Guys,

I just logged a run a few days ago (with TTSDM) and I am getting some knock at ~5400RPM at WOT. This obviously engages the spark retard. I want to eliminate the knock obviously, but here is my issue:

I have set the spark advance to 27 deg in the two spark advance vs RPM tables in Tunercat for when I am at (or above) 100 (MAP). But for some reason, DM is telling me that my spark advance is at 31 degrees when the knock occurs. This should have been at 27 deg according to my tune. Also, the cool temp was 91 C , so in the table that is a 0 change to spark advance (in spark advance vs cool temp table). Also, according to my boost gauge I am getting more boost than the 103.7 Kpa that is reported in the DM file. What gives?

I am going to lower my spark advance to 21 degrees (which is a good starting point for tuning). But my concern is whether or not the change is going to be made.

If someone is willing to post my datamaster file so you guys can see it, I would be happy to email it.


Current setup:
94 corvette MN6 LT1
procharger P1SC
MSD ignition 6A
I have already bought some larger injectors ( I freaked when I saw the inj duty cycle) and a bigger fuel pump to replace the FMU and inline booster pump (just haven't installed yet). Will be tuned on a dyno.

Also, on a somewhat related note. I bought 42# injectors (lucas) and wanted to know a good start point for the tune as far as WOT. I think I know the right tables to use (use % change AFR vs RPM tables, right?).

Thanks,
Scott

 

Yes

 

Thanks. Any clue as to the dilemna if the first paragraph above?

 

I just checked on of my dyno run logs and I'm seeing 42* advance. My tune is set at 37*, my camshaft is advanced 2*. So, I guess 3-4* on top of that may be normal.

Maybe Tom Wong will chime in. I'm sure he can explain this situation.


-Mike

 

Yeah, Mr. TJWONG normally knows the answers. He seems to be the expert.

Should I be concerned that mine is 4 degrees advanced (in datamaster) with the stock cam? Maybe this is just a Datamaster thing.

TIA

 

Oh yeah, what about the MAP question too?

EDIT: Also, I calculated that my max inj pulse width should be 9.5 ms and I noticed that I am at 20 ms pulse width at the time when the knock occurs (calc inj DC is at 110%). Maybe this is my problem? I KNOW that this is a problem and I am going to address it with the new injectors and fuel pump, but it is the only thing?