Help me, I'm sinking!!!!

[odd boy]

Gents,

I've got a WB and V2 kit, I have two LS1 cars at home. I want to learn how to tune them from A to Z. Please advice me how?

I looked at the Auto tune, it easy to apply , but I need to understand when I have to follow it. a lot of things are going around me but I don't understand them, like what are the parameters I need to tune, what does SD mean, what tables I need to concentrate on to start with.....etc

Please help

[joecar]

Odd Boy,

It's a long story that gets shorter the more you do it... :D

You need some "definitions":

SD = speed density
The PCM's method of calculating cylinder airmass from engine speed and intake air density (which is computed from MAP and IAT);
i.e. not using the MAF for calculating airmass.

CL = closed loop
Using closed loop feedback from the O2 sensors to trim the AFR to the stoichiometric AFR.

OL = open loop
Ignoring closed loop feedback from the O2 sensors.

AFR = air-to-fuel ratio
14.7 is stoichiometric (the ratio of air and fuel to chemically achieve a "complete" burn),
this is too lean at WOT/load meaning that it is not safe for the motor (detonation), but it's good for cruising.
12.6-13.2 is suitable for best peak torque (at the peak torque RPM at WOT) and is safe for the motor.

VE = volumetric efficiency
The VE table is probably mis-named... it is really the airmass table;
it gives the pressure/temperature "normalized" airmass for any given RPM/MAP operating point;
the VE table has units g*K/kPa (i.e. mass normalized for pressure/temperature).

Bascially, by going into OLSD, you eliminate any influences from:
- AFR trimming from CL O2 sensor feedback,
- airmass calculated from MAF sensor.

This leaves the VE table being the only source for computing airmass.

The goal of the AutoVE procedure is to get your VE table "corrected" such that the wideband measured ("actual") AFR matches the PCM commanded AFR...

when actual and commanded AFR's match, you can then simply set the commanded fuel table for the specific AFR's that you or someone else determined (by experiment) produces the best torque and/or power; this makes tuning for torque/power easier (what you say is what you get)...

it also means that you know without a doubt what AFR your PCM will produce at any operating point; this is how you keep your motor in the "safe zone" and make the best torque/power.

By reading thru the AutoVE tutorial you might be able to see (read between the lines) the relationship between some of the tables mentioned.

Cheers,
Joe
:cheers:

[odd boy]

Odd Boy,


The goal of the AutoVE procedure is to get your VE table "corrected" such that the wideband measured ("actual") AFR matches the PCM commanded AFR...

when actual and commanded AFR's match, you can then simply set the commanded fuel table for the specific AFR's that you or someone else determined (by experiment) produces the best torque and/or power; this makes tuning for torque/power easier (what you say is what you get)...

:cheers:

Well, before I tweak the VE table I'll set my AFR through {B3605} and {B3618}, between 12.5 and 13.2 or on dyno. I will supply {B3618} with the same value for all RPMs. Then at {B3605} I will but the same value for temp between 80C to 120C.

Next step will be connecting the WB and checking where the PCM is from the required AFR at the same time with (PID for VE table). Then based on the differences, BENS correction will take place. Then will check AFR again with WB tell reach the desired AFR.

Last step for me will be the spark values at {B5913} on dyno or road test. Then I will copy what I have from high octane to the low octane table.

does it sound :coool:

[joecar]

A few more points to keep in mind

Regarding commanded AFR:

...
PE is included, but if you're not careful it will produce "transition" errors in the BEN as the PCM transitions in/out of PE.
...
...
Some people set the PE they want and do AutoVE like this...
this may work, but the transitions to/from PE won't be BEN'd accurately.

...set PE to 14.63 and set the righthand columns of B3605/B3647 to the PE AFR that you want, and ramp up to there from the flat part of the table (ramp, not step)... this way the AFR transitions will be curves (not steps) which the BEN's will be able to track.PE can then be changed back after you have a good VE table.


Regarding throttle use:

...
The important thing to do is to operate the throttle smoothly (opening and closing)...
this will give you better data vs having the BEN filter throw out 70% of your data.

The parts of the map that you don't hit, you won't ever hit, so they don't matter.

As you drive, you'll see where the MAP-RPM operating point travels on the BEN map...
(enable scantool->tunetool linking, then playback your log, and follow the highlighting the VE table in the tunetool).