Tuning turbo

whitegmc06

Member
May 19, 2025
97
9
8
Indiana
Hey, I've built a new turbo for my lbz, I did have a made up kbdiesel 68mm front with an lly back half and a 9 blade turbo ran good with my 100 over injectors, but i sold it and made a different turbo to be a little more sneaky for truck pulling, its a 63.5mm front cover with a stock lly exhaust turbine wheel on the exhaust side with a ported out lbz exhaust housing to fit the lly wheel and put lbz high flow vanes, it runs good for one rip and then the turbo falls to default at 45% vane pos and won't go back out of it until you shut the truck off and start over again and has no check engine lights for anything i am posting up some logs i have and any help would be much appreciated i am pretty lost on what is going on and it seems like it gets worse the more i am messing with the tune, i am usually cruzing at 3-5 pounds of boost


number 24 is normal and the turbo didn't drop off number 25 i got into it just enough to make it drop off and then 26 i took a log with it in the condition that it has like no turbo and you can only get like 1 pound of boost and you really have to try to get 1 pound of boost.

thankyou in advance
 

Attachments

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whitegmc06

Member
May 19, 2025
97
9
8
Indiana
Maybe mass airflow sensor needs revision to accommodate airflow I would think it would have been fine especially with it just being a 63.5mm turbo?
 

Jakezed22

Active member
Dec 2, 2016
329
178
43
Doesnt look like you are over the ceiling of the factory map (366 kpa)

Perhaps the is some dtc that are off that should be on?
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,552
3,058
113
Norcal
Have you tried making a map by logging the actual vane position and having it fill in the cells. Them use that as a starting point for your vane table?
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,516
590
113
At Da Beach
Might be the code from boost not coming up fast enough for the ecm. I can’t remember which one it was now though. The LMM’s were famous for it when you swapped turbos.