So I am setting up my rom for the track this weekend. I decide to copy my alt maps (set for e85) to base maps and have a sort of "low boost" high boost map set up.


Alt map fuel = base map fuel Exactly same map.

Alt map timing = Base map timing Exactly same map.

Now boost:

Alt map boost = 27.5psi

Base map boost = 24.5psi

Here is what I have found:

during spool up ( around 10psi or so ) I always would get random knock 3-6 counts using ALT map.

during spool up (around 10 psi still) using BASE maps I get no knock.

Again all this is before car gets to either boost limit so not sure it would be boost curve related.

After this weekend I will set boost to exact same and see if there is some how making a difference there. I found this odd and wonder those of us with "phantom or random spool up knock ( the 3-4k range) were on ALT maps or not..

Any thoughts? I will have logs next week trying to solve this.

 

post up your maps, and logs

 

will do ill see what it does on track tomorrow. also i tried swapping higher boost to base map, then 24psi to alt map. again fuel ignition tables the same. will post monday

 

For my car when 3-4 k knock occurs it's because timing is so high in the lower load cells 38-4200 and between 80-130 load and transitioning from or to boost will cause a little knock every so often 1-4 counts. For me if timing is pulled by a couple of degrees the knock disappears. The ultra slight loss in performance due to less timing is not really relevant at that low of load so in the end it is worth it to run less timing for me. YMMV

Good Luck