Running KSB on a switch?
 

I had a question for you guys running your KSB on a switch. When do you guys have the switch on?

Most run the KSB on when in a race type of situation so as to take advantage of the possible advantage of the injection event timing advance.

There's a fly in the ointment though. The KSB is designed to provide substantial injection timing advance in the low engine rpms so as to improve engine operation / emissions when the engine is stone cold after start-up. When in the engine rpms come up, the substantial timing advance tapers off to a much smaller measure of advance.

The following image depicts how Bosch has the KSB advance curve set up . . .

Attachment 36902



Those who have the static injection event timing well advanced over stock/OEM to begin with, may notice a pronounced engine "rattle" at lower engine rpms with activating the KSB, till the engine rpms come up.

Hope this helps. :pca1:

:appreciated it, that graph helps alot thanks!!:tu:

Did some testing/tuning on a dyno recently and with making 12 or so test-runs, had the opportunity to specifically compare engine performance both with the KSB ON and OFF.

- Torque is the top curves, HP is the bottom curves.

- The BLUE plots are with the KSB OFF.
- The GREEN plots are with the KSB ON.

Notice the difference in the plots of both HP and torque. HUGE difference! (NOTE!: Your power results may NOT be the same running your KSB as that shown in the following image).

Attachment 36658


(As an FYI: I left the dyno that day with almost 50 more HP than when I got there. Just from dialing in the IP timing. ;) )

I can't believe the torque number's tank that hard without it. Where is your static timing at, skipped tooth or just pump to head?

I just installed a new (old stock) IP and was dialing in the timing roughly. I haven't had a chance to put the timing light to it to see where it's at. Suffice it to say I'm around two teeth advanced with the IP bolts in the center of the adjustment slots (approximately). I'm fixing to screw around with the dynamic timing thingy in the IP so the final static timing will be changed . . . . . again. :s:

One can see that using the KSB to get a little more power out of the top-end comes at a fairly substantial cost of power at the bottom-end.

Ignoring the KSB stuff, the above image does clearly illustrate the typical loss of torque VS the HP gained by advancing the injection event timing.

wow 2 teeth, how's your idle?

Actually, it's very close to being equivalent to one tooth advanced, with the IP to the head (plus a little maybe).

It just allows one to back the IP away from the head and have room to work on the head side of the IP when needed. ;)




Around 700rpm in gear, 850ish in neutral (with a pretty tight converter).

nice. I guess I've got some more fine tuning to do. Thanks for all the info.

Ksb on most of the time with stock wiring
 

Revive /jack thread is dead but my truck refuses to do the same.
I've had my 91.5(june) for 5 years . Just put in a new Cummins pn 4327029 ( supersedes PN 3921642)
marked 90°f thermal switch( rear one in the intake). It seems to be on all the time except on long grades were I'm making enough boost to get the intake charge warmed by the turbo. I read that its bad juju to run the KSB on all the time(eg toggle ).

So how bad is it if the intake air temp is only above 90°f (thermal switch set point) for 30min from sept.- may and 15k mi@70-90mph

stock down to the 2° retardation of the recall in 91.
only modd as of yet H1C w/16cm BD housing , exhaust wrap from head to down pipe. EGT @70MPH 700 pre turbo
When not pulling a grade IAT is 10-20° above ambant (eg 40outside =IAT 40-60°f. I see sub 0 IAT in winter.