3900 GM Training DVD info

[SappySE107]

I bought the DVD off ebay, and wrote down everything important (to me).

58x timing sensor (60-2)
LS1 piston size
Hollow tube cam like the 3400 cams
25 degrees max advance and retard from the home position
72mm TB
The intake tuning valve is open most of the time. It is closed for 1600-3800 RPM and high load.
Multec 3.5 injectors (tri coil, no internal o rings, less restrictive internally)

Tools
EN46745 Piston Pin Remover for the full floating piston setup
EN47719 Leaf spring tensioner tool for timing chain
J33049 Cam bearing installer kit (same as other 60V6 engine)
J43690 Rod Bearing Checker and J43690-100 is the adapter kit
J5892D and EN47823 Valve spring removal tool

[robertisaar]

is that 25 in both directions? or just total(and in that case, would it be 12.5A and 12.5R?)?

and the IMT is open most of the time? meaning short runners are constantly used? or is that backwards?

[SappySE107]

25 in both directions supposedly. The vane is open, so it has the full plenum area. Has nothing to do with runner length, just plenum area that each bank can draw from. It is only closed off (which kills flow on the bench) when you need torque from 1600-3800 RPM. If you are cruising around at low load in this RPM range, it is open just like 3800+ at WOT.

[robertisaar]

oh, weird.... i assumed it was a dual-runner setup, but it just modifies the plenum size....

so, the only time it's even anything other than a full-size plenum is from 1600-3800 RPM with large amounts of throttle? that seems kinda...... odd. and it kills flow on the bench? it seems like it would be best to just have it opened at all times, unless i'm missing something?

[SappySE107]

The smaller plenum will increase torque at the bottom end. It would starve the motor though past 3800 or so. We would have to run it open and closed to see if there is a more optimal point to open/close it.

[robertisaar]

hmm.... so any reason why it would be opened at those RPMs with less then WOT? or would that mess with fuel efficiency?

[Joseph Upson]

I bought the DVD off ebay, and wrote down everything important (to me).

58x timing sensor (60-2)
LS1 piston size
Hollow tube cam like the 3400 cams
25 degrees max advance and retard from the home position
72mm TB
The intake tuning valve is open most of the time. It is closed for 1600-3800 RPM and high load.
Multec 3.5 injectors (tri coil, no internal o rings, less restrictive internally)

Tools
EN46745 Piston Pin Remover for the full floating piston setup
EN47719 Leaf spring tensioner tool for timing chain
J33049 Cam bearing installer kit (same as other 60V6 engine)
J43690 Rod Bearing Checker and J43690-100 is the adapter kit
J5892D and EN47823 Valve spring removal tool

Is there any info on the knock sensor frequency? I just connected one to my scope and tapped on it lightly and produced a wave pattern. I don't have the old style handy to compare the waveforms.

[SappySE107]

I am not sure why it is open at low load and low RPM. The knock sensor was not discussed on the DVD so I have no idea on the wave pattern.