SOI Advice

[Unilevers]

(01-24-2017 )AussieISX Wrote:  

(01-24-2017 )Unilevers Wrote:  typically most trucks under heavy load run 1-3.5 in the SOI tables. A max (and slightly risky) would be 8 degrees BTDC total which would give you 4.5 on the increment to be there. Personally i would run the increment down to 2-3 to give you more of a safe margin and a total BTDC of 5ish.

if you are unsure of the driver and loads run a 0 increment to be on the safe side. a running engine is better than i blowed up efficient one.

my 0.02c

There is nothing slightly risky about running 8 degrees total in either 3774 or 2965 Cpl cals , As the stock cal peaks at 7.5 degrees @1650-1750 Rpm in the alpha 1 tables . That is why I said 8 degrees total advance . If he added the 2-3 degrees you advised he would have ended up with a total of 10.5 degrees. Just putting an incremental increase on these tables is bad in my opinion and they should be edited correctly . I think before giving advice you need to be familiar with the cal in question. I have trucks running in the north of Australia pulling 167,000 kg ( 368000lbs) on 24hr operations using the same timing I suggested. Those trucks are not owner driven and have been running this tune for nearly 2.5 years without any cracked Pistons or any problems outside of normal issues.

wow so quick to jump down my throat - i think you need to calm it down. i did base my advice on a north american cal, my mistake as i see the cal in question is a aussie one.

i said 8 total of advance and a TYPICAL truck should run 8 degrees or slightly less under full heavy load max, and if you are already running 7.5ish in the table then take that into consideration. personally i think 8 is slightly high but you have more testing in your neck of the woods than i do. i do not know what timing you guys run in your stock cals or what you get away with. also what you get away with does not mean everyone will as many things change everything including fueling, baro, ambient temp, state of engine, good fuel, etc.

on a side note is there a stock cal that fuels to 400 in aussie land? cause there is no north american cal that does.