Posted this on another forum (monodax) but did not get any responses. Going thru list of tuning to-do's I am looking at my BLM Cell utilization. My logs show I'm only using about 9 of the 16 cells. My stock A4 BLM boundary settings are 700-1200-2000 RPM and 32-50-80 MAP. After installing my CAM the idle is now set at 800(D) and 850(N/P) my idle MAP is around 50 in N/P and 60 in D. I never use BLM cells 0, 4, 8 & 12 (RPM below 700) and rarely see 1, 2 or 3 (MAP below 32kpa) except for high deceleration. Are there any recommendations or advise on changing the boundaries to utilize more cells. Is there any significant advantage or disadvantage to doing this. I was thinking of 1000, 1500, 2300 RPM and 50, 65 and 85 MAP. Has anyone done this, any comments on how to proceed ??

 

I moved mine to 1600, 2200 and 2800. Yes this was based on true life testing and where I equally utilized all cells.

Also went 45, 60 and 80 for my MAP.

For some reason the stock PCM's utilize about 1/2 of the blocks so doing what I did really helped with part throttle tuning to dial my car in quickly.

 

Blackhawk, Yep, right now it seems about 90% of my street driving is in 4-5 cells. Two of them are running rich (BLM averages 114-119) but they cover a wide range of MAF (gm/sec) ranges. Then when I get up the cell 15 during high TPS% it leans out to around 131-135 prior to hitting PE mode. If I could spread this out to more cells it looks like I could tune the real culprit ranges, not a shotgun approach to a bunch of MAF readings. Going to spend some time on logs to see what my boundaries should be. and do some testing. Just for my info , I know your an M6, what is your idle RPM and MAP reading at idle , also what rear gears R U running in the RX7. My RPM's are a lot lower, seems the A4 wants to get into 4th at any speed over 35.. LOL.

 

I idle at 1000 rpm and MAP averages 61 KPA so approximately 10-11" vac.

The RX7 T2 rear ends came with 4.10's.

I have not worked on the cam surge as of yet and so I generally keep the rpms above 2K while driving to keep from bucking. Gotta love big cams.

 

yea, I figured your numbers would be higher than mine with M6, big cam and 4.10 rear. I changed the boundaries to 1500,2000,2800 RPM and 45,60,80 MAP and ran a Datamaster for about 20 mins of around town driving. What a change, instead of using & 5-6 cells I am now utilizing 15 out of the 16 base cells. With new data the Datamaster Histogram has BLM's down in cells 0,1,4 & 5 showing PCM correction of 3-7%, going to drop my MAF tables 4% in the 12-22 GM/sec range to see how that works. Getting close to 128 +/- 2% across all driving ranges. BTW ran it thru GA (sniffer) emissions last week and passed with flying colors, NOX, CO2, CO HC were way below allowable ranges.

 

Can someone give me a site to post my XLS file that I use to do MAF tunes? I want to make sure that people are calibrating correctly.

Make sure and graduate the 4%. just making radical changes in the MAF tables and the BOOM back to stock at some point later upsets the BLM's. It is easier to see on my spreadsheet than to explain.

Ben

 

Blackhawk, can you send me a copy of the excel file. I lowered the MAF table 1 numbers about 3-4% and blended the new values to ease into table 2. My ST BLM's in the low end are now averaging in the 127-129 range. My next move is raise MAF tables 3 & 4 to correct 1-2% lean readings (130-132) up in cells 14 & 15 above AFGS 90 however I don't have a lot of cell 15 data since thats the high throttle range. I need to do some 0-60 sprints and collect more data.

 

PM sent! sounds cool, can you send me a copy