely considerable error at idle, even cylinder to cylinder and cycle to cycle variation will be quite significant down at these PW's.  So dont sweat it too much.  You obviously arent going for economy or emissions with those injectors so who cares. 

A VE of 55-60% is very typical at idle so you are somewhere in the ballpark.  VE & hence air mass will only get more accurate as you increase load and start operating at a PW where the injector behavior is more definable or linear and no longer erratic.  

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3 hours ago, Adamw said:

Assuming your injectors flow what the data that defines them says and your lambda is on target then the air mass calculation is correct - your VE must be correct (ignoring the small error from charge temp influence in this case).  However, with injectors that large you will be well down in the region where even SPWA wont be enough to deal with the extreme changes in flow gradients and the erratic variation.  So there is likely considerable error at idle, even cylinder to cylinder and cycle to cycle variation will be quite significant down at these PW's.  So dont sweat it too much.  You obviously arent going for economy or emissions with those injectors so who cares. 

A VE of 55-60% is very typical at idle so you are somewhere in the ballpark.  VE & hence air mass will only get more accurate as you increase load and start operating at a PW where the injector behavior is more definable or linear and no longer erratic.  

Hey Adam, Thanks for the response. Thats pretty much what I wanted to hear. Iv ran my data through a few different calculators and scenarios, and all seems to fall in line very closely to what I am seeing. I have had communication with FIC about my injectors and the data entered, and that is spot on so im not worried about the injector data being wrong. Iv been very pleased with the idle quality and drive ability of the FIC 2150 injectors. Im running on E85 currently and fuel use isnt terrible. Thanks again for the input.

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