Low end R 2.8

[jackstraw]

We are in the finishing stages of an R2.8 swap using a 6l80E. The engine generally runs well once the turbo spools up. There is no power until we hit about 1200RPM. Below that there is only black smoke and a lot of lag. This occurs both when starting from a stand still and any time the RPM drop below 1000. For example cruising down hill will the engine just above idle with my foot off the pedal. when I go to apply the pedal the engine stumbles and smokes until it gets up to boost. The 6l80E came from the folks at zero gravity and has a stall set at 2500. Generally once it gets moving it really pulls.

Any thoughts?

 

[MountainD]

Sounds at first like torque converter isn’t building pressure, it is low on fluids, or the stall is set improperly for the R2.8. Smoke is strange though. That’s over fueling and has its litany of reasons.

I have an 6L80E in the 6.2LS swap but it has a TCM. Which TCM are you using and/or conversion box/programming integrating with the R2.8? I honestly think that combo (or the latter 8/10 speed trannys) make a ton of sense with small displacement diesels. I still opt for manual out of preference/simplicity.

 

[KW1985def110]

If it's not your torque converter like MountainD mentioned and assuming you aren't throwing a code on your murphy gage b/c you didn't mention one, maybe try recalibrating your MAF?