nasty hole in torque curve

[donmagicjuan]

Forgive me if my attachment doesn't work; this is my first post on the website. I've attempted to attach a screen shot of a 2nd gear pull from ECU+. Has anyone ever seen this kind of noise in the timing curve before? It happens right around the time I hit full boost, so my best guess is mutual inductance from the BCS. Also, if that's the case, will a MBC correct it?

Note: the spike in knock voltage around the same RPM in this particular run is incidental; the noise is there regardless of whether I'm knocking.

 

[GVR4592]

I can't tell from those pictures what's going on. But if you are having knock at the same time the ignition timing freaks out, then the knock is most likely the problem. Is that A/F from a wideband or is it from the stock narrowband?

Oh I just noticed what you said about the knock not being there all the time. My mistake.

 

[GVR4592]

If you think the bcs is at fault you can disable it. Just run a vacuum/boost source directly to the wastegate and leave the bcs disconnected. It will give you the default spring pressure, which is around 9-11 psi.

 

[donmagicjuan]

The AFR is from a wideband. I've actually heard of disabling the BCS before, but I wasn't sure if doing so would conclusively identify it as the problem. I'll give it a go and log another capture. I guess I can at least rule it out if the noise persists. Thanks for the advice.

 

[GVR4592]

I wouldn't go any leaner than that. If you plan on increasing the boost a bit you will probably want to richen it up some, just to be safe.

 

[donmagicjuan]

I did plan on adding more fuel (especially up top) after viewing this run. When increasing the boost, I will of course be tuning for no knock. I just installed the ECU+ last week, so my tuning adventures are far from over, I suspect.

On a brief sidenote, how the heck do you post positive reputation points?

 

[jaredgsx]

Under the persons name you will see their online status and next to that are a pair of scales, just click on those and type a happy little messege.

 

[donmagicjuan]

Word.