VE tuning 201: idle table and VE Table edges and overlap... - Tuning Forum

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VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 11:38 AM
Why is it that no one ever talks about tuning the idle VE table... Shifted didnt even mention it in his sticky. there are no histograms available for the idle table... and there is not a single post in the tuning forum that comes up when you search for idle ve, except for one dealing with megasquirt.

I tried to make my own histogram for the idle table... but it is upside down... and if you reverse it, it doesnt fill in anything but the first row.

anyone know a better way to adjust the idle table? or know why no one ever asks about it or talks about it? what exactly distinguishes whenthe computer uses what table? like is idle used anytime there is 0% TPS? or what? does low kick in anything above 0%? or is there a different trigger?


And i was also noticing that ALOT of the tables overlap.... like the idle table goes up to 1600rpm... and the low rpm table goes as low as 600...

so how are we to treat these overlapped cells? do we need to make sure they match in both tables? or if we change it in one, should it effect the other?

And then table borders... if you notice, when you go off the edge of a table... it just lumps all values higher that the table into the edge cells... so you can sometimes get some REALLY screwy numbers in those edge cells... what is suggested to do about this?




Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 12:14 PM
Do you really need to make this many post essentially asking the same thing? Every post is WHY, WHY, WHY, WHY, WHY? Seriously, you WAY over think stuff. 90% of the stuff you ask you bascially answer yourself. If you are having this much trouble and it has taken you this long to tune your, give up... Take it to a professional... I'm not trying to be a d!ck, but damn dude... A question here or there is one thing, but you make thread after thread and it all has the same questions wrapped in another.....



P&P Tuning
420.5whp / 359.8wtq

Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 1:15 PM
Haha.

I edit my idle tables. Making the histogram isn't hard. As for off the chart values sticking to the edges, use the damn filters! That's what they're there for. Filter it so the RPM must be at least 1600 to log in that cell, etc. My histograms have tons of filters so I only get good data.

You also type way too much about your problems.


2001 Olds Alero (LD9)
636 whp / 543 ft-lb
@turboalero
Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 3:48 PM
adjust constant and leave it alone. I never had a single problem with 440cc injectors.. course I realized that our ecu's are screwy and decided to go stand alone for the 750cc I have now.

you can't solve a puzzle without all the pieces. HPT is good for tuning WOT crap and getting it to run half decent everywhere else.

thats it. end of story.






Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 5:50 PM
DaFlyinSkwir(LS61) /PJ/ OEM+ wrote:adjust constant and leave it alone. thats it. end of story.
x2



Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 6:21 PM
ImPhat0260/Cavattack2000 wrote:Do you really need to make this many post essentially asking the same thing? Every post is WHY, WHY, WHY, WHY, WHY? Seriously, you WAY over think stuff. 90% of the stuff you ask you bascially answer yourself. If you are having this much trouble and it has taken you this long to tune your, give up... Take it to a professional... I'm not trying to be a d!ck, but damn dude... A question here or there is one thing, but you make thread after thread and it all has the same questions wrapped in another.....


Gee I am sorry for wanting to know how things work. Maybe i am here to actually learn something... and not just follow the pack and do this cuz so-and-so said that is what they did and it worked for them. Yes i want to know why. if all i wanted was a fast car there are plenty out there for sale. I took this project on to learn about fuel injection and forced induction, and a fast car is just a pleasant side effect.
If you notice... i never get answers to my WHY's i typically just get alot of "just do this". So i have to figure the WHY out on my own... and then come back here to run my theorys past you guys...

So yes i TRY to answer my own questions. Would you rather i just be some idiot who wants everything spoon fed to him? And i put in my own information in as well for people in the future.. so when someone else searches they can find my threads and it might help them. The point of a forum is for everyone to share info.

[ion wrote: C2]Haha.

I edit my idle tables. Making the histogram isn't hard. As for off the chart values sticking to the edges, use the damn filters! That's what they're there for. Filter it so the RPM must be at least 1600 to log in that cell, etc. My histograms have tons of filters so I only get good data.

