Upon logging after adding an exhaust, LICP, and boost control, I am seeing a rich dip (10's) in the AFR log around 3500 RPM. It seems to get back into the 11's before 4000 RPM. It is consistantly occuring around these RPM and is more drastic than any other dips that I see.

Since I am fairly new to all of this, I am not sure if this is normal and if there is any reason why I wouldn't want to smooth this dip out.

Any feedback would be appreciated. Let me know if more info is needed. Thanks!

 

After re-reading my post, it sounds like a stupid/newbish one. I am just wondering why there is such a notable consistant drop. Obviously, I need to tweak the AFR to remove the dip but it just stuck out like a sore thumb. I do have a lean idle issue going on right now too.

I guess I should re-phrase. What possibilities cause this after adding the mods listed above? This is more of the engineer coming out of me wanting to know why, not simply how to fix it.

Maybe this is just the response of the current maps to the mods but I feel like someone else probably saw the same thing that I did.

 

well your probably running more boost which in turn would make you hit a higher load or your knocking a lot when you hit peak boost and it is going to your low octane map....get a tune...not to hard to fix

 

Log your pull and see what the load you are hitting the rich condition. I assume that your map has a rich spot in it some place. Another idea is that in th lean spool tables there is an AFR adjustment. It might be set a tad off.

Based on the RPM it very well could be exactly as stated above. Post a log of a pull. We can figure it out from there.

Did you change the Boost Control settings in the ECU after adding the BC? Might cause some issues too.

 

4G63 4EVR: did you get this problem sorted out? I'm having the same issue which seems to only happen at peak load...I will be running 12.1-11.9 during spool up till about 3500rpm then all of a sudden it drops to like 11.1-10.9 for a split moment and back to normal by 4200rpm...there is no drastic change in my fuel table at that load/rpm and even leaning it out doesn't cure it. I guess I could try leaning it out even further but it just seems like I'm doing a temp fix and not getting to the actual reason for the dip.

 

???

 

I'm not sure about this myself but in my reading I remember GSC stating that the stock DV opens for a moment when boosting then closes causing the dip in AFR. I did notice when i went with the Tial the dip went away now that i'm on speed density.

 

I've heard numerous theories about this but nothing concrete...I'm thinking bov isn't my issue as I'm now running the forge DV with the upgraded spring.
I've tried with LS on and off and still get the same dip...it only lasts for a few hundred rpm and always within the 3800-4200 range right around peak load. My tables have been scaled to match my load so I don't think falling off the table is the issue here. I also plan on going the SD route but I would like to get this resolved before...anyone figured this out?

 

bump for help