As the subjecct reads, I'm wondering how you experienced tuners base your decisions on how to adjust your fuel maps.

I just got my Tech Edge WB20 interfaced with my Datalogit...Woo-Hoo.

I did my first datalogging drives yesterday. Now I'm just trying to to do some analysis and lean out my idle and my non-boost/cruise map cells.

~ I'm going to be careful and practice in the non-boost cells for now.

Do you guys make you adjustments based on the Max value(leanest condition) or the avg value? No I know that my question is "loaded" knowing that I will see 19 AFR's on decel.

John

 

John

I suggest using Max values since there will be times when you will peak dangerously high AFRs that would be masked if you used the Average option.


To control false readings on decel:

Open FC-Edit and on the "Window" dropdown select MapWatch. Set the MaxVal to 15 (as lean as you want to ever go and still ignore deceleration readings) Set the "Hold off" set to 200 msec which reduces the number of inputs but also eliminates "high" transient readings.

Hope that helps

 

Jeff, thanks for the tips. The max values tip is a good one.

 

I don't use max I use average. Same settings as above. but then I look at average. however, I don't make a change without toggeling from average to NUM and verifying that a min of 4 samples were taken for the cell Im changing. I feel that average does a good job removing the transients. There is a minor amount of error in the WB o2. this is easily seen by ttaking 2 pulls back to back with nothing changing. The average for a cell can change .2 very easily for no reason. I attribute this to slow mildly inacurate instrumentation.

 

My thoughts on this is that I would pay more attention to the max AFR values on a WOT pulls to log max boost AFR's. A momentary lean spike could pop my motor.

However, last night I was duing some cruising speed(non-boost/partial throttle) datalogging and found that the max values aren't going to be as helpful because I know that my car is running extremely rich(since I cranked up all the fuel correction numbers a while back), but the max values logged show 14-15 AFR's when the avg's are 11-12.x's which is more believeable to me. At least that's what I see most from the display.

John

 

John

You are right. At cruise, you will want to monitor average and keep the averages below 14. But be careful here make sure you are constantly logging above the P10 (0 boost)row.

Finally make sure your fuel maps always increase or stabilize fuel flow as they progress from P10 to P20 and N1-N20. (Steve Kan-ism)

 

Thanks Jeff,

I have been trying figure out what to do about my timing maps for my street ported motor. I found this site on Nopistons.com: http://rx7.homeip.net/pfc/

How do guage what map is right for my car? I've looked at the IGN maps for ported motors. But they are all so different. Any thoughts?


John

 

I use the average values and I only use values for which there are at least around 4-5 samples.

In order to make the actual adjustments, I just dump the BASE map (normalized) and the AFR mapwach chart (I go in and delete the ones that don't have enough samples) into an excel spreadsheet I wrote that makes a new base map for me. I grab that new base map and load it in and just go test some more. Works great for me.

Brian

 

By the way another good important tip is to not stab the throttle and then try to use those cells right there. Stabbing the throttle can make momentary lean spots which are normal for a split second...

I prefer to pick a "boost level" like 5 PSI and then start from very low RPM like 2000 and try to hold 5 PSI to redline. I usually use 2nd or 3rd gears to "rough in" the fuel curve and then 4th to really nail it down and confirm it. (4th loads the engine much harder).

THen I'll do 7, then 10, then 12, 15... whatever.

Go slow... and you're smart to stay in the vacuum cells while you get your feet wet.

Brian

 

By the way another good important tip is to not stab the throttle and then try to use those cells right there. Stabbing the throttle can make momentary lean spots which are normal for a split second...

I prefer to pick a "boost level" like 5 PSI and then start from very low RPM like 2000 and try to hold 5 PSI to redline. I usually use 2nd or 3rd gears to "rough in" the fuel curve and then 4th to really nail it down and confirm it. (4th loads the engine much harder).

THen I'll do 7, then 10, then 12, 15... whatever.

Go slow... and you're smart to stay in the vacuum cells while you get your feet wet.