You also type way too much about your problems.


How did you make the chart upside down like it is in HPT? (maybe your engine is different... but my idle table has 0kpa at the bottom and 40 at the top. if you set the histogram up this way, it only fills in the top row. and the rest stays empty. And if you set the histogram up normally, 0-40 then when you paste the data into the editor, it pastes it all backwards.)

Great advice on the filters... i should have thought of that... that helps alot.

And i purposely type alot about my problems... once again i am trying to be a team player.... nothing pisses me off more than searching for a something on a forum... and you find posts from some guy that SOUNDS like he has your problem but he is so vague you cant be sure. Or even worse is when someone has your problems, and then the next post is "hey i PMed you" and the rest of the thread is them talking about how well that solution worked. GEEEE Great!! thanks for sharing guys! I am not just in this for myself. where do you think we would all be if guys like shifted and sweetness just asked questions and never gave anything back? I try to explain my issues in detail, and then offer up my insight and opinions on the matter... and hope for others to chime in.

K. Vega..Mr. M62 L61 himself. wrote:
DaFlyinSkwir(LS61) /PJ/ OEM+ wrote:adjust constant and leave it alone. thats it. end of story.
x2


What? Constant? who said anything about a constant? How does that have anything to do with what was asked here?
I ask about table overlap and idle tuning... and you say "adjust the constant"... See... how does that help anyone? constants are for injector size changes, how does this apply to the topic at hand?



Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 8:47 PM
PJ is basically saying with the correct injector constant there should never be a reason you have to touch the idle VE tables.

The only time I would need to edit idle VE tables would be if you swapped in cams, larger throttle body, or something to that effect and were trying to tune idle a little better.


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Re: VE tuning 201: idle table and VE Table edges and overlap...
Wednesday, March 18, 2009 9:04 PM
VE = Volumetric Efficiency

Your VE doesn't change when you add different injectors. VE is how efficiently your engine is at burning fuel that is delivered. If your injector constant is correct, your VE table does not have to be adjusted. You only adjust the VE table when you change the VE (adding a turbo, supercharger, cam, etc). That being said, these mods (other than a cam) probably won't affect your idle VE table at all. So if you are having problems with your idle, your injector constant is probably incorrect.





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Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 7:06 AM
BlackEco wrote:PJ is basically saying with the correct injector constant there should never be a reason you have to touch the idle VE tables.

The only time I would need to edit idle VE tables would be if you swapped in cams, larger throttle body, or something to that effect and were trying to tune idle a little better.


hit the nail on the head and besides your secret cams shouldn't destroy your idle. with the correct injector constant like blackeco said you shouldn't even need to touch your idle table



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 7:16 AM
Shifted, I agreed with you completely until i put in these new injectors in.
Again, maybe i just dont fully understand how this stuff all works... But i followed your directions for injector changes... did the math, figured out new constant. installed injectors, changed constant, fired it up... and she was CRAZY lean... like in the 20's. hardly even ran. wasnt until it maxed out BOTH LT and ST trims that is got even close to stoich. and as soon as you touched the gas at all, trims would reset and car would instantly fall on its face.
Believing the whole "VE has nothing to do with injectors" i figured i must have the constant wrong... so started pushing it around to try and get it to run normally. my original constant was .32359 on the 310cc's math showed .13375 for the new 750cc... well the only constant to get it anywhere close to stock fueling was a .22700 or something. That idled pretty good... but drove like garbage. and everyone told me i was on crack for thinking i could drop in new injectors and expect to just change one number and drive away... they all said that an injector change requires a total re-tune of the VE's to compensate for the different flow patterns of different injectors.

So i stuck with the .227 constant, and re-tuned everything... got it running pretty well... untill i changed and re-gapped my plugs (i had way to large a gap, dropped to a 30 but it totally changed everything AFR wise)... suddenly the car would not idle at all. but ran ok... So i started over... set the constant back to the calculated .13375.. loaded the stock VE's and spark tables. Again, it was way too lean... and hardly ran. So i fully re-tuned. had to increase my VE offset to 35%. got the car pretty close in low rpm tables... but still idles like junk... so started playing with idle tables, got it to idle almost perfect for the 4 cells it is supposed to sit in at idle... but EVERYTHING around it was like 30+ points off... so if it ever overshot the idle the car would start coughing or surging real bad.

