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View Full Version : Fear of the unknown (sorry long post)



Van B
10-16-2009, 08:02 PM
Some of you may know that I changed engines in my 67 Camaro this year. In the process, I felt it was time to switch to EFI as well. I ended up going with a Pantera ECU882C mainly because at the time, my engine builder hadn't really worked with anything else as far as I knew.

I sent the car to Wegner for a week to get it dialed in a little better. When I got it back it was at least driveable, but still nowhere near what I expected. It was great at wide open throttle, but way rich most places below that with at lot of little hiccups here and there.

A month or so ago I downloaded a tuning manual for the Pantera ECU and spent a little time on the phone with Lance at Pantera. Daylight is getting short in the afternoons here in WI and weekend time has been scarce but I have gone out driving around a few times in the past couple of weeks tuning as I go. Make a change, drive, make a change drive, etc.

I have taken a lot of fuel out of the tune and it is still running 12.8 or 13:1 air fuel ratio in most part throttle situations. At WOT running up thru the gears it dips to 12.6:1 as close as I can see while trying to keep my eyes on the road and the laptop. I know, you're asking "you can't get a friend to drive while you tune?"

So given everything I have been told, I should still have some room to lean it out more, shouldn't I? I have been going by seat of the pants feel and most of the hiccups that it used to have are gone. I guess I want to leave it a little fat for safety's sake, but what should I be shooting for all around? Should I be tuning it to an "optimum" A/F ratio?

On a side note, on one of the drives I matted the throttle in 2nd gear and it took off getting all kinds of loose with tire spin which it had never done before. I always figured the Toyo RA1s were so sticky it eliminated a lot of obvious tire spin. So either I have the tune a lot better than it was or the sub 50 degree temps on that day were not giving me much traction. Most likely it was a combination of the two.

I am glad I finally got out and just started playing with it. After studying the tuning manual I started getting more confident that I wouldn't totally screw it up. I will most likely take it to a dyno tuning shop once I have it as good as I think I can get it-that is if I can get to that point before the snow flies.

camcojb
10-16-2009, 09:23 PM
yes, it looks like it can be leaned out. The engine combo, cam intake, gears, etc. will determine what it likes, but that's pretty fat for cruise and part throttle areas.

Jody

parsonsj
10-17-2009, 05:21 AM
I agree with Jody. I spent hours and hours tuning mine. A dyno is really really good for WOT and idle tuning, but part throttle and cruise tuning needs to be done on the street. My XFI has data logging that can be superimposed on the fuel table so you can see which cells are being used, and I slowly brought my car into line.

I was able to get my tune to right at stoich for idle and cruise (and a little leaner than that for highway cruise). It sure took a long time.

How's your start? I got my cold start working pretty good, and I had just started in on hot start tuning. That can be frustrating, but still fun to learn.

jp