Shoptalkforums.com

How Do We Do It: The delay chart is in the advance settings tab of Auto Tune. A cross
reference between idle, low mid, wot - rpms and at low, mid, high - map readings. Datalog at a
few different rpms. You want a big injector pulse change so you can spot it. Use acceleration
enrichment. So drive around and cruise at different rpm's and crack the throttle. Now go back
and look through the datalog. Bring up pw1 and o2 #1 in the top chart and then rpm and map in
the 2nd chart. Look for the injector spike from the acceleration enrichment. Click on the graph
exactly at the pw upward peak. Write down the time at the bottom of the screen. Note map and
rpm reading to know what cell in the lambda chart to fill in with the new delay setting. Now click
on the graph at the o2 sensor downward (rich) peak. Write down the time. Subtract the time's
and this is the sensor delay. (it takes that many milli seconds for the sensor to read that pw.) The
4 digit time is in seconds with the 3 digits after the decimal point being milli second (one
thousands of a second). So a number like 2456.166 compared to 2456.300 has a delay of 134
ms. It will always be the last 3 digits you will be looking at. Subtract the lower number (pw) from
the higher number (o2). This is your lambda/ o2 sensor delay. Enter that delay in the lambda
delay chart. As mentioned, it is different for every install and varies with rpm. Now go back and
change the log chart to pw2 and o2 sensor 2 and do the second cylinder. Fill in the chart for VE
table 2 lambda delay.

Hints:

Feel free to change the chart positions as well. (change 3000 rpm to 4500 or 6000rpm) Use the
same info your datalog shows. You do not have to try and make your datalog fit the chart. Make
the chart fit your datalog / rpms you used while riding. If map was at 60kpa and rpm at 4000-
then change chart to 60 & 4000 and enter your delay. Don't keep datalogging to try and get the
map at 49 and rpm at 3000. Just use what you get for a mid point.
Use low range to get the high rpm points. (its easier to drive 50mph than 80mph with a laptop)
Low rpm bins are easy to get. Datalog the following:.
· startup- this will give the high map.
· Idle- this will give the mid map.
· Decel- this will give the low map.
Map readings occur at the following:
· wot- gives high map readings
· cruising or steady state rpm- gives mid map readings
· close throttle/ deceleration- gives low map readings.

Example:
With Megalogviewer, If you click view at the top, you can add or remove the tuning console (fuel table
area) and dashboard (bottom gauges) to have a bigger chart if you want.

Here is how I personally find lambda delay. I find a place in the log where the driver suddenly lifted out of the throttle and use the time measuring function built into MLV to see how long it to for the wideband to register a change/stabilize. In this motor, the delay is about .2 sec as seen at the bottom of the screen in the white box.

http://www.nbs-stl.com/tuning/Turbo%20D ... 0Delay.png

Notice how quickly the motor the motor goes from full throttle and hard accel to backing down as seen in the RPM per Sec trace. This ability is rare in a turbo car.

Have fun tuning

Andy