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Hi guys,
Before I dig in and do a spring job, I thought I'd ask for opinions about whether this looks like valve float or not.
Ignore the green lines, it's a comparison to a previous dyno at 10psi with very restrictive exhaust.
The Red line is after dumping the exhaust post-turbo and on 12psi. Exhaust helped, but still dropping hard.
Details:
80k mile LS6, 100% stock except a mild boost cam, and MAYBE 12k mile old upgraded springs. It's a mystery what they might be, if not stock. Previous owner (not original builder) says springs were done, i can't find in the build sheets that it they were done.
Here's an old video of the original build, and I have done some work since to iron out some wrinkles.
2nd question, with 12k miles on hypothetical upgraded springs... is it time to do them anyway? Is it common with heftier springs that they need to be done anyway?
the "jagged" looking graph is actually kinda normal if they have the smoothing set to 0. The drop off at the end could be valve float. Either way an upgrade is always nice to have just in case.
Yes. Running knock sensors. Will cause retard, but that's not happening here.
Thanks for your input guys. I'll let you know how the existing springs look. Stock, or tired upgrades.
My graph looked very similar to yours and mine ended up being too much back pressure. Made 705 at like 5500 rpms and then a nose dive and it got jittery looking. Replacing the springs helped very marginally .What turbo and what size motor?
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Does this look like Valve Float to you? 