And that is where i am at now....

you can see my other recent posts here in tuning for more details. but yeah... this is just kinda screwy... I read and hear about these things and it sounds so simple and easy... but then you do exactly as told, and get some whacky results... its like following a recipe for a cake, but out of the oven comes a pot roast. Im like WTF!!

Maybe my car is possesed... but you all make this sound so simple. but i have done the "simple" things... and they dont work... so i ask for other ideas, usually am told i am on crack... so i have to try something else on my own... and then i am told i am overthinking it and dont know what i am doing and to give up and take it to a pro. (but to be honest, i have spoken to alot of "professional tuners" and they all tell me different and contrasting things... and when i have listened to them i end up worse off. so not sure i trust a "profesional tuner" at this point, which is why i am still here.)


(speaking of following directions, Shifted... you really should edit your sticky on VE tuning the easy way... change the part about "paste special > add" to "multiply by" and there are a few columns missing in the histograms you link to.. Alot of people use that as their bible and reference... so might be a good idea to make sure it is accurate. And as you are the god of tuning, you should not have mistakes for all to see.. gods dont make mistakes, or at least they cover them up well.. lol)



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 7:59 AM
Quote:


original constant was .32359 on the 310cc's math showed .13375 for the new 750cc


I don't know where you got your numbers from, but they are wrong...

New Constant = Old Constant * (Old Injector size / new injector size)

So...

.32359 * (252/310) = .26305 for the 310cc injectors

.32359 * (252/750) = .10873 for the 750cc injectors

My constant for 440cc injectors is a lot less than .2, and I haven't touched my idle VE tables, my car idles fine.

What is your fuel pressure? Your 750's may not be getting good atomization at low pressure. Have you screwed with the low RPM parts of the timing tables? Do you have any multipliers added in? There is something else making this happen. What you are doing is tuning AROUND the problem, instead of solving the issue, your car will never run right, no matter how much tuning you do, until you fix the root issue.

Maybe find out why your wideband is off first?

Or figure out why you are so rich in closed loop? (I'll give you a hint, your INJECTOR CONSTANT IS WRONG)





4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!


Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 9:18 AM
Shifted wrote: What you are doing is tuning AROUND the problem, instead of solving the issue, your car will never run right, no matter how much tuning you do, until you fix the root issue........

Or figure out why you are so rich in closed loop? (I'll give you a hint, your INJECTOR CONSTANT IS WRONG)


DING DING DING!!!! Like I said, take it to a professional. You are simply "not getting it"... I have said it before and I will say it again.... Just because you can afford to buy HPT, does not mean you should buy it or use it if you have no clue what you are doing....



P&P Tuning
420.5whp / 359.8wtq

Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 11:38 AM
Well since we all know what the issue here is I'm going to touch on something else you said:

Quote:

(speaking of following directions, Shifted... you really should edit your sticky on VE tuning the easy way... change the part about "paste special > add" to "multiply by" and there are a few columns missing in the histograms you link to.. Alot of people use that as their bible and reference... so might be a good idea to make sure it is accurate. And as you are the god of tuning, you should not have mistakes for all to see.. gods dont make mistakes, or at least they cover them up well.. lol)


.

I want you and others to comment on why we should be doing "paste special>multiply by, and not paste special>add.

I want to hear what people have to say about this.




FU Tuning



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 1:03 PM
Shifted wrote:
Quote:


original constant was .32359 on the 310cc's math showed .13375 for the new 750cc


I don't know where you got your numbers from, but they are wrong...


Well GM gave me the first constant. those were the injectors and the constant, and the tune that gm put on the car at the dealership after the supercharger install.