Brian

 

I look at the number of samples, average, and max AFRs from the datalog, sometimes min as well. If there are less than 2-4 samples in a cell the data is thrown out, same thing goes for the spool up regions. If the AFR spread is greater than 0.4 AFR in a WOT cell I worry about misfire. Assuming that is not a concern, I load the max and avg values from multiple datalogs into a spreadsheet and have it calc corrections to get to my target AFRs ... get two results, one from max's and another from avg's. If all the data passes a funny look test I make adjustments, occasional check to see that the recalc'd base map is linear and then go back out.

 

Wow, you guys only use 4-5 samples. I was using at least 20-40 sampled values for the avg. w/ a max logged value of 15 AFR.

I guess I'm just a bit caucious(sp?)

I'll try wargasm's tip and try to hold boost for an extended period to get a wide range of RPM readings.

Thanks for your all of your advice guys. Keep the tips coming ... This is great info for us newbie PFC/Datalogit/WB would-be tuners.

Thanks.

 

Smooth is key for tuning... lay INTO the gas smoothly and from well below your intended tuning area. So if you're tuning 3000-8000, try to roll on the throttle smoothly starting at 2000. This way by the time you get to 3000, you are at a fairly steady throttle position... gives more reproducable numbers so you know where you are at.

Another tip is to figure out where on your maps your car operates. For example, obviously nobody makes 15 PSI at 800 rpm. And there are other cells like that.... you want to identify the "never used" areas. Assuming you've already identified that you WILL NOT blow your engine in these areas, just put the car in 5th at a very low RPM like 1500 or something and then floor it until you are at full boost. The car should try and try and try to build boost, but it will take a few seconds. When you look at the log, this will give you an idea of the "edge" of your map where you need to do active tuning work. It is unlikely your car will get past those areas, so now what you do is manually bump up all the never-to-be-used areas so they are nice and rich. Just because you can't get into them NOW doesn't mean that you won't end up there one day by accident. What if your wastegate sticks? What if it's really cold and you get boost creep? Anyhow, for all the "never used" areas on my map, I just make them nice and rich.

 

I first edit the log file with EXCELL, and remove the lines before getting on boost and after getting off boost. These line are trash since we are talking about adjusting AFRs for boosting. Plus it reduces the file size
a lot.

Second I pratice a common method used in analysis of data, remove OUTLIER DATA, that is data not under the
BELL CURVE. One false/bad data point if way off the norm is included, then your results is bad.

Edit with EXCELL and look for AFRs that for an area are out of place and delete that line. I.E. If you have a 12.0 reading surrounded by 11.5s/11.4s/11.6s, then it is a bad reading and should be deleted.

After all of this I use average for my changes, but I do also look at max values. You want to do this for at lease
2 back to back runs. Three or more runs are better, and you want to compare or add them all together to get a real idea of what is happening.

TWOKRX7 and I usually test together and we end up with very steady AFRS.

 

ummm, you guys are way over my head. can someone give me a wideband tuning for dummies book, or a link. jpandes, help me out please. i want to use the force.
kris

 

Wargasm said it right......start on the vacuum side and work your way up on boost slowly.
Set ignition maps safe while tunning for A/F.

I see many tune for high boost and forget whats in between.....start low and work up and you'll notice how much faster the engine will rev when low end is tuned.

Here's my traget A/Fs vs boost.
0 psi= ~13.0:1
0-5psi= 13.0-12.7
5-10psi= 12.7-12.5
10-13psi= 12.5- 12.0
13-15psi= 12.0-11.5
15-17psi= 11.5-11.0
17-18psi= 11.0-10.8

Is anyone using the chart option over the map watch for logging??
It gives you a nice A/F curve like on a dyno.

On "monitor" the more items you check off for logging results in less samples per sec. So uncheck anything that's not important such as... sensors, map ref...

 

Here's one of my logs using the graph option...

Shows boost, inj duty, knock, air temp, water temp and lower graph shows A/F and TPS voltage.

Log of a 1/4 run...all 4 gears

 

Sorry..here's a better pic.

 

Are those AFR's safe? Every thing I read says that 11.5 is about as lean as you're supposed to go. based on my WOT logs, at 13-14psi my afr's are 10.8-11.5 and my knock readings pretty low <20... Maybe I can go a bit leaner...Like your target AFR's.

Here's my target AFR's