VE calculation and tuning

[01blkss]

hey guys i am looking to tune my VE...my car is fairly stock with just exhaust and a lid(LTs ORY and a catback) It is an 01 camaro. i am mainly tuning right now just to get a hang of what i am doing learn the system...nothing has to be final.



How do i determine what my VE values will be? i have seen various threads on Ls1tech.com and other places...but i am still in the dark. i have datlogged some MAF, MAP, IAT, RPM, readings at WOT. and i start to put the readings into a calculator...but i am not getting any results that even romotely compare to the VE table. please help me with this.

Also what is a good timing table to use on an engine like this? what timing works well with an LS1? i hear that rediculous amounts of timing are not required or necessary, so what is the limits? i lowered mine from around 25 to 26 at WOT to like 23-24...is this too low? toop high?

Thanks

Also how should the timing table look? do i want timing to increase at RPMs increase? or do i want a fairly flat timing from 4000 rpm to 6500 rpm?

thanks
Louie

[Doc]

Have you tried the AutoVE tuning tutorial yet? It has you use lambda values, that is where stoich, 14.6 = 1.0 So anything below 1.0 is rich and anything above 1.0 is lean. With this method it is easy to adjust incrementaly. Basically, follow the AutoVe Setup carefully. This will put you in Open Loop Speed Density OLSD. OLSD allows you to essentially block out all the annoying erratic sensors, & stuff for example the MAF, DeAcceleration Fuel Cutoff DCFO, Long Term Fuel Trims etc. You want to isolate the Voulmetric Efficiency tables VE {B101}, {B103} from these other bad actors so you can concentrate on getting what you want commanded to equal what you are actually getting via your wideband. So log and look at the values. The proceedure will have you fatten up your VE tables for safety. From there you will trim and add where needed. For example, if you have a cell that says .90 it is rich so you will have to lean it out by 10 % in the tuning tool in the corresponding cell. Richening the VE table causes the numbers in the table to increase and Leaning out, they go down. This is a good start. Oldbies, newbies, friends chime in if I am hosed on anything. Could somebody else go on with the next parts of his question?

Harrison

[01blkss]

hey doc, thanks for the info and i will definately do that..however i was just trying to learn how everything worked myself first....

my wideband 02 will be here any day...then i can get into really tuning it.

Thanks
Louie

[SSbaby]

That's an excellent explanation, Doc. :exactly:

Just out of curiosity, has anybody calculated their VE table using the algorith and then compared their AutoVE table to their calculated table?

[ringram]

What algorithm are you referring to dude?

[ace68]

I have around 28* WOT in my 01 hawk.

[SSbaby]

What algorithm are you referring to dude?

There's a few formulae here:

http://www.installuniversity.com/install_university/installu_articles/volumetric_efficiency/ve_computation_9.012000.htm
http://www.epi-eng.com/ET-VolEff.htm
http://www.edelbrock.com/automotive/math.html

Just curious to know how many have used these in their spreadsheets and arrived at an educated estimate? :nixweiss:

[ringram]

Nice, it looks like most of these use cfm info or mass air, which is MAF based. No doubt why MAF systems can run a dodgy VE.

The edelbrock link has a good comment on spark timing though.

"Spark timing must be matched to Volumetric Efficiency because VE indicates the quantity of charge in each cylinder on each stroke of the engine. Different engine families require distinctly different spark advance profiles. And even engines of equal CID but different CR require their own unique spark advance profiles. Rule: Expect 0.1% to 0.5% loss in Torque for each 1 degree error in spark timing advanced or retarded from best timing. Also, detonation will occur with spark advanced only 3 degrees to 5 degrees over best timing and detonation will cause 1% to 10% torque loss, immediately, and engine damage if allowed to persist."

[Tordne]

My head hurts reading that stuff :)