And the second constant was derived by using the formulas posted on here by you and aproved by other "profesional tuners" .

.133750 = .32359 x (310/750)

Shifted wrote:
New Constant = Old Constant * (Old Injector size / new injector size)

So...

.32359 * (252/310) = .26305 for the 310cc injectors

.32359 * (252/750) = .10873 for the 750cc injectors


You tell me it should be .10873

I calculated it out at .13375

but I have had people tell me.....


Shane @ Innovative Tuning wrote:When I use PJ's formula to calculate the constant, it comes out to something like .059808 for 750's.

and
jimmyc99z24 wrote:These injectors are my old ones from my Cavy... but the constant that I was using that worked best for me was this ... 0.12850


So really, how is a guy supposed to get the constant right when he gets 4 different right answers from 4 different reliable sources?

Shifted wrote:
My constant for 440cc injectors is a lot less than .2, and I haven't touched my idle VE tables, my car idles fine.

What is your fuel pressure? Your 750's may not be getting good atomization at low pressure. Have you screwed with the low RPM parts of the timing tables? Do you have any multipliers added in? There is something else making this happen. What you are doing is tuning AROUND the problem, instead of solving the issue, your car will never run right, no matter how much tuning you do, until you fix the root issue.


Stock Fuel Pressure. Stock regulator. Just about to install my fuel pressure gauge, so i can see if there are any issues with pressure.

When i was doing my last round of tuning i wiped all my mods clean and went back to the stock gm reflash values for all VE's and spark maps. Messed around with pulsewidth at the very end just in hopes of stumbling on something... but no mulitipliers till like my last 15 min of tuning before coming back on here and writing all this up.

I was thinking the same thing... that something else has to be screwy... cuz no one else seems to have any of these issues. i am hearing all these people tell me they dialed their car in perfectly on 2 drives.

I found my spark gap was WAY to large... but i was told by several "pros" that gap is good and you want as much as you can get without misfire.. well mine went up beyond 50 and never misfired... not even under boost. so i left it at 50. Well wasnt till recently i tried gapping it back down, and noticed instant power gains. but everything else seemed to have been thrown off. alot more KR, more afr errors, higher levels of fuel trims... Wasnt till just the other day someone explained that with the full MSD ignition i am running that i could have a inch wide gap and not misfire... but it wouldnt be ideal, so that the "as much as you can get" theory doesnt apply to aftermarket ignitions but no one told me that when i needed to know...

So that is when i decided to step back to square one and re-tune from scratch using the "proper" constant and all. Hoping that my 50 gap was my "other issue" and now maybe i could tune my car as it should be... and that is where i am now.

Shifted wrote:
Maybe find out why your wideband is off first?


It is all better... must have been moisture as you said... slowly the afrs crept back down to a normal range, and now the NB and WB are almost dead on. so unless they are both skewed in exactly the same way I think im good on the WB. all fluctuations seem to be pretty accurate.. So short of a fancy and expencive professional WB calibration... i think this is as accurate as my WB is going to get. So that is no longer an issue. (i wouldnt waste my time tuning on a skewed WB)

Shifted wrote:
Or figure out why you are so rich in closed loop? (I'll give you a hint, your INJECTOR CONSTANT IS WRONG)


And the car doesnt run richer than it is asked to... It is that my CMD AFR just ALWAYS seems very low, and my car follows that. I dont see anywhere in HPT to change the CMD AFR in closed loop. It appears to figure that out on its own some secret way.... So unless someone can explain how it comes up with that figure, i dont know how to figure out why it is always demanding to be rich.



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 1:08 PM
John Higgins wrote:Well since we all know what the issue here is I'm going to touch on something else you said:

Quote:

(speaking of following directions, Shifted... you really should edit your sticky on VE tuning the easy way... change the part about "paste special > add" to "multiply by" and there are a few columns missing in the histograms you link to.. Alot of people use that as their bible and reference... so might be a good idea to make sure it is accurate. And as you are the god of tuning, you should not have mistakes for all to see.. gods dont make mistakes, or at least they cover them up well.. lol)


.

