Tuning large injectors/rattle100%

[ronnyenns]

I?ve been reading around this forum and there?s a lot of great info, thank you!! I?m new to tuning so anything helps!
Haven?t found info for larger injectors, i have tried many different things for my truck after BBi stage 3 (100%) overs, I run a s464 and makes great power at stock pressure and 1800us, I would consider it a hot tow tune, but I have a bad rattle/knock problem underboost until 5 psi or so that I can?t figure out!!
Things I?ve tried that made it less is lower timing overall to around -5 to 0* underboost at 1000-1500 rpm, but it?s still there, and tried lowering the pulse but seems like that made it worse, tried messing with pilot as well but no luck there.. Also they haze a bit at cruise speed 65 mph..

[Jim P]

Do you have your pulsewidth table mapped out to the BBI stage 3?s? Tried lowering your boost/fueling table in the areas you are getting rattle to reduce fueling in those spots? Also try reducing timing a little earlier in the spool region a bit more than -5* or use post injection in the spool region to get the turbo spinning more to get the air needed for the fuel going in, go too far though, like spinning it too fast to early for the lower rpm range you can drive the turbo out of its range and cause it to start surging.

[ronnyenns]

I tried lowering pulse in that area around 15% and it seemed to haze more..ill attach my tune that currently works the best and see what changes I should make, also forgot to add I'm at 5500 ft elevation

[Jim P]

try mapping your pulsewidth table to your BBI's, they come with a flow sheet, map out for the main and the pilot, smooth out your rail pressure. Timing seems kinda low in the cruise region for the crazy amount of fuel you are dumping in. Your injectors flow twice as much as stock injectors at 140mm3 and 160MPa but must of the pulsewidth table you are using stock duration. Not only are you flowing more fuel on the main but on pilot as well so pilot should be taken into consideration as well. use the Boost Limit A to help control fueling for your boost. Turn down your lambda equivalency table. Also your highest commanded timing is 27* but you are limiting yourself to 25*.

[Jim P]

As a side note if you look at your injector flow chart it takes your injectors a little longer than stock at low pressures to flow the same amount of fuel but as pressure increases it very rapidly begins taking much less time to flow the same amount of fuel

[Dom_c13b]

Pilot Duration and timing will help with the rattle a lot. And your Rail tables are pretty ugly. Smooth that out and drop a little rail pressure in that area.

[Noah]

Pilot Duration and timing will help with the rattle a lot. And your Rail tables are pretty ugly. Smooth that out and drop a little rail pressure in that area.

So far, in my experience, this guy knows what he's talking about. Helped me a great deal with rattle in my rig.

[ronnyenns]

Thanks everyone for helping, mapping out the pulsewidth to the injectors helped a lot also lowering the timing more, I like the way it runs now, what can be done with white smoke/haze on startup..seems like it does more on a warm engine

[Jim P]

What?s your main and pilot timing and fueling at idle and RP at idle?

[ronnyenns]

Main timing shows -3* at idle and pilot timing can?t be read on my truck but according to the tune it should be around 15*, fueling is around 11 mm3 hot idle and about 20 on a cold engine, rail pressure is around 7000 psi

[Jim P]

Weird you can?t log pilot timing. Pilot timing, assuming at idle main and pilot timing is about stock your pilot is probably around 9-10*BTDC unless coolant temperature is at full operating temperature and doesn?t dip too far below full operating temperature to cause it to switch over to the ECT correction table. Bring rail pressure up a little bit more at idle, 7500-8000 psi and see if raising main timing at idle helps. Your pilot event could possibly be a contributing factor to the white haze as well. In cylinder temperatures too low for amount of fuel going in leaving unburnt fuel going out the tailpipe, low enough ambient temperatures can affect it as well.

[Noah]

Ill try to post my tune for you, but have you messed with your correction tables? I did some corrections that stevo on cummins forum suggested and it got rid of the rattle.