SPRAYED 01

iTrader: (22)

Just got done freshening my forged 370. The only thing I really changed that makes a tuning difference is the cam.

I'm going to redo my ve table, this is a 3bar speed density turbo car.

Ive been messing around with HP for about 3 years now but mainly with wot tuning of ve and spark tables and tuning for meth injection. This is my first time basically redoing the entire ve table to not only wot but for normal driveability.

Wanted to get every opinions on whats the easiest way to rewrite the ve table. For example do most just open the real time tuning in the scanner maybe have a friend drive and you go off your 02 or lambda histogram?

Also, let say you are tuning normal driving and you log for 30 minutes. As an example lets say you get good hits in 2k rpm from 35kpa to 80. You change those and all is well. How do you treat the cells in 2k past 80? Normally you dont even hit those driving so do you just smooth those out?

Any other tips would help just wanted to open the convo.

Alex

SPRAYED 01

iTrader: (22)

One last thing. I know how to force open loop an all but do you leave the pe enrichment table at what ever you want wot afr/lambda to be or should I put 1 across the board and just make sure not to floor it?

truckdoug

iTrader: (25)

i never got the RTT to work right. it was very hit and miss around idle kPa

but the way im doing it now is how RonSSnova showed me.

yeah force open loop. no dfco. thatll **** it all up. ask me how i know.

nah dont put the PE/BE at 1. put it where you actually want it to be so you can compare commanded afr against observed afr

you set up a histogram that plots commanded afr against observed (WBO2) afr and give you and error % in those cells.

I think you're with that program right?

ok so there I copy>paste special>multiply % like three times on three separate drives. just rolling into it. nice n smooth. set the cell requirement to like 25...get some good averages

then I do a couple more drives with a lil more spirit. and copy>paste special multiply by half %


save each file under a different name and use file compare them to see any trends.

the border cells I blend by hand. or use the smoothing function over a small portion...like a 9 cell box or so.

mcdonald77

iTrader: (21)

Im with truckdoug. I like to do the same. It seems I get my cruising area great but I really need to work on my WOT and idle areas.

Darth_V8r

iTrader: (4)

I do everything truckdoug described except I convert commanded AFR to commanded lambda by dividing commanded AFR by stoich. Then I log lambda error.

If I switch fuel or something I don't have to update anything. If you convert voltage to AFR you need to change the equations for different target stoich. Lambda always works

truckdoug

iTrader: (25)

agree lambda is better. i'm still learning to "think" in EQ ratio though

JakeFusion

iTrader: (7)

I do lambda as well. It's easier.

Easiest way to tune VE is to tune the idle first. Lean it out until it idles without adaptive spark. Then set it to idle in OL all the time. No reason to trust O2s with headers.

Next, go on easy cruises. 30 min logs are good. 3x is plenty good enough to get most of the 25-75kpa range from 1200-4000. I always try to start low around 40mph and pull up to 70-80 using various throttle inputs in 1:1 gear to get good data for cruising. And then let off from 80mph a couple of times, from 70, 60, 50... etc. Get 3-4 coast downs in there so you can tune the 20-40kPa region of the VE table. What you'll find is you want to be around 1 Lambda or 14.6:1 AFR in gas terms. You want to be there or a little richer on coast down to control bucking. And if you make any changes to the timing map - you have to log VE again.

Then do 3x WOT trying to run through at least 2nd and 3rd gear in an auto or 6-speed and run through the gears 3-4 times. Then apply the changes. Then apply changes at half time after that for 2-3 more runs. Get a good mix of 80-85kPa 50-60% throttle and 90-100kPa 90-100% throttle blasts.

Hand blend. And use 20-25 counts to get transition garbage out of the VE table.

And set the table for how you intend to use it. That means enable PE and use it for those 75kPa+ regions where you're at 40% throttle and need PE engaged.

RonSSNova

iTrader: (3)

I write two histograms.
One for the wideband and one for STFT.

I'm not at all opposed to using trims to set up the part throttle areas. I don't own a wideband that is calibrated to the national bureau of standards....


WOT of course I use the WB histo.

joecar

For street tuning and chassis dyno I use LTFT's at CL PT and WB everywhere else.

On the engine dyno we use two widebands, we have a calculated pid that uses the lambda from the leanest wideband (i.e. on the fly).

kingtal0n

iTrader: (1)

from scratch, my way is fast but not proper. I use global adjustment like injector flow rate to get cruise where I want it using a stock VE map, takes a couple minutes. Then I jack up wot fuel until I see what I want on the wideband, which is a map similar to global (only one row) another couple minutes. Then all thats left is idle area, which I always leave for last since changes you make to tweak part throttle and cruise globals often affect idle also. To put it another way, I've spent 30 minutes tuning an idle region only to completely obliterate any meaning it once held by moving on to the rest of the map.

If the map is smooth you are driving fine in 30 minutes. The numbers in the VE table, and any "ratio" or correlation displays are completely meaningless. forcing them to line up with "actual" is just for human viewing pleasure. All that matters is the wideband display, and how the engine actually feels and drives.

Attached is a video of my first HPtuners 5.3L, 4l80e driving at part throttle through the gears. I've only looked at the VE table one time to ensure that it was smooth and 'made sense' (numbers go up as pressure goes up, smooth). I set fuel pressure to 44psi for the time being (eventually it will be 38~), and I have no clue what size the injectors are atm. The only thing I did do so far is change global fuel flow rate for the injectors for high 14's on the wide band during idle and cruise so I can put some miles on the car. When its ready to WOT tune I will do as suggested above- add fuel to PE and the 2-bar boost compensation to drop the A/F ratio where I want it until I am out of injector. The car needs bigger injectors and a different fuel pump, so any time I spend fine tuning now is a loss, therefore, the less time I spend, the better. Unorthodox maybe, but it works and I don't have to care about what the computer "thinks" is going on, just focus on the wideband and how the engine acts and feels. Its also nice to pull a plug and verify a nice clean whiteish colour.