I want you and others to comment on why we should be doing "paste special>multiply by, and not paste special>add.

I want to hear what people have to say about this.


We should NOT multiply by. That would be if you are VE tuning a MAF based table, You don't want to multiply your VE table by the error in the signal, you want to add it.

For example, if your fuel trims in the VE table are -10, if you multiply by, you are introducing a HUGE error in the wrong direction. If you add then you are doing the right thing by moving the table in the direction that the trim is.





4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!

Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 1:30 PM
Shifted wrote:We should NOT multiply by. That would be if you are VE tuning a MAF based table, You don't want to multiply your VE table by the error in the signal, you want to add it.

For example, if your fuel trims in the VE table are -10, if you multiply by, you are introducing a HUGE error in the wrong direction. If you add then you are doing the right thing by moving the table in the direction that the trim is.



SEE this is a great thing to know.... I read through the entire FAQ... and someone in there said "no dont ADD... you will murder your VE's" and quoted a line from the HPT manual saying that you need to "multiply by" So i figured... "ok well i guess the HPT manual would be the way to go..." several people chimed in and said "oh yeah good call that is better" and no one else in the FAQ (or anywhere else till now) said any different. So i just assumed that this was the way to go. And always wondered why the FAQ was never updated... (but now i wonder why no one ever explained why this was wrong and to ignore the comments about multiply by)

As is one of the biggest problems about a public forum... is that you have so many cooks in the kitchen... and everyone claims to be right and that they know best... but for every person to say A you will find two more who will say B. And it appears to be my luck that i always choose to listen to the WRONG advice, or get partial advice that just so happens to not apply to me... (ex. multiply by is for MAF.. add is for MAP. ex2. run the biggest gap you can UNLESS you have an MSD ignition. this is yet another reason i am so wordy and detailed on here, been screwed many times for not giving all the info, so better too much than not enough)



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 1:36 PM
Shifted wrote:
John Higgins wrote:Well since we all know what the issue here is I'm going to touch on something else you said:

Quote:

(speaking of following directions, Shifted... you really should edit your sticky on VE tuning the easy way... change the part about "paste special > add" to "multiply by" and there are a few columns missing in the histograms you link to.. Alot of people use that as their bible and reference... so might be a good idea to make sure it is accurate. And as you are the god of tuning, you should not have mistakes for all to see.. gods dont make mistakes, or at least they cover them up well.. lol)


.

I want you and others to comment on why we should be doing "paste special>multiply by, and not paste special>add.

I want to hear what people have to say about this.


We should NOT multiply by. That would be if you are VE tuning a MAF based table, You don't want to multiply your VE table by the error in the signal, you want to add it.

For example, if your fuel trims in the VE table are -10, if you multiply by, you are introducing a HUGE error in the wrong direction. If you add then you are doing the right thing by moving the table in the direction that the trim is.


This is how I have known it to be and what I have always done and never had a issue.

I will take up for Ken on this and I saw the same post he did where people same to multiply and I thought that was wrong, and knew what I was doing worked.



FU Tuning



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 2:42 PM
yea I use paste special add, if you multiply you'll end up maxing your VE more than likely at certain parts and have a choppy fuel table.



Re: VE tuning 201: idle table and VE Table edges and overlap...
Thursday, March 19, 2009 11:43 PM
My My My... what a difference good advice makes.....

I nuked everything and went 100% back to my gm reflash....

forced open loop... increased injector constant to Shifted's calculated .10873

Bumped offset up to 35% started the car... got like an error of like 15% pretty evenly across the board.. so added another 15 to the VE offset bringing it to 50%

took her for a spin... she idled fine and Ve was pretty dead on out of boost....

got some logs... copied my VE errors... PASTE>ADD'ed them... smoothed it out a touch.. and HOLY COW it worked like magic!!!

i have never seen so many 0's on a AFR error histogram. did another round of fine tune logging... some high rpm logs....

