Cam/Stall/Headers and STILL Slow! Logs inside.
Dec 18, 2009 | 10:16 AM
#51
to add to what Justin was stating....
My 4.8 pulls around 37lb/min.... Also my DCR is alot higher (cam in sig)... So that re-enforces what Justin and others are saying in regards to your timing chain being off a tooth... Potentially you could have turned that 112+4 cam into a 114+4 or 116+4, thus decreasing the DCR, overlap, etc... Making your cam smaller than it actually is... IMO hank the front of the motor off and recheck the dot-to-dot alignment.. Roll the engine over a few times to make sure it lines up...
Additionally, in the first log file there, with the air filter on, total airflow peaks at 34lb/min at 5400rpm. With that cam, peak airflow should be MUCH higher than that and should be increasing steadily til the shift point, not flattening out like it is. A stock 5.3L pulls 32-33lb/min on average.
Cam a tooth off, retarded specifically, causes idle airflow requirement to increase due to decreased DCR. Tune is looking for right at 10g/sec of air to idle at 675rpm. Should be PLENTY for that cam to idle nice and stable without any fluctuation like that. Recent one that was tuned in person was idling with 9g/sec with no issues with a similarly sized TC and two other tunes that I've pulled up with the 220 are right where yours is without these issues.
For reference, Spoolin's truck required nearly 50% more air idle than a similar truck with 1 point more CR.
You can send your other PCM back in and I can update it; make it idle just fine given it's increased airflow needs, bump your shift points up like they should have been in the first tune. However, I would not expect the extra 600rpm bumping you up to 6500 that you're asking for to make up for the lack in a significant power gain in your mid-range.
For reference, Spoolin's truck required nearly 50% more air idle than a similar truck with 1 point more CR.
You can send your other PCM back in and I can update it; make it idle just fine given it's increased airflow needs, bump your shift points up like they should have been in the first tune. However, I would not expect the extra 600rpm bumping you up to 6500 that you're asking for to make up for the lack in a significant power gain in your mid-range.
My 4.8 pulls around 37lb/min.... Also my DCR is alot higher (cam in sig)... So that re-enforces what Justin and others are saying in regards to your timing chain being off a tooth... Potentially you could have turned that 112+4 cam into a 114+4 or 116+4, thus decreasing the DCR, overlap, etc... Making your cam smaller than it actually is... IMO hank the front of the motor off and recheck the dot-to-dot alignment.. Roll the engine over a few times to make sure it lines up...
Dec 21, 2009 | 10:50 PM
#55
Yeah I don't have knock sensors... I won't until I have a new motor... We will find out this weekend whenever we take it all back apart... I need to check and make sure everything is tight too
Jan 2, 2010 | 11:20 PM
#56
well it was off a tooth... so thats fixed and its running alot better but it still needs some adjustments in the tune. but its alot better than what it was atleast by driving it you can tell its better
Jan 2, 2010 | 11:29 PM
#58
and my third gear doesnt just slide in
Jan 2, 2010 | 11:46 PM
#59
