Converter lockup causing lag off the line?

[Dozerboy]

Now that I know you don't have a major restriction in the system (thanks Mark), I'll say two things:

1. Your converter seems to be way too tight. Aftermarket turbos, even VGT, need RPM to spool.

2. I know others have had a different experience than me, but I've never had any luck getting turbos to spool by lowering timing. I've always had the best luck cleaning up smoke and making trucks responsive by adding more timing.

Thanks I will revisit timing. I honestly haven't seen a much of difference in lag reduction in any of my test. Other then adding more fuel.

I'm really just trying to rule out an upcoming catastrophic failure of the torque converter or trans. Now, I don't know if that's the case or not. It doesn't seem like it since this has been goong on for over 3 years. All this started when I wanted a clean running truck. Maybe the bad choice in TC didn't show itself until then.

 

[JoshH]

I guess I probably wasn't exactly clear in my response. I have not seen timing itself make a truck spool a turbo quicker, but it does seem to make a little more power. It also allows me to add more fuel sooner because it is a little cleaner which does help spool the turbo quicker. It's not a huge difference, but it was noticeable for me. I don't see anything in the log that would lead me to believe there is anything wrong with your converter, but like I said earlier, it looks like it is very tight. Because of that, you might consider a different converter just to help get the turbo going sooner. RPM is the easiest way to light a turbo.

 

[2004LB7]

Are you modifying any of the shift points at all?

 

[Dozerboy]

I guess I probably wasn't exactly clear in my response. I have not seen timing itself make a truck spool a turbo quicker, but it does seem to make a little more power. It also allows me to add more fuel sooner because it is a little cleaner which does help spool the turbo quicker. It's not a huge difference, but it was noticeable for me. I don't see anything in the log that would lead me to believe there is anything wrong with your converter, but like I said earlier, it looks like it is very tight. Because of that, you might consider a different converter just to help get the turbo going sooner. RPM is the easiest way to light a turbo.

Thanks for the clarification. That's been my main battle. Making changes to timing, fuel pressure, and vanes just to go through and then see what changes I can make to Lambda to get it to spool better. Then remembering how the smoke was vs spool. My approach was probably a little flawed in looking for improvement in the other tables without seeing if I could put more fuel to it. Maybe I should try and over fuel a little and then see if I can clean it up with the other tables.

 

[Dozerboy]

Are you modifying any of the shift points at all?

Not 1st or 2nd. The others shifts are at 3600RPM IIRC and then down shifts are set to 60% throttle and above. I used to run lower RPM shifts in 1st and 2nd IIRC, but it hurt me when I started to work on reducing smoke.

 

[2004LB7]

Not 1st or 2nd. The others shifts are at 3600RPM IIRC and then down shifts are set to 60% throttle and above. I used to run lower RPM shifts in 1st and 2nd IIRC, but it hurt me when I started to work on reducing smoke.

If the converter is too tight, have larger tires you might benefit from raising the shift points for those lower gear shifts. I know it helps big time on mine