PASTE>ADD'ed them in too... and i'll be darned if that isnt the best she has ever run. almost dead on in every cell she hits now.

my idle is just dandy... no bogging, surging or stalling.... but histogram still shows some funky high spots all around the target idle zone... but i also have yet to change my coast down...
What is the proper method for correcting coastdown? I have heard that coastdown is supposed to mimic ve offset. So since my VE offset is now 50, should my coastdown also be 50?

If that corrects my funky idle spots i will have to say that within a few hours and with the help of some correct info, and help of you good people... I have gotten my car running like a top...

You have NO IDEA how frustrating it is to hear all you people make this sound like it is a walk in the park... but i would go out driving for HOURS... copy my logs, paste multiply... upload... and go driving only to find it is almost worse than before... so log more... stop.. update.. flash... drive more.... repeat... i seriously have spent WEEKS trying to tune this damn car.

I am going to send a bill for all the hours i wasted trying to tune my car by multiplying the tables to the idiot that posted that up in the FAQ of all places... I need to find that boy and smack him around. Seriously, i was going nutty. no wonder nothing seemed to work.

Shifted, you my man are Da Shizzle! If i was gay i would kiss you! (dont worry im not)



Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 11:12 AM
Ok so i went to go and tweak my coastdown to match my VE offset (which i learned is what you are supposed to do ONLY on the GM Reflash)

But sure enough when i went in there, it was already changed... I checked and found it automatically updates itself when you change the VE Offset.

So i am already at the proper coastdown. and i have to say my idle seems just fine. doesnt bog or sputter or fluctuate anymore. The only thing that i see is that my Idle AFR error histogram i made shows significantly off all around the designated idle... but i dont know.... maybe this is normal.

But car is running great now... so just wanted to thank you all again for your information and patience.

And I also want to appologize for all the threads i have posted... i just figure "man this tuning stuff is tricky, people (including myself) are going to need to know how to do all this" (since i have been wrestling to get mine tuned to my liking for MONTHS, but never could figure it out) But now that i have the right info and setup, Tuning was a breeze. So i feel like an idiot for all my questions and pestering everyone... but hey... if it saves one guy all this grief from reading about my problems down the road it was worth a lil tarnishing of my "online" reputation.



Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 12:46 PM
Shifted wrote:
Quote:


original constant was .32359 on the 310cc's math showed .13375 for the new 750cc


I don't know where you got your numbers from, but they are wrong...

New Constant = Old Constant * (Old Injector size / new injector size)

So...

.32359 * (252/310) = .26305 for the 310cc injectors

.32359 * (252/750) = .10873 for the 750cc injectors

My constant for 440cc injectors is a lot less than .2, and I haven't touched my idle VE tables, my car idles fine.

What is your fuel pressure? Your 750's may not be getting good atomization at low pressure. Have you screwed with the low RPM parts of the timing tables? Do you have any multipliers added in? There is something else making this happen. What you are doing is tuning AROUND the problem, instead of solving the issue, your car will never run right, no matter how much tuning you do, until you fix the root issue.

Maybe find out why your wideband is off first?

Or figure out why you are so rich in closed loop? (I'll give you a hint, your INJECTOR CONSTANT IS WRONG)



Just curious... going back and looking over things....

Shifted, i noticed when doing my constant you used the GMSC reflash constant of .32359... but you used the injector Size for a stock cavalier...

It was just my understanding that you either stick with the reflash numbers, and use the stock .32359 and the 310cc... or you use the stock cavy constant, and the stock cavy injector size...

I was just wondering why you mixed them both. I used entirely reflash numbers to come up with my .133750 = .32359 x (310/750)

But shouldnt it be the non-SC constant x (252/750) if you are going with a non-SC injector?




Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 2:01 PM
The GM s/c tune is a hack. They adjusted the constant to make the injectors look SMALLER than 310's to the computer so it would purposely run rich. Because the VE tables are skewed stock, you use the 310 constant, but the 252 number to get a closer approximation of the right value to use. Otherwise if you plug in the stock VE table (and then extend it out for the 2 bar section), you can use the 252 constant AND the 252 injector number.





