New PB, 4.8l 76/68 Magnum
02-26-2017, 08:44 PM
#1
New PB, 4.8l 76/68 Magnum
Got to the track today after changing from 12psi springs in the wastegate to 16.5psi springs on the Magnum 76/68. Pretty sure the turbo is maxxed out as it was dropping about 1.5psi in the upper RPM range. So, 17psi tapering to 15.5psi, AFRs were mid to high 10s, 15* timing through the mid range and 16* above 6000rpm.
On the ride home I had a pleasant whining coming from the trans/converter - so something is up which would explain 1) 2-3 shift taking forever, 2) 800rpm shift extension (usually 1200rpm) on the 2-3 shift, 3) and the trans shifting at a much higher rpm than usual (1-200rpm higher). Think the whining is the trans pump, but I'd think that if the trans was the culprit it'd be the clutches that would be slipping - I really don't know transmissions that well. Just hoping the converter is fine since I have more $$ in that then the trans. Trans is a stock 85k+ pull out with a shift kit.
Any way to determine from the data logs if the trans is slipping vice the converter? I unfortunately wasn't logging input/output shaft speeds.
On the ride home I had a pleasant whining coming from the trans/converter - so something is up which would explain 1) 2-3 shift taking forever, 2) 800rpm shift extension (usually 1200rpm) on the 2-3 shift, 3) and the trans shifting at a much higher rpm than usual (1-200rpm higher). Think the whining is the trans pump, but I'd think that if the trans was the culprit it'd be the clutches that would be slipping - I really don't know transmissions that well. Just hoping the converter is fine since I have more $$ in that then the trans. Trans is a stock 85k+ pull out with a shift kit.
Any way to determine from the data logs if the trans is slipping vice the converter? I unfortunately wasn't logging input/output shaft speeds.
