Hi all, I just got my car back from the tuning shop after some major mods (will list below) and a day or two into driving the car I noticed some strange bucking / surging while driving at steady speeds, even at 2,000 - 2,500 RPM. I ran a log file and I'm seeing MAF values all over the place but my throttle position is not changing. When this happens it's a noticeable cut in power, my wideband will drop briefly from 14.7 down to 12.x and you can feel a sudden drop in power for an instant. It's like the airflow cuts out for some reason, the fuel goes way fat for an instant, then the air (and power) comes back. Acceleration and WOT are fine. I had been logging pulsewidth but my laptop crashed and I did not realize the pulsewidth was not being logged when I restarted, but idle is around 1.1 ms and WOT / 6800 RPM is around 8.x
It's a pretty big cam and admittedly not the best for a blower but it ran great as an N/A cam above 1,800 RPM or so.
Mods are:
2011 Corvette Grand Sport
Manual trans
Forged bottom end
Stock compression ratio 10.7:1
235/243 cam 111/115 centerline, 113+3 .622/.624 BTDC 6.9 ABDC 48 BBDC 57 ATDC 6
ECS 1500 SL, no restrictor, Turbosmart BOV, 10# with current cam setup
Twin pump return type system, 58psi base pressure
ID 1050x
AlkyControl single nozzle, 15 jet, controller @ 6
1 7/8" headers, no cats
Tune is likely maf only. I’ve had similar issues with an intake. Tune your vve table and then run blended up to 2500 rpm or so and it will drive a lot better.
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