I have looked at two tables. One is the "%change to a/f vs rpm at wot" and the "VE vs RPM vs MAP". Are these right? I was going to use the %change table first but it had values in increments of 400 rpms and that wasn't small enough. Also, I wasn't sure what percentage would give me the number I was looking for. I am guessing that the pcm has a set af ratio and it multiplies that value by the number in this table at the specified rpm to get the ratio it wants. Is that right?

For example, I am running about 13.2:1 at 3k. That is richer than the reading at 2800 and richer than the reading at 3300, so you can imagine a small dip on the af chart. How would I bring the value up a 3000 to level out the af from 2800 to 3300?

Thanks for any input.

 

VE is closed loop stuff, not WOT, WOT is "open loop" with information gathered from closed loop operation, which is why split BLMs will ruin top end performance as well, so your first listed table is correct for WOT. You may also want to balance out the temp tables.

I really dont remember the % stuff in my own tables offhand, but they are not even at every RPM level at all, in other words you can't do this accurately without wideband dyno time.

You can expect about a 400 RPM lag on most dyno/wideband setups, get the AF as level as you cant and dont worry if its off by .1-.2%, that is not a big deal at all especially at a meger 3000 RPM, if you were a top fueler obviously that would be a problem, but those guys dont have the same computer limitations that we do. The percentage is an 'additive' to base numbers, in case you weren't sure of that, so higher % is more fuel and etc

To help make things easier for me I also started out with Open Loop tables and took the 90-100 MAP stuff and leveled them off to something like 128 (12.8:1).

 

make the number at 3000 rpm in the % to change a/f vs rpm a little smaller.this will lean it out at that rpm only.you should also consider the time delay discussed by dr mudge.i imagine that when you were on the dyno they had the o2 up the tail pipe causing the readings to be behind the rpm.meaning your rich spot could have been at 2500.the help menu on tuner cat has a formula to help you figure out your target afr.

 

after looking at a stock file in tuner cat i would say try lowering the number by 1.0 at 2800 in the %to change vs rpm and you should be close,or just ignore it because your car is not at 3000 rpm at wot much.the stock chart has a large jump at 2800 that is the cause of your problem imo.

 

For WOT enrichment in Tunercat there is a file that is called % Enrichment. Thats the one you want to use to add fuel. Don't quote me on that file, i don't have my laptop right now to look at it, but from memory thats what i think it is. It is a very small file, like only 1 column

 

Thanks guys. I was doing some calculations tonight at work and have a couple of ideas to try. I still don't know how you could the get the af to be steady across the graph if the rpm increments are 400 in the percent to change af table.

Do you think that if I plotted each of those points of the table onto the afr line(on the dyno sheet), saw the difference in what happened and what I want to happen I could come close to getting it in the ballpark?

Also, am I correct in thinking the "af ratio x 10" table is the target af ratio at each rpm and map? If that is the case then, why couldn't I just change those numbers to raise or lower the af ratio at the specific spots on the dyno sheet?

Sorry for all the questions but I need guidance

 

Thats open loop only, you can use 90-100 MAP to help level off WOT though.

Remember that the PCM interpolates data, so every 400 RPM doesn't matter that much.

 

Remember that the PCM interpolates data, so every 400 RPM doesn't matter that much. [/B][/QUOTE]Let's say there was a big dip right between two of the values. Started at 13.5, went to 12, and then back to 13.5 all in 400 rpms. How would you fix that on that table? Or would you use the afr x10 table?

 

I've never seen a big dip, but to avoid wierd things on the dyno like that, I took AFR x 10 values in the open loop table, and for 90-100 MAP put a range of temps at 128, select the cells and put FILL, and enter a value.

After that, I took the enrichment vs temp (% change AFR @ WOT vs coolant temp or something like that), and took a temp range that I expected to run in, and leveled them off, I can look what value later if you like but I probably took something from 68º ? I can't recall, I again selected and filled.

This way, I would have nothing wierd on the dyno, and since I live in a moderate climate I do not see very high, or low temps, so I had no issues in leveling things off like this. From here I did all my WOT tuning in one single table (for fuel), % change AFR @ WOT vs RPM (or whatever).

Things will be VERY level, if you have a strange dip then please post, because it would be somewhat a mystery, at least to me.

HTH
-W