Guys, is this AFR looks okay? I think there are some lean area in the P14-15. Is it due to being to quick on the gas pedal?

 

You are a little lean there but most of it looks a little rich to me...

I have found that the cells on the edge usually always contain a couple 19.0 readings so if you are using the "average map" they are figured in. Either use the "minimum map" or go into the raw data and remove the 19.0's.


Here is what I am trying to tune to:

 

One thing about AFR logs as presented, under what state are the values taken?

Cells under de-acceleration will be different than the same cell under acceleration.

I test idle, cruise, and acceleration individually as to make things clearer as to what is happening. This way most of the cells are in the same "state" or use.

If you mix acceleration and deaccleration together and the same cells are hit both ways, the ending results show are useless for tuning. Also the surrounding cells need to be under the same state to see what is happening.

Normally rows above 6 will only be used when accelerating. Thus that is the condition to test and adjust them. At row 6 and below log and tune them under
steady cruise conditions.

So your AFR log is useless to us unless we also have the boost log for that run.

I always edit my TXT logs before viewing to remove the misleading data.

Just my opinion.

 

Uhm..that is 25 minutes drive from home to work. many deceleration, stop and go, few WOT to 11.4psi.

Now I learn something new from you all. So is it better to just log one run with 2000 to 8000rpm WOT versus a couple of runs? Thus shorter versus minutes of data?

 

To tune boost, you start off at the lowest you plan to run. Lets say you never really plan to run lower than 12 psi. Set you boost at 12+, see my notes about P row tuning. After you have steady boost for 12psi, then make your 3rd or 4th gear runs from 2500 or 3000 depending on non-seq or seq or single turbo. Make two or three runs. Let your intake air temp stabalize to the same temp for each run. Average the cells for the runs. Then make changes. Redo the process over and over untill your AFRs are within .2 of each other or you target. The fuel adjustments also include the transistion area above P6.

Then you bump your boost up for the next higher P row and repeat all the above.

After your P rows are done, then start on the transistion areas by setting boost back to 12, and make runs starting at 1000 increments so that you go across most of the transistion area. Like from 2k, 3K, 4k, and 5k up to you hit 12psi. These are shorter runs.

Then lastly I go for the idle and cruise areas.

By the way, timing has little affect on AFRs but more affect on EGTs and power.

**** this is part of volume two of tuning which we have not started on.

 

Chuck, Thank you, that clarifies a lot. I think it should be in volume 1 ?

 

Okay, here are some log as you suggested.

1. 2000 to 8000rpm with .80 boost. 3 runs back to back after warm up run.
What do you do about these lean area as I put in circle? I think this is lean due to boost building up, and the ecu is late in giving more fuel.


2. This is 4000 to 8000rpm with .80 boost. 3 runs back to back after warm up to similar condition as above. Somehow nothing in between cruise area to row 16/17. Maybe boost build up too fast.


3. This 2000 to 8000rpm with .60 boost, 3 runs back to back, similar condition.
Still the same situation of what I think lean while building boost in circle area.


So should I go leaner or this is good enough. I feel what missing is the measurement of how much power the car make on certain cell. If datalogit has that info, tuning would be easier than just AFR, and butt dyno.

 

In previous posts this year, Kyle and I have mentioned about adjusting transistion areas. In fact if you were to read all of our posts, you would have volume two and know all we know.

(1) cruise should be set for best smoothness plus mileage. This is P5 to P6 normally. Set high 15AFRs to low 16AFRs.

(2) P10 is 0 vacuum/boost, go for 14.7AFR, stoich.

(3) For P7 - P9, taper between (1) value and 14.7AFR, or set all the same as cruise. If you look at your boost gauge, when you floor the throttle from cruise, your boost gauge goes instantly from vacuum to 0 + boost, So in reality, P7 - P9
are useless unless you find a place where you can cruise at 100+ mph. Yes in Germany you would use these.

(4) Your P16 and P17 are way too rich. Go about 11.5AFR for P17 if you have a large IC.

(5) For P11 - P16 taper the AFR from 14.7 to 11.5AFRs. I'll do these using simple logic. Since stoich (14.7) is about ideal for normal driving and power, we will set 0psi at that then richen up linerally until we hit our first tuned boost area of P17.
P10 14.7
P11 14.5
P12 14.0
P13 13.5
P14 13.0
P15 12.5
P16 12.0
P17 11.5


Unless you can afford to dyno power tune all P rows, this is your best bet.

 

Chuck,

Thank you...I have read your previous posting as well.
How about the area in circle?
It seems hard to tune them, the result from log to log are not consistent. I think this is due to the fast spooling, and ECU is late in giving in fuel at different runs.
how do you tune this area? drive at part throtle?(I don't think this is good since its different than WOT condition).

I only have Greddy SMIC, pretty small. Purpose of tuning will be towards more reliability in using the car for drifting. A lot of high rev, and up/down the power band in instant.

 

Try a 4th gear pull through that area. Your spooling wont be to fast in that gear...


It does look lean. Add some fuel and start working from the rich side back to your target. Get some consistant logs before you consider it done.

Shawn

 

Did you see my notes on making runs from cruise to 12PSI boost in 1000rpm steps from 2000 or 3000 up to 5000 rpms? Do this in 4th gear, and get the average AFR for each P row and apply it across the P row. Then repeat the runs and this time instead of averaging across the whole P row, localized it around it 1000 rpm area. Do not spend too much time as it is not worth it to get the transition area perfect. Just get it close.

 

Chuck, Yes, I actually did 2nd gear run from 2K, 3K, 4K, 5K to 8K rpm. Then 3rd gear run from 2K,4K,5K to 8K rpms. All the chart look similar except 4K and 5K usually jumps from P6-P8 to P15/P16 until 8krpm.

Here is a chart of one of the run. Here you can see the boost dip for 250msec.

 

Chuck...thanks for that post...extremely helpful! What AFR should we aim for at idle? Stoich?

 

I set my idle in the middle of the smoothness band for daily driving. Mine is about 14AFR. I do this by going to the FUELl-IG TEST CORRECTION menu to lean and richen the fuel to finf=d the midpoint.

For emissions testing, just above lean idle stumble.