I was street tuning one of my friends car's today with wide band and crome, we got the partial throttle fuel and ignition maps from a stock B16 basemap; after building the rest of the basemap with very conservative fuel/Ign retard, the car was feeling good in the 3.5-5.5K rpm range under boost (tuning for 8PSI until he gets larger injectors) but once in vtec it sounded odd, like a secondary muffled popping noise seperate from the exhaust. I thought that this might be partially due to the open Wastegate but I am allways weary of detonation. It took about 6 or 7 burns of adding advance to get it running / sounding better up till redline but it's still slow. 23deg table advance 7500rpm @7.5PSI, I told him that until I get my EGT on it i won't add any more advance. the AFR's are in the very, very safe 10.5:1 range across the board. how much advance is usually acceptable for 9.0:1 compression B16's running 90oct pump under boost?

 

Anyone? what kind of total advance you guys tuned for on 9:1 B16's?

 

Lean the mixture out to 11.5:1 you are running the setup too rich
Crome's ignition timing retard isn't always what it says it is.

 

yea, you are running it crazy rich. get into the 11.5-12.1 area and you'll free up a good amount of power. The best way to determine your ignition timing is to get on a dyno and check the plugs for detonation or signs of problems.

 

OK, just got it re-tuned at 10PSI (still hasn't gotten bigger injectors) Its pulling 12-12.2AFR's at 10PSI. I noticed the engine makes much more power with 12.2AFR and about 15.5DEG advance (7500RPM@10PSI) than it does with 11.6-11.8 AFR's, even if I add a degree or so of advance. I know anything above 11.8 is a lil dangerous but wow you can feel the difference, plugs look clean and det-free piston tops are slightly black with a few speckled shiny spots. we run the motor on 90 Oct+torco so its like 100 octane