I've been trying to learn how to tune my 42 and 61 bins and I was wondering when your tuning the Main VE Table do you need to touch the VE adder table? I've read a few guides on how to do the VE tables but most talk about a high and low VE table or just talk about the main VE table.

Thanks.

Oh and when switching from a 305 to a 350 TBI in a 8756 ecm would it be recommended to just start from the stock 305 bin and tune it for the 350 from there or start off with the ANLU bin?

 

Yes you need to do the mult factor on both tables.

It has been a few years so I forget but you can zero out table 2 and add table 2 fuel values to table 1. That I did when I ran $42-7747. But you need to not zero out the higher RPMs of table 2 just those that appear in table 1. Also it was said to not zero out 400 rpms in table 2.

maybe somone can confirm.

 

what i like to do:

take the base table(2D table based on RPM alone), and add all of it's values into both the main VE and idle VE tables(well, actually i interpolate and extrapolate to get my idle VE numbers, but the point remains), up until the highest RPM column that the main VE goes to. then i zero out the base table up until that point and forget about it.

since the ECM adds the tables together anyway, it comes out to the same VE number used for injector calcs, but it makes fine tuning the table much easier IMO.

 

So for example if the 400 rpm value is 20 on the 2d table, I would go to 400 rpm on the 3d table and add that value to each cell on that row for every map kpa value? And then just put 0 in place of the 400 rpm cell on the 2d table? That seems simple enough, thanks

Oh and do you know what the idle VE table is referred to on a $42? I'm just going off memory but I didn't recall seeing more then the main and adder VE tables, but Ill take a look again.

 

some masks have it, some don't. i'm not very familiar with $42 though.

and yeah, you have the process right. well, you would add the 20 to every 400 RPM cell, not kPa.

 

Yea that's what I meant, since the x axis is kpa, like since the y axis is rpm I would add the 2d value to every cell in that "row" for 400 rpm. Sweet, thanks for the help.

 

No learning done there so I recall best to leave it alone. I will search to find out why(Grumpy).

 

that's odd.... i always zero out both the 0 and 400 RPM columns(or is it rows?)...

doesn't seem to be an issue for me, car still fires VERY quickly, possibly faster than usual.

 

I searched....

From Grumpy:

VE#2
15 400 rpm
15 800
15 1200
14 1600
13 2000
13 2400
11 2800
11 3200


VE#2 modified
4 400 RPM
4 800
4 1200
3 1600
2 2000
2 2400
0 2800
0 3200


If you subtract 11 from all the values in VE#1, then you can change from the VE#2 to VE#2 modified.


If your asking if #2 is just an adder, then the answer is yes.

It's typically used to maintain the same AFR as the last entry in VE#1 generates. ie slightly leans out the fuel as RPM increases.

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Last edited by Grumpy; 10-17-2004 at 07:08 PM.

Ronny says: I would suggest you use Grumpys advice...

 

More from out friend Dimented:

The best thing to do would be to shuffle the ve between the two tables in order to get the VE adder table to be flat at some constant value up to 3600 rpm. This way you can move some of the VE over to the main table and still have the VE lean out at higher rpms. In addition itll also allow you to easily see what the engines VE curve looks like. To elaborate, lets say the table is the following

VE RPM
25 400
40 800
18 1200
15 1600
30 2000
15 2400
17 2800
14 3200
18 3600
25 4000
23 4400
21 4800
...

Id pick some value that Id want the VE 2 to be, say 20 as an example. Id add and subtract the following from the main VE tables at each rpm and subtract or add to teh values in the above table to get:

VE RPM
20 400, add 5 to main VE
20 800, add 20 to main VE
20 1200, subtract 2 from main VE
.
.
.
20 3600, subtract 2 from main VE

...and Id have to add two to all the
rest of the values after 3600 rpm to
maintain the proper VE after 3600 RPM

25 4000 -> 27 4000
23 4400 -> 25 4400
21 4800 -> 23 4800
etc.

The idea is that there always has to be some VE in the adder table in order to have the VE lean out at high RPMs. If the ve adder table is zero, you cant reduce the VE after youve gone off the edge of the main table.

 

Might be a cranking fuel issue, not something that would effect running.

 

Hmm, I'll have to test that theory on my test bench when I get a chance.

Saar's experiance seems to be indicating that it might not effect fueling like previously thought.

 

See info I added in post. I cut off bottom sentence.

 

So in both of the examples you posted what exactly would be the point of either evening out the ve adder table or just zeroing out the bottom rpms if you still have to multiply both the main and adder ve table values? Or like in grumpys example would you only change the main ve table after you zero out the bottom rpms on the adder table?

 

Dimented says: It's typically used to maintain the same AFR as the last entry in VE#1 generates. ie slightly leans out the fuel as RPM increases.

I used to zero out table #2. But I think I later kept a value of 5 in table #2. But then it being such a small % compared to table 1. If you are doing and adjust with manuual calcs 133/128= 1.04 I would just use 1.043 to account for no adjust on #2.

 

I'm working with an '8062 ECU now running a 3.4L (swapped from 2.8L) that has nothing in the VE adder.

The Main VE only runs up to 3200 RPM like the '7747, think I would benefit by filling in the Adder table?

 

the lower RPMs? probably not, since doing so would require modifying the main VE table, but unless the motor can retain the VE that's in the 3200RPM cell all the way to redline, you may want to think about removing a portion from the 3600 RPM cells, adding it into the adder table, and then scaling down as necessary to match the VE of the motor to however high you plan on revving it.

 

I did end up populating the VE Adder table, using a 4.3L $42 BIN as my guide. I subtracted the 400-3200 adder values off my Main VE table so they would net the same across the board, but now I have the adder for > 3200 RPM.

I took it for a spin, drives great. I think it pulls a little harder at the top now. Certainly not a night and day difference, but it's something.

 

Just came across this thread. I've been ignoring me VE adder, which has significant values in it, like 40. No wonder it's been taking so long to dial in my BLM values. My plan is to push all the values down to a constant small value as suggested.

My question is: I'm doing a 7747 and it has a 0 RPM row in the adder table. How do you think about that? There's no place in the main table to offload it. Should I just leave it be and deal with the rest? The value is on 25 now.

 

I think Grumpy once posted to leave 0 RPM alone on adder. When i used the above method I left a +5.0 in remaining tables.