'03 5.3L and 4.8L bog help

[nickp223]

hey guys im not a noob but in no way any sort of veteran to HPT. ive been reading for a few years now how to tune and have a few vehicles under my belt. I am having a problem tuning silverados, 4.8 and 5.3 in the 2003 year model. it has severe bog from a launch. I was just wondering how what i could do to have you guys help me out.....or if yall could help me out by telling me where exactly to start out at.

Thanks, Nick

[69lt1bird]

Post one of the tunes and log so we are all looking at the same thing.

[axekick]

I notice that too. I get most of it out by reducing Burst Knock in the RPM's up to and just past the stall. Also, do a hard launch and see what cell gets hit in the timing map. It will be negative in timing. Work the timing maps until you get 12* or so during the launch. That helps a lot. Mine was pulling timing with IAT advance in that area so I reduced the multiplier table at low RPMs and it helped. Log all your timing parameters and you'll be able to see where its going. I can't bust the tires loose on my Tahoe but it launches much better that it used to.

I am interested in what else you find here so keep us updated. I think I should be able to spin tires freely but maybe I'm asking too much until I get a higher stall.

[nickp223]

alright well ill post up the tune and a scan log tomorrow. im excited because it sounds to me like a pretty simple fix.

[nickp223]

Attachment 24715

Attachment 24716

[nickp223]

Hope yall can help me out with this little knock problem.

Thanks