4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!

Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 2:22 PM
Seriously? The Paste Special -> Add was not a mistake? I've been using Paste Special -> Multiply by %/b] ever since I started tuning this thing, and it seems to work perfectly.

If my actual AFR in a certain cell is 10% higher than my commanded AFR is at that moment, that means it is 10% leaner in that cell than it should be, so by multiplying the VE cell by the +10% error, I always thought it adds 10% to that VE, which adds that much fueling to compensate and get closer to 0% AFR error. BUT, the VE table is a set of percentages itself... so by ADDING the AFR error, it gets it almost spot on immediately. That's my understanding of this revelation here.

Damn, no wonder it took me like 8 times tuning to get my AFR perfected. Haha. I was multiplying the percentages over the existing VE numbers instead of adding, which in effect, slowly raised or lowered my VE cells instead of instantly making them about what they should be.

I should go re-tune and see what happens.



2001 Olds Alero (LD9)
636 whp / 543 ft-lb
@turboalero
Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 2:23 PM


Sorry for the massive amount of bolding. Should've previewed before posting.


2001 Olds Alero (LD9)
636 whp / 543 ft-lb
@turboalero
Re: VE tuning 201: idle table and VE Table edges and overlap...
Friday, March 20, 2009 2:56 PM
[ion wrote: C2]Seriously? The Paste Special -> Add was not a mistake? I've been using Paste Special -> Multiply by ever since I started tuning this thing, and it seems to work perfectly.

If my actual AFR in a certain cell is 10% higher than my commanded AFR is at that moment, that means it is 10% leaner in that cell than it should be, so by multiplying the VE cell by the +10% error, I always thought it adds 10% to that VE, which adds that much fueling to compensate and get closer to 0% AFR error. BUT, the VE table is a set of percentages itself... so by ADDING the AFR error, it gets it almost spot on immediately. That's my understanding of this revelation here.

Damn, no wonder it took me like 8 times tuning to get my AFR perfected. Haha. I was multiplying the percentages over the existing VE numbers instead of adding, which in effect, slowly raised or lowered my VE cells instead of instantly making them about what they should be.

I should go re-tune and see what happens.


Dont worry, you are not the first, and for sure not the only one to do this.

Nope. it is not an error... shifted was dead on... and some shmoe just cut and pasted something he read somewhere and had half the forum thinking he was right and shifted just typoed. And since no one bothered to clarify that shifted was right, and that the other people were wrong... everyone who read the whole thread just assumed that they should do what the later people in the thread explained.

the multiply isnt actually as bad as it sounds like it would be. it actually takes the figures you are pasting and turns them into a percentage increase.

So if you are pasting in a 10... lets say your cell is at 50... if you add... you obviously get 60. Which is where you want to be.
but if you multiply by % what it does is takes your ten, turns it into a percent... so 0.1 and then ads that percentage to the original figure. so essentially multiples your cell by 1.1. so your 50 would become a 55 (1.1 x 50)
(sort of like adding the tax onto a purchase.. if you tax rate is 5% you multiply purchase by 1.05 to get your total after tax)
so in that cell you are 5 points off where you should be...

a 90 in your cell, with a 15 paste>multiply by'ed in... would give you 103.. but you should be at a 105... so here you are 2 points LOW.

but if you have a 30, and paste>multiply a 5 in you get 31.5 where you wanted a 35... so you are 3.5 LOW.

A 130 by a 8 gives you a 140.4 so you are 2.4 too HIGH.

So it isnt like you are trippling when you only wanted to ADD 3. But it is almost worse... because it skews each cell differently... so you might move one cell closer but the 2 next to it way high, and the one below it too low... and you would never know. It is more like playing roulette with your VE tables than actually tuning them. one time you may get lucky, and it will work well... next round of tuning might knock you further off than you were before the run before it.

So yeah... those of us who did the multiply by thing were basically life long tuners... you could tune all day and all night and never get dead on... one day your lean, next your rich, another your half and half....



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