I have an Accel gen7 that I'm working with..The trans is a t-56 6 speed,I know 4th gear is a 1:1 ratio...should i be tuning in that gear for fuel??? Because lets say I'm in 3rd gear in a particular cell it may be lean but then if i shift to 4th and the map is in the same cell the a:f is right on...How should i go about this?any tips??? Also can anyone take a look at my ve table it seems like the motor like a lot of fuel..just wondering if it looks right..it a 383 with afr 195's,10:1 compression 224/230 cam.....
Mike

 

I using different software, but also tune with the T56. I like to be in 4th gear when doing WOT pulls, but sometimes it's hard to find areas to go 120+mph. So I do most of my tuning in 3rd.

I'm assuming you have a wideband O2. Can you keep it in closed loop all the time? That way it will automatically add/remove fuel if different gears cause it to be slightly lean/rich. I run mine that way, but honestly I only see a 1-2% discrepancy between different gears.

 

I'm going to reply in a couple emails. First on "gear" choice - most of my WOT tuning is on the drag track on actual runs, and what I find is my 1st gear (3 speed auto) is NOT used to tune. The 2nd gear pull is pretty good to find weaknesses in 3500-4500 range, and again in the 5500-6500 range, but the middle there is too transient. 3rd gear is nice only because of the time it takes to ramp up RPM's, so you have more actual reading per the delta in RPM increase. So, I would suggest any gear you can spend some time in...2nd gear *might* be too early, but you certainly can use 3rd gear.

 

Fuel map - this only makes sense if we see your AFR table as well. But assuming 14.2 or so around idle, 14.4 for cruise, and 13.0 for WOT except for peak torque (assuming 4500-5500) which I'd run more around 12.8, your chart looks (appears) to be way fat. Not sure what you're doing to tune, but it just looks fat. There is hardly any change in the mid-table area from near-idle to WOT. Something isn't right there.

 

Finally on lean in one gear and not on the next. Likely it's that you weren't "steady" state enough around that rpm/map because it should not matter what gear you're in as long as it is steady state and no modifiers are affecting it.

 

Higher gears (3,4,5th) will put more load on the motor than say first or second. So if the ecm doesnt have a compensation factor for this, you may see leaner conditions in the higher gears than the lower ones.

My turbo car on the dyno ran .3-.4 or so richer at same boost because the dyno doesnt load the car the same way. On the street/track, its a good bit leaner. I see some fluctuation between gears too but its not a drastic change and I live with it.

For both of my combos, i've tuned in 2nd gear since I didnt have a place I could wind out 3rd. I have automatics. I used 2nd to get higher rpms the best I could and 3rd to load the lower midrange rpms. My 383 went to 6800 rpms and in 3rd gear thats well over 130 mph. Not easy to do that on the street. My turbo car is significantly faster than that. Less rpm motor wise but less rear end gear, it will see 150+ in 3rd. I have to tune that at the track. So I stick with 2nd if I can get traction.

Atleast with a manual, you can dial in spots much better than a high stalled auto. You can gear up to 4th or 5th to really load it down and lay into it at lower rpms to really get the top end(high map areas) of the fuel table dialed in. Plus you can hold rpm spots to pick off cruise cells.

 

One more followup - make good use of the data logging feature as it'll help you a bunch.