93z383

I have read the Transmission sticky, but having a 4l60 this doesnt do me much good. My main tuning issues are how to optimize my fuel and spark tuning with my SD system to enhance the higher stall of my set up. I use a 3200 yank stall converter and tuning the 383 to idle, manage split BLMs etc has always been a challange, now that its running well, Im focusing on fine tuning.

In my VE tables, how should I tune close to the stall range of the converter under part throttle and WOT to get the most power. I feel as though the car has more potential than I have tuned in passed the 3200 rpm range, once it hits that higher MAP range because of the higher load. I dont want to just throw numbers at it, Id like to know if anyone has any insite into this tuning area.

Also, how should I adjust my Spark Adv in the same area.

Look forward to some practical application.

93z383

Nothing, really...

bobdec

I would do a couple of things. #1 download a copy of TTS Datamaster-DA if you don't already have it. Get it running and take a data log of some normal street driving. Then run a Histogram of the log and observe your fueling in the RPM Vs MAP chart and see if you have any rich or lean conditions. Then repeat that process for some aggressive driving. You can then adjust your VE tables to get you fueling correct in all driving conditions. #2 Next look at the same logs, and correlate the log to a printout or copy of your Main and Extended timing charts, assuming you have something like TunerCat or TunerPro for tuning. As you move out of the TPS closed timing table and into the Main Table circle the entry point, by looking at the RPM and MAP on the Datamaster log. Continue the process circling each cell of the main table as your RPM increases and your and MAP changes. With an auto you will see your shift points droping RPM and MAP changes, draw a lile connecting the circles to show your cars progress. Then observe the timing setting in each circle as you accelerate and make sure you have enough advance in each circle. You do not want to see any timing drops during the acceleration. A cam'ed car running low MAP (high Kpa) enters the Main table at a point where the stock tune thinks its bogging under load and actually pulls timing when in actuality your cam is just getting going and you need more timing. As an example say a stock tune enters the main timing table at 1000 RPM and 35 Kpa its timing will be 39*, but with a cam you are probably entering the table at 1000 RPM and 55 Kpa and the stock setting is 31* so you will see timing drop as you want to accelerate, this creates a hesitation or flat spot on takeoffs. in that case you have to set the low RPM higher MAP cells in the table to a higher advance. A good tuner should have already set that range of cells correct if it was done for your setup. But I have seen some mail order tunes that did not..

93z383

Excellent, exaclty what I was looking for. I use datamaster and Tunerpro RT, with VE master. I have been messing with this tune for several years, I keep getting stuck with Transmission issues, so I cant continue with the Fuel and timing tuning. I have a wideband Autometer gauge as well, with a SD system, how would you tune with the Wideband, for instance, I know with the Maf cars the tables area actual AF ratios you put in, with mine its only percentages. Is there a formula for computing manual adjustments like VE master does, OR, what BLM should I us in VE master between 2-3000 and 3-4000 etc. the MAF cars use 14.7 then alittle richer in the higher MAP RPM range liek 13.5 then 12.7 etc, I need to corrilate the BLM with the AFR for correct AFR. I am editing a PCM for less tune which Im sorry to say left alot to be desired.

93z383

How do I correlate the histogram with the VE tables when correcting a lean or rich condition.

bobdec

You can use VE master or do it manually. To get a Histogram.. select a log with Datamaster then select VIEW tab and then Histogram a separate Histogram screen will pop-up.. then slide the record number bar on the main Datamaster screen to record #1 and then click in the start tab. The program will start scrolling through the log automatically and you will see the cells in the Histogram screen display start to fill up. In the Histogram screen select OPTIONS then click View Enhanced Histogram on to see RPM Vs MAP results. The red/pink cells are rich and the green shades are lean. You can click on a cell to read the average BLMs. For example if cell for RPM 1600 and MAP 50 is red then click on it and look at the average BLM's if the BLM average is say 115 then (128-115)= 13 and 13/128= 0.10 that says you are 10% rich at that RPM and MAP. You then go to your VE table and add 10% to the VE cell value for that range. You add 10% to tell the ECM you are more efficient than the VE table says and you would then actually pull 10 of the fueling to get the BLM at 128 or 14.7 AFR. You can use the wideband the same way but the problem is you have to correlate WB AFR to RPM and MAP cells in the VE tables.

93z383

Boy, I thought adding from 75 to 77 in the ve table for instance would increase fuel to correct a lean condition in that rpm and map area, what your saying is opposite. I use Tunerpro RT and datamaster, and have for some years, I can not however "In the Histogram screen select OPTIONS then click View Enhanced Histogram on to see RPM Vs MAP results. The red/pink cells are rich and the green shades are lean. You can click on a cell to read the average BLMs." I dont have an options selection in the histogram, and when I select the cell it only shows hits not an average blm, am I missing something somewhere? Thanks for the help BTW.