Hope someone can shed some light on this. I have an "instability" at around 1500 RPM that I can't seem to iron out. Engine runs smoothly at idle and above 2,000 RPM. The trouble spot is between idle and 2,000 RPM, with 1500 RPM being the worst.
(My log file and tune are at the end of this post)
Load is constant, spark is steady...but see how the lambda bounces around? (Other RPMs the lambda is steady, and the car runs smoothly).
Screen Shot 2021-02-08 at 9.12.45 PM.png
Points of interest:
1) This only started happening after I added the Edelbrock blower.
2) It *doesn't* happen for the first couple minutes of run time. It runs smoothly after the engine is started. I suspect that the engine is running in open loop...? (running off cold start maps...?) It's like someone throws a switch after the first minute of driving and then it starts to run poorly between idle and 2,000 RPM.
3) It runs like a my old carbureted Mustang after I put a single plane intake on it. The engine spit and sputtered below 1800 RPM.
4) I wonder if this is reversion in the intake manifold that's creating a feedback loop and throwing the mixture off.
Question:
1) Any idea how to address this?
Engine details:
2012 GT
Manual Trans
Edelbrock blower "stage 1"
LT headers
Stock MAF
Stock TB
Log file:
Edelbrock 1500RPM instability v43_1.hpl
Tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v43.hpt