When I look at a timing table, it makes sense to me that there should not be any huge gaps between any table cell and an adjacent cell right? I mean logically if all the transition from cell to cell are smooth the car should run smooth. So somebody please explain this: When I look at my bin file which was originally modified by bryan herter, and a stock LT1 bin file, and open the wot tables in tunercat (%increase to afr vs. rpm vs. map), why does the curve look like a klingon forehead???

Everything else on the car is constant. Map is 1.04, timing is at 26*, only the RPM changes. So why shouldn't the curve be smooth??? Or linear? Or something that... just not all jagged.

I think understanding this will help understand a lot of things about tuning. Anybody?

 

I don't know why that is, but I do know the stock wot table is overly rich. It seems like whoever put that there just decided to dump in a lot more fuel at high rpm as a safety measure or something.

 

The timing should transition smoothly from cell to cell, yes.
The fueling you'll need to talk to your tuner about. They could have also changed the maf table and ve table along with the pe stuff.

 

I compared the VE and MAF calibration tables to a stock 95 m6 bin file and they are the same. The PE table is different of course. It peaks at 14% and some change. I was worried because the graph was all over the place even the car seemed like it was running okay.

What do you guys think of those DynoTune excel spreadsheets on LJ's web page that calculate your new PE tables based on your old tables and a log of your wideband AFR vs. rpm??? I was going to try that spreadsheet to get the wot tables right.

VE tables on work in open loop correct? So would there be any point to using VE master or should I just play with the open loop AFR for open loop tuning?

 

HP Tuners has a smoothing utility, but they don't make software for the LT1. For what it's worth, just because it looks good to your eye, doesn't mean your car will like it the same. There is a good reason why some of the stock GM tables also look like a 'klingon forehead'. The car may like a degree more here and a degree or two less there. If you try and smooth that out, you may be surprised with worse driveability.

 

That makes sense... I tried smoothing it out and it made it worse.

 

If you have access to a wideband go for it. I've never used a spreadsheet for this before though, I've always found a good rule of thumb is 1 afr point is equal to 10 in the pe vs rpm table.

 

Thanks I think I will try that first rather than use the spreadsheet. All I know is I want the a/f ratio below 12.0