JakeFusion

iTrader: (7)

That probably works on a stock cam turbo car.

However, when you put a giant cam in the car, the VE map deforms pretty dramatically. So it's a good idea to map it using the Wideband or STFTs. Or, to use the MAF to populate the VE table...

SPRAYED 01

iTrader: (22)

Thats one beautiful graph. I am starting with the ve for my last turbo cam. I was shocked to see how much different the ve is so far. The last cam was a 232/236,585/.600 on a 114+4. The new cam is something like a 232/228 same lift and lsa but on softer lobes. The first was xer.


I had to pull about 20% fuel out of the 400-3200 rpm up to 80kpa range. It was super rich with the previous tune.

truckdoug

iTrader: (25)

hey ron how do you use fuel trims? do you have the narrowbands still hooked up?

JakeFusion

iTrader: (7)

Doug, you can just log STFTs just like you do the wideband. Setup an error histogram. Just make sure you log them in the channels.

And one thing to remember... CLEAR YOUR FUEL TRIMS before logging.

Yep. Even cams that are close can behave differently if the lobes are softer, etc. Btw, that VE graph is my current cam. Probably 20 hours of logging to get it like that. Car drives pretty much perfectly. The only hiccup is the occasional surge with A/C on at coast down below 45mph (wants to be richer than CL allows) and sometimes the 102mm TB is just a bitch.

RonSSNova

iTrader: (3)

Yes I do. Even on my Turbo car.

of course if you don't have the narrow bands in place, you have to tune with the wideband.

01ssreda4

iTrader: (96)

This is terrible information, please no one follow it. The other stuff posted by others above are the correct way.

joecar

seriously...!?!?

I can view the VE table in units g*K/kPa (EFILive)... at some pressure (kPa) and temperature (K), I can calculate the cylinder airmass (g) that the VE table is modeling, and this correlates with the airmass I calculate from the MAF;

your shortcuts/hacks are just side-stepping the PCM's ability to mathematically model the engine's physics... do you want the model to work as designed, or do you want to just mess/hack around with it in an ad-hoc manner...?

if you correctly model the injector characteristics and the airmass model (and they may possibly need to be scaled together in cases where the PCM's airflow limit is being exceeded), you then set (i.e. command) the PE fueling and OL fueling that you desire to achieve (hopefully you choose sufficiently safe/rich AFR), and then your engine will run correctly and safely under all conditions as expected (with good driveability and good throttle repsonse) with no hidden surprises or corner-cases

( there's a lot more to what the wideband shows )

the other side to this is that correct airmass modeling gets you correct spark table lookup

( i.e. it's separate steps: model air, command fueling on top of air, command spark based on air )

( and with boost you seriously don't want to get fueling/spark wrong )


also, I find that doing it right actually saves you time... shortcuts/hacks actually cause you to waste more time screwing around with it.

subeone

iTrader: (5)

[QUOTE=joecar;19729169]seriously...!?!?

I can view the VE table in units g*K/kPa (EFILive)... at some pressure (kPa) and temperature (K), I can calculate the cylinder airmass (g) that the VE table is modeling

Hey​​​​​​ joe, never used efilive, but how/why is the ve table in those units? Im a little rusty in the arithmetic, but isn't the VE a normalized value, i.e. unitless? Do you have a string in your logger/editor adding units to the number?
g*K/kpa= g*K/N*m^2 N=kg*m/s^2 so the mass units cancel, leaving the end result with K*s^2/m^3 which I can't recognize currently as anything significant, maybe there's a missing constant i.e. gas constant that ends up cancelling the units and leaving KG as the final unit. Just thinking out loud while I toss in bed..lol.

Anyways, the rest of the stuff you mentioned is 100% accurate IMO.

cam

iTrader: (9)

I need to learn this. Im in for the read and maybe a question or two

joecar

Hi subone,

I'll try my best to answer your questions

EFILive has options to let you view the VE table in g*K/kPa, g/cyl, g/sec, or % volume (% being calculated from displacement and IGL);

from what I understand, the VE table's natural units are g*K/kPa (what has been called "GMVE" by Marcin Pohl), and the other units are calculated;

g*K/kPa is "normalized" in the sense it is normalized for pressure and temperature... i.e. if you multiply it by pressure and divide it by temperature it gives you g, the cylinder fill airmass; also note that it is mass, regardless of displacement;

when viewing the VE in g*K/kPa in EFILive, if you change the displacement in the tune there is no effect on the VE table, closing and re-opening the tunetool shows the VE is the same.

Pa = N/(m^2) and N = kg*(m/s^2)

so Pa = kg*(m/s^2)/(m^2) = kg/(m)/(s^2)
( pressure has really strange base units! )

so kPa = Mg/(m)/(s^2)
where M is k*k (i.e. 1,000,000 x)

so g*K/kPa = g*K/(Mg/(m)/(s^2)) = (g/Mg)*K*m*s^2

you can't cancel the g's because then the M would have no units (it would be in the denominator all by itself, but it is not allowed to be by itself) (and also because g/Mg is a conversion, you really can't cancel out the g's);

( lol, you were close, swapped a * for a /... and that nasty unitless M went away )

that is a strange unit, but it is nonetheless g*K/kPa which is more meaningful than (g/Mg)*K*m*s^2 (or K*m*s^2/M if you cancel